Cupping Rear tire

Hi,
I am new to the site and new to BMW motorcycles.
I have owned bikes for a long time H.D. and Yamaha cruisers mostly.
I now have a 2013 R1200RT great bike. I have put 5k of the 26k miles that are on the bike.
The tires are Michelin radial pilot road GT on the front and Michelin radial Pilot Road 3 on the back.
The rear tire is cupping on both sides, but not the front tire. The man I bought it from said the tires had about 5k mile on them when I bought the bike.
I keep a eye on the air PSI. Run them a little lower when riding alone and pump it up when riding with my honey.
Is the rear tire cupping normal for a RT?
How many miles should I get out of a set of Michelin radials?

Thanks
Aride

aride said:

Hi,
I am new to the site and new to BMW motorcycles.
I have owned bikes for a long time H.D. and Yamaha cruisers mostly.
I now have a 2013 R1200RT great bike. I have put 5k of the 26k miles that are on the bike.
The tires are Michelin radial pilot road GT on the front and Michelin radial Pilot Road 3 on the back.
The rear tire is cupping on both sides, but not the front tire. The man I bought it from said the tires had about 5k mile on them when I bought the bike.
I keep a eye on the air PSI. Run them a little lower when riding alone and pump it up when riding with my honey.
Is the rear tire cupping normal for a RT?
How many miles should I get out of a set of Michelin radials?

Thanks
Aride

Click to expand...

Hello Aride, my story is a little opposite to yours. I had Michelin PR4GT on the front and rear for 2 sets including the original on my '16 RT and each set went 10-11K miles for me. The rear cupped a little but the front tire cupped badly after less than 2K miles run at the stock pressure of 36.x psi. Rear was at the stock pressure of 42.x as well. Increasing front tire PSI to 40 slowed down the rate of cupping worsening. The next set of PR4GT I ran at 40psi on the front tire from the start and that tire had minimal cupping during its service life. I'm trying Perelli Angle GT 'A' spec now and I believe they are a better tire in terms of resistance to squaring, turn-in is lighter, tracking is at least as good, and they don't need to be overinflated as much to not cup. I run them at 38 psi just for the lighter turn in.

aride said:

Is the rear tire cupping normal for a RT?
How many miles should I get out of a set of Michelin radials?

Thanks
Aride

Click to expand...

Welcome to the forum.
I have not heard of cupping rear tires, it's normally the front that cups.
What pressure are you running?

As for mileage, you will get all kinds of replies. It depends on how you ride and where you ride.

Thanks for the reply.

When riding alone with little gear to work on mostly straight roads I run 32 in the front and 36 in the rear.
If I am riding two up with my wife, gear, or riding alone in north Ga mountains I run 36 in the front and 42 in the rear.
I check the bike over every time i ride.
Cupping the rear and not the front on a motorcycle is new to me.

Thanks
ARide

I run PR4GT front and rear and this set have tried 40 front and 42 rear whether loaded or not. At 10k right now after a 21 day tour out west in June with mileage left on both and no cupping.

mikegalbicka said:

I run PR4GT front and rear and this set have tried 40 front and 42 rear whether loaded or not. At 10k right now after a 21 day tour out west in June with mileage left on both and no cupping.

Click to expand...

I have run several sets of tires at this configuration until close to the threads and never have observed rear cupping but do see it most times on the front which makes replacement a must as riding corners gets 'chunky' and just not fun. Dunno what would cause a rear cupping situation.

aride said:

Thanks for the reply.

When riding alone with little gear to work on mostly straight roads I run 32 in the front and 36 in the rear.
If I am riding two up with my wife, gear, or riding alone in north Ga mountains I run 36 in the front and 42 in the rear.

Click to expand...

Those pressures are too low. Note that those in this thread who are running 38-40 front and 42 minimum rear are not reporting cupping, especially on the rear. I had a tire engineer from a certain tire company tell me at a rally that pressures for the PR4 should *start* at or near the max listed on the sidewall. OTR, of course.

I run 40 front, 42 rear solo and add 1-2lbs when adding camping gear; I never ride 2-up.

Best,
DG

I experienced what I'd consider ridging on Pilot Road 3 rear tires on my R1200R's. It appears as a lumpy raised ridge at about the transition from hard center rubber to softer outer edge rubber. It's about 1.25" out from the center of the tread on each side. It got bad enough on some that I took to using a belt sander to try to grind off the high spots. There is some evidence of cupping in the ridge, one edge of the block of rubber being higher than the adjoining edge. That's generally due to the tire tread pattern and how it distorts under load. Low pressure may make it worse - but higher pressure is no assurance it won't happen.

What fixed it was the Pilot Road 4 tires. No more ridging. There is very little unevenness on my current (12,000 mile rear) despite it being flatted in the center thanks to Oklahoma and Kansas. There is still tread in the center above the wear bars - but the shape changes the handling enough that I'm putting new rubber on it front and back next week (once again - Pilot Road 4's - front and back.) The "GT" may have slightly different characteristics since it's a harder tire to begin with - meant to hold up under the weight of the RT..

The track coach I have used in the past has always had me lower my pressure slightly when we are training.
For street riding I now raise the pressure considerably which seems to improve the wear patterns considerably as mentioned already. On the street I ride in a manner not requiring that additional traction (God Willing).

I guess it is all a compromise from what I have learnt.

Lowering the pressure on the GS for off road requires putting the pressure back up when returning to pavement. I prematurely wore out an Anakee front tire by not airing it back up.