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Just converted to tubeless and had my first few rides on it.
Invested in a digital (geek!) pressure gauge as track pump gauge is vauge.
My first local wooded trail ride using the track pump gauge, turned out to be around 17psi!!
I did 3 laps of FoD Verderers yesterday, first lap at 18psi rolled on the rim a bit and dinged a couple of times, second lap at 23psi slid a little, third lap at 21.5psi felt [i]just right[/i].
On a hardtail with Conti BC TK 2.2s if it matters.
So what psi do you run your tubeless at then???
(and why do Conti advise 50-65psi on their website?)
Not that low really. Just under/over 30PSI front/back on Maxxis tyres. I might let them drop to around 25 if it's not rocky. I find I end up going lower with Schwalbes as they've got really stiff sidewalls.
i start at about 35 and generally end up with zero overnight, and lots of swearing
Tyre manufacturer recommended pressures are as much a legal thing as technical.
I use the (weight in stone) / 2 then -1 for the front and +2 for the back formula. I'll adjust it slightly for conditions but haven't fully experimented with just how low I can realistically go. Bontrager XR4 on front, XR3 on rear FYI.
17 front 25 rear is my preference
like a ripe mango on the front and a ripe orange on the back
For my local woods, which is littered with wet roots, I run the front so I can just get my palm to the rim with a hard push. The back slightly harder.
For trail centres and faster rolling surfaces I stick more air in though.
I use the (weight in stone) / 2 then -1 for the front and +2 for the back formula.
I'm 12 stone. Divide that by 2 and subtract 1 gives 5 PSI in the front!!!
I like my tyres soft... but that's a bit too far! Are you sure that formula is correct?
[i]whitestone[/i] never heard of a bodyweight formula before, but Stans website throws up:
Rider Weight in pounds divided by 7 = x
x - 1 = Front tire pressure in PSI
x + 2 = Rear tire pressure in PSI
Example: 185lb rider
185/7 = 26.4
Front tire pressure: 26 - 1 = 25 PSI
Rear tire pressure: 26 + 2 = 28 PSI
So (naked) 21 front, 22 rear for me, so currently not a million miles away.
Doh!! 😳 Multiply by two (wanders off to corner of room and picks up big pointy hat)
Since there's 14 pounds per stone dividing weight in pounds by 7 is the same as multiplying weight in stone by 2.
If you look on various tubeless manufacturer websites like stans etc...they give recommended pressure for tyres rims etc...based on rider weight. The original premise of tubless was less punctures and you could get better ride handling and feeling for similar pressures as tubed. Then the obsession with running loe pressures arrived via the web and lots of people became convinced that tubeless was crap as a light weigjt racing tyre at14psi could be a bit a squirmy, roll off a rim or wear faster. ..this was obviously down to the tubeless not operator error :-). So basically..about the pressure the system you are using recommends for your weight, plus or minus a bit.
I use that stans one but er downwards slightly to get a nice feel. (according to my inaccurate trackpump).
Both formulas would be the same if the first was multiply stone by two.
Edit: You noticed 🙂
Rear, 30 psi, maybe 25 psi in local woods (not too rocky).
Front, 25 psi, maybe 20 psi local woods.
Don't think my track pump if very accurate so I just give them a squeeze.
Not come across that measurement before. Would be 28 front, 30 back so not far off either.
Nobody has mentioned their weight, which can make thier psi completely irrelevent to the OP.
I'm 13st and run Minions or HR2s at 28 rear 25 front. Flow rims.
Well I mentioned neither my weight nor the pressures I'm running at: 13st and 25psi front, 28psi rear though occasionally drop 1 or 2 psi on both.
Edit: my tyres are 2.35 front and 2.2 rear on a Solaris.
Nobody has mentioned their weight
Er, yes they have. More than once.
I'm 13 1/2 stone (probably more with sack on) and ran late twenties on the back with some Spesh Purgatory on Flow EX. They burped air too easily so now I'm nearer 30. Will try Stan's formula...
Somewhere in the region of 22psi for me. Much harder and I get no grip, much softer and the tyre deforms under hard cornering. I weigh about 9 3/4 stone but still managed to put several dings in my rear wheel. I'd imagine you can get away with running lower psi on a full suspension bike than a harsh hardtail.
30-35 for me. I'm not that fussy about tyre pressures, but I do hate it if they squirm on bends.
I've come to the conclusion, after a number of years, that interweb strangers quoted tyre Psi values are completely irrelevant. There are simply too many factors affecting the performance of the tyre in addition to it's (probably inaccurately measured) pressure to actually tell you anything useful.
Rider weight + amount of kit carried, Suspension (or lack thereof) and it's set-up, tyre width, Carcass, profile and tread pattern, Rim width, Accuracy of equipment used to inflate/measure pressure, temperature, general riding style, condiitons and terrain...
A 20 stone Man-Monster on a Rigid Fatbike will have totally different needs to an 8 stone whipper-snapper on an 8" travel DH rig or a 12 Stone #Enduro chariot riding "Middleweight"...
