Jump to content
Speed

Rear tire wear pattern

Recommended Posts

At NCM, Todd noticed this 'scalloping' or wavy pattern on the edge of my rear tire, on both sides. I never noticed it before and when I brought it up to Eric (Velocity Calibrations) and James (GGR), both did not seem too concerned.

I checked rebound damping and it was 2 clicks from full stiff, so I don't think that's it. The bike was not acting weird, the rear end was not overly unpredictable...etc. It did slide when I pushed it, but I knew why, and the tire was tearing like Todd's tire, but not as bad (because I'm not as fast).

The scallop is 1/8 to 1/2 inch at most, in waves on the very edge of the tire. I've tried to Google it, but it goes to cupping and scalloping that is a lot more defined at more in the meat of the tire and not on the very edge.

Would wheel alignment create that? I guess it could be the swingarm (bent)?

Then, I found this. I use the marks on the sides to align the axle, but I guess those can be wrong. So, I ordered this to help.

Any other ideas would be appreciate it. Thanks.

Share this post


Link to post
Share on other sites

I don't think it would have been alignment issues, but who knows? Did we get any pictures of it or can you still see it and get a picture of it?

Share this post


Link to post
Share on other sites

I can't help but wonder if it is just something in the way the tire is made?

Share this post


Link to post
Share on other sites

It could be, but wouldn't you think they make all their tires in a similar way?

I may be able to still get a picture, but the one you posted was very close. I just had some areas where it was less and some where it was like that.

Share this post


Link to post
Share on other sites

One comment suggested rubbing on the swingarm (or hugger, or some other part). Did you check that? Another comment said it was something to do with Pirelli's molds, but I haven't seen it before on the ones I've run, but I've never run an SP.

Share this post


Link to post
Share on other sites

It almost looks like its rubbing on something like the swingarm to me judging by the way the ripples face in that picture.

 

Have you checked for tire clearance around those areas keeping in mind that tires can deform significantly under throttle and braking? Ideally you could take off the wheel and look for any evidence of rubbing on the swingarm itself.

 

 

 

 

And the article I linked sort of adresses it: "Is the affected area uniform in width? – Have a look at the thickness of the tear. If you notice that the width of the tear is not uniform and changes considerably as you follow it around the tyre, then this is a good indicator that something is wrong with the suspension, usually rebound being out of adjustment."

 

Still you're right that it doesnt appear to be exactly the same thing.

 

 

 

 

How about wheel balance?

Share this post


Link to post
Share on other sites

Actually, in this one picture from the other guy it does appear that it's very close to the swingarm if not touching:

 

qobzndK.jpg

Share this post


Link to post
Share on other sites

Ha, beat you to it (on the rubbing swingarm part)! :) If it is I would expect a couple of nice shiny patches on the inside of the swingarm. :)

Share this post


Link to post
Share on other sites

Ha, beat you to it (on the rubbing swingarm part)! :) If it is I would expect a couple of nice shiny patches on the inside of the swingarm. :)

 

Damn, what do you win if that's what the problem is?

Share this post


Link to post
Share on other sites

I free tooth extraction? Oh wait, I don't think he does that, but I bet he could. Hell I guess I could too as far as that goes. :)

Share this post


Link to post
Share on other sites

I free tooth extraction? Oh wait, I don't think he does that, but I bet he could. Hell I guess I could too as far as that goes. :)

 

 

  • Upvote 1

Share this post


Link to post
Share on other sites

I free tooth extraction? Oh wait, I don't think he does that, but I bet he could. Hell I guess I could too as far as that goes. :)

Yes I do! But hopefully you don't need any.

Rubbing sounds like a possibility. I will check tomorrow night (not there tonight). That would be such an easy answer.

Share this post


Link to post
Share on other sites

Actually, in this one picture from the other guy it does appear that it's very close to the swingarm if not touching:

 

qobzndK.jpg

Posted in your thread :) but actually the first picture you found in the other thread also shows it touching the swing arm!

Share this post


Link to post
Share on other sites

I'm not sure touching the swing arm is an easy answer or at least not an easy solution ? I guess that could be alignment and I know Terry don't go just by the marks.

Share this post


Link to post
Share on other sites

The marks were on both sides so it would have been touching on both sides (if that is what caused the marks). In that case it would be a simple case of a tire being too wide for the swingarm. I'm wondering if the Pirelli SP is wider than other tires. Not all 190s are the same width. A 190 can be anywhere between 185 and 195mm wide.

Share this post


Link to post
Share on other sites

It could be, but wouldn't you think they make all their tires in a similar way?

I may be able to still get a picture, but the one you posted was very close. I just had some areas where it was less and some where it was like that.

I read some time ago somwhere that Pirelli is more automated and more precise then most others making THIER tires very constant from one to anouther .

Share this post


Link to post
Share on other sites

The marks were on both sides so it would have been touching on both sides (if that is what caused the marks). In that case it would be a simple case of a tire being too wide for the swingarm. I'm wondering if the Pirelli SP is wider than other tires. Not all 190s are the same width. A 190 can be anywhere between 185 and 195mm wide.

Oops missed the both sides part.

Share this post


Link to post
Share on other sites

I know a lot of us only check cold pressure and since SC and SP tires can start out as low as 22-24 psi maybe they are not getting up to the recomended pressure (more like 28) mostly and Josters tire deformation is the answer ?

Share this post


Link to post
Share on other sites

We can speculate all we want but we won't know until he takes off his wheel and just looks at his swingarm. If it is in fact rubbing it will be very very clear once he looks.

Share this post


Link to post
Share on other sites

Yup but speed has lots of speed especially at the track and since he has a dedicated track bike it's time for slicks and tire warmers.

 

At least that's my advice.

Share this post


Link to post
Share on other sites

That's true. I won't get to do that till tomorrow or Friday at the earliest.

Edit: The response was Joester's comment. I almost bid on a set of slicks but was advised to get something better if I decide to go that route. I'm just lazy and I don't want to put the warmers on every time :)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...