karlito Posted September 20, 2017 Share I'm 80kg with 2.25" tubeles tyres on 19mm rims and I run 26psi rear(1.8bar) 23psi (1.6bar) front. Rim width also impacts the ideal pressure for a specific rider. I can run the same pressure on my 23mm rims even though I am 10kg heavier Link to comment Share on other sites More sharing options...
Christofison Posted September 20, 2017 Share Try the Stan's formula : Example:185 (lbs) / 7 = 26.43 -1 = 25.43 psi front185 (lbs) / 7 = 26.43 +2 = 28.43 psi rear If you only know you kg weight ( this must be with full gear) x 0,453592 to get to lbs. This is for tubeless and you must use an accurate gauge not a floor pump. if anyone knows of a better starting please post. OP would therefore need 36.5psi rear (2.5bar) & 33.5psi front (2.3bar). Link to comment Share on other sites More sharing options...
Spinnekop Posted September 20, 2017 Share 29er Full susser Tubeless Rider weight: 80kg Mostly commute and trails over weekend 1.6bar front and rear Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted September 20, 2017 Share OP would therefore need 36.5psi rear (2.5bar) & 33.5psi front (2.3bar).which is bloody stupid. That's why these formulas never work. They're for a narrow band of applicability with a certain rim / tyre / riding style combo. Nobody should be running those sorts of pressures on an mtb on anything other than tar. Link to comment Share on other sites More sharing options...
georges Posted September 20, 2017 Share Try the Stan's formula : Example:185 (lbs) / 7 = 26.43 -1 = 25.43 psi front185 (lbs) / 7 = 26.43 +2 = 28.43 psi rear If you only know you kg weight ( this must be with full gear) x 2,20462 to get to lbs. This is for tubeless and you must use an accurate gauge not a floor pump. if anyone knows of a better starting please post. Link to comment Share on other sites More sharing options...
georges Posted September 20, 2017 Share OP would therefore need 36.5psi rear (2.5bar) & 33.5psi front (2.3bar). Correction: Multiply by 2,20462 to convert from Kg to LBS. Link to comment Share on other sites More sharing options...
Christofison Posted September 20, 2017 Share Correction: Multiply by 2,20462 to convert from Kg to LBS.110kg = 242.5lbs divided by 7 = about 34.5psi plus 2 for rear = 36.5psi = 2.5bar which might be advisable if the OP was riding 2.1 tyres on a 17mm rim. But for 2.3 tyres on a 25mm rim you could probably drop that by 0.4 bar or so. Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted September 20, 2017 Share Correction: Multiply by 2,20462 to convert from Kg to LBS. or just replace your * with divide. Link to comment Share on other sites More sharing options...
karlito Posted September 20, 2017 Share Or just get a proper tyre pressure gauge and go ride your bike at the local park. 1. Ride a short section you are familiar with and the then drop the pressure a bit and repeat. 2. Eventually you will reach a pressure where the tire squirms a bit around tight corners or you bottom out the rim. 3. Inflate 0.1 bar and try again, pretty soon you should have found your sweet spot! Link to comment Share on other sites More sharing options...
Simon Kolin Posted September 20, 2017 Share A great Podcast that addresses the topic https://cyclingtips.com/2016/08/cyclingtips-podcast-episode-9-rethinking-road-bike-tire-sizes-and-pressures/ "Can’t quite allow yourself to believe that a 30mm tire at 70psi might be faster than a 23mm one at 100psi?" Link to comment Share on other sites More sharing options...
dev null Posted September 20, 2017 Share I am 84kg and use:- - 2.2 Bar front and 3.0 Bar rear for road and hard pack flat stuff - 1.7 Bar front and 2.0 Bar rear when the trails does not include lots of loose rocks and sand - 1.5 Bar front and 1.8 Bar rear when the trails is sandy and have loose rocks etc. Basically, on my technical ability limit. Link to comment Share on other sites More sharing options...
Mr lee Posted September 20, 2017 Share I run my 26' at 3.5 but it is only on tar. I weigh 67kg and had no issues so far. You are like half my weight....might be the reason you haven't had it blow off on you like mine did Link to comment Share on other sites More sharing options...
Prince Posted September 20, 2017 Share You are like half my weight....might be the reason you haven't had it blow off on you like mine did Mmmm. That could explain it Link to comment Share on other sites More sharing options...
ScaredShiftless Posted September 20, 2017 Share I ride a 29 Full Suspension MTB, weigh 82kg, internal rim width 30mm, 23mm tyres, tubeless. Pressures are 1.8bar Front and 2.0bar Rear. Works like a dream for me! Link to comment Share on other sites More sharing options...
cadenceblur Posted September 20, 2017 Share use a digital guage so pressures should be spot on, I have found my normal floor pump to be be a bit out. Running trail wide rims IR 30mm 1.6b front and 2 rear. Weight between 97 - 100kg Link to comment Share on other sites More sharing options...
ChrisF Posted September 20, 2017 Share Time to buy a proper pressure gauge .... or get an adaptor so I can use my proper 4x4 tire pressure gauge .... on my commuter the sidewalls are SUPER thin and flexible - actually the one constant negative feedback on the reviews of my bike. Anything under 3,5 bar (according to my floor pump gauge) and the rear wheel has the most awkward flex around tight corners !! NOT nice !!! Have checke the rims and shafts etc, pump up the tire and it feels good again. and by the sounds of things I am running way too hard when off road .... Link to comment Share on other sites More sharing options...
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