What pressure do you run your tyres at?

JesseD

I have a Vitoria Terreno Wet tyre on the back and was running it at about 50psi today but found I lost a lot of traction when climbing on mud and rocks and in a low gear (basically spinning). I lost traction so much so I stacked it into a bush whilst climbing as I couldn’t get my feet out quick enough.

Am I running to high/low pressure or am I using the wrong tyre (hope not as it’s new) it’s a 33c as I don’t have clearance for much bigger!

Bergwerk

The lower the better for traction. So in wet muddy situations run clinchers as low as possible without risking pinch flats or bottoming out. Start at 40 psi and work your way down.

ktuludays

for most cross races i set mine at 30 psi as a starter and after a sighting lap decide what to set them too. yesterday's race was a total mud bath and i was down at 24 psi. i reckon a few lower may have been better.

obviously if your riding lots of ruts and roots a little higher may be better to prevent pinch flats

JesseD

Riding tubeless so no pinch flats, but good to know that I can go lower with pressures.

joey54321

IMO 50 is way too high unless you are incredibly heavy (sorry for mentioning it if you are).

I am 80kg and rode on Saturday's mud fest at 24psi. Should have gone a bit lower as even that was slipping around in places.

tgotb

I haven't been above 25psi all season, either racing (tubs) or training (tubeless), and I'm a whopping 95kg at the moment. We haven't even raced in mud yet, but when we do I'll be straight down to 20ish or below on the tubs and 21/22 on the tubeless.

If there's the odd root on the course and you're worried about pinch flats, it can be worth babying your bike over them to get the benefit of more grip everywhere else.

40/50psi is crazy, I'm surprised you haven't rattled yourselves to death!

JesseD

Cheers chaps, cross is new to me and coming from road, PSI's that low are a bit alien. Will give it a crack at around the 25-30 psi mark and see how i get on, here's hoping i dont stack it again

joey54321

JesseD wrote:

Cheers chaps, cross is new to me and coming from road, PSI's that low are a bit alien. Will give it a crack at around the 25-30 psi mark and see how i get on, here's hoping i dont stack it again

I remember I was in exactly the same situation last year. First cross race I ever did I ran 50psi, thinking "well, thats a bit lower than the road"...I completely stacked it and was like bambi round all the corners. Its a bit of a revelation when you drop down to 20-30. Different courses do require some changes but anything over 30psi and you should be questioning it. You're lucky, you'll be much better in your next race, much smoother and much more grip

roger_merriman

joey54321 wrote:

JesseD wrote:

Cheers chaps, cross is new to me and coming from road, PSI's that low are a bit alien. Will give it a crack at around the 25-30 psi mark and see how i get on, here's hoping i dont stack it again

I remember I was in exactly the same situation last year. First cross race I ever did I ran 50psi, thinking "well, thats a bit lower than the road"...I completely stacked it and was like bambi round all the corners. Its a bit of a revelation when you drop down to 20-30. Different courses do require some changes but anything over 30psi and you should be questioning it. You're lucky, you'll be much better in your next race, much smoother and much more grip

Its not that surprising really since cross racing runs lower pressures than all but Fat Bikes!

JesseD

Ran them at 30psi on Saturday afternoon for a solo cross ride along the cliff paths near where I live and it was much better, loads more grip in the mud and sand and not a bouncy over the rocks. Had to get off and walk a bit which made me think about N+1, I reckon i now need an MTB as well.

igsta

Running 25psi front 30 rear on my ghetto tubeless setup without issues. As you did i started with 50 psi (roadie) and found the jarring on my wrists too much.

joey54321

I ran my tubeless at 22psi in Sundays cross race, had quite a few bumps and tree roots so was a bit worried but they held up pretty well. Was bottoming out quite a bit though.

JesseD

As I am quite heavy at the moment I have settled on 35 in the rear and 30 in the front and it seems to do me well on 33c Vittoria tyres.