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I'm doing Gritfest this weekend and I'm going to ride it on my hardtail. I bought some 2.25" Mezcal tyres but was wondering what pressure to run them at. I normally run 27 or 28 psi on MTB trails but the event is going to be mainly on fire roads. I want the bike to be as efficient as possible so was thinking of putting them at about 50psi, does this sound like the best thing to do?
Id maybe not go that hard 35/40 id say.
Just cos its hard doesn't make it as efficient
I run my gravel bike around 35 psi on 40c tyres so although I am light, unless super heavy, I think 50psi would be overkill.
Not a good idea. Gravel in the UK is quite bumpy and harder tyres are only faster on totally smooth surfaces. I did a gravel event in the Cotswolds which involved a lot of hardback dirt with tractor marks or dry footprints and having fat MTB tyres at low pressures was a distinct advantage.
I find the Silca tyre pressure app really useful, you can choose terrain type too.
https://silca.cc/pages/sppc-form
maybe slightly harder than normal, but 50psi is insanity!
Put em up to 100 I should. You can always let "a bit" out to taste once you've given it a mile or so to decide whether it's any good.
50 psi is not far off tubeless road tyres pressures for 28mm tyres!
45mm gravel tyres at 78kg and i go mid 30's.. bike is still fast on hard pack
big ole 2.25's i wouldnt be passing 30 psi myself
I run about 30 on my ht for gravel and definitely feel the bumps. Depends how long you’re riding for as you could get smashed around.
Take a pump, add or subtract at leisure as you ride. Only you will know on the day. I know this is an old fashioned way but the above app telling you what tyre pressures to run is hilarious!
25 front, 28 back on 700 x 50. Just got back from a 3 day bikepacking tour of Dorset on my scale and must have ridden most types of “gravel” the UK has to offer. Even with the bike loaded those pressures were perfect.
I run the 2.35 mezcals on my rigid hard tail and have them around 38psi but I'm a heavy ****er.
Take a pump, add or subtract at leisure as you ride. Only you will know on the day. I know this is an old fashioned way but the above app telling you what tyre pressures to run is hilarious!
so you can start far away and stop regularly to mess about, or you get some advice and hopefully start closer to an ideal pressure and maybe not start at all. I just shoved me and the nursery run bike (with 650b 47c WTB Ventures) and the kind of riding we do on it into the Silca app and it shoved out pretty much exactly what I've settled on for those tyres.
Edit: though I've had a muck around with the app, and taking my son (15kgs) on anf off the weight, and taken the speed from recreational to pro tour and back, and results go from 25 to 27.5, both of which are well within "fine" for me on that bike!
So Jon, whack your numbers in the app, start there. As good a place as any!
Putting the pressure up might help on the road
Every where else I don’t think you gain anything. Tyres absorbing bumps makes you faster not slower.
I cleary don’t push it on the tough stuff. My 2.3 inch tyres on my MTB are 20 psi and 18 psi. My 50mm gravel tyres are at 25 and 27 psi
I’m no light weight either
so you can start far away and stop regularly to mess about, or you get some advice and hopefully start closer to an ideal pressure and maybe not start at all.
But asking people what for instance would be my ideal tyre pressure is without knowing the conditions on the day, the tyre width, the rim width, my riding style, how heavy I am, how heavy the bike is unladen or laden and the weather conditions is just silly when you can get to the ride, pedal for 100 metres and the add or release air yourself and have the perfect pressure in seconds. Unless it's a race and the OP is hoping to get on the podium a few minutes pre riding the course near the start or when the event has started isn't going to matter
I did the Badger Divide on tyres pumped up to 40psi. This was on a loaded 120/115mm full sus with 2.25" MTB tyres. Worked for me. Try 40psi and if it's a bit harsh let a bit of air out.
I'd also look at fitting barends inboard of your grips, much better for climbing and getting aero on the flat.
https://singletrackmag.com/forum/topic/inboard-bar-ends/
The app is definitely a bit iffy. For 2.5 mtb tyres on type 4 gravel it reckons I should be running at 10psi
agreed, chris! same for me. 1ps more than I used to ride 4in tires with!
@ampthill nailed it.
I’m 95kg and run high 20’s to low 30’s in my gravel tyres and mid 20’s in 2.25 rocket Ron’s.
At 40 or heaven forbid 50 psi, your entire bike will be going up and down a billion tiny micro-mountains.
There still a lot of people thinking low pressures puncture easier too- so I always think about how hard it is to pop a nearly flat baloon!
I like higher pressures than most - 2.2 tyres on my MTB get 25 / 30 psi for rough terrain and 35/ 40 for road / smooth gravel
50 is too much
I wouldn't be a fan of stopping and adjusting pressure on the trail unless you have a good pump with a gauge. Remember every time you attach the pump the tyre pressure initially DROPS so it's hard to know where your final pressure ends up.
40psi in 40mm gravel tyres for me, 30psi in 2.1" Barzos on the hardtail, I'm 88kg.
2.25" I'd personally start at 30psi also but maybe even go a touch lower.
I’m old school and the “squeeze them, do a dry run and adjust them” advice is bang on for me. Most pump gauges probably aren’t accurate anyway.
50psi in a 2.25” tyre is way high, though. To be honest I find tyres that wide suck for gravel: if you add enough pressure not to be draggy they bounce off very last stone, and if you drop the pressure enough to be compliant they’re horribly draggy. YMMV.
Prob been said enough but 50 psi sounds way too high to me too, unless you weight ~150 kg
I'd suggest upping your mtb pressures by no more than about 10%, so to 30 psi-ish. That alone will likely be quite noticable
As another datapoint, I'm between 75 and 80kg and I run 29 x 2.2" mtb semi-slicks at 20 psi, 700 x 45mm gravel tyres at 26-28psi, and 32mm gravel tyres at 40-45 psi
To be honest I find tyres that wide suck for gravel: if you add enough pressure not to be draggy they bounce off very last stone, and if you drop the pressure enough to be compliant they’re horribly draggy. YMMV.
This must be very tyre dependent, I was amazed how fast my Vittoria Barzos felt, even on tarmac. Am looking forward to trying the Mezcals (same size, same compound) as I expect they'll be even quicker.
There still a lot of people thinking low pressures puncture easier too- so I always think about how hard it is to pop a nearly flat baloon!
crosshair also has a good point here
I used to unknowingly run way under recommended pressures for my weight. Since I got an accurate gauge and upped my pressures a bit, I think I've had more punctures
50 psi is way too high for tyres that wide. I'd be looking at 30 in the back and 25 in the front as a starting point.
I’ve got a fairly well calibrated squeeze-o-meter but I used the silca site out of curiosity for road and gravel. It confirmed my preferred pressure within a few psi so I’d happily use it to get a good starting pressure for new tyres. Not sure why using an online tool to help is ‘hilarious’ though.
Yeh I find the Silca app useful, especially for some one like the OP who has no idea where to start, and it's free.
Obviously you can fine tune to taste afterwards, but I bet a lot of people are surprised with the 'modern' thinking of how low you can or should go. The guys at Silca do have some idea what they're doing 😉
I'm going to try 40 psi for the start of the ride and I think will drop the pressures a bit if the ride feels really rough. I'm heavy at 124 kg so will give 40 a try, it's easier to go lower by letting air out than increasing it on the ride. It's like an enduro event in that only short parts of the stages are timed so there's no problem stopping to adjust the bike.
Thanks for all the advice everyone