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Basic Mountain Bike Geometry And How It Affects Your Ride | Ask GMBN Tech

Basic Mountain Bike Geometry And How It Affects Your Ride | Ask GMBN Tech

(dramatic music) – Welcome to ask GMBM Tech,
this is our weekly Q&A session. If you’ve got any questions, let us know in the comments below but please use the hashtag ASKGMBNTECH if you’re asking the question cause makes it super
easy for us to find them and add you on next week’s show. If you’d rather send us an email, the email address is right there at the bottom of the
screen, [email protected] Get crackin. Okay, so this one’s
from Gabriel Alexander, Can you give a basic bike
geometry introduction? I have no idea how a shorter
chainstay or a longer wheelbase or anything like that,
affects how a bike rides. Yeah of course we can do that. This is huge topic and I
think it is one that deserves it’s own video, but for now,
I’m going to go old school and get a pen and a bit of paper and do a very bad sketch of a bike and just show you a few things in here. I’m gonna tell you exactly what they are and roughly what they do and what it means to
you when you’re riding. Okay, so, firstly let’s look at the basic geometry of a bike. So, we’ll do bottom bracket height first. Now if I was gonna draw a horizontal line it would go in between the wheel axles. And you would measure, there’s
two ways of measuring this, you get bottom bracket drop,
which is from that line down to the bottom bracket axle, itself. And then there’s bottom bracket height, which is the height of
the bottom bracket axle to the floor, on that axis. So that is your height. Now you’ll see bottom bracket height referred to in manuals and
spec sheets or websites. The lower the bottom bracket is, the more stable your bike will feel. The higher it is, the
more agile it will feel. Pretty simple. Now the chainstay length,
that is the measurement from your rear wheel axle
to your bottom bracket, that is this measurement here. Or should I say, this measurement here. Now the shorter the bottom bracket is, the easier the front end lifts, the more traction you
directly get, however, if it’s too short, the
bike can feel unbalanced. If they have a nice long chainstay, i.e.your axle’s further out, you’re gonna get more
weight on the front wheel so you’ll get more front wheel grip. But there’s a trade off to that. It’s gonna be harder to
lift the front wheel, so you end up having to
have a higher handlebar. Okay so that’s getting a bit complex, so I’m just gonna move this aside so we’ve got another one
I’ve already drawn here. Now, so to go along with
your chainstay length you also have wheelbase, so that is calculated
from the rear wheel axle. So let’s draw a line here
and the front wheel axle, that is your wheelbase. Now you might also hear front center used. That is the measurement
from your front axle to you bottom bracket. So you have front center,
you have chainstay, and you have total wheelbase. The longer a bike is,
the more stable it is. The shorter it is, the more agile it is. But also, it can feel very
nervous when it’s short, likewise, it can feel
real lazy when it’s long. Now the next two things
I’ll talk about are angles. Now you hear about the seat
angle and the head angle. They’re both very important
to how a bike rides. The seat angle is representative of, imagine a line going from this axle here, which is your fulcrum of the bike, up to where your saddle is based. Now that angle is calculated
from the flat ground that you’re on. So you get a steeper
angle or a slacker angle. Now a slacker angle,
traditionally, you woulda seen on road bikes and other bikes for comfort. The slacker the angle is,
the less that shocks are transmitted from the ground to the rider. However on a mountain bike
this is not important. What is important is
having a steeper angle because when you’re
climbing and you’re going up steep terrain, it means
your saddle stays closer over your crank for
good weight distribution onto the front wheel and
a good climbing position, which means you can really use your legs to maximum advantage. So the steeper the seat
angle is, the better a bike will climb off road. Now the last one I wanna
talk about is the head angle. So this is affectively the
angle from here to here, running through here. And it’s measured in exactly the same way. The slacker the head
angle is, the more relaxed a bike will feel, more
stable it feels at speed. The steeper it is, the
more agile it will feel and the more responsive it will feel. But also when you’re riding
fast or steep terrain, it can feel a bit nervous
and a bit twitchy. Now to get all of these
elements correct together can be very hard. You can’t just make a bike
with a nice long chain state, a steep seat angle and a
good head angle because you mess with the whole
geometry of the bike. Now the final thing I wanna
talk about is not an angle, it’s a measurement called reach. Now this is something that’s
commonly misunderstood but it’s actually very important. And it refers to basically
the length of a bike. Now you get various
different ways to measure the length of a bike
but the reach simply is a vertical line that goes
through the bottom bracket axle, this is supposed to be a vertical line, if you excuse my drawing here, and it’s the horizontal
measurement that goes to the center of the frame
so between here and here, give or take. That is the reach and it’s
a bit more of a universal measurement to work out the
distance between here and here which is more accurate than
just measuring the top tube because that only really counts
when you’re sat on the bike because of the fact the seat angle varies. This measurement will always be the same. That’s why the reach is
a good one to understand what works for you. A 500mm reach is about perfect for me and it’s a good idea to sort
of get an idea on what works for you because then you
can start comparing bikes and try to understand
what’s gonna work for you. Okay and one more just to
summarize all these points. You have your wheelbase, which
is calculated from center of the front wheel axle to
center of the rear wheel axle. You have your front center,
that is a measurement from the bottom bracket axle
to the front wheel axle. You have your chainstay
length, which is your bottom bracket axle to the rear wheel axle. The seat angle, quite
