Tumbleweed Posted August 29, 2012 Share Please explain? Also would like to know. At 67kg, I run mine at 3 bar front and rear. Link to comment Share on other sites More sharing options...
Smolly Posted August 29, 2012 Share Sheesh! Do you folks have any teeth left after a ride. I run 1.7 in the front and 2.0 rear. Link to comment Share on other sites More sharing options...
Corvus Posted August 29, 2012 Share Also would like to know. At 67kg, I run mine at 3 bar front and rear. There was some research done on this: http://www.mtbonline.co.za/info/mtb-tyre-rolling-resistance.htm The conclusion is: Anyone who wants to ride really fast off-road needs to decrease tyre pressure. The rougher the ground, the more pronounced the effect. In addition traction and comfort increase, too. Due to their thin and flexible structure, semi-slicks offer the best start-up values for minimizing rolling resistance off-road. With a reduction in pressure, however, the risk of a flat increases. And traction with the semi-slick is limited. So the answer to the question of which width is best off-road clearly reads 'fat tyre' both for superior traction and snake bite prevention. For cross-country-races and marathons involving only a small percentage of tarmac a wide tyre with low pressure is recommended. The most overestimated aspect here is the frequently criticized extra weight of the wider tyre. To accelerate a pair of tyres with an extra weight of 500 g from 0 to 25 kph in 4 seconds requires an additional 4.2 W power. On the other hand the wider tyre on a grassy surface saves you 15.5 W against a narrower specimen, and this at the low speed of 9.5 kph. Moreover the rolling resistance reduction has a continuous effect while lighter weight is only of relevance during acceleration. Link to comment Share on other sites More sharing options...
Tumbleweed Posted August 29, 2012 Share There was some research done on this: http://www.mtbonline.co.za/info/mtb-tyre-rolling-resistance.htm The conclusion is: Anyone who wants to ride really fast off-road needs to decrease tyre pressure. The rougher the ground, the more pronounced the effect. In addition traction and comfort increase, too. Due to their thin and flexible structure, semi-slicks offer the best start-up values for minimizing rolling resistance off-road. With a reduction in pressure, however, the risk of a flat increases. And traction with the semi-slick is limited. So the answer to the question of which width is best off-road clearly reads 'fat tyre' both for superior traction and snake bite prevention. For cross-country-races and marathons involving only a small percentage of tarmac a wide tyre with low pressure is recommended. The most overestimated aspect here is the frequently criticized extra weight of the wider tyre. To accelerate a pair of tyres with an extra weight of 500 g from 0 to 25 kph in 4 seconds requires an additional 4.2 W power. On the other hand the wider tyre on a grassy surface saves you 15.5 W against a narrower specimen, and this at the low speed of 9.5 kph. Moreover the rolling resistance reduction has a continuous effect while lighter weight is only of relevance during acceleration. Yeah, I get all that. But I can't stand the "feel" of a "dragging" tyre. So, I know what I should be doing; I just don't like doint it. Link to comment Share on other sites More sharing options...
Cassie Posted August 29, 2012 Share There was some research done on this: http://www.mtbonline...-resistance.htm The conclusion is: Anyone who wants to ride really fast off-road needs to decrease tyre pressure. The rougher the ground, the more pronounced the effect. In addition traction and comfort increase, too. Due to their thin and flexible structure, semi-slicks offer the best start-up values for minimizing rolling resistance off-road. With a reduction in pressure, however, the risk of a flat increases. And traction with the semi-slick is limited. So the answer to the question of which width is best off-road clearly reads 'fat tyre' both for superior traction and snake bite prevention. For cross-country-races and marathons involving only a small percentage of tarmac a wide tyre with low pressure is recommended. The most overestimated aspect here is the frequently criticized extra weight of the wider tyre. To accelerate a pair of tyres with an extra weight of 500 g from 0 to 25 kph in 4 seconds requires an additional 4.2 W power. On the other hand the wider tyre on a grassy surface saves you 15.5 W against a narrower specimen, and this at the low speed of 9.5 kph. Moreover the rolling resistance reduction has a continuous effect while lighter weight is only of relevance during acceleration. There you have it!! This dude got a PHD from this study....so it must be true!!Get over the weird feeling and drop your pressure!! Link to comment Share on other sites More sharing options...
Kranswurm Posted August 29, 2012 Share Yeah, I get all that. But I can't stand the "feel" of a "dragging" tyre. So, I know what I should be doing; I just don't like doint it. Interesting..To be honest I don't know what pressures I ride at on the mtb.I squeeze it and if it feels right,way to go.I am lucky that I run 2bliss wheels and tyres so I can run fairly low with no chance of burps or farts or whatever. On the road it's different.I pump them to the max on the sidewall and rarely get snakebite or punctures Link to comment Share on other sites More sharing options...
