Any guidance on setting tyre pressure?

peug26

Just wondering if there is any guidance/rule of thumb when setting my tyre pressure? I have a Marin Nail Trail 7 2018 MB with 27.5" x 2.35 tyres. Currently I am running them tubed. I weigh 130kg. Predominantly will ride of flat towpaths and gravel.

The guidance i have found so far from Wiggle UK is this:

Suggested tyre pressure for mountain bike tyres - for a ≤70Kg rider:

Inner tube tyre: 36PSI (2.5Bar) Front / 38PSI (2.6Bar) Rear
Tubeless tyre: 26PSI (1.8Bar) Front / 28PSI (1.9Bar) Rear

Adjust for weight:

Add 1PSI for every 5Kg over 70Kg

Does that sound right?

mattyfez

In reality 36psi is quite high for a 70kg rider.

It does depend on type of tyre and terrain too, as well as weight.

I'm 97kg and run 27-30psi front and about 30-33psi rear.

Much more than 30 in the rear is too hard for me as the back end tends to buck a bit going over rougher surfaces, and the saddle kicks you up the ass more so you want it soft enough not to 'bounce off' small obsticles, but not so soft the tyre squirms or punctures if you hit a curb or something similar.

Takes a bit of experimentation, a digital guage is useful, I have a topeak D2 and it's a very handy tool for tuning tyre pressures to your preference.

The above wiggle calculation would have you running about 47 PSI which is rock hard for a mountain bike, even given your weight it sounds a bit much to me.

steve_sordy

It's B0llocks! :shock:

I weigh 92kg in my riding gear and i have ridden tyres narrower than that (2.2") ,on a 27.5" tubeless tyre. If I followed the above calculation, it would suggest 32psi front and 35psi rear (allowing for the narrower tyre)

What I actually used was 22 psi front and 24 psi rear. That was mostly in the woods, if I went to somewhere rocky and fast, like Bike Park Wales, then I'd add 2psi to each of them. Still a long way away from the recco you were given.

For a 2.35" tyre, tubed (and at your weight I strongly recommend that you go tubeless with sealant - you will have fewer problems) I would start with 32 psi front and 35 psi rear. If your tyre is a lightweight one, add a couple of psi.

The ride the bike and see how it feels to you. If the pressure is too high the ride will feel harsh and the bike will skitter a bit. If the tyre pressure is too low, you will hear and feel a "ding" as the rim hits the rock edges (or kerbs).

I have attached link to a Pink Bike video from their "Tech Tuesday" series on finding your tyre pressure sweet spot. Read the words, watch the video, go do it!

Since I saw the video and saw the light, my rides have changed for the better. Over the years, I have also lost count of the number of riders that I have advised to drop their tyre pressure. I promised to pump them back up for them if they didn't like it. I have had not had to pump up a single tyre for one of those riders!

I remember flowing down a rooty trail without pedalling, and my mate behind me said what have you done to your bike, I have to pedal to keep up! Remember that when you watch the video.

https://www.pinkbike.com/news/Tech-Tues ... -2011.html

MiddleRinger

Thanks for that PinkBike link, have watched all the Tech Tuesday vids now!

For reference I am 140lbs/63kg* and run 22F/24R psi in my tyres (2.2" 29er tubeless).

* After a big meal.

billycool

Tyre pressure can be a very personal choice.

I rub tubeless tyres and weigh 200 lbs. I tend to run mine at about 35 psi R and 32 psi F. I also run my forks fairly firm as I'm not a fan of super bouncy forks.

It is a case of trial and error to find what works best for you and the riding/terrain that you undertake.

kajjal

What you are looking for is not to little pressure so the tyres don’t hold properly round corners and not too much so they are rock hard. After that it is personal preference, my hardtail has fairly firm tyres but my full suspension bike has less pressure.