MTB Specific: What Tyre Pressures

[_freak_]

[flymango]

I'm 105 kg's.

 

MTB tubeless 2 bar as a rule of thumb. Wet/sandy/rocky conditions slightly less, dry/firm conditions slightly more (+- 1 bar)

 

Road tubes with slime 8 bar always.

[XXL]

On any tyre, don't exceed the maximum pressure and load, as recommended on the sidewall of the tyre. Lots said about the damage caused by low pressure, but too hard and you increase the risk of an impact fracture. My entry level GT has tubes, but its no coincidence that that most vehicles sold today are fitted with tubeless tyres....

[29" MAN]

Hmmm... on 2 occasions I've run the tire completely off the rim with pressure being too low. Since then I've been hesitent riding too low pressure. I also weigh 90kg and not 65kg like the race whippets...

Obviosly has a lot to do with what type of rim you run, you get the tubeless ready type which creates a way better seal and then you get the tubless compatible one's, basically any other rim that doesn't state that it is tubeless, which doesn't create as good seal which if I had to take a shot in the dark were the ones you ran off the rim ...

[arendoog]

Obviosly has a lot to do with what type of rim you run, you get the tubeless ready type which creates a way better seal and then you get the tubless compatible one's, basically any other rim that doesn't state that it is tubeless, which doesn't create as good seal which if I had to take a shot in the dark were the ones you ran off the rim ...

My weight is 97kg .29inch tubeless tyres. i run 2 bar front 1.8 rear.Recently i have dropped to 1.7 allround just to experiment and it feels great .My daughters bike has tubed 29inch tyres and she weighs 68kg .2 bar seems to work fine for her.Experiment until you find what works best.The same goes for shock pressure

[arendoog]

It also depends on what tyre you are running.

My 2.0 Saguro's felt right at about 2 to 2.1 bar. The 2.2 Sag's are running beautifully at 1.8 bar.

 

And I'm not a lightweight either at about 92kg.

 

Higher volume tyres can be safely run at lower pressures.

Same weight. tyres and pressures Saguaro 2.2 works great at 1.8 bar

[arendoog]

What is the reason for your front being 1.9 and rear 1.8? Should the front not be less than the back or equal? I have my front (Schwalbe 2.25) at 1.5 bar and rear (Crossmark 2.1) at 1.8 and I weigh about 85kg.

Sharp steering front = harder tyre .Traction and most of your weight rear= softer tyre

[The Ghost]

 

Obviosly has a lot to do with what type of rim you run, you get the tubeless ready type which creates a way better seal and then you get the tubless compatible one's, basically any other rim that doesn't state that it is tubeless, which doesn't create as good seal which if I had to take a shot in the dark were the ones you ran off the rim ...

 

What exactly is tubeless ready, and what needs to be done to make them tubeless?

 

Also, scuze my ignorance, but what is burping?

[Capricorn]

burping is when the tire (tubeless conversion) bead separates sufficiently from the rim releasing air from the tire, and looks like a puff of white smoke from the tire. The white smoke is normally the sealant spraying out.

This is an extreme version of what i described:

http://mountainbikingzane.files.wordpress.com/2009/09/burp-1.jpg

 

A decent rock garden hit hard enough on a tubeless conversion can easily result in burping. Most times, the burps are minor and result in a gradual decrease in tire pressure. Only in extreme situations as above does the tire completely deflate.

 

http://mountainbikingzane.files.wordpress.com/2009/09/burp-2.jpg

Edited January 21, 2012 by Capricorn

[Capricorn]

Richard: some nice reading material for you on the subject

 

http://www.pinkbike.com/news/Tech-Tuesday--Wider-Rims-Are-Better-and-Why-Tubeless-Tires-Burp-.html

[The Ghost]

Ha ha ha ha, that is funny, sure the rider doesn't think so tho.

Thanks

[DJR]

@ Capricorn

 

Are there more pictures of the guy on his way over the bars with the burping front tyre? It must have been a proper pile up!

 

By the way, that is a brilliant way to explain burping - truly the picture that tells a thousand words!

[Skuimkop]

Just don't make the mistake that some riders make of running their pressures too low after they have done a tubeless conversion using standard tyres. Those sidewalls are not designed to run very low pressures and you are bound to end up with your tyre running next to you and seeing views of certain body parts that you are not familiar with.

hahaha! saw the inside of my own armpit from a strange angle.. had delusions on the pressures my new 29er tyres could tolerate.. with my slight 105kg frame. Definately above 2bar for me!

[Caerus]

Are those portable pumps any good? I saw them at the camping store and almost bought one. Just not 100% sure about them, but they seem great for home use.

[ramsew]

burping is when the tire (tubeless conversion) bead separates sufficiently from the rim releasing air from the tire, and looks like a puff of white smoke from the tire. The white smoke is normally the sealant spraying out.

This is an extreme version of what i described:

http://mountainbikingzane.files.wordpress.com/2009/09/burp-1.jpg

 

A decent rock garden hit hard enough on a tubeless conversion can easily result in burping. Most times, the burps are minor and result in a gradual decrease in tire pressure. Only in extreme situations as above does the tire completely deflate.

 

http://mountainbikingzane.files.wordpress.com/2009/09/burp-2.jpg

Been there done that - could not walk for 4 days because my hips were busted up!!!!!! changed my rims to crests now can run at 1.6 front and 1.8 back (Hardtail) no problems - so moral of the story [for me] get decent rims and tires before you start messing with tire pressure!

[wings47]

I weigh 60kg, ride a 29er with tubeless wheels (ZTR Crest) and Schwalbe Racing Ralphs (previously used Spez Fast Track, e.g. 2011 Epic etc). Run front tyre at 1.2 bar, rear 1.4 bar. Never burped. When I pump them to 1.5/1.7 it feels like I'm on a bouncing ball being thrown about ... feels much better and far grippier at lower pressures. But need right wheels and tyres ...