Ideal tyre pressure?

[Journosergio]

Hi guys,

 

I'm running Stans ZTR Flow EX rims with Maxxis Crossmark LUST tubeless tyres and wanted to know what tyre pressure I should have my tyres at for XC and downhill racing?

 

I know some downhill guys actually prefer using tubes to prevent the tyre from burping when the bead momentarily slips off the rim while doing a high speed corner. Does that mean I should perhaps have an increased pressure?

 

Traditionally I have my tyres at around 1.8-2 bars.

 

Looking forward to some feedback!

[V12man]

Hi guys,

 

I'm running Stans ZTR Flow EX rims with Maxxis Crossmark LUST tubeless tyres and wanted to know what tyre pressure I should have my tyres at for XC and downhill racing?

 

I know some downhill guys actually prefer using tubes to prevent the tyre from burping when the bead momentarily slips off the rim while doing a high speed corner. Does that mean I should perhaps have an increased pressure?

 

Traditionally I have my tyres at around 1.8-2 bars.

 

Looking forward to some feedback!

 

 

How big are you?

 

I would say you are WAY too hard if you are running tubeless - drop it down to 1.4/1.5 as a start point - I have never burped a tyre at 1.3 bar - although I use 1.5 bar for 100k plus days - just to have more air for punctures.

[carbon29er]

Take your weight, divide by 3.181818.

 

Take the answer to the above. Add 2 for back and subtract 1 for front.

 

Pump your rear tyre to the back number in psi, pump your front tyre to front number in psi.

 

Always respect the tyre manufacturers minimum and maximum.

[Bobbo_SA]

Got a face full of Stans the other day on a rocky section where the front wheel slid down an edge and "burped" it, running UST tires on UST rims @ around 1.7-1.8bar, and I'm only 75kg soaking wet...

[Nofearnofun]

I am 105kg's and run my back ar 2 bar and front at 1.8 bar which works well for me.

 

Maybe use the formula provided by carbon29er and while on a ride let your tyres down a bit at a time until you find the sweet spot for your tyre and type of riding.

Edited September 13, 2013 by Nofearnofun

[Sven137]

Hi

 

We mountain bike for fun, we do not race or go extreme , we cruise along at 12kph around NF, Van Gaalen, Modders and Hero..

 

What would the ideal pressure be for our tubed tyres

 

I am 85kg and my friend is 70kg

 

Why does the wall of the tyre say 2.5 to 4 and all the members are way under that ?

Edited March 4, 2014 by Sven137

[madbradd]

Vittoria/Geax has a tyre pressure app... iTyre. Its even called iTyre on android.

[didi]

Have you looked at Geax website.

the have app for tyre pressure

worth a look

cheers

Dion

 

SNAP

Edited March 4, 2014 by didi

[Capricorn]

Got a face full of Stans the other day on a rocky section where the front wheel slid down an edge and "burped" it, running UST tires on UST rims @ around 1.7-1.8bar, and I'm only 75kg soaking wet...

 

which UST rim and tyre was that?

[LazyTrailRider]

what tyre pressure I should have my tyres at for XC and downhill racing?

 

Pressures for these two types of riding can vary hugely, I'm presuming you're biased towards XC?

 

I weigh 68kg and have run most of the tyres I've used (read: many) at 25-27psi rear, 18-20psi front for general XC/trail use. For DH a little harder to prevent slamming through.

[NotSoBigBen]

Pressures for these two types of riding can vary hugely, I'm presuming you're biased towards XC?

 

I weigh 68kg and have run most of the tyres I've used (read: many) at 25-27psi rear, 18-20psi front for general XC/trail use. For DH a little harder to prevent slamming through.

 

Ah a fellow 'PSI' user

[Spoke101]

First off I don't want to step on anyone's toes here so this is my experience.

These are factors which I take into account:

• Weight of rider + weight of bike.
  
• Riding discipline. ie. DH/4X/XC/AM
  
• Type of bike. ie. Hardtail/Softtail & Amount of travel.
  
• Riding terrain. ie. Rocks/Sand/mud.
  
• Type of rider. ie. Racing snake/weekend warrior.
  
• Make, Model and Width of Tyre. 29/26 & 1.9/2.25 & Protection/snakeskin.
  
• Riding style. ie. Do you ride silky smooth or tend to just smash through/over everything.
  
• Width of Rim In & Out. ie. ZTR vs Reynolds
  
• Suspension setup. ie. Soft/Hard
  

You might think I'm going over the top here but I find all these factor add up and I really don't wan't to smash a 30k Reynolds wheelset.

• I weigh 60kg and my bike is 9.4kg.
  
• Mostly XC but some Enduro stuff as well.
  
• Hardtail 29er.
  
• Mostly soft/clay with some sandy and rocky stuff in between.
  
• Racing Snake
  
• Schwalbe Racing Ralph Snakeskin 29, 2.25
  
• I would like to think silky smooth but maybe not.
  
• Wheels Reynolds Carbon 29mm out 21mm in
  
• Suspension fairly hard.
  

I currently run 1.5 bar up front and 1.7 out back.

 

I found that i can run 1.4 up front but the tyre tends to roll quite a lot in the corners and 1.7 work great out back apart from on the odd occasion when I feel a rock or tree root make contact with the rim.

 

I also try to check before a ride by pressing down on the tyre with heal of my hand where it meets your wrist and with all your weight and if i can feel the rim then I know they are to soft.

 

Hope this helps.

Edited March 5, 2014 by Spoke101

[jcza]

MTB - soft as possible (max. 1.8)

Road - hard as possible without destroying pump (min. 8)

[Sven137]

.. but isn't the flatter your tyre the more energy is used to move forward.

 

As in a car the flattert the types the more petrol is used ?

[Sven137]

Vittoria/Geax has a tyre pressure app... iTyre. Its even called iTyre on android.

 

Found it ... its called ITIRE .. LOL

[Dicky DQ]

I currently run 1.5 bar up front and 1.7 out back.

 

I found that i can run 1.4 up front but the tyre tends to roll quite a lot in the corners and 1.7 work great out back apart from on the odd occasion when I feel a rock or tree root make contact with the rim.

Hope this helps.

 

and then they want to tell me how important a tapered headtube and through axle is WTF.