Captain Fastbastard Mayhem Posted September 6, 2013 Share Smim, that's pretty much what I run mine at but it was all through trial and error. Link to comment Share on other sites More sharing options...
ACM Posted September 6, 2013 Share Thanks for the input gents. Based on this formula I should be riding 1.5bar back and 1.3front which I (my 2 cents...) feel is way to hard :-) Link to comment Share on other sites More sharing options...
SeaBee Posted September 6, 2013 Share I ran into another problem of running too low pressures last weekend - sideways roll! It happened to be the front wheel that lost air along the way... then started climbing and the first time I stood up, I nearly went down - front end just went sideways. Well.. if I thought going up was interesting, coming down was a nightmare - front end kept wanting to wash away with the slightest sign of any lean on either the surface or the bike. Link to comment Share on other sites More sharing options...
madbradd Posted September 6, 2013 Share i have the Giant P-XC2 rims, they came with the bike. currently running tubes and racing ralph's @ 3bar. Im 110k and anything lower i get snake bites. well, i have not yet had a snake bite on this bike but my previous bikes i had plenty.before i bought my bike, i had a test bike, (29er with the same rims and tires) and was running @2.5bar. i had a snake bite at Groenkloof along the fence near fountains. now im wanting to go tubeless...  so the question is, are these P-XC2 rims tubeless read/tubeless and can i do the conversion with NON-tubeless tires and still run @3 bar? might try 2.8 too. Or will i have issues with side walls etc....? Hi Neg. I'm 105 to 110kgs, Used to ride 3/3.5 on my 26inch. Riding the giant P-XC2 wheels on my anthem, geax saguaro and aka 2.2s at between 2 and 2.2 bars now with no problem. I would seriously recommend going tubeless. Well worth it for grip and convenience. Link to comment Share on other sites More sharing options...
RockCoach Posted September 6, 2013 Share Knowing what the correct tyre pressures are is all good and well BUT not all pump gauges are created equally. There are 5 floor pumps in my bike room and each one has a different reading for the same pressure. If I recall correctly when the Birzman reads 1.8bar, the Parktool is the highest at 2.7bar... So unless you know you have an accurately callibrated gauge it really is a bit of trial and error. To find what works for you establish what is much too hard and much too soft and try and find the ideal somewhere in the middle. Front is usually around 10% less than rear. Another way to get a good starting point is to begin with a rear pressure which flexes the tyre slightly on a square edge (pointy rock, step etc) when you sit on the bike. This is also usually the pressure where your thumb will be able to flex the top tread a bit. It's good to know how hard your ideal pressure is by feel. nonky and JXV 2 Link to comment Share on other sites More sharing options...
Guest Smimby Posted September 6, 2013 Share Knowing what the correct tyre pressures are is all good and well BUT not all pump gauges are created equally. There are 5 floor pumps in my bike room and each one has a different reading for the same pressure. If I recall correctly when the Birzman reads 1.8bar, the Parktool is the highest at 2.7bar... So unless you know you have an accurately callibrated gauge it really is a bit of trial and error. To find what works for you establish what is much too hard and much too soft and try and find the ideal somewhere in the middle. Front is usually around 10% less than rear. Another way to get a good starting point is to begin with a rear pressure which flexes the tyre slightly on a square edge (pointy rock, step etc) when you sit on the bike. This is also usually the pressure where your thumb will be able to flex the top tread a bit. It's good to know how hard your ideal pressure is by feel. For this exact reasoning got myself an electronic gauge. Link to comment Share on other sites More sharing options...
ACM Posted September 6, 2013 Share Just for FYI, I use a topeak electronic gauge & have tested mine readings with another topeak electronic gauge just to make sure mine is bot 'broken' and on this i ride 0.8 & 0.6bar Link to comment Share on other sites More sharing options...
RockCoach Posted September 6, 2013 Share   For this exact reasoning got myself an electronic gauge. Yeah, an accurate gauge solves the problem. Johnny 1 Link to comment Share on other sites More sharing options...
ScottCM Posted October 23, 2013 Share I took my bike into the LBS last week, got it back on Friday. my chain kept jumpiing / Slipping when changing gears. This was sorted out perfectly. as i was leaving i asked the guy, who is apparently an avid MTB'er what my tyre pressure should be, 3BAR was the answer!!! Now although i knew this was way to hard, it started playing on my mind. I took the bike for a test ride and it feels like there is something not lekker. i dont know if this is just my mind playing tricks on me because of the tyre pressure thing or if there really is something wrong. Another thing they did to sort the gearing issue out was loosen my saddle and drop my seat post!! Thanks for the info on here about the correct pressure though as i now know and answer that makes sense and i can apply accordingly. Link to comment Share on other sites More sharing options...
Caltrigger Posted October 23, 2013 Share I'm 65kg and run my tyres between 2 and 2.5bar mostly. Hate the feeling a "dragging" tyre. It's been proven by a number of tests by one of the major tyre manufacturers that lower pressures do not increase the drag and in fact the added grip negates any loss caused by a lower pressure. I weigh 65kgs and run a 11kg bike (incl water) and run 1.4/1.5bar with no issues. Trails are well maintained and don't have many rocks though. That's on a 29er Htail btw Edited October 23, 2013 by Caltrigger Link to comment Share on other sites More sharing options...
Guest Smimby Posted October 23, 2013 Share . Edited October 23, 2013 by Smimby Link to comment Share on other sites More sharing options...
Caltrigger Posted October 23, 2013 Share It's frustrating to see guys spend hours training on bikes worth thousands of rands and spending time and money on going faster yet they don't own an accurate pressure gauge to measure a component of performance that is totally free!  Whatever your weight, strength, race or fun rider you need to know your pressure and at the very least ride the same pressure every time you ride! How else will you ever learn the capability of your equipment or yourself? Get a gauge, find a pressure and ride the same setup! Capricorn and nonky 2 Link to comment Share on other sites More sharing options...
Peat Posted October 24, 2013 Share I weigh 93kg. Front 1.8 Rear 1.9 Tubless 29er. Maxxis Lust tyres. Just rode Burg & Bush with these pressures. For flatter non technical rides Front 1.9 Rear 2.0 Edited October 24, 2013 by Peat Link to comment Share on other sites More sharing options...
BicycleMech24 Posted November 27, 2013 Share I weigh 78 kg's and I like low pressures. Front tire 1.4 bar/ rear tire 1.8 bar. Can ride basically everything on those pressures. Link to comment Share on other sites More sharing options...
Uni Posted March 17, 2014 Share Is my pump bust? Tyres (tube) are soft, I can press it a bit without too much effort (not flat) but when pumping it, gauge is showing over 4 bars. Maxxis sphinx tyres Link to comment Share on other sites More sharing options...
jaaki Posted March 17, 2014 Share 4 bar will feel like there are rocks inside your tyres.I got a pump that reads 4 bar when it's actually 2 bar, so it's in my 'maybe I'll fix it someday pile'Â Â I run my tubes at 1.4-1.6 front and 1.7-2.0 out back.... 72kg Link to comment Share on other sites More sharing options...
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