What causes front tire to cups?


CAT3

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#1
Looking over my Busa this morning, I noticed the left/outside tread of the front tire is cupping. WTF?
 

PaNDeM1C

Your Disease.....
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#4
When I changed both tires (very early @2.5k) I noticed my rear tire was way uneven. The right side was higher than the rest...
 

BA BUSA

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#6
(CAT3 @ Sep. 18 2006,22:48) Looking over my Busa this morning, I noticed the left/outside tread of the front tire is cupping.  WTF?
You need to have your suspension adjusted...it is similar to having worn shocks
on the front of your car...in a turn if your front end isn't set properly, the tire is rebounding
off the pavement causing the cupping  
wink.gif
 

LadyHawk

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#7
My Katana front wheel did that... the pressure was too low. I'm better about checking my tires now. Expensive lesson right there.
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8Daytona8

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#10
PSI, longer turns to the left, crown of the road! Where they drive on the other side have more wear on the R-side.PSI the biggest cure though
rock.gif
 

PaceMaster

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#11
Tire tread design has alot to do with it too....My Mich Pilot Sport front is cupped right down the middle.-- seems a Mich Pilot Power wont cup--we'll see soon. Getting very low wear on rear Pilot Power...Hmm sticky enough that it doesn't spin as easy as a harder compound.
 
#12
If either of the front forks is damping the road bumps to a lesser degree than the other, it will actually cause cupping on one side of the front tire. This is because there is still flex in the forks when the one side is weak at damping the road bumps. This flex causes one side of the tire to wear and/or cup before the other. The weak fork causes wear on the other side of the tire, as the weak side is the first fork to retract over every bump causing a slight cocking of the tire and the opposite side to wear.

I sold my 97 YZF1000 (in pristine condition with just under 10,000 miles on its odometer) to my cousin who almost immediately, I later found out, nearly lost it over the top doing a wheelie early into his possession of the bike. My son said he planted it HARD when he came down and he thought it was going to throw my cousin right over the handlebars. Thankfully, and good for him and myself, as he was still making payments on it to me (still owing most of the balance), he managed to stay upright but needless to say, it immediately blew out the right fork seal. Actually, it didn’t blow the seal, it simply forced the round retaining spring off the underside of the seal, which was responsible for applying the uniform wiping pressure on the inside of the seal. It still required fork disassembly and replacement, so I was less than pleased but I took it well considering he defaulted on payments altogether.

He was too afraid to tell me when it happened, but kept on riding the bike anyway. The garage where he was keeping it said they were going to keep the bike, as he owed them money as well. The bike was still in my name however, so I walked into the garage and took the bike and they called the cops, at which point I told them, “When the police show up, YOU will be charged with theft, since you were in illegal possession of MY motorcycle and I have the title and registration with me to prove it!†They put down their phone and said, “Get it out of here!†I replied, “I believe that’s exactly what I was doingâ€, then I chuckled.

It was then that I found out about the oil soaked front brake pads and I could hardly stop using the front brakes as I left their driveway. So I pulled over up the street and that’s when I found the whole right front side soaked with fork oil. It would also try to pull me completely out of a turn in one direction only. My son later told me the whole near death wheelie incident. Upon pulling the forks, there was very little fork oil remaining in the right fork tube.

My cousin only rode it for another 1,000 or so miles in this fork leaking condition in which time, it ruined a perfectly good, previously well wearing front tire. It cupped on the left side very badly and the bike would try to literally pull out of leaned over turns in the one direction only. It handled VERY SCARY and I don’t know how he could even think to drive it that way. It was a challenge just driving it home safely to work on it. He told me he hadn’t noticed any change in handling or braking so I knew he was just trying to cushion the blow.

As soon as I replaced the blown right fork seal, and replaced the fork oil of BOTH forks with the same type and the same amount of fork oil, installed a new tire and new front brake pads, it handled like new once again and it also wore the next new tire evenly as it always had.
 
#14
Well I think it's the way you ride... Hard braking and hard cornering will cause cupping too, despite the tire pressure. This happens on car tires too.
 
#18
(busavas @ Sep. 19 2006,12:03) Well I think it's the way you ride...  Hard braking and hard cornering will cause cupping too, despite the tire pressure.  This happens on car tires too.
BINGO ..HARD BRAKING DOES IT !!EVEN WITH PROPER PSI
 
#19
(mikeo @ Sep. 19 2006,16:35) All front tires will cup. All the reasons covered can accelerate the cupping.
Unfortunately, your statement is 100% incorrect. All front tires do NOT cup. Some do and some don't.

I've had PLENTY of front tires in my 31 years of riding that didn't cup all the way down to below their wear markers. My front Pirelli Diablo Corsas and my Sportec M1's did NOT cup on my Hayabusa, tire after tire. There are a number of reasons why some tires cup and others do not.
 

Gunnybusa

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#20
(Quasar @ Sep. 19 2006,15:29)
(mikeo @ Sep. 19 2006,16:35) All front tires will cup. All the reasons covered can accelerate the cupping.
Unfortunately, your statement is 100% incorrect. All front tires do NOT cup. Some do and some don't.

I've had PLENTY of front tires in my 31 years of riding that didn't cup all the way down to below their wear markers. My front Pirelli Diablo Corsas and my Sportec M1's did NOT cup on my Hayabusa, tire after tire. There are a number of reasons why some tires cup and others do not.
And those reasons would be?
 

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