Author Topic: cupping front tire...  (Read 3614 times)

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Online DUMB A$$

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cupping front tire...
« on: June 30, 2011, 04:30:31 pm »
On my second FRONT tire now and like the first one it too is now showing signs of cupping. Is this normal for this bike or is something out of whack on mine?

Offline Scott_Kaplan_ME

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Re: cupping front tire...
« Reply #1 on: June 30, 2011, 04:39:44 pm »
What brand/model tire? How many miles before cupping/replacement? Do you keep an eye on tire pressure?

Scott

Offline Sparkie

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Re: cupping front tire...
« Reply #2 on: June 30, 2011, 04:53:24 pm »
On my second FRONT tire now and like the first one it too is now showing signs of cupping. Is this normal for this bike or is something out of whack on mine?
Air pressure issue. You must be running less than 39 psi. Mark
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Offline Greg

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Re: cupping front tire...
« Reply #3 on: June 30, 2011, 04:58:10 pm »
My tire was cupped when i bought the bike, not bad, but cupped.  It had 30psi in it.  I now have 40psi in it.  Will the cupping eventually go away??? or are the cups like ski moguls and just keep getting bigger. 

It's noisy in the corners (read: how to tell you have a real quiet motorcycle, when you can hear the front tire in a turn). 
Greg Means
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Re: cupping front tire...
« Reply #4 on: June 30, 2011, 05:09:37 pm »
running about 6 psi below max on tire rating. (would have to go and read the label if you need to know what it is)

I too can hear the tire growling in turns, thought it might be a wheel bearing, but no play or sound from bearing. That is when I noticed the cupping.

Had a factory Dunlop on the bike when I bought it and I went to an Avon when I changed it out. Not sure how many miles, maybe 5k plus.


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Re: cupping front tire...
« Reply #5 on: July 08, 2011, 03:09:17 pm »
Looks like this is the post-em and forget-em page....

Offline GF-in-CA

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Re: cupping front tire...
« Reply #6 on: July 08, 2011, 03:22:47 pm »
You haven't stated what pressure you are running, but if it is less than 40 psi, then that is probably your main issue.  Even with proper tire pressures, it is very common to have some cupping on the front, especially if you do a lot of hard braking.  Unfortunately, the cupping won't even out as the tire wears, unless you "wear" the tire with a belt sander  >:D
Gary F.

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Central Valley California

Offline Greg

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Re: cupping front tire...
« Reply #7 on: July 08, 2011, 04:28:07 pm »
My front doesn't have that much tread left, and i've already planned it's replacement to be here soon.  Avon's will be ordered in a week or so. 

 :P Goodbye k701/k700 dunlops...
Greg Means
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Re: cupping front tire...
« Reply #8 on: July 08, 2011, 11:12:10 pm »
So, is tire pressure the only thing that can cause cupping?
Tire says 42, I was told to run 6 psi lower, so I am at 36 psi. Should I increase psi? Might that correct cupping?

Offline GF-in-CA

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Re: cupping front tire...
« Reply #9 on: July 08, 2011, 11:27:13 pm »
It can be a major factor, especially as low as you have it.  Who recommended that pressure? I would try running between 40 and 42 on your next tire.  HTH,
Gary F.

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Central Valley California

Offline jathkajoe

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Re: cupping front tire...
« Reply #10 on: July 09, 2011, 03:03:26 am »
An old motorcycle road racer I know told me cupping can also be caused by aggressive late braking.  I think he's right.  I've run tires at 40 PSI front and still had them cup.  It doesn't bother me that they cup.  It just tells me it's getting time to replace the front tire.

Ride safe, all

Joe

Offline Greg

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Re: cupping front tire...
« Reply #11 on: July 09, 2011, 04:08:41 am »
...it is very common to have some cupping on the front, especially if you do a lot of hard braking. 

Ya know, i've heard that somewhere else too.

 :))

I suspect mine was from a low pressure situation, as the gentleman i bought my Connie from doesn't appear to be the late braker style.
Greg Means
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92 Candy Red Aspencade
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Offline coffee_brake

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Re: cupping front tire...
« Reply #12 on: July 09, 2011, 05:46:06 am »

I don't think too low pressure causes cupping. This because I've run at least 40 (and usually 45) on my fronts for years. In every case, the tire has cupped badly. The stocker, the Avon, the Michelin, and now the oddball touring Dunlop that was an emergency replacement for the dual-density compound Michelin (that failed down to the carcass with less than 4k on it....)

I can't find a way around the cupping. I must assume that it's my braking habits that cause it. The current Dunlop looks like a new tire but at the treads but it is so badly cupped that the bike goes into a tank-slapper at any speed below 60 mph. And it really, really hurts to ride as it vibrates the front end so much. I hate to do it, but I'm going to throw away a very new tire because of the cupping. Yet I do most of my riding in urban commuting and riding about town, so there's a LOT of braking in any of my normal rides.

I thought over 70% of a bike's braking power was in the front end. Therefore since I was a newbie I have braked harder on the front than the back.
But these tank-slapping cupped tires are just as dangerous IMO...

Heck I just got my "resuced" VFR and have put only 4k on the new tire, it's already started cupping. I'm pretty disgusted with the whole thing but...I think it's insane to purposely get out of the habit of braking more with the front.....
Jenn in "Chaahlston, y'all...."

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Re: cupping front tire...
« Reply #13 on: July 09, 2011, 02:32:42 pm »
Most of my braking is with the rear and downshifting. I do use the front brake at the last few feet and then to hold me in place, but not a lot of front end diving for me.
   I had wondered about too soft a shock in the front, I.E. fluid old, springs worn, not as firm as they should be letting the front tire bounce a bit more than it should causing the tire not to be enguaged with the ground as firmly as it should. All just a guess as to a cause.

Tim

Offline Mike

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Re: cupping front tire...
« Reply #14 on: July 10, 2011, 11:51:05 pm »
My (new to me) 2000 has cupping front and rear.An earlier post in another Topic asked where the 36 psi front recommendation came from.....the service,owners,and supplement manuals.I just checked all of them and the Kawasaki advises 36 front and 41 rear.If I am understanding the members suggestions they are saying the factory specs are too low.On my previous ZRX 1200 I used the front brake HEAVILY and put 14,800 miles on it in 2 years.I never had a cupping problem ever using the factory specs.I am starting to wonder if this is a connie shaft drive issue.Since a shaft drive tries to climb the rear suspension I guess theoretically it could be possible that it might cause cupping of the tires on certain machines,depending on individual quality control,machine specific clearance and tolerance issues.I have read a few posts that have said that they didn't have any cupping problems period,on machines with 75K plus.So,finally,since Kawasaki has produced a LOT of connies it isn't beyond the realm of possibility that this is a connie issue.Some have it,some don't,or so it seems anyway.Mine has it in spades with 12,800 on the clock.It needs new tires BADLY also.Thx for your time.
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Offline Robert_Elliott_GA

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Re: cupping front tire...
« Reply #15 on: July 11, 2011, 01:55:49 am »
The Dunflop K700/K701 combo that is stock really seams to cup.  Changing to an aftermarket tire means the original manuals pressure recommendations are not completely applicable.  On the Avon's, I have yet to cup a rear and after tightening up my stem bearings and making sure I am running above 40psi on the front, I haven't had any cupping up front in over 20k miles.
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Offline Hi Tower

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Re: cupping front tire...
« Reply #16 on: July 11, 2011, 05:22:26 am »
Looks like this is the post-em and forget-em page....

Are you running the 110/80-18 or the 120/70-18 ??