simply, is an imaginary line between the bottom
bracket axle and the top of the frame there. Now the misleading thing on
some bikes is if you have a frame design unlike this
one that has an interrupted or a curved tube. Don’t be drawn into looking
at the tube too much, you need to just basically do
the plumb line to get that. And then there’s the
head angle, which is the steering axis up front. And they all have big effects
on how a bike handles. But there’s much more we can
cover in a lot more detail because there’s further things
to talk about like offset, stack, trail, all those
sort of things and we’ll get into that on a detailed video soon. Byron Farrington. Can you have a SRAM mech
but a Shimano shifter? Sometimes it is possible but
it’s not always that simple so it does depend on a particular
sort of speed transmission you have because they’re
gonna pull different amounts of cable. So a rear derailleur on a 10 speed. Shimano pulls 3.4mm of cable,
SRAM pulls 3.1mm of cable and for 11 speed it’s 3.6
and 3.48 so as you can see there is difference between the two. Now the cassettes themselves
have the same pitch so you can use a SRAM
cassette on a Shimano system and vice versa, which is
why you see brands like YT, for example, specking
E13 cassettes in place of a SRAM cassette. It’s not about the brand you
pick, it’s about the speeds that you pick. However if you are really
interested in mix and matching your componentry like your
SRAM and your Shimano, with, in particular, with the
shifter and mech combinations like you’re talking
about, there’s a really cool little invention
called the Jtek Shiftmate, this is it on the screen here. Now there’s various different
amounts and it basically has a cam in it and it
compensates for different amounts of cable pulled
so you could use a certain SRAM shifter with a certain
Shimano rear deraileur so this is a really
cool little bit of kit. Now on screen now is just a
screen grab from Arts Cyclery. I’m gonna put a link to that
in the description below this video, you should
definitely go over to their site and check it out. It’s a really, really good
resource for looking at all the stuff like cable pull
between different deraileurs, different shifters, the pitch
basically you get between different cassette sprockets,
spacings, all of that sort of stuff so you can
actually fine tune and work out the exact ones that
you wanna try yourself. And let us know, actually,
what you get on with. If you end up using one
of those Jtek Shiftmates. I’ve never used one, I
just know that they exist so I’d be dead keen to
find out if it works and it works out well for you. Good luck. Next up’s from Live Your Dreams. Is it possible to use a tapered fork on a straight tube, as in a straight frame. If it’s possible, is it safe? Well it totally depends on
the head tube size you have on your particular bike. Yeah you can use a tapered
in a straight head tube if you’ve got a 44 more
head tube you can do that, if you’ve got a 1.5 you can do that. But it completely depends
on your particular frame and what headset options
there are available. I’m gonna throw a link
in the description below to the Cane Creek headset
finder and it’s a really, really useful tool I always
talk about and it means you can input your frame and
you can put your fork in there and it will find a headset
combination to see if that is compatible in there. But if your headset tube is
inch and an eighth and your steering tube is inch
and an eighth straight, you’re not gonna find a
way of getting a tapered one in there. And also one thing to note. Never try and use ex
tunnel headset cups on an internal style frame. I’ve heard some horror
stories about people pressing those in and they either
crack or they crack and damage the frame. Not safe either. Mm, this is a puzzling one
from Kimmo P and I’m not sure I know the correct
answer, actually for this. Dry or wet lube on
chains when temperatures are sub-freezing. Well for starters I think
there’s a couple of schools of thought on this. So a wet lube, in theory,
shouldn’t freeze because it’s got oil in it anyway and
also in theory the wet lube itself would drive away any
moisture that could freeze, i.e rain or mist or anything like that. So that school of thought
would suggest that using a wet lube should be fine in
sub-zero temperatures. But at the same time, a dry
lube, really the only thing that’s a liquid in it at
all is the solvent that gets those lubricating particles into place. That will evaporate or
dry into a film and that shouldn’t freeze either. However if you’re riding
in sub-zero temperatures and that gets washed away,
the moisture from the water or anything that washes it
away is likely to freeze. So technically I think you
should go for wet and I would say wet lubricant is the best
for that but I’m actually really keen to find out
from anyone that does ride in sub-zero temperatures a
lot because it’s not something we get a lot over here. We get a few cold days of snow,
perhaps two or three a year, and it’s enough to turn the
whole country to a standstill, which is pretty amusing
considering half the rest of the world has got insane
levels of snow and everything functions correctly. So I’m really keen to find
out what people use in genuine sub-zero temperatures. Maybe you’re a phat biker
from somewhere extreme like Alaska, I don’t know. Give me some feedback guys
I’d love to know from all you people that ride in
super cold temperatures. Tell me what else is affected as well. Is your tire pressure affected? Does your suspension react differently? Anything that reacts
differently, I’d love to know a bit more about it. Alternatively drop me an
email and [email protected] I’d love to hear from you. There you go, there’s
another weekly Ask GMBN Tech in the bag if you’ve got any questions,
let us know in those comments. Don’t forget to use the
hashtag ASKGMBNTECH if you’ve got any questions specifically
for this show to go on next week’s show and if
you wanna see a couple of great videos, click
down here for my sort of Pandora’s box of cool kit
that I like to have in addition to my tool kit,
and click down here if you wanna see Blake’s bike
that the crazy nutter raced the Valparaiso Urban Downhill on. As always don’t forget to
give us a huge thumbs up if you love GMBN Tech and don’t forget to subscribe and share.

