Tire cupping

[chefkev121]

Ok so I noticed that my tire is wearing really bad on one side it's a E3 Dunlop with 15000 miles on it and I have fairly new brakes on the bike also my forks were rebuilt about 7500 miles ago I run 42 psi in the tire. Is this normal wear for a Dunlop I know they tend to cup.

[virgilmobile]

Dunlop E3 front and rear.All pressures kept up.7k or so.
Both have scalloping on the left sides..
Not as obvious as yours but there and buzzing in a left curve.
I'm suprised you got 15k on them.10's about my limit.
I might try a Avon venoms next time along with the Dyna beads for balancing.

[chefkev121]

I'm glad to see I'm not alone in this problem. I have a austone ct on the rear with 10000 on it so far it looks brand new I think I'll go with Michelin or a bridge stone I'll need to do more research but the way my tire looks now I better research fast. Does any one have any suggestions on which ct works the best on a. Front? Where can I get dyna beads and how much do they cost?

[deepsix777]

you can the beads from cyclemax.com for 27.00 enough to do 2 tires

[Phavas]

Either you only go around left handers or your forks are bent.
I used to get this on my BMW's the forks of which are notorious for going out of alignment if you hop a curb or catch a pothole.
The clue you gave me is the "rebuilt forks" line. If your seals were leaking it could be due to a slightly bent fork tube.
You can check them with a pane of glass (4mm) held against the tubes with the front fender off. If you can rock it corner to corner in any direction, one of the tubes is out of true. The good news is that they can be retrued - at least to one another - by rotating them in their tree clamps until the rocking stops.

As an aside, if the front is out of alignment - and I'll bet a beer yours is - the rear tire will also show cupping - generally on the same side as you are continually compensating.

Cheers,
Zaphod

[ct1500]

Definitely not a normal tire wear with suspension/alignment issues the likely cause.

[Viking]

The information on a possible bent tube is good info. As far as a CT on the front - I have not heard of this ever being done.

[chefkev121]

Thanks for the information I'll look at the forks and see if they are bent. I meant to rear mc tire for the front wheel

[chefkev121]

I've put 35,000 miles on the bike since last October. This is my second tire and I never had this issue before.the E3 that was on before cupped slightly. Would unevenly wearing brakes cause this possible.? I haven't dropped or laided the bike down. Just a little more information

[ct1500]

Sudden uneven pad wear would more than likely be another symptom that all is not well in the front suspension/wheel assemblies.

[chefkev121]

Sudden uneven pad wear would more than likely be another symptom that all is not well in the front suspension/wheel assemblies.

I was just asking if the pads were wearing unevenly could that be a cause. Not suggesting mine are. Persay

[mrtwowheel]

At 15,000 miles I would think that you would have uneven wear on any tire whatever the conditions, because motorcycle tires do not wear evenly. Cupping is normal tire wear on a motorcycle. Looks like you got good use from that tire and it is time for another one.

Scott

[chefkev121]

Thanks. My thoughts exactly

[Phavas]

No, un-even pad wear won't twist your forks but, I'll bet whoever put your forks back together after changing the seals didn't put the fork tubes back in the same position and didn't do the nose-against-the-wall-bounce-everything-into-place ritual to seat them before he tightened them. As a simple test: loosen your front axle retaining bolts. If everything is lined up the axle should just slide out.
If it binds you've found your problem: its out of alignment.

Slacken the axle keepers and retaining bolt, loosen the upper and lower banjos on the triple trees and the fender,
Rythmically rap the forks (a rap is between a tap and a whack - not a Yo Mama) with a rubber mallet.
Then with the forks against a wall, bounce the hell out of it for a few minutes. Nip up the lower banjos first, then the uppers, the fender then the axle keepers, lastly the retaining bolt.

If your forks seals aren't leaking, this may straighten things out a little without doing the pane of glass test, as well as get your forks dampening better.

Worth a try.

Cheers,
Zaphod

[HawkeyeGL1200]

I'm wondering how much "stuff" you have in your bags and if one is loaded with more than the other. I had a fairly severe pull to the left on my 1100. I looked at all manner of things in search of a solution. As it turns out, I had a bunch of accumulated (tools mostly) in the left bag, and when I cleaned the bags out, the bike rode straight as an arrow again.

I'm not saying that's the cause of the cupping... From what I've read about tire wear, cupping is inevitable based on how tires work. I thought my rear tire was smooth as a baby's behind until I got down on the ground and looked at it really hard, at which time I could see the beginning signs of cupping on it as well. Apparently the cupping always starts on the rear side of the raised area on the front side of any grooving in the tire due to compression and slipping of the rubber against the road. Slower take offs can limit the rate at which cupping is seen in a tire, but can't eliminate it. I wish I could say I understand tires better than I do, but I can't. I keep a close watch on them, make sure the pressure is where I want it and change regularly to make sure I'm safe.

Please let us know if you figure out what is causing that.

[everready]

That's a front tire.42 pounds of air is way too much. 36 pounds is about right.

[chefkev121]

I run 44 in the austone and 42 in E3. I thought under pressure would cause cupping more then over pressure

[everready]

That tire is worn different than normal under pressure cupping.

[chefkev121]

Does anyone run. DD? if so which tire do you recommend for the front.

[Phavas]

I run Darkside on my side-car rig but I have specially built wheels and suspension.
I'm running 15 inch all round. If I get cupping it's because the chair is out of alignment
(operative word).

Cheers,
Zaphod

[joeincalif]

I think 42 is to high for an E3 front. 38 is about the norm.
here is a serious case of cupping

[redial]

Very amusing photo!! Have you any mug shots?

[chefkev121]

I think 42 is to high for an E3 front. 38 is about the norm.
here is a serious case of cupping

Now that is funny