Francois_Dumas Posted September 27, 2007 Share Posted September 27, 2007 A question to which I haven't been able to find an answer yet... I know my tires (like any tire, I think) have more 'grip' when they are warm. So the temperature 'does' something to the rubber. What I am wondering about is if this effect is influenced at all by having the bike in freezing cold all winter? Does it PERMANENTLY effect the ability to increase grip after warming up or does it have no effect at all? Link to comment
Mr_Ed Posted September 27, 2007 Share Posted September 27, 2007 I'm not a Tire Guru and not a Chemist but my gut feeling is that that doesn't have an effect. I suspect what does have an effect is that over time the tire hardens anyway.... if there's less grip after a long winter it may be attributed to tire age. Link to comment
Lone_RT_rider Posted September 27, 2007 Share Posted September 27, 2007 What I am wondering about is if this effect is influenced at all by having the bike in freezing cold all winter? Does it PERMANENTLY effect the ability to increase grip after warming up or does it have no effect at all? Just getting them cold for extended periods of time will not harm them to the extreme that heat cycling them will. Example: Take a few "hot laps" in cool outdoor temp of say, just over 0 degrees C. Your tire temps are likely to climb to at least the 40 degree C mark and then head right back to the cool side the minute you stop riding. This is called heat cycling or a more technical term for it is "Thermal cycling". This can and will over time affect the physical structure of the material such that it will increase the durometer and therefore make the tire harder or less sticky. Does that help? Shawn Link to comment
UberXY Posted September 27, 2007 Share Posted September 27, 2007 When I raced, we were always told by Goodyear to store tires somewhere warm and dark, as prolonged UV was bad for the tires, and getting below freezing wasn't good. But this advice was for tires made from real rubber, whereas street tires are not. My impression is that cold/heat/sun/heat cycles will not affect your tires. Link to comment
Francois_Dumas Posted September 27, 2007 Author Share Posted September 27, 2007 Thanks for the replies ! I keep the bike covered from direct sunshine when not riding it, but can't control the temperature Tom, don't worry, I won't tell Joyce Link to comment
blkvelvt Posted September 27, 2007 Share Posted September 27, 2007 I worked for Bridgestone Motorsports as an engineering tech for aout 6 years following the IMSA, and SCCA circuits. As mentioned in a previous post here, we always scrubbed in (Thermal cycle) as many sets as possible before a race. There are a few reasons. The compounds will cure a bit and this will stabilize the designed grip and wear for a peticular compound. I had 17 different dry compounds to work with on any given day. The optimal grip/wear was to last exactly one tank of fuel. The compounds used more rubber for softer and more grip, and more plastic (generic terms used here) for more wear and durability. Hot days would need harder compounds and cool days would use softer compounds. Each compound was monitored to within 10c degrees. If the running temperature went outside this window, we went up or down a compound to get the most out of a tire set. Too soft and the tires would wear out too fast and too hard would lead to oversteering and understeering and a lot of dirttracking to keep the temperatures up. After a tire gets some time on it, the compound will naturally keep curing from thermal cycling and will require a little more running temperature to get back the grip it had when it was new. Time is the enemy of softer compounds. We shipped the race tires by air freight to get them to the track from Japan because the boats took too long. Winter is a small part of the tire losing grip, sitting and aging are just as bad. Thermal cycling is the worst. Even if it has tread on it, the tire doesn't necessarily have the grip it once had. A tire stored in a hot warehouse for a few years will lose grip before it has been sold. Now that this is clear as mud. Ride it and wear it out and get a new tire at the beginning of the riding season. Store the bike for winter on the old tires and go fresh after winter. Link to comment
Big D Posted September 28, 2007 Share Posted September 28, 2007 The optimal grip/wear was to last exactly one tank of fuel Geez, and I thought I ran through a set of Z6s too fast! D Link to comment
Francois_Dumas Posted September 28, 2007 Author Share Posted September 28, 2007 Heh, good advice except for one thing.. I don't store the bike, I RIDE IT ! Thanks for the interesting information nonetheless ! Link to comment
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