100 comments on “Basic Mountain Bike Geometry And How It Affects Your Ride | Ask GMBN Tech

  1. @GMBN For things that fail in deep cold on bikes, Air forks, they can seize up completely. Machanical disc brakes too, the return springs on the pads and calipers can get lazy. Bottom brackets with square taper spindles can start creaking real bad in deep cold. You also have to be real careful with your tire pressure if you re-inflate outside, I once filled up at a gas station in sub 20F conditions and when I got back home my bike warmed back up and one of my shrader tubes blew the valve core from overpressure.

    Great video also, I was just watching a video about converting straight steerers to tapered and the person doing the conversion gave very little details on how/when it's possible to do so. Your explaination of frame geometry was actually very nice, from an inexperienced persons viewpoint.

  2. #AskGMBNTech : Hello!, I had a question regarding retrofitting axles. I have on older 2011 Trek Mamba Hard Tail. I'm getting back into riding so I cant justify buying a new bike, So I figure I'd just upgrade parts as they fail. As such I've been looking into basic upgrades(I've got a new handlebar and stem on the way..) and after watching hours and hours of your guy's videos(which are great) I've noticed that most newer bikes now come with thru axles instead of QR Skewers(that my bike has). Eventually I'll be looking into getting better wheels(for tubeless setup) and upgrading to a thru bolt set up if possible. Is my frame compatible with a thru bolt set up? And what features on a frame would be required for a conversion. Maybe make a tutorial video(ones on YT not very thorough) on the subject? Thanks!

  3. Ya I was riding in sub zero temperatures uhhhhhh it was a bit to
    Cold tho -30 to be exact and my fork sunk into its travel its negative airspring got overcharged and it sunk the fork like 75% of its travel and we had to take the lowers off and we had to yank the airspring out but we fixed it

  4. Riding in Montréal all winter, we get sub zero temp for a fair amount of time. Wet lub is my go to. And yes it impacts tire pressure, for example when you get your bike inside be sure to let some air go to compensate the dilatation

  5. Everybody is flipping out about geometry, whilst im sitting here like "if it feels good its fine by me ¯_(ツ)_/¯

    " is that bad? Ill probably get some slack (see what i did there?) For saying this

    #askgmbn 😉

  6. #AskGMBNTech re: chain lube in subzero weather:
    Outside of lubes, I’m wondering if belt drives have an advantage for cold weather. My guess? Probably. If we look at a more extreme case: Snowmobiles, & their shift to belt drives, it suggests they would be more ideal for bicycles in harsh conditions as well.

  7. Doddy,
    That was an awesome explanation of geometry, probably the best one I've seen so far. You should find more excuses to draw, that stuff was entertaining and you're not half bad.

  8. #AskGMBNTech I want to upgrade my front fork (suntour xcm rlo 27.5 120mm) what would be my options on a fairly low budget (something like Manitou Markhor or an Epixon). I would really like to keep at least 120mm of travel (how bad would it be if I wanted to run more travel on my Ghost Kato 3 2016?). Could you tell me more about the suntour Epixon and suntour upgrade program?

