The Tyre Pressure Thread

[The Duckmeister]

I've got fat & now weigh around 70kg..... My main wheel/tyre combo is carbon rims with 26x2.25" Crossmark II, typically 18F/24R. Spare aluminium wheels with Maxxis Ignitor 2.1s or Ardent 2.25s I run a touch higher due to the softer rims. All tubeless, no inserts.

 

[Plough]

Front -29x2.6 DHR 2 exo+ 28psi
Rear - 29x2.5 Aggressor Double down 30psi
both setup tubeless and on 30mm internal rims.
98kg. Running the rear at 25 was squirmy on berms. Too scared to play around with psis after unthreading valve core with a mini pump.
Xc hardtail gets the same psis but 2.25 onza canis tires and 19mm internal rims as well as barely ridden.

 

[Ultra Lord]

I've got fat & now weigh around 70kg..... My main wheel/tyre combo is carbon rims with 26x2.25" Crossmark II, typically 18F/24R. Spare aluminium wheels with Maxxis Ignitor 2.1s or Ardent 2.25s I run a touch higher due to the softer rims. All tubeless, no inserts.

Fuck dude such a chonker (cries while >100).

 

[ozzybmx]

Re assessed my pressures, now 2.5WT, 21 both ends. Took me 9 months of slowly dropping, 19 is too low, 21 seems the sweet spot on 30mm rims.

 

[Stredda]

Currently running a Minion DHF on the front at roughly 22psi and a Highroller at around 25psi on the rear, no inserts.
I do tend to be slack about checking the pressures and quite often just put a bit more in when I feel the tyre starting to squirm on the rim.

 

[ashes_mtb]

Are tyre pressures fairly relative to weight? So, all else being equal in riding style, tyre type etc, a 120kg rider/bike combo would need 20% more pressure than a 100kg combo to have a similar outcome?

 

[Tubbsy]

Front -29x2.6 DHR 2 exo+ 28psi
Rear - 29x2.5 Aggressor Double down 30psi
both setup tubeless and on 30mm internal rims.
98kg. Running the rear at 25 was squirmy on berms. Too scared to play around with psis after unthreading valve core with a mini pump.
Xc hardtail gets the same psis but 2.25 onza canis tires and 19mm internal rims as well as barely ridden.

I'm around the same weight kitted up to ride, and run similar pressures.

I also disliked the squirm on the berm at lower psi.

(got an mtb-themed Dr Seuss thing going here)

 

[hellmansam]

Thread digging, but I'm the same weight and wondering if you're running those pressure with or without cushcores?

No protection ! I do often pick my lines like I'm riding a '91 full rigid bike though. Hardly ever bottom out the rims, haven't (yet) pinch cut a tyre. I was in disbelief when the bike shop dudes set the pressures for my demo hire. I got over it and when I got my own bike the plan was to up the pressures if necessary.
Did try higher pressures at Linga Longa one time, as well as firming up the suspension a bit. Stacked it after getting out of sync with some small rollers at speed. No harm done but reverted back to my safe settings.

Early on I rode at Meelup and didn't check my tyre pressure after not riding it for 2 weeks, stopped at the car for a drink and noticed some wet spots on the tyre sidewall and that telltale crisscross pattern on the sidewall that says pressures are too low ! checked it and whoopsie I had 15psi in the rear. That was after a burp or two so I dunno what it was initially but that's the only time I've burped a tyre.

If you don't smash into rock gardens without a care, just try working your way down in pressure a little bit at a time.

 

[Scott2227]

I established in my intro post that I am a complete dickhead newbie.

Rode MTB for the first time with my neighbour 18/8/21, bought a bike 19/8/21, got lost in the Royal National Park and had to walk out 20/8/21 and so on from there.

I am coherent enough on the bike now that I am paying attention to some of the variables.

the (29-in) tyres on my hard tail said 35-65psi so I inflated to 50psi on the basis of my 102kg weight (just big-boned …).

I was aware that struggling for traction on climbs may be the consequence (and has been for those who who know Creek Track climb between Signalhouse Track and Savilles Creek Track at Loftus) but I rode again with the neighbour today and he was like “oh shit no way that’s way too high”.

