I have 32c Marathon Plus tyres on my Arkose 2, what sort of formula/calculator should I be using to work out what pressure to put in there? I don’t know how much I weigh, need to go find that out, prob around 14 stone

They felt too low a while ago, and I was worried about pinch flatting on pot holes, so I pumped them up and now they’re too hard. Rather than zig zagging my way to the ideal pressure, it would be helpful to know what’s recommended

Mostly used on the road, the odd track here and there, lots of pot holes, bumps and things (commuting into Central London)

65 ish IMO

Anyone got any formulas to use?

I found one online, from a fairly old looking pdf, with lines for different tyre widths on a graph with weight and pressure axes, but figured that was for road bikes only

Maybe try 65 ? 🙂

It’s not rocket science, or even formula based, hard enough to not pinch at your weight, soft enough for comfort.

A formulae for tyre pressure? 😯

Fwiw on my tripster running on-one gravel road 40mm tyres set up tubeless I stick between 40-50 psi, running tubes on a bike is just a pain in the arse.

Perhaps try a better quality tyre than marathon plus, for sure they have good puncture resistance but the ride quality on them is horrendous

What does it say on the side of the tyre, 40-65 psi ? Just pump them up to that !!!!!

I’m happy with my tyres nice and hard I use 80 front 90 rear, (my new digital pressure gauge tells me my track pump may be 5 psi high).
I recently had a puncture on the Quantocks and pumped the replacement tube up using a pocket sized mini pump, the rest or the ride was spoilt due to the squirmey feel of the tyre and the worry that I’d used my spare tube.
I checked the pressure when I got home, 65 psi.
I’ll stick with my high pressures and avoid wasting time fixing trailside pinch flats.

I checked my pressures last night. I have 45ish front and 65ish back. Felt to hard, dropped the rear to 45ish and feels much better

Might try going up to 50 and see, doesn’t feel so harsh hitting all the bumps in the road at the moment but want to avoid a pinch flat

I was thinking something along the lines of the Stans tyre pressure formula, but with some variable factors – I guess it’s the formula for each line of best fit for the graph in the bicycle quarterly guide – http://www.bikequarterly.com/images/TireDrop.pdf

double post

Just work out what feels best for you. Any tyre pressure formula will at best only give an indication as to what will work for you. You’ve nearly found it what it is.

I run my 35C Clement Xplor USH at 60 psi, seems to be about right for me at 100kg.

40 psi here… 32c tubeless maxxis mud wrestlers….

i’m 80kg

Formula schmormula.

Off-road you generally want as low as you can go without getting pinch punctures or risking dinging the rim.

On-road you want whatever feels fastest and corners best.

These two are to some extend mutually exclusive, so balancing the requirements is a matter of subjectivity rather than following a formula. Try a few and see how you like them. Bottoming out off-road? Use a higher pressure. Tyres wandering on hard cornering on tarmac? Use a higher pressure. Smashing your teeth out off-road and on rough roads? Use a lower pressure. Tyres feel draggy on tarmac? Use a higher pressure. Tyres feel skittish off-road? Use a lower pressure.

It even depends on your tyre carcass: a heavy one with stiff sidewalls will generally prefer a lower pressure to a thin and more supple one.

Up to you where you feel comfortable, but it’s somewhere between “pinch-puncturing frequently” at the low end and “no grip off-road” at the top. “Zig-zagging your way to the ideal pressure” is the best—and realistically the only—way to do it.

That’s cool, I wasn’t expected a silver bullet, just an indicator

Not helped by the fact that my pressure gauge is average at best!

Yeah, throwing away your pressure gauges is wise for most people IMO, because an educated squeeze with experienced fingers is as good as most gauges and you’ve always got the equipment with you 🙂