  9. I used a j tech to convert a Shimano drivetrain with some old campag shifter and cassette .yes it was on a rd bike for a friend's father but it worked beautifully and the quality is exceptional

  10. #askGMBNTech hi doddy I've successfully changed the bearings on my nukeproof mega 290 a couple of times over the last few years using the awesome RRP bearing tool .
    I do struggle with the rear chainstay bearings that are blind .there's 2 either side .
    I have been using a puller gently to get them out but wondered what you guys use to get yours out .

  11. I ride in snow and sub zero temps here in Wisconsin, I use a wet lube as it keeps the snow from freezing to my chain and cassette. My brakes used to freeze in place from bits of snow getting in the lever and then freezing as the wind blows. A bit of oil based lube in the levers stopped this from happening even in -15C.

  12. #askgmbntech Can I use lithium grease (for bearings) on my front wheel axle? When I got the bike, the axle came covered with a layer of some kind of grease or lubricant, what exactly is that grease they use? (Canyon bike)

  13. #AskGMBNTech I have an old Schwinn that I got at an auction for $5 that I've been trying to fix up, but the seat post is stuck in the lowest position. So far I have taken the quick release clamp off and tried putting a mix of chillzone and T9 inside, but no effect so far. Any suggestions?

  14. #askGMBNTech I've got a 26 inch hardtail with pretty slack geometry. I was thinking of buying a dirt jumper because that's the kind of riding I do, mainly street and jumps. Do you think I should buy one or is my hardtail ok for that?

  15. #AskGMBNtech Hello GMBN, i wanna know what will happen if I'd put a 120mm travel fork on my bike that was made for a 100mm. Is it safe for my frame?

  16. Sub-zero lube. Rex domestique. Made by ski wax company. Use it on all weathers.

    Higher tire pressures are needed after -10-20c, using rigid fat bike, not bothering to damage my MTB suspensions seals in those temperatures.

  17. Hi Doddy and everyone else! I commute everyday here in Finnish Lapland and been using MucOff's Drylube (the yellow stuff) and haven't had any problems with frozen chains all winter in temperatures of -5c to -35c. The main thing is to store the bike in a dry place like a cold storage room like I have and if you do take the bike inside to warm it should be there long enough to dry absolutely completely. Plus temperatures and then freezing is the worst but we don't have that here mid winter.

  18. i ride a fat bike here in northern New York State. often sub-freezing I have ridden down to -18F but usually low to mid 20'sF. I use a wet lube no problem.. chain tends to stay cleaner when everything is frozen as no dust or mud can fly up. so actually lube less. suspension (Bluto) is slower as you would expect but no real problems. Only place I have had an issue in the cold is when riding mixed wet and cold. and the moisture gets into the brake cable housing and freezing. literally losing all breaking to that wheel. I use BB7s still cause of their reliability in remote backpacking situations. But have considered switching to hydraulic for winter.

  19. I live in central Alberta and it’s very rare to see above zero temperatures in the winter. The cold effects my fork
    , tyre pressure and if it’s really cold my breaks.

  20. My mate sent his rear shock of his canyon strive al race 7.0 into service and he still wants to ride his bike. My question is can he use a wooden plank with two holes drilled to the same distance of the shock and use it as a hardtail or will it be too much force for the screw to handle? Greetings from Germany

  21. For Sub freezing temperatures Mucc Off offers a sub zero lube. I personally have used wet lube, specially in the last days when temperature has been bouncing from sub zero to plus few degrees (Finland). I want to try next winter the Mucc Off sub zero lube.

  22. #askGMBNtech what 800mm wide handlebar has the least amount of sweep? I would love a wide riser bar with minimal sweep for dh but cant find one.

  23. #AskGMBNTech Hello there, i had my marzocchi 888rc fork serviced recently and on the first ride i noticed a small amount of oil on the stanchions, like an oil ring. Is it normal for something like this to happen after a service? Should i keep riding or have the fork sent back? (all seals were replaced and the fork is not damaged in any way)

  24. Fatbiker and everyday commuter here in Ottawa, have ridden in temperatures below -30 C (though at that point temperature scales almost meet). I use whatever lube, doesn't seem to make much of a difference. The truly challenging conditions are sub-zero salty wet roads with grit which will result in lube washing off quickly, increase wear and corrosion from the salt. So the key is to wipe and reapply as frequently as needed. I had KMC chains developing bits of rust overnight. ProGold, Squirt (that one built up and gummed a bit), WD40 (bike specific), Muc-Off, Purple Extreme (promising corrosion resistance, not delivered. Still like it in general), maybe a few others.