SwissVan Posted August 29, 2012 Share Also would like to know. At 67kg, I run mine at 3 bar front and rear. No wonder you fall off so much lower pressures will vastily improve your grip / traction resulting in less oops moments Link to comment Share on other sites More sharing options...
Tumbleweed Posted August 29, 2012 Share No wonder you fall off so much lower pressures will vastily improve your grip / traction resulting in less oops moments Hahahahahahahaha! I tried running my 29er tyres at a lower presure, and managed to burp both doing a broady… Link to comment Share on other sites More sharing options...
Hairy Posted August 29, 2012 Share Also would like to know. At 67kg, I run mine at 3 bar front and rear. Is that for your road bike Tumbles? Link to comment Share on other sites More sharing options...
Tumbleweed Posted August 29, 2012 Share Is that for your road bike Tumbles? Hahahahahaha! Nope, sold my last road bike almost two years ago. My sorta road bike - my fixie - has tubbies running at close to 10 bar. Link to comment Share on other sites More sharing options...
SwissVan Posted August 29, 2012 Share Hahahahahahahaha! I tried running my 29er tyres at a lower presure, and managed to burp both doing a broady… Yeah me to, 2 weekends ago decided to try a lower pressure and my front tyre came off turning a sharp corner...in hindsight i think i had a slow puncture which contributed to even lower pressure...and yes my sealant was from last year summer and all dried up... Link to comment Share on other sites More sharing options...
Tumbleweed Posted August 29, 2012 Share Yeah me to, 2 weekends ago decided to try a lower pressure and my front tyre came off turning a sharp corner...in hindsight i think i had a slow puncture which contributed to even lower pressure...and yes my sealant was from last year summer and all dried up... Hahahahaha! My sealant was relatively fresh, and left a funny trail for the 100-odd metres I had to walk home. Link to comment Share on other sites More sharing options...
martinsnyman Posted August 30, 2012 Share Ok, So I got my bike back yesterday, the tyre reads Schwalbe Racing Ralph Pline (performance line) What I have gathered from all this is that I will be riding at 2.5bar front and rear, at least for a while to allow the tyre to seat properly and will then gradually decrease the tyre pressure. Thanks for all your help! Link to comment Share on other sites More sharing options...
Hermanus Cycles Posted August 30, 2012 Share Ok, So I got my bike back yesterday, the tyre reads Schwalbe Racing Ralph Pline (performance line) What I have gathered from all this is that I will be riding at 2.5bar front and rear, at least for a while to allow the tyre to seat properly and will then gradually decrease the tyre pressure. Thanks for all your help! They are seated and will not seat better over time.(sounds like the kind of answer a poor shop gave you.) Performance Line is the cheapest of the Scwalbe tyres.The ones that many bikes are fitted with out the box.They are NOT great as tubeless.In fact ,they are not rated by Scwalbe as being compatible with any tubeless system.You will however find many guys trying,some with more success,but at 105kgs,dont take the chance. Ditch them in favour of the Snake skin version. Edited August 30, 2012 by 20niner Link to comment Share on other sites More sharing options...
Wes84 Posted August 30, 2012 Share Got a band new bike, 29er, this is week 4 on the bike, Giant rims, Scwalbe Racing Ralf tyres made tubeless, put in latex sealant, they deflated slowly the first 2 days. Took the pressure to over 2 bar for 2 rides, then deflated. No problem, then tried to align the logo on the tyre with the one on the rim, the sealant had literally "glued" the tyre to the rim!! Get latex sealant, put in a fair amount, run at pressure as high as possible for a day or two then deflate to desired pressure. Also remove the wheel and hold it sideways, spinning very slowly, very slowly so the sealant can get on the sides of the rim as well. You can even take a small paint brush and paint the sides of the tyre where it touches the rim with sealant before inflating. I think I nearly bent my rim last night, tyre dint even feel it. Edited August 30, 2012 by Der Meister Link to comment Share on other sites More sharing options...
martinsnyman Posted August 30, 2012 Share Got a band new bike, 29er, this is week 4 on the bike, Giant rims, Scwalbe Racing Ralf tyres made tubeless, put in latex sealant, they deflated slowly the first 2 days. Took the pressure to over 2 bar for 2 ridesfelt hard even with the dua , then deflated. No problem, then tried to align the logo on the tyre with the one on the rim, the sealant had literally "glued" the tyre to the rim!! Get latex sealant, put in a fair amount, run at pressure as high as possible for a day or two then deflate to desired pressure. Also remove the wheel and hold it sideways, spinning very s Thanks - sounds like good advice, will try this - did a quick ride tonight at 2.5 bar, sheesh it was terrible!! No traction in the sandy patches, even struggled on the gravel next to the road-felt hard even with the dual suspension! Will do another quick ride tomorrow morning and then start deflating at 1bar intervals till I am happy. Thanks for all the help and advice guys, makes getting into the sport we all love a lot easier!!! Looking forward to the trailseeker Saturday! in for 40km. Link to comment Share on other sites More sharing options...
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