Weird front tire issue

[Blake]

Hi everyone, I do not really post all that much but have been wondering around the forums for a little over a year now, love this forum!

Anyways.. I have been riding street bikes for about 6 year now and have never seen a front tire do this before and was just wondering what could have caused it. It is kind of hard to explain but when you rub your hand on the tire it has lumps everywhere? Mostly right outside of the center line of the tire. It's not a good feeling in corners either, lol. This is the stock tire as well and I only have 6K miles on it.

Thought I would share, kind of curious to what may have caused it.

 

[bd43]

The deformation is commonly known as "cupping". My front tire is starting to show some cupping but I have over 18,000 km's on them and will probably change them at the end of this season.

Here is a blurb on cupping from the Dunlop website...

Frequently Asked Questions About Dunlop Tires

 

[Motogiro]

I had a Bridgestone BT-020 that did that. It was the original tire. Never had as bad a cupping problem as with that tire.

 

[REO Scorpio]

My stock Bridgestone did that as well, and I noticed it at 6K, too. When I got the PR2's on, the front end felt soooo much smoother.

Scorpio


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[RJ2112]

Hi everyone, I do not really post all that much but have been wondering around the forums for a little over a year now, love this forum!

Anyways.. I have been riding street bikes for about 6 year now and have never seen a front tire do this before and was just wondering what could have caused it. It is kind of hard to explain but when you rub your hand on the tire it has lumps everywhere? Mostly right outside of the center line of the tire. It's not a good feeling in corners either, lol. This is the stock tire as well and I only have 6K miles on it.

Thought I would share, kind of curious to what may have caused it.

Cupping happens when the tire bounces off the pavement. This is either due to the fork's action being too stiff, or too soft... or the tire being maintained with too low tire pressure for a long period of time.

Some tires do this more than others.

 

[deeptekkie]

My (front) stock Bridgestone tends to do this (to a tiny degree) if I do a lot of straightline riding, (ie; interstates). When I push the turns and/or do a lot of curvy roads it seems to vanish. These tires are EXTREMELY sensitive to tire pressure as others have pointed out.
While my back one is not as nearly as sensitive as my front one - If my front tire pressure is off 2 psi I can tell it when I ride! I'm betting either the pressure is slightly low or you do a lot of straight roads. (My 2 cents worth : )

 

[iSteve]

I think cupping is caused by braking. When you brake, the rubber wears down "obviously". Tires with groves across the tire face will wear unevenly as the rubber to the front of the grove gets scuffed more. Just take a pencil eraser and push it across a rough surface and you will see the front wears more.

My 020 did this, started noticing it a 4000 miles got rid of them a 6000 miles. I have 5000 miles on my 023's and no cupping on the front yet.

 

[CCHOUSEKY]

I had a Bridgestone BT-020 that did that. It was the original tire. Never had as bad a cupping problem as with that tire.

I had the exact same experience with the 020. Of course, I got 10k miles out of those tires, so I really wasn't complaining...lol.

I've got 3-4k on the 023's now and not a hint of cupping. But, admittedly, I'm much more conscious of my pressures now than I was the first year I had the bike (I check it before each ride). This seems to help alleviate the problem somewhat as well as building good habits that you should have.

 

[Blake]

I am sort of a tire pressure freak. I can tell when it is off by only a couple, I do a lot of straight line riding though so this is probably the issue. Not maney curvy roads in central IL

 

[FinalImpact]

This is just an observation but looking at tires which are ran at low pressure also has these attributes: each of the individual lugs show small cracks all the way around them from excessive flex damaged. So take a close look at that tire for cracks. Also when riding keep the tire temperature in mind. Tires that are running hot usually do so because they're under-inflated for the load imposed and continuous flexing builds heat.

There is no one pressure that works for everyone as it must be determined by the load on that tire. The manufactures give us a guide to get us started. Now add in riding style and it adds another variable.

In short: the higher the GVR (gross vehicle weight) the higher the recommended pressure should be adjusted too within the limits of the tires pressure range.