Front tire cupping

[Bartman]

I have put 10K miles on my bike and the front tire is getting cupped. I have ordered new tires and will be putting them on next week. My brother said that cupping is normal at that many miles and he was thinking it was braking related.

So my question is to the guys that have the front brace. Do your tires cup or wear smooth? Just wondering if more stability in the front end would prevent this.

Or is there some kind of alignment check that I can do when the new tires go on?

By the way my back tires don't last but about 4K since I like to do the 11 sec quarter every once in a while!

[motoman]

I have put 10K miles on my bike and the front tire is getting cupped. I have ordered new tires and will be putting them on next week. My brother said that cupping is normal at that many miles and he was thinking it was braking related.

So my question is to the guys that have the front brace. Do your tires cup or wear smooth? Just wondering if more stability in the front end would prevent this.

Or is there some kind of alignment check that I can do when the new tires go on?

By the way my back tires don't last but about 4K since I like to do the 11 sec quarter every once in a while!

Bias tires should NOT show cupping, unless low inflation or pulsing front braking from a rotor.
A fork brace WILL stabilize the top of fork tubes, eliminate majority of wear on the fork slider guides, AND transform bikes handling!

I DO run radials on my other ride, and minimal underinflation, REAL heavy front braking, or riding like a hooligan WILL cause BOTH front and rear to cup!.....BTDT, but the high cost of QUALITY tires wiped 'clean' is better well spent on fuel..........and just keep dreamin', WISHING for that 11sec./ 1320ft.....cause it ain't happenin' on these ole' 11's.

[skids]

I had a Continental on front that cupped horribly. Simply changed the tire and after several other tire models, have not had one cup since.

[jetmechmarty]

Fork brace won't fix it. It's an antique, possibly worn out suspension. I rebuilt mine with newsprings and emulators. No more cupping, no matter what tires are on it, even a front on the back.

[Rasputin]

If I had tire cupping I would check the front forks first. Change the fork oil and fully clean it out. Check everything in the forks for proper operation.
Check the steering head bearings and be sure your brakes are equally working. Different oil levels in the forks (or different air pressure) will affect the tires ability to work correctly.

[Bartman]

I changed the fork oil 10k ago when I went through it all. But the book said to replace @ 10 k if I remember correctly. So it is time to do it again. I did check steering head movement the other night and it felt ok.

When I put the new tires on I will go through it again and also rebleed the brakes.

I had planned to put emulators in my keeper bike if I can ever start on it!

Also, it might not run 11s anymore but it feels real good for what it can do!

[trbig]

and just keep dreamin', WISHING for that 11sec./ 1320ft.....cause it ain't happenin' on these ole' 11's.

Why? What's changed between then and now on these motors? Granted, the guy that actually did it back then weighed a buck fifty soaking wet, but the same HP that broke the 11 second barrier is the same HP that's getting to the ground now on the 78-79 models if tuned right.

[Bartman]

I wondered the same thing but figured I would be nice.

I never have timed it but it sure will move when you get on it!

[motoman]

Why? What's changed between then and now on these motors? Granted, the guy that actually did it back then weighed a buck fifty soaking wet, but the same HP that broke the 11 second barrier is the same HP that's getting to the ground now on the 78-79 models if tuned right.

Well, the soakin' wet rider was a professional, 115lbs., could cut a light and make 60ft.times.....unmatched on ANY bike. That was PeeWee Gleason who rode for ALL the Jap. manufacturers doing OFFICIAL straight-line performance numbers, but sure you already knew that. You can also bet there were present a whole herd of Japenese engineers/tuners crawling over and around that scoot getting your last two most important words dialed in, with a whole-lotta pre-testing.
I can just imagine, having seen this scenario decades ago at moto-cross races with factory support riders/bikes.
So, impossible?......not for the well seasoned or professional quarter miler ,but not likely for even a GOOD average rider.
Remember too, those braggin' rights were on the big end of 11sec., .79 IIRC........just under the 'wire'. Throw in a non-professional react time of .50-.85 and a bit slow 60ft. times, those ole' high 11's of the day are gonna be tough to reach, let alone match even at sea-level where it all originally took place.

[trbig]

Understood, but many of the bikes now are making more HP than what the original bikes were. Cody (Maximan) did a lot of work to his and was getting 95 HP to the rear wheel.

You just made it sound as if it was impossible for some reason just due to the bike's age. So just to nitpick a bit.. Many of the bikes are still capable, but finding the right person would be tough. And an 11.79.. or an 11.9998.. is still an 11 second 1/4 mile and gets bragging rights.

[BA80]

Wanna race?

[BA80]

BTW......my front tire cupped after 3 years and ? miles. I don't care.

3 years is too many for a tire anyways.

[Bartman]

That is what I figured too.

Plus I learned a long time ago on a 80 Mazda RX7 that putting headers and such on may add a few horses but unless you are at Road Atlanta with a stop watch that you won't be able to tell any difference.

All I can say is that my Standard cranks, runs, gets good mileage and is more than willing.

[motoman]

That is what I figured too.

Plus I learned a long time ago on a 80 Mazda RX7 that putting headers and such on may add a few horses but unless you are at Road Atlanta with a stop watch that you won't be able to tell any difference.

All I can say is that my Standard cranks, runs, gets good mileage and is more than willing.

.....best part,,,,,,paid for and never done.

Tod, no confusion intended. Another consideration making it hard to repeat was it was all done on 'pump' gas, which even then still had more 'bang' and BTU's than todays fuels. You can also bet that initial timing was getting tweaked to fit the ambient temp/humidity levels too. Doubtful anything was left to chance......go big or go home.

So, with that, everthing being equal to then, except the fuel, gonna have to rethink that as the bike also not capable of that anymore either........but hey, it still gives a thrill and surprises many with the now rare occassional throttle twisted tight making redline shifts.

[Radioguylogs]

?

Curious....Anybody reading this post that has timed their 11 at the track?