20-25 Front / 25-30 Rear here... which will mean pretty much nowt to anyone else...
9/11 psi on 2.35" Hans Dampfs on Flow EX rims.
Probably go 15/17 if it's properly rocky.
About 70kg fully loaded.
Interestingly enough having seen that Stan's formula and applied it to my now reduced to 17 stone body weight comes out at 33 front 35 rear.....which spookily enough is what I dound in practice prevents any burping or rin dinging.
I never have understood why you would run your pressures that low that you would want to touch the rim let alone slide a sidewall....I would be slithering about all over the place on some of those quoted tyre pressures and that's with UST rims and full on tubeless tyres.
Based on the cyclocross method of putting edge of hand across tyre, lifting body of the ground and not touching the rim, I come up with about 20 PSI. I ran cyclocross Pro tyres on my mtb at 18 in a very sticky muddy race (no rocks or roots) and the front burped on a corner. I'll go higher for trails but not as high as 30. I'm 10st 10lb.
My road tubeless go as low as 100 PSI 😉
On my mtb, 20 front, 25 rear
On my CX, 50-55psi both for CX type rides or 40 in both if riding 'proper' mtb trails
26/30 F/R 120kg, maybe should be a little higher for my weight?
You're about the same as me (well I'm a little less) so your numbers sound about right to me.
well im eleven stone, fourteen with my camelbak on.
i have my tyres hard, or im a wimp, as i cant squish a tyre to the rim ^ unless its in need of fixing
hth
20/24 @ 71kg. That's using my track pump so the numbers will be consistent but probably different to other peoples 20/24!
15/20 at 72 kg according to my track pump but I am sure it under reads. Push the front wheel against the corner of a kerb and the right psi is just enough to prevent you from touching the rim... That's 2.4/2.3 tyres
27 rear 23 front is my preferred magical combination at the moment. 26 spesh Captain front, Ground Control rear. About 80kg kitted up.
I weigh 10 stone and ride like a fanny, a little over 20psi usually does the job for me with fat singleplies. I've got a nice rocky descent near my house so every tyre setup gets charged down there once with an ear open for rim boings. If it works there, it works most places.
Weight and aggressiveness has a fair bit to play when it comes to blowing off the rims, or burping, from what I experience. Hence why I never have a problem at just about 11 stone and favouring the chicken runs.
Myself, 20 front or lower if I haven't bothered to pump it up for a bit. 25 rear. Even then I feel could be lower, but depends on the conditions also.
On the alpine 35 psi is my minimum. The fatty is rideable at 8-12psi. 15 is way too hard!
5 in the front. 8 in the back. 17.5 stone.
At 14 stone I am running 26-28 psi on big Magic Mary out front and 30-32 psi out back on a Minion.
I am more concerned with big rock hits and no punctures than cornering because I don't tend to pull Gs through the turns like the lads in them videos...
10 stone
hans dampfs supergravity on mavic 521
17 psi front 20 rear for teh gnarr
It depends how you ride (smooth or clumsy, fast or mincer), what sort of trails you ride, how many rim dings/flats you're prepared to put up with and what the weather's like (I generally run a couple of psi lower in filth as I'm not getting the speed up to flat the rear wheel).
Oh and also full sus/hardtail - the rear of my hardtail is far more prone to pinch flats than any other tyre I own, particularly when going for it!
I'm generally pretty fond of not having punctures, and run about 5psi lower than I do with tubes in (can only be arsed with tubeless on the bike that has one set of tyres on all year round for now.)
I'm running Spesh 2Bliss tyres here on Roval rims at 30psi front and 35psi rear. I don't like the rear feeling like it's rolling from side to side, plus if they go below 25psi then they tend to burp when cornering leading to much slinging of profanities.
14 English stones here. I've found that as I've become a more experienced trail rider I can get away with lower pressure without suffering as many snakebites. Also, as my tyre air volume has increased I've also generally gone a bit lower.
On 2in 26ers with tubes back in the back I'd run c. 35psi. Tubeless 2.3 inc 26ers brought me down to about 30psi. Then I bought 26in flows and I ended up running 26-28 with the same 2.3 tyres. Making the move to 2.3in 29ers on arch type rims let me to drop to 22-24. A year ago I set myself up with 35mm light bike rims in 29er flavour and with 2.35 in Hans dampfs, I'm running 18-20, although never below 20 on the rear!
With those kind of pressures at my weight on a 140mm 29er, I'm perfectly capable of snake biting by slamming extremely hard into square edged bumps if I'm not paying attention, but in the whole of last year of excellent and very frequent riding, this happened once.
im 15 1/2 stone and usually go 30 psi front 35 rear on my hard tail.
30 front 33 rear on my enduro rig, (same as the formula by coincidence).
lower than 25 ish I feel the rear tyre squirm and ding the rim.
At ~71kg I'm running 20psi in a 2.25 ardent up front and ~24psi in a 2.0 beaver on the rear. Both on crests FWIW
This is on a rigid SS and I'm a massive xc jey boy as well.