    Other things that get challenging when it gets really cold: freehubs stick and stop working. Either they don't freewheel at all or the pawls fail to engage and you can't propel the wheel. Use a high quality, low viscosity, synthetic motor oil (class 4) if you have this problem. And I've heard that disc brake oil gets viscous and retracts slowly so DOT systems are preferable (or mechanical discs for fat bikes) but haven't had problems with the Magura Trail Sport brakes. Maybe their oil is less viscous than Shimano's?

    One more: metal contact points are horrible heat sinks. The aforementioned brakes are the cheaper model and come with alloy levers. Even with thick gloves that's a big problem in very cold conditions. So I brushed a few thick coats of rubber insulation coating. Carbon bars are also better, etc.

  25. #AskGMBNTech Hi Doddy, looking for some advice please. I have a 2016 Kona Cinder Cone that I'm back riding trails on after a time away from MTB. Is this scandium frame good enough to upgrade the bikes components around it . . . . like the fork, drivetrain, dropper post etc or am I better off putting the money towards a brand new bike, a Hardtail like a Trek Roscoe? Thanks in advance.

  26. About sub-zero lubes I'd concur with Mike Williams comment here: it isn't the cold you need to worry about, it's the dirt. So you need to pick the option that allows you to keep the drivetrain relatively clean. For me, that's dry lube. It works fine, even at below -20°. I'd started out using wet lube on my commuter bike, following the reasoning that it's more mobile and can re-lube the surfaces it gets pushed out of, but that ended up catching a truly ridiculous amounts of dirt. I got so fed up with cleaning it out from the cassette that I let it go for a while until I ended up with it being just a solid cone of dirt with some teeth protruding from it. I had to lever the dirt out of there with a screwdriver before scrubbing it in solvent so I can switch to dry. Dry just works. Apply enough, rotate pedals to make sure it works itself in, wipe clean thoroughly, but make sure you use a pretty dirty rag so it leaves a tiny amount of lube on the surface of the chain, otherwise it will rust.
    Other than that the bikes are remarkably unaffected by cold. If you use grease on your freewheel the pawls will stick and will take ages to engage again once you've freewheeled. Hydraulic brakes somehow pump themselves up when you heat up the calipers by descending so there is practically no lever travel before they engage, but they still work (still haven't worked out what's going on there – perhaps a topic for #askgmbntech?). The weakest link in this system is probably the human. I never ever managed to put on enough clothes to keep my hands and feet (and later arms and legs too) even approaching acceptably warm after 3-4 hours of riding in temperatures below zero. Contemplating getting electrically heated gloves and insoles.

  27. My mates dropper post froze on a cold day in wales a couple of weeks ago! Wouldn’t stay in one position when you sat on it, it would go down and if you took your weight off it would go up

  28. #AskGMBNTech Hi Doddy. I've been watching the vids for a while and I need your opinion, should I get the trek marlin 7 or the diamond back line?

  29. Head angle I thought was the angle of the head tube and doesnt reference/measure from the front axle at all… the offset and travel (axle to crown) would change it otherwise…frames are stated with a head (tube) angle based on certain fork dims, but the actual head angle is that of the head tube I.e. also the steerer (only) of the fork (std headset), not its axle to top of head tube?

  30. #askGMBNTech 27.5 2019 YT Capra or 2018 Banshee rune?
    I love the Capra, but I could get a sweet deal on the banshee. The only thing I don't like on the banshee, though, is the fact that the linkage system looks… flimsy

  31. #AskGMBNTech ive recently bought an orange crush (2009) and wanted to upgrade the deore shifters that came with it. its running 3X9 gears with an slx rear mech, no clutch. i have a 9 speed saint shifter which i put on, but the pull ratio seems off. the mech worked fine on the deore shifter, but with the saint one, it pulls the full mech range in 8 gears (7 clicks) instead of the proper 9 (8 clicks). any ideas? please help!!!

  32. That was a terrific description of geometry. I’ve had to read a number of articles to understand what’s what on a bike as far as the numbers go. This was the most straightforward and understandable and I wish I’d watched this first.

  33. Sub zero riding tips: no wax lubes as they get gummy and can even cause chain suck. Otherwise wet or dry lube is fine. I don't wipe off the excess as it helps to shed the snow build up. If the chain gets gritty then wipe clean with rag, maybe some wd-40 as a degreaser and cleaner and another wipe, then re-apply lube.

