MTB Specific: What Tyre Pressures

[Iwan Kemp]

try this works like a charm for me. http://mtb.ubiqyou.com/

 

Way out for me. I ride 20 - 25psi (MAX!) front and 25 - 28psi rear. MTB Tech suggests 31 front and 33 rear.

[covie]

Jeez dude how much you weigh if it suggests 31/33 Im 87kg and spot on with 24/26, Also remember is a generalized gauge, different rubber might have different sweetspots, Rim width as well as rider ability also plays a role, but as a starting point for most I find it 95% acurate.

Edited October 22, 2012 by covie

[Iwan Kemp]

Jeez dude how much you weigh if it suggests 31/33 Im 87kg and spot on with 24/26, Also remember is a generalized gauge, different rubber might have different sweetspots, Rim width as well as rider ability also plays a role, but as a starting point for most I find it 95% acurate.

94kg.

 

As an online tool it's okay to use as an initial guide. But will obviously never replace experimenting for yourself out on your local trails.

[covie]

94kg.

 

As an online tool it's okay to use as an initial guide. But will obviously never replace experimenting for yourself out on your local trails.

 

Defintily not, I agree with you there. But its based on avg's and only supposed to be a starting point. It is however the most accurate one i have managed to find in the world of avg based stats.

[Mylolylo]

1. Tubeless or tubed?

2. If tubeless to you run dedicated UST or TLR tires?

Tubeless.

UST? TLR? HUH????

[covie]

Both are essentially normal tubless tyres, manufacturers that work label theirs UST pay royalties to use the term, TLR tubless ready, or TNT tubes no tubes, are the same thing they just call it a different name to avoid royalties.

 

I guess his question is more meant are you running a gettho setup with foldable tyres or proper tubless tyres.

[Iwan Kemp]

Tubeless.

UST? TLR? HUH????

UST (Ultimate System Tubeless) TNT and TL are all acronyms used for tyres that are full tubeless compatible. TLR and WTB's TCS (Tubeless Compatible System) is the new wave in marketing talk. They are essentially beefed up normal tyres or slimmed down UST tyres. The aim is to have a full TL tire without the extra weight of the thicker sidewall.

 

Anyway, now that I know:

1. Could be that they are pumped too soft for your weight or riding style
   
2. Could be that the size of the tire and the width of the rim is not gelling lekker
   
3. Could be that your fork needs a bit of a setup tweak
   
4. Could be that you need to unload the front of your bike better when hitting rocks
   

[Mylolylo]

Oh ok cool I get it now. My wheels are Stan's No tubes with Maxxis Crossmax tyres. I know the machanic who did my tubeless conversion mentioned that the tyres were't "proper" tubeless tyres so maybe that is the issue. Its the back wheel where I tend to feel the rocks hitting the rim through the tyre so maybe just a bit higher pressure wouldn't hurt. I weight about 78kgs...any advice on the tyre pressure?

[Iwan Kemp]

Oh ok cool I get it now. My wheels are Stan's No tubes with Maxxis Crossmax tyres. I know the machanic who did my tubeless conversion mentioned that the tyres were't "proper" tubeless tyres so maybe that is the issue. Its the back wheel where I tend to feel the rocks hitting the rim through the tyre so maybe just a bit higher pressure wouldn't hurt. I weight about 78kgs...any advice on the tyre pressure?

 

First thing would be to get proper TL tires. Std tires' sidewalls are simply to thin and weak to run without tubes. You can, but usually not with great success.

[Paul Ruinaard]

Hmm - seen this on many forums. FWIW - my 2 cents - worth, there are some things you need to look at: to get an answer:

 

1.) What type of rim you are running. Newer tubeless specific rims like Stans have a bead like car tubless tyres which means at lower pressures you will not burp the tyre as it has popped in to the lip and it will not come off the bead, which is not true of older or lighter rims or non UST or tubeless type rims, So older rims equals hihger pressure

2.) Do you have UST or TNT tyres (stronger sidewalls). This makes a huge differnce to your traction and the likelihood you will cut a sidewall. Harder sidewlls = lower pressure.

3.) Your weight (small factor). Fat boys need more pressure, to some extent, although i dont think it is that importnat

4.) What are you doing with the bike. If you are XC racing then a cut sidewall ends your day and negates all the weight and time and traction benefits. Ask Kevin Evans about the ebenfits of this and other lihgter pieces on the bike.

