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Getting a bike with 2.8s on, which I've not had before. Curious about what's the typical pressure you run in 2.6-2.8 tyres.
I've stopped running 2.8s but 2.6s usually somewhere between 15-20 depending on tyre and terrain. If its my local (Hamsterley) I tend to set them about 19/20 and that works really well.
I've a 3" tyre on the front @ 12psi and a 2.8" on the back @ 15psi. I'm 85kg.
I'm on 2.6s, I'm ~68kg and ride rocky stuff mostly (Mid Wales). I run ~15-20 psi in the front and ~20-25 in the rear I think.
dhf/dhr 2.8 at 9 and 12psi. 75kg on a mix of rooty/loam/flint.
WTBs with Tough sidewalls. 3.0 on front, 2.8 on rear. 12 and 14psi respectively. Flint, loam and roots. I weigh somewhere around 75kg.
Running my 3.0's at 8-9psi, experimenting with 2.6's and 20psi is too firm so working down to c15psi.
I'm 84Kg and have a fairly heavy backpack most of the time.
Peak district rocky, muddy & wet.
Assuming you are tubeless
The OP hasn't actually said whether they're running tubes or tubeless.
Anyway, the answer is how long is a piece of string, there are so many variables, that really trial and error is the only way forwards.
No mention of rider weight, specific tyres, riding style, trail conditions etc etc etc.
I've not seen an equivalent to the Stans formula for Plus tyres but as a starting point: your weight in stone minus one for the front, plus two for the back. If the tyres are squirming around put a bit more in (steps of 1psi or even 0.5psi if your gauge can measure it). If you are pogoing about then take a bit out.
WTB bridger front and trailblazer rear. Around the 12psi mark rear, 11 in the front. Tubeless, I'm just over 80kg.
Oh yeah - buy a digital tyre gauge OP. 😉
Digital isn’t necessarily the best answer, but for most riders in typical UK conditions the Topeak D2 is a sensible option that will be close enough and last well.
Yep, pressures in the low to mid teens is probably where you’ll end up, general region of 10psi more than a fatbike and 10psi below a regular tubeless mtb. Exactly what pressures you favour are going to depend on what tyres you fit, what you weigh and how you ride and the terrain and conditions. Pick someone's numbers from the thread and go for a ride, adjusting up or down as you see fit then note the numbers you end up with...
8-10psi on my 29+ with 3" tyres - any firmer and start losing grip, but don't go any faster
'No mention of rider weight, specific tyres, riding style, trail conditions etc etc etc.'
well, apart from those of us who have listed those things, but you carry on... 😉