  34. wet lube in sub freezing conditions…. but, apply it inside, warm lube on a warm chain, because it gets less viscous the colder it gets, and if it thickens enough it won't go into the nooks and crannies of the chain

  35. #AskGMBNTech Is it alright to ride a 150mm rockshox lyrik fork in -20F winters? If so, is there a limit as to how long i should keep my rides?
    And if it is not okay, what is the max coldness i should ride in, and for how long?
    Also, will this break down the fork over time? Thanks!!!

  36. #AskGMBNtech Can you find a dropper post for any seat tube size Particularly on a really cheap entry-level bike and wood it even be worth putting a dropper post on one of those cheap bikes thanks

  37. 10:2510:25 I found Muc Off wet lube works well in most conditions, I can use it all year long really, and I can use it in -11c( the coldest I rode so far) without any problem, the chain stays well lubricated, even riding trough deep puddles, or snow.
    Written review:

    when its deep snow and water puddles, slush, Weldtite Wet Extreme worked well, but Do not use it in dry, and after applying make sure you wipe off all the access lube, and don't go too crazy with application cus it will create lube webs.
    Written review:
     I haven't tried Muc-Off -50c yet, but I don't need it, it usually gets around -10 to -15C at most, but if -15 its not for long.

  38. remember that thicker lube & grease will thicken up, so hubs for
    example get silenced, cheap Shimano free hubs like m475 will stop working at -10C, unless you really you roll and pedal like mad, to make it work,
    eventually it will work, but I no longer use those hubs, they need
    special tools to service anyway not worth the hassle. I don't have
    problems like that on my current hubs.
    no proper weather sealing, and hubs that can't be serviced properly without special tool, and that I bend axles on in few rides, is a bad idea, but those are common, I wish m475 hubs were not sold any more. water/melting snow gets in, or the seals are no proper seals, and it's a mess. garbage, not any water in -10c but maybe there were some water in the hub from a ride before, I don't know.
    but I don't use garbage like that any more.

  39. Re winter set up.
    Frozen Tundra (So. Central WI, USA) all year rider here. I'm an ASE certified auto tech of over 25yrs (GM, Chrysler etc) and private shop owner + LBS TREK/Cervelo bike mechanic.

    I have been around almost every chemical used in mechanical systems and just use a full synthetic transmission or transfer case fluid all year, only because I clean my bikes (road and trail) at least every few rides or when dirty. Those types of fluids are designed to be a light viscosity, high temp resistant, high adhesion to metal…which also includes dirt, and hydrophobic.. I have run my drivetrain dry and harsh shifting a few times due to not pre lubing after several snow rides as a result of the constant washing from the snow.

    Sub -15F temps I notice the slower brake returns on Shimano systems but it's not an issue for most non pumping, light braking situations, my modified R.S. Yari 130mm fork also responds a little firmer as I tend to keep all settings as set up in my warm shop. Depending on snow/ice pack I run the tubeless 29×3" XR4'S @ 11-14 psi. I've gone down enough times on ice to know that so far nothing on my modified 2018 Stache 7 is too brittle in sub 0 temps.

    Has anyone broken things and which parts due to sub 0 temps?
    Happy trails!

  40. yes suspension drops about 10psi in the winter, the pressure drops so it drops in the suspension too, the suspension gets very harsh, probably due to the oil thickening.
    in the autumn and spring I can go from harsh fork to plush as I heat it up.
    I haven't tried a proper winter suspension tune yet, But i sohuld look more into this, I don't know which lubricating or damper oil I should use in -10c.

  41. Stay away From Ron N' Roll lubes in the winter, they wash away in minutes, and the chain will make horrible friction sounds.
    Written Review:

  42. great answers. bu there is plenty of info on geometry, on several places, pinkbike is one of the places I remember, also some brands even offer detailed geo numbers with a drawing, Nicolai does that, most in depth I have ever seen, I wish all brands did that.

  43. Subzero temp doesn't matter that much. If it is dry and cold, use dry lube if you please! But, remember SNOW IS WATER!!! TBH I use Weldtite TF2 Extreme Wet all winter. It is sticky as hell, and may be the closest thing to chainsaw-oil, but it works! On my route to work; we are several commuters, and almost everyone else has a squeaky chain! Today I was chasing wind from a fellow commuter, and he was pedalling as hell with his squeaky chain. I felt like I had to do no effort at all with my well lubricated system! I do not wash my bike daily, but I clean chain and sprockets with a rag weekly, and give it a oil. Washing is difficult, as it is freezing, bit maybe once a month? Depends on temps! Did I forget to mention, this is daily commuting, and 2-3 weekly exercise, at 69 degrees north? Tromsø, Norway! (BTW: Schwalbe Ice Spiker Pro Evo never lets you down! ;-))

  44. #askGMBNTech i have a xt m772 rd on my 3×9 haibike. I was wondering, is it possible to simply replace the rd cage assembly and put one with a clutch like the one from xt m780 so it would reduce chain slap. I guess it would need some machining as it is not ment to be disassembled that way. As i understand the 'brains' od rear derailleur that tells it how far to move is in the body and the pull arm of re mech, it has nothing to do with the derailleur cage itself?