Deflated rhem to 33psi front and about 35psi back and it seemed to climb nicer, handle 60-80cm drop-offs better (Savilles Creek) and not set me back too far on firm ground fire trail riding.

Does this seem where you’d have a 100kg learner on a hardtail inflating his tyres to?

 

[beeb]

I established in my intro post that I am a complete dickhead newbie.

Rode MTB for the first time with my neighbour 18/8/21, bought a bike 19/8/21, got lost in the Royal National Park and had to walk out 20/8/21 and so on from there.

I am coherent enough on the bike now that I am paying attention to some of the variables.

the (29-in) tyres on my hard tail said 35-65psi so I inflated to 50psi on the basis of my 102kg weight (just big-boned …).

I was aware that struggling for traction on climbs may be the consequence (and has been for those who who know Creek Track climb between Signalhouse Track and Savilles Creek Track at Loftus) but I rode again with the neighbour today and he was like “oh shit no wat that’s way too high”.

Deflated rhem to 33psi front and about 35psi back and it seemed to climb nicer, handle 60-80cm drop-offs better (Savilles Creek) and not set me back too far on firm ground fire trail riding).

Does this seem where you’d have a 100kg learner on a hardtail inflating his tyres to?

Thereabouts, yep (depending on tyre choise and trail condition, maybe a touch lower up front? Dunno, 99% of the time I just go by feel). 50psi is crazy high though. That's what I use to seat and stretch the tyres on a fresh install.

 

[rextheute]

For me also depends on tyre size , I run 2.8 on a 35 mm rim - front 21 rear 23 , if I want more grip in the front I let a bit out.

For context , I am 100kg .

 

[The Duckmeister]

Pressure ranges stated on tyres tend to be fairly conservative both ways, but for off-road riding you want to start at the bottom end & tweak from there.

Too high pressure affects traction in all conditions, not just climbing; the tyres bounce off trail bumps rather than squishing around them, so handling is loose.

Too soft and they squirm and can burp or pinch-flat (even tubeless can pinch flat, the rim bead can cut the tyre sidewall).

Due to weight distribution on the bike, it's nearly always better to run lower pressure in the front than the rear.

All things considered, the exact pressures will be dependent on multiple factors, so there will be some experimenting required to find what's best for you, but everything else being equal, bigger tyre = lower pressure.

 

[Scott2227]

Thanks all, very much appreciated.

 

[HamboCairns]

I run about 27psi front (2.5 Minion DHF Exo+) and 28psi back (2.4 Rekon Exo+) on a 30mm inner rim - I'm 105kg.

 

[Chriso_29er]

For a lighter guy at 75kg I tend to run pressures on the higher side. I dont run any rim protection and hate squirming tyres so tend to run around 28psi rear and 22psi front. I've recently moved from 23mm rims to 31mm rims. Amazing how much lower I can go without squirming now, but still run higher in the rear for rock and root strike damage avoidance.

 

[droenn]

Just under 2 bar.

 

[ashes_mtb]

I run about 27psi front (2.5 Minion DHF Exo+) and 28psi back (2.4 Rekon Exo+) on a 30mm inner rim - I'm 105kg.

26/29 for me with 2.5DHF/2.4DHRII on same rim width and at similar weight. I could probably go lower but did all my DH racing back in the days of tubes running 40psi to avoid flats and find it hard to break out of a high psi mindset.

 

[pink poodle]

I happened to stop by the servo on my ride home today and put 33psi of servo air in front and rear. Why 33psi? Because that number called out to me from across the universe as I stood and looked at their device.

 

[DougalStrachan]

You running tubeless? Also tyre width will dictate the pressure (you need more pressure for narrower tyres)

I'm 110 - 115kg running 2.4 wide tyres normally run 27 PSI in back and 25 in front, but that is as low as I can get or else I'll start burping and slashing sidewalls
Also tyres type make a difference, I'm running the DHR a little higher than I normally would @30-32 PSI as they squirm about a fair bit

 

[Asininedrivel]

FWIW:

Mid-travel bike: 20/22psi F/R; 2.4 tyres on 30mm internal rims.

Big bike: 18/20psi F/R: 2.6 tyres on 30mm internal rims. DH casing rear.

No inserts in either. Around 95kg kitted up.