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#11
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OK to overinflate tires?
On Sun, 09 Oct 2005 14:53:17 GMT, "Dave Reckoning"
wrote: (please forgive me the long URL, TINYURL is down!) And that, ladies, is why shouldn't use tinyurl or similar services in the first place. Well, one of the reasons. a) Single point of failure b) link target is 'hidden', which can be used for fraud, goatse, and other shenanigans c) privacy, tinyurl has massive datamining potential and d) if they ever go bankrupt or lose all their systems without benefit of backups, which is not that unlikely, not even archive services will be able to help you see what the hell a post from yesteryear was pointing at. And since there's no good reason to in fact stick to the 80 character limit for things like urls, they don't even serve any purpose. Jasper |
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#12
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OK to overinflate tires?
"Dave Reckoning" wrote in message news:x9a2f.228887$084.24624@attbi_s22... "mort" wrote in message ups.com... I'm a lightweight, at 150 lbs, so I was wondering: what's the downside of overinflating my tires somewhat? For instance, I am commuting on a Schwalbe Marathon Slick that says it should be inflated to 85 psi. What would happen if I routinely inflate it to 100? Tire explosions? Rim damage? Earth crashes into Sun? Jobst admits that wheels hang from their spokes? Any other bad effects? I've ridden Conti tubulars that take 160lbs, and didn't notice any difference in the time it took me to ride a known circuit, though the ride was noticeably harsher. I prefer tubulars like Vittorias at ~115lbs for my 160lbs. This is unscientific testing under varying conditions, but I rode it (timed and heart rate monitored) at least twice a week for years on Vittoria, then a season on Contis (thought the higher pressure would be faster), then back to Vittoria. The Contis -I forget the model- were equivalent in price to Corsa CX/CG. It doesn't really answer your question about overinflation since the Contis are designed for 160lbs, but I imagine that factors others have explained negate any advantage derived from tire pressure in this range. |
#13
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OK to overinflate tires?
Dave Reckoning writes:
I'm a lightweight, at 150 lbs, so I was wondering: what's the downside of over inflating my tires somewhat? For instance, I am commuting on a Schwalbe Marathon Slick that says it should be inflated to 85 psi. What would happen if I routinely inflate it to 100? Tire explosions? Rim damage? Earth crashes into Sun? Jobst admits that wheels hang from their spokes? Any other bad effects? Bicycle wheels, like most machines, are systems which contain many components. While the maximum pressure rating of the tire is important I would be just as if not more concerned about the rating of the rim to handle the tire size and pressure. Mavic shows maximum inflation for their rim at: http://tinyurl.com/8zskk As you can see from this chart some of the strongest Mavic rims are rated as low as 49 PSI for wide tires. I assume these are conservative ratings but I would recommend that you pay attention to them as you don't want to have a rim come apart on your front wheel at speed! It's not the rim that comes apart but the tire that blows off the rim, something that can occur even at the recommended maximum inflation if you use rim brakes on a long slow (much braking) descent. The critical pressure results from the width of the inside-to-inside edge of the rim bead (the area on which inflation pressure acts). Larger tires have greater casing stress that could case a blowout but about the same blow-off pressure. That is what these pressures are about. Jobst Brandt |
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OK to overinflate tires?
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#16
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OK to overinflate tires?
On 8 Oct 2005 13:32:59 -0700, "mort" wrote:
I'm a lightweight, at 150 lbs, so I was wondering: what's the downside of overinflating my tires somewhat? For instance, I am commuting on a Schwalbe Marathon Slick that says it should be inflated to 85 psi. What would happen if I routinely inflate it to 100? Tire explosions? Rim damage? Earth crashes into Sun? Jobst admits that wheels hang from their spokes? Any other bad effects? Rough ride. Increased fatigue due to vibration. Increased possibility that the tire will unseat from the rim flange, allowing the tube to blow out. Increased wear down the center of the tread area. Slight reduction in the tendency to have pinch flats due to road hazards. Increased probability of rim failure if the side flanges of the rims are weak or badly worn. For me, the first item is enough to make me lose enthusiasm for overinflation. YMMV. -- Typoes are a feature, not a bug. Some gardening required to reply via email. Words processed in a facility that contains nuts. |
#17
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OK to overinflate tires?
the marathon's carcass is not the complex layup found on a conti tt is
it?? the TT at the rec pressure of 70 pounds flattens out on the bottom when the bike is loaded with 50 pounds on the rear racks. pumping to 85 pounds shapes the tire's contact area back toward the form found when pumped to 70 pounds with a 160 pound rider. handles and rides better at increased pressure for increased load-not slippery the TT which is not normally slippery but grippppy gradually gets slippreier with load but no increase in pressure or at the high end of things that may be the focus here the TT gets slippppreier under 70-80 pound loads even with the extra 15 pounds air like glazee covered with water eeeeeyyahhhhh!!! but maybe the layup prevents the tire from leaving the rim even at 110 pounds?? haven't tried it. |
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