What tyre pressure?

What tyre pressure for riding mainly Forestry mountain bike centres – mixture of wet roots, some mud and the odd gnarly rocky descents. I ride an XC type bike (Stumpjumper) and currently weigh just under 13st?

Should I run same pressures in both front & back?

Thanks

How long is a piece of string? It will vary with your weight, riding style, terrain, tyre carcass, etc.

The below will give you a starting point but you might want higher if you find yourself puncturing (or toughtler tyres), less for more grip/wetter conditions

Stan’s NoTubes offers a simple formula as a starting point for tubeless tire pressure for most XC riders. Divide your weight (in pounds) by 7, add 2 psi for the rear, subtract 1 psi for the front. For a 140 lb rider, that would yield 22 psi rear, 19 psi front.

Depends on the tyre/rim width, the sturdiness of the tyre etc, whether or not you’re running tubeless, and how ‘careful’ a rider you are. Most people have 1 to 2 psi lower in the front than the rear.

There are some ‘recommended’ tyre pressure calculators. Best thing is to start with that and experiment until you find the sweet spot between grip and pinch flat/burp risk.

https://axs.sram.com/guides/tire/pressure

Depends massively on your weight and the tyres you’re running. Best to buy a digital gauge that you can carry and experiment a bit. With XC tyres of around 2.3 inch width, I generally run about 20 psi front and 25 rear, but wider tyres or heavy duty casings will probably need lower pressures. Just experiment a bit and find what works best for you.

The sram calculator gives a good starting point. after that, go off feel

https://axs.sram.com/tirepressureguide

I run as low as 10psi for a 29er 2.4 on 30mm rim. But then I’m 59kg.

If its rocky, I’ll go up to about 20 in the rear and 15 in the front.

I hate the feeling of pinging off roots with too much pressure.

Normally you run slightly more in the back. On my hardtail I run quite a bit more when compared to a full suss.

Otherwise try the calculator. It’s probably best to start a bit higher and drop down. Unless you have a calibrated pressure gauge it is a lot of guess work comparing to other people. My track pump is massively different to my pressure gauge and I see variation to other peoples pumps also when I’m at events. What is useful is to know what number you need on your pump so that you can repeat it. Also useful to have an idea of what it looks/feels like with the calibrated squeeze/sit on test that you might need to do at the trailside.

FWIW I think it matters if you are wildly off (running 30psi when you should be running 20) but a few PSI is not going to be that noticeable for many riders – especially when you consider the ground conditions will change over time – even over the day when riding.

For those with very expensive bikes, wheels, tyres, there’s also the Silca Tyre Pressure Calculator

How long is a piece of string?

This……

Ben Cathro has a good piece on tyre pressure but he’s a rapid Enduro rider whose bias will be down hill whilst riding with big grippy tyres with tough sidewalls.

https://www.pinkbike.com/news/video-pro-mountain-bike-setup-guide-with-ben-cathro-how-to-bike-episode-2.html

It varies massively between tyre choice, rim width, riding style and terrain.

If I use minions with EXO casing (2.5f 2.4r), I’ll have 19 front, 22 rear. May e slightly higher if I’m somewhere rocky.

Bontrager SE6/5 combo, I’ll have 15 front and 19 rear. Both a bit soft in rocky terrain and I have to be semi careful to avoid pinch flats but if I have them any higher, they’re a bit too pingy. I recon with an insert, I could easily go lower on these as they have a tougher casing.

I think you need to experiment with pressures to find out what works for you. You could have the same tyres as me at the same pressure and hate how it rides. It’s all subjective.

I squidge them with my hand until they feel about right. When I hear the rim dinging off things a bit too often I put a couple more PSI in.

I usually like to run as low as I can get away with it.

There just isn’t a right or wrong answer. I like soft tyres, mine are just “as soft as I can go without the air getting out”, and I did arrive at that by experimentation and punctures and dents and it was totally worth it. They’re squirmy in hard corners etc, I just don’t care about that, I hate the feel of a hard tyre (tbf I’m not even going to claim it’s faster or slower or that I ride better or worse or anything like that, I just fundamentally hate it, it feels totally undermining and confidence de-inspiring.

But equally there are people at the other end who cannot stand the tiniest bit of squirm and run their tyres hard as a rock, and they’re just as correct, because it works for them. ALl you can do is experiment and learn what works for you.

https://www.schwalbe.com/en/pressureprof/

But equally there are people at the other end who cannot stand the tiniest bit of squirm and run their tyres hard as a rock, and they’re just as correct, because it works for them. ALl you can do is experiment and learn what works for you.

thats me 🙂  Squirmy tyres just feel horrible to me  Not rock hard tho but maybe 5 – 10psi more than most of you seem to run.  I’m also a pootler these days

29 x 2.6 and about 85kg.

I run 20psi in the rear and about 15 in the front

I’d prefer to run them a bit lower but i normally cycle to the trails on a mixture of tarmac and unsurfaced farm roads so have found this gives me an acceptable compromise.

29 x 2.6 and 95kg

23 front 25 rear in specialized butcher grid ( trail weight sidewalls)

21f 23f same tires with grid gravity ( enduro weight sidewalls)

71F+R with conti gp5000 tubed on road buke. Which is almost exactly what that silica calculator suggested.

But equally there are people at the other end who cannot stand the tiniest bit of squirm and run their tyres hard as a rock, and they’re just as correct, because it works for them.

I think it depends on the tyre/rider intent too. I like my normal trail tyres somewhere in the Goldilocks-style middle ground, but running the same bike with  lighter wheels and xc race-type tyres, I run higher pressures and embrace the pinginess. I’d start with the Silca pressure calculator and adjust up and/or down to taste with around 2psi more at the rear than the front.

Think I’ve mentioned this before, but a mate asked Peaty what he’d got in his tyres at Steel City – 40psi lolz

But then it’s mostly hardpack and that bloke can probably find grip where we didn’t think grip existed

So – no one size fits all for tyre pressures, but I’m generally around 20 rear, 18 front for Derbyshire Dales/Peak stuff

All the useful advice has already been given in this thread, so I’ll just present my info here,  for extra data in the mix. Rimpact in all rear tyres.

96kg riding weight. 15.5kg bike, 2.4 tyres on 35mm iw rims. 20psi Fr/22psi Rr in the dry, 2 PSI less in both when wet.

Ebike is 25 kg and has 2 PSI more, so 22Fr/24Rr in the dry and 20/22wet.

Probably 24psi front and 26psi rear to start with. Bit more if squirmy, bit less if it’s pinging off things.

I squidge them with my hand until they feel about right. When I hear the rim dinging off things a bit too often I put a couple more PSI in.

Haha, could have written this myself.

I’ve tried using a pressure gauge but I’m not sure they work properly with inserts anyway.