  45. North Pole Alaska the past 5 yrs I've used white lightning dry lube on my fatbike year round. All I ever used is dry lube. Anything else seems to make a mess… Now I've had problems with my rockshox bluto fork in subzero. Nope, not even the subzero seal kit worked. So I bought a rigid fork for the winter time and put the bluto back on in the summer. Air got past the shrunk seals to the other side of the airspring and was trapped. When disassembling the fork the airspring rocketed back to inside and unknowingly cracked the top plastic cap of the airspring. JB weld still holding after two years…

  46. I crank up my rebound speed a couple of clicks in sub zero temps. Technically the air in the tyres and shocks is affected as well but i can't really feel the difference there, so i just run normal pressures. I go down in tyre pressure for snow riding for grip, just like i would in sand/mud. I tend to run wet lube in winter, but i also at least hose off my bike after every ride so don't feel like reapplying lube that often. Love the vids!

  47. For those who like to know: Due to pain in the joints of my hands/fingers I had problems using the Shimano XT shifters on my 2×11 full XT Canyon Neuron. I asked for some advise for a J-tek converter so I can use SRAM GX twisters. The lads over there said the difference between the cable pull of Shimano 11 speed XT and SRAM 11 speed GX is so small, there is no solution for it other then just use them together and that is what I did. It works very well and after ridden grip shift for years in the past, I got used to it again in my first ride. I am riding this combo for about 14 months now without any problems. Keep up the good work @GMBN Tech. I love it.

  48. Take a look to the muc-off -50 ( ) . I sometimes leave my bike in my car in swiss winter temperatures. I was wondering if other bike fluids get affected (brake fluid, tire sealant, grease). Cheers!

  49. I loved the pen and paper explanation of geometry – the best I've ever seen!! If I buy another mountain bike I'm copying your drawing myself to keep things straight. #oldschool Thanks Doddy!

  50. I think local associations and blogs provide winter tips. I think I read V-brakes and motor oil. I'm trying to get an all-season and have learned to stay away from mechanical disks (rot).I've used XT/SL and less expensive Shimano hydraulics at -30C without problem. I've used Phil's and WPL so far and only lube – no clean – except for jockeys and between cogs. I might try dry lube next.I never bring the bike inside.Cassette free-spins at beginning of season at beginning of few rides – then OK for rest of season. I've never taken it apart.

  51. I'm from Michigan's upper peninsula where in winter it gets to -40 f regularly. I use tri-flow wet lube and it's the only thing I've had not freeze on me.

  52. Hey Doddy love the show.
    I got myself a roll of the 3M tape and want to get my bike dead silent. I want to make the chainstay protector you made on your scott genius with these three surveys. My bkie has a front mech und i already put some tape on the inside of the shifter guard. Can you make a video where you show us all the little hacks and maybe bodges to get a super silent bike ?
    Keep up the great work I learned everything from your videos since i started mountainbiking last spring.

  53. #AskGMBNTech Why are pedals threaded with left hand thread on the non-drive side? It would seem you would want them to (potentially) tighten in the direction they spin on the cranks and not loosen? In that case you would want conventional thread on the non-drive side and left hand thread on the drive side.

  54. In Montreal Canada, I use wet lube during winter. The chain does need to be degreased about every month because of road salt accumulation but that's just part of living in a cold place. I would not use dry lube since the temperature does drop below freezing sometimes and the roads become quite wet. Dry lube simply won't stay onto the chain in those conditions. Wet lube also helps to protect the chain from all that road salt. Dry lube doesn't really do much for that.

  55. #askgmbntech Hi Doddy, i need help with my hard tail when i go out and ride the rear wheel rubs, but it only happens when i pedal and didnt happen before. i also have not changed my tyre width. Thanks

  56. SubZero and relatively wet in Munich, Bavaria – using mostly wet lube, usually using slightly higher tyre pressure (tubeless 2,2 inch @ 30 psi), during really nasty weather – spiked 2.35" tyres @ 35 psi, intentionally avoid changing pressure in fork (bike itself is hardtail). Eventually having fun in the forest nearby, the pressure is the same.

