Hi all,

I have a flat spot all the way around on my rear tire. I know that it is a natural wear on tire. I'm planning on racing with this tire. My question is, should I keep it or replace it? The flat spot isn't obvious with naked eyes until you feel it with your hand. The width of the spot probably 1/8 - 1/4". No inner layer comes up, still plenty of rubber left. The tire is GP4000s. Mileage: 1000-1500.




Thanks in advance!

That's normal wear. The flat spot's width represents the width of the contact patch when you're riding straight. The tire deflects from round to flat where it meets the pavement, and that's how they wear.

The only way to get rid of it is to ride twisty mountain roads on a regular basis. That'll have the bike banked to either side more of the time, and keep the crown round.

Otherwise, stop looking so close, and ride the bike.

Ride it until the cord shows or the number of flats goes up.

Yes, this is normal wear, especially on the rear tire. Some people will let the rubber wear all the way down to the cords before they replace the tire (the rubber is completely worn off in areas). Most people will replace the tire sooner than that. Tire performance does degrade when the rubber gets very thin (less grip, less cushioning, more flat tires), so you need to do your own performance vs money analysis. Some tires have wear indicators (grooves in the rubber that disappear as the rubber wears down) to help you make the decision, but these are really just suggestions. Replacing a tire only takes a few minutes, if you buy the new tire before you need it.

Flat spot? Panic Braking?

i run 'em down to the cords (with tire liners) as others have noted. IME, they start to look just like that before the cords start showing. if you remove one and flex it along the wear line, you can tell when it's about done. it will flex real, real, easy. easier than the sidewall in many cases.

Thanks for the responses. I'm concern with the cornering performance when I'm racing. With that flat spot, I would imagine the transition isn't so much. I maybe thinking too much. But I don't want to take chances as I already crashed badly once (not mechanic issue). I guess riding on Houston's long flat straight roads takes its toll.

Most economical and sensible solution is to discard the more worn rear tire, move the less worn front to the rear and buy one new tire for the front. That way your steering is dependent upon a new tire and you still get good usage from them both. Assuming of course you want to continue with the same tires. Bike fashion does not allow the mixing of brands and models.

Robert

GP4000s have little holes in the tread in a few places. When these little holes are gone from wear, that means the tire is officially worn out. In practice you can get some more miles out of them.

No, normal wear. Look at the picture.

Ride till the cords show. In my experience, tires flat no more frequently when worn then when new. My theory is that thick tread rubber traps and holds shards and allows them to work through the cords and tube over many rotations whereas the thin rubber of worn tires is less likely to trap shards in the first place.

Anyway, note my sig.

I'm with most of the people here in that I ride my tires till the threads show which means having flat treads for awhile. I wouldn't do that for racing though as the flat spot can cause a little squirminess when rolling into a turn and possibly losing traction in a hard corner. With the likelihood of having a pack of rabid racers behind you any slip or fall can be a disaster. Do yourself and your fellow racers right by using reasonably fresh tires.

Back tires start showing a squared off tread after just a few hundred miles. It's due to the extra force applied to the tire by pedaling. But I think that as the squared off part gets wider, it takes a lot longer to get worn down to the cords under the rubber tread. I get at least 3500 miles from my rear GP4000.

I cut an old GP4000 in half to see how much tread was left when the holes were worn off. It's paper thin. So it's still rideable, but it won't be too much longer until the cords show through the rubber tread.

The wear indicators are two pits about an inch apart:

Doing it this way you'll constantly be rotating a tire, I just put the new tire in the back. Usually 2-3 rears/1 front completely worn

Race on New tires problem solved..

I don't get it. You have the bike and I presume are riding it. Do you notice a handling problem? Of so, replace the tire. If not, why are you looking for a problem you don't have.

Obviously, the OP has never ridden enough to wear a tire slightly. Safety first.

But he has the tire and should know how it handles. It's not suddenly going to change when he races. I can understand being worried about a failure on a cut tire, but not a so-called handling issue. Tire handling doesn't suddenly or magically change overnight.

Yeah, I used to do that too until I got reamed out here. Apparently it is inportant to have a fresh tire on the front.

Only to some AR types who post on forums and try to make bicycling more complicated than necessary.

If you want to move fronts to the rear as rears as the rear wears, that's OK and might ensure that your tires wear out before UV and ozone age them out. OTOH, many old time and experienced riders never rotate tires, and don't remove them at all once mounted unless it's necessary such as to fix a flat.

Likewise, many use different tires in the front and rear, making rotating impractical.

Whatever woks for you is fine, there's no hard rule or better "correct" way in this regard.

Yes. I started riding 3 years ago. This is my second year racing. That tire is on my race wheel. About 1 year old.

I didn't try to make this a big deal. My intention was to get some opinions about it. I've never completely worn a tire out as I'm still fairly a noob especially in racing scene.

Maybe I worried too much. But at the end of the day, safety first. At least in my book.

Nothing wrong with safety first, but there's no safety issue here. OTOH, it's your bike, your money and your decision.

Thanks for the reference pic.