Rear Tire flat spot

[pano]

I put a set of Shinko Tourmaster 230 tires on my 821100e about 1000 miles ago. All was well until just recently I started getting a rear thump.

I thought it was a loose chain but after tightening the chain the thump was still there. I then put the bike up on the centerstand and discovered a flat spot.

There was one time I locked the rear tire in an emergency stop when the tires were just put on. I remember it because I was surprised the rear broke loose.

If I line-lock and smoke the rear tire a bit do you think it will smooth out the flat spot? Anybody do this before?

[Billy Ricks]

Your rotor could be causing it to lock in the same spot every time when you're hard on the brakes. You'd probably feel a little fishtailing though if it did. Could be the tire isn't and never was balanced right.

[pano]

Your rotor could be causing it to lock in the same spot every time when you're hard on the brakes. You'd probably feel a little fishtailing though if it did. Could be the tire isn't and never was balanced right.

The rear brake feels smooth when depressed, I don't feel any pulsing.

I have been using Metzler's and decided to try a cheaper priced tire. The Shinkos look good and seem to ride just fine. I just never had a flat spot develop on a bike before and I can't imagine 1 short skid would create one.

I think i bought them at Bike Bandit - I wonder if I could get a replacement.

[chuckycheese]

Balance

I'd suggest you check out the balance, as Billy suggested. Also, check to see that it was mounted correctly on the rim. A non-concentric (fancy term) tire is essentially 'out of round' because it will cause a high spot.

If it doesn't look like it's in exactly the right spot on the rim, it could certainly cause that probem but it's an 'easy fix'...(deflate and remount.) Also, tire tolerances on expensive tires are really close but on 'cheapies', who knows?

[SqDancerLynn1]

Shinko's are inexpensive. Just buy another tire

[chuckycheese]

Curious?

Shinko's are inexpensive. Just buy another tire

Don't you think it would, at the very least, be worth trying to figure out the problem before buying a new tire??

It's awfully easy to say "buy a new tire" but jeeeeeeeeeeez, what's wrong with, at least, trying to figure it out? After all, what if it's not the tire? Did you even consider that? If that's not it, then you've still got a problem...and 2 new tires.

I think it's worth a little more consideration...but that's just my opinion.

[SqDancerLynn1]

He said it himself !! !!! HE locked up the rear brake shortly after install !!!! He may not have had the tire properly broken in before this happened

[chuckycheese]

Huh?

Locking up the tire one time would cause what he described?? I think not. I was known to lock up my back brake every now and then when I was younger(also just recently when I put on a new rear brake line).....and I've never experienced that phenomenon.

[pano]

If you stare at the tire while the tire is spinning up on the center stand, the rim and the tire look true everywhere except for the flat spot. I don't see anything else out of the ordinary.

Since the tires where put on my riding has been commuting back and forth to work (30 mile RT @ 40 MPH ave)

The flatspot developed after a 250 mile ride and I propably noticed it at about 150 miles into the ride. My chain was a bit loose and thats why I initially thought is was the chain.

Thanks for all the inputs so far.

I will take it to the shop who mounted the tire and see what they think.

[Skateguy50]

Good luck with finding the solution but perhaps a skid could do it.

I never had this issue on my GS and only ever locked up the rear once (you got a nice view of that.... could not decide to follow the group through the yellow or stop, did both lol)

Anyways on my skateboard I used to love doing power slides, basically stopping from going pretty fast by sliding the board sideways and using the wheels to stop you. However depending on the wheel rating some would flatspot very easy creating a highly annoying clacking ride after that. I soon gave up that move as the only solution I had was to buy new wheels.

I suspect the softer the tire the more likely it is for that to happen, I heard my tire has a harder rubber in the middle of the tread and softer compound on the edges for cornering. So what might not flatspot on some tires might on others, but leaving a patch of rubber on the road from a locked up tire will flatspot the tire. The questions is how much and would it be that noticeable.

[DanTheMan]

I put flat spots on two out of my four brand new tires on my pickup once avoiding a herd of deer one night. One good lockup can do it, depends on the tire heat/composition and length of skid. I had to run those tires on the back of the truck, the place I bought them from refused to replace them.

[pano]

My last resort will be to smoke the rear for 10 or 15 seconds or more to see if it wears it even. It has been a long time since I have done that.

[dcil]

Been there, one skid WILL flat spot a tire. Replace it, or do a burn out. The latter is more fun, might as well get some use from the tire instead of throwing it out. Also price wise shinko is less expensive than a metzler, that doesn't make it a peice of crap. Seen them with 12,000 miles on them with some life left to go, and that was on a buddy's crotch rocket.

[themess]

It would be a very soft tread compound or one heck of skid to flat spot it in one skid.

Is it a flat spot or a tread separation? The description you provide could easily be a tread sep. If it is, the tire should be replaced under warranty. And you should not ride it again, as the conditions leading to tread seps can lead to losing the entire tread or to blowouts.

[chuckycheese]

It would be a very soft tread compound or one heck of skid to flat spot it in one skid.
.

Amen! If it happened very easily, I would have done it dozens of times.