 

I am 110kg, and run 1.9 bars on Stans Rims with Schwalbe tyres. i could go lower but they hook up well at that pressure. (29er). Also some myths and experiences:

 

1.) Rolling resistance: Look at the science and google the topic. Summary is resistance decreases with lower pressure up until a point:

 

http://velonews.competitor.com/2007/06/bikes-and-tech/technical-faq/technical-qa-with-lennard-zinn-rolling-resistance_12493

 

2.) Using non tubeless tyres with flexible sidewalls and running them tubeless gives incredible traction, to the point I actually managed to pull one off a rim braking in a straight line (big guy, good brakes big 203mm discs). The problem was getting them to seal (nightmare) and then riding to avoid rocks as the sidewalls were toast if I snicked once.

 

Seems like you will have to make your own decisions...

[mariusvdw]

I'm 78 Kg's and run 2 at the back and 1.8 in front using hardtail and 2.5 and 2 respectively for softtail. This on

Crossmarx.

[Cycle Factory]

Too many variables to give a recommendation over the net. Yeah, there's a ball park figure, but the only way to know for sure is to take your floor pump with you on a ride and loop a section with varying features and experiment till you get what works for you. Will also aid a great deal in building a knowledge base of how tire pressure influences your bike's handling and feel.

[covie]

Too many variables to give a recommendation over the net. Yeah, there's a ball park figure, but the only way to know for sure is to take your floor pump with you on a ride and loop a section with varying features and experiment till you get what works for you. Will also aid a great deal in building a knowledge base of how tire pressure influences your bike's handling and feel.

 

isnt it easier to over inflate, do a section, let a litle air out, do it again, rinse and repeat till you feel you have the optimal pressure, then go home, use the floor pump with a single depression, then the current pressure - a little bit would be your ideal. Beats the hell of riding with a floor pump lol

[Dudes]

I am 104 kgs. I ride an XL 29 er dual tubeless. I ride 2 at the back and 1.8 at the front. Sometimes it drops even lower before I re pump. Nice ride.

[Captain Fastbastard Mayhem]

30 in front, 35 in back.

 

I'm a heavy oke - 105kg. But as I get lighter, I'll release pressure.

[Bicycle Supply Chain]

Hi All,

 

Here is my take on it:

 

Firstly I think the pressure some guys run here are scary hard! but in saying that, it depends greatly on lots of variables.

1. what tyres you run, tubeless/ tube

2. what rims you run

3. diameter and width (26v 29)

4. full rigid, full susser or in between?

 

and probably the biggest factor:

5. the riders experience, riding ability and RIDING STYLE

 

here is what i run on the list above

 

I have 2 bikes:

 

single speed

 

 

1. what tyres you run (Maxxis crossmark 2.1 tubeless)

2. what rims you run (ZTR arch)

3. diameter (29)

4. full rigid, full susser or in between? full rigid

 

 

Bike 2:

 

1. what tyres you run (Maxxis Ikon 2.2 tubeless)

2. what rims you run (ZTR crest)

3. diameter (29)

4. full rigid, full susser or in between? HT carbon

5. I am experienced, good technical rider that tends to "float over" rocks rather than bash through them. found the faster you go the better it is. I ride smooth and flowing picking smooth lines. I weigh 62kg.

 

On my SS I used to run 0.9bar (13.3psi) front and rear. it was great on everything except fast decents. not cos i was hitting through to the rim, but the bike squirled around a lot. so I now run 1.1bar f &r and to get more stability. I havent burped them yet. I do hit through (to the rim) about 3-5 times a ride. but I am happy with that and it is very very seldomly a hard hit through.

 

On my HT I run 1.5bar only because I am not confident in the strength on the crest rims (running a 1400g wheelset) yet in terms of denting the lip. I haven't hit through to the rim yet on the HT. will be going down to 1.4 bar for the next race.

 

Generally a good rule of thumb is your weight in pounds /6 if you a beginner, or /7 if you want a softer ride

 

So for me:

 

62 x 2.2 = 136lbs /6 = 22psi = 1.35 bar

62 x 2.2 = 136 / 7 = 19psi = 1.5 bar

 

which is not far off where i am.

 

Mike