  57. Metals expands and contracts with different temperatures. How does this affects the shifting cables? #AskGMBNTech

  58. #AskGMBNTech kind of a tech question – but could you do a feature for all the riders that wear glasses when they ride? What options they have for protection and prescription alternatives? or is it just me who wears specs and rides? :S

  59. #askGMBNtech
    I've got a stock Cannondale Trial 6 2018, nothing too fancy but mostly ride cross-urban or typical walking trails want to do a few upgrades to it but not sure which order.
    Should I first clean it up with a 1x train or go tubeless? OR should I consider something else entirely?

  60. Wet lube for freezing weather. Even if it gets real thick or freeze up a bit, it will break loose, warm up, and function while providing protection against corrosion from road salts.

  61. I run a shimono slx 11 speed shifter with my box one derallieir. I was very impatient when i was building my new bike. All of the box one shifters were sold out and i had to get riding the new bike. Thanks for the great vids

  62. #AskGMBNTech what is the little “hook thing” for on the bottom of the piggyback on the RockShox super deluxe shock? Thanks

  63. Can you please touch upon wheel flop as I have just got a bike with a slacker head angle and have only now felt this sensation and found out about this, and if possible how to possibly ease this sensation. #AskGMBNTech

  64. Hi Doddy with reference to fitting a tapered fork to a straight steerer of 1 1/8" i have used a Hope bottom cup 1.5", EC44/40 – Type H and a top cup 1.1/8", ZS44/28.6 – Type 2 to do this successfully. I am sure there are other brands that offer this I just happened to use Hope.

  65. #askgmbntech : Hi Doddy, The SRAM guide R are well known to be underpowered while it seems that Guide RS thanks to the Swinglink are more powerful. Is it possible to transform a guide R lever to a guide RS lever without changing the all unit ? Thanks for the show 🙂

  66. Sub zero will depend on what you mean, 32 Fahrenheit and 0 Fahrenheit are different. I would say 32 Fahrenheit is no big deal at all.

  67. #AskGMBNTech when you do a geometry episode or series, could have a section where you specifically discuss things which the owner can change? Seat position (height, horizontal, tilt), stem length, bar height & width & rise & sweep, crank length etc?
    Structured videos with time stamps would also be really handy, we can study them like a text book. Love your work Doddy.

  68. Hey Doddy, I am running a older Fox Float 36 R fork and I am unable to run volume spacers in this model. Is there any way of making this fork more progressive with out the volume spacers? Thanks a lot

  69. #AskGMBNTech

    Hallo GMBN,

    I’m from Denmark and I have a suspension question: I’m the owner of a 2016 Cube Stereo 120 HPC Race 29 Carbon bike that has been build from the ground up by myself. At the moment I have a RockShox Reba RL 120mm fork with 37mm offset on the bike. From what I can find on the WWW the original offset on the Fox 32 Float Factory CTD is 46 mm offset (this is the fork the bike was sold with back in the days).

    I have found quite good offer on a RockShox Pike RCT3 Solo Air Forks 2017 130mm travel with 51mm offset.

    I’m riding most XC trails and medium single track here in Denmark.

    Can you help me to answer following questions?

    – Is it possible to fit a 130mm fork on my bike? And can I damage my frame?

    – How will affect the handling of the bike at slow and fast speed? In regarding to the trail of the fork and the head angle.

    Is there anything else I need to take in to consideration?

    Thank you for your help and keep up the good work with the show!

  70. one thing that never gets talked about is tire pressure with different tires. I've found that certain tires seem to like more air pressure. to say 'i run 20psi' for example is kind of to generalized. i am using high rollers on my trail bike and i feel like using 30psi and above makes them feel a lot better.

  71. #askgmbntech could you possibly do a couple of videos for us less experienced riders looking to upgrade ( etc. Cranks, wheels & brakes) covering best in the lower, mid and upper price brackets of subject part, would also be good to know what applications of mtb it suits best. Thanks !

  72. My KS Lev Integra post drops down about an inch when I sit on it. I added air to it to bring it up to 200psi as per the manufactures spec, but it still drops a little bit. What else can I check to determine why that is happening. #AskGMBNTech

  73. Instead of wet or dry lubes, use a special cold weather lubes like Squirt Chain Lube Low-Temp. I'm using it and it works very well (plenty of sub-zero rides, even at around -15*C).

  74. #askgmbntech Hi ! My question is, Is it possible to replace a 216×57 fox dhx 5.0 air 57mm stroke stancion with a 216×63 's 63mm stroke stancion ? (So do i need an other air can for it or it fits in the 57mm stroke version body? )

  75. #AskGMBNTech great videos I am looking to buy a Marin San Quentin 1 which comes with a spring sr santour XCM fork which is not ideal, is the sr santour upgrade program something i should consider (if it is eve available in England) thank you

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