Tyre age

[trix]

Like many of you on here I now have a fairly substantial number of bikes. But I've only recently recognised a slight downside with this; each bike does very low mileage. Some may not get any more than a short spin around the block now and again, maybe less than 200 miles a year. The result is that I'm ending up with tyres that are essentially unused but getting very old; like maybe 10yrs but barely worn. I have a kr1s that I got about 6yrs ago and I haven't really ridden it at all because I haven't got around to fixing a few problems with it. It's got "brand new" Bridgestones that are now over 12yrs old. It seems crazy to bin them for new ones that won't be used very much either. To you guys with multiple bikes; what's your policy on changing tyres???

[ixe13]

Sun exposure and UV are the real killer , if your bikes are always stored inside and your tires don't show any cracks and the rubber is still soft , I don't see any concern .

[Speed Freak]

I guess you dont use the bikes if it rains?!
If it's warm and dry old tires are not too bad.
I would replace them as soon as they get visible cracks in the rubber or after 20 years...

[silverstrom]

As mentioned above, UV is a killer. My rule is that as long as there are no cracks and my fingernail test shows the rubber to still be soft I keep using the rubber. When you see those tiny sidewall cracks appear and the rubber hardens it's time for new rubber.

Your Millar bike looks very familiar, and unique. Was it recently in a UK magazine?

[trix]

This seems sensible advice.the bikes are kept in a garage that's relatively cool all year round and i keep the blinds closed. I bought new michelin power rs tyres for my aprilia last week and when i got home i noticed the rear is already 3yrs old. Michelin recommend a shelf life of 5 years so if correctly stored a 5 yr old tyre is still considered new by Michelin. Then i started looking at some of the other manufacturer's advice. Continental says;

"Continental is not aware of any technical data to support the removal of service for tires past a specific age. But the same principle applies to the tires of your vehicle as it does for any other part of your car – age matters. Together with other members of the tire and automotive industries, Continental advises that all tires (including spare tires) made more than ten years ago should be removed from service and replaced with new tires."

I put pictures of the millar bike on this forum about a month ago, thats probably where you've seen it!

[AHAMAYfrank]

Automobile related comment. Just an FYI

Just last week I had new tires and wheels put on my 1965 Ranchero. We overestimated the amount of room we had available and the in stock tires rubbed while turning.

To get home, they put my original rims with new tires back on. My old tires were over ten years old and I was told they couldn't legally put them back on. Lots of tread, no cracks, complient tire with a good ride. In the bin.

Frank S.

[2manyprjx]

I'm not proud of this but I'm still riding on a set of 30 year old Metzler Comp K's on my SRX. They still look great but I know they're past their prime. Then front still handles hard braking without misbehaving but I've felt the rear slide a few times accelerating around a corner so I don't push them. Like all my bikes, it only sees a short local ride or to an occasional bike night. I do plan on replacing them but new bike projects keep getting in the way.....

[MK]

Once upon a time I bought a cheap Dunlop KR108 slick.
It was cheap because the DOT number said it was 12 years old. In addition it was a medium or soft compound and I needed a hard one.
The tire was unused so I thought I could give it a try for 30 Euros (regular price is something slightly above 200!).
It was the best deal ever! Worked like a charm.

For used race tires it would have been different. Using them triggers a vulcanisation process that is not reversible. Parts of the compound then dissolve through the surface and form this well known blueish color on the tire surface.
The process is time dependent, so storing used slicks is just for the very next seasons and then you can bin them.
(This was explained in a presentation hold by a guy from Michelin racing service)

Now for the road tires.
First you have to distinguish between lets say hypersport stuff like a Bridgestone RS10 and touring stuff like a Metzeler Roadtec 01.
Sport tires are almost 100% rubber/soot based compound. It is similar to race tires, so everything above applies here. (Which means old sport tires decrease rapidly with age and you'll notice it when riding).
Modern touring or touring-sports tires contain silica compounds that greatly enhance durability and wet grip. But along with that people also report decreasing grip with high mileage.
As already pointed out that's a result of UV exposition but also of extended contact with water (for passenger car tires).
So if the surface of the whole tire is free from cracks and you don't notice any sliding whith your normal riding style, it should be ok. But be warned, that it will be tricky in rainy conditions or if you try to go to the grip limits. That'll be significantly lower than with a new tire.