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Yikes! New Tires --OMG-- Handling Surprise!


Michael B

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Just took my 2011 R1200RT into the BMW dealer for its 12,000 mile maintenance. Got new PR3's installed to replace well worn Z6's (11,902 miles). I knew that new tires came with an oily surface, so I took it easy leaving the dealership, but almost dumped the bike puling out onto the street. The handling was WAY weird! Now, I've been riding for 49 years, bought a bunch of new tires, but never had this happen.

 

Could it have been as simple as the wrong tire pressure? The installing tech told me he put 36 psi in the front and 42 in the rear, the same I always have used. The next day I checked the tires. The front was dead on 36 psi. However, the rear was 35...a full seven pounds low. I don't know if the tech thought he put in 42 but didn't, or if the 111 mile return trip home revealed a slow leak. Good news is that once I pumped the rear tire up to 42, it has maintained pressure.

 

Got any ideas, gentle riders? I've since put on about 100 miles and scrubbed he sidewalls good so twisties are no problem. However, the handling still feels strange compared to the OEM Z6's even when they were new. I can't imagine that changing tire brands would make that much difference. Your thoughts, please.

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Can't speak to PR3s or RTs.

However, I ran Metz Z6s on my K-RS. Switched to PR2s and thought it a great change. The Z6s felt heavy, wanted to run straight and still felt secure. The Michelins felt much different. The bike wanted to turn in. At low speeds this happened quickly and without a lot of effort. It required a different rhythm to the bike. It was a different as night and day. I decided it was one I liked and continued with the PR2s a while longer. A friend just finished a set of PRs on his R12RT PR2 on the back and PR on the front. He went back to Metz Z6 and feels like he has been welcomed back home. They are different tires, different feel. Both good for those that want what they sell. You will have to decide if it is your flavor. In the twisties I thought the PR2s felt better planted, would allow a line change with less effort and allowed easier transitions. The Metz offered better straight line performance. I have since moved to Q2s as my tire of choice.

NCS

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I run 32-34 psi on the front tire (PR3), feels more planted. But it could also be that you need to add more preload to your rear shock.

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Hi:

 

Which end of the bike caused the problem?

 

Metzler reps advised me to bump up the pressures on an RT by 4 lbs to avoid irregular wear (cupping) and the results were good. Tire guys at the track advised me to run very low pressures on the track on an F800 (upper 20's) and again, good advice. So my feeling is that the the BMW pressure specs are a good baseline from which to start experimenting.

 

BTW did the rear wheel cross a paint line when you had the problem? I had an S1000RR with mind boggling traction control, but the rear end will still step out if cornering and accelerating across a paint line on the road.

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I've run PR2's and now PR3's on my 06 RT and I love them (same pressures too). Since you say "twisties are no problem" I assume you mean other times are "weird". The only thing I can think of is, with 11+k miles on the old set you may have seriously flatted the center of the tire. This will make for what feels like a very stable straight line configuration. Going to new "round" tires can make things feel a bit twitchy.

 

The only other thing I can think of is, BMW has a specific procedure when it comes to installing the front wheel in order to insure the axle is properly seated. I'm not sure how you'd check this short of simply repeating the procedure but it might be worth looking into if you really feel things are unsafe. Might also be worth checking the torque for rear wheel bolts and front axle. Good luck.

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Danny caddyshack Noonan

In answer to your question, yes. Even with the same brand or model. When I was riding a KZ1000P all day, 4 days a week, a tire change would make the bike completely different for the first go 'round. I don't notice changes as much anymore but, that is probably because I don't get the seat time in that I did then.

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The only thing I can think of is, with 11+k miles on the old set you may have seriously flatted the center of the tire. This will make for what feels like a very stable straight line configuration. Going to new "round" tires can make things feel a bit twitchy.

 

Agreed. When I rode my RT out to the West coast I had to have new rubber installed in San Fran. I went from a VERY squared off Avon Azarro to brand new round Z6's. The techs were laughing because they had the old tire sitting there next to the counter up on end all by iteslf. Ohio, Indiana, and Nebraska were not kind to the profile. You probably could have rested a glass of water on it with no issues. I just about fell flat on my face when I made the first turn out into traffic. I really had to watch it for the first day till I could get used to having a round tire again.

 

+1 on the PR2's and PR3's. I loved those tires on my RT. Great stick and the best mileage out of anything I tried.

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CoarsegoldKid

Well Michael you went from a square off tire to a rounded profile tire. It will certainly make the bike want to turn-in quicker. Add to that high air pressure and you get power steering. The new rubber should serve you fine sticking to the pavement if the air pressure is set properly. Remember that few people calibrate their air pressure gauges. Especially the shop or me bye the way. So your psi may be different than you think. Stick with one gauge. Monitor the psi and tire wear and performance. Find what works for your setup. Or just ride the beast and smile.

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I'm another fan of the PR2s and now PR3s, so much so that I have a full set on my RT and my Ducati Monster, which is off to the track on Sunday.

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aterry1067

I agree with the tire wear idea. I know you have ridden a long time with several sets of new tires, but once we get used to something and then feel something different, it's arouses our senses; human nature. I have been through 2 PR3's on the front of my 1100rt, and the last one really helped me realize that, as I was in the middle of a long ride. With the old worn tire, I had to push it into a turn, and when it finally fell into the turn, it was a much harder dive than I would have liked. When I had the new tire installed (half-way to NC with a premium price) the bike handled like a new showroom model. It fell into turns on its own, and came out of them just as smooth.

 

I'm also guessing the tech didn't get (or maintain) a full 42psi in the rear, and this probably also led to your discomfort.

 

Only my $0.02. And that's what it's worth.

 

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Thanks everyone for your comments. I think you guys are right about how an old worn tire profile vs. a new "round" one (especially in the front) could significantly effect handling. Being down seven pounds in the rear surely didn't help. But having never had that new tire Yikes! moment before really surprised me. It opened my eyes a lot and tightened other sphincter areas even more.

 

By the way, this is such a good forum for information like this and other bike issues. I rarely miss a day here. Thanks again!

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Just took my 2011 R1200RT into the BMW dealer for its 12,000 mile maintenance. Got new PR3's installed to replace well worn Z6's (11,902 miles). I knew that new tires came with an oily surface, so I took it easy leaving the dealership, but almost dumped the bike puling out onto the street. The handling was WAY weird! Now, I've been riding for 49 years, bought a bunch of new tires, but never had this happen.

 

Could it have been as simple as the wrong tire pressure? The installing tech told me he put 36 psi in the front and 42 in the rear, the same I always have used. The next day I checked the tires. The front was dead on 36 psi. However, the rear was 35...a full seven pounds low. I don't know if the tech thought he put in 42 but didn't, or if the 111 mile return trip home revealed a slow leak. Good news is that once I pumped the rear tire up to 42, it has maintained pressure.

 

Got any ideas, gentle riders? I've since put on about 100 miles and scrubbed he sidewalls good so twisties are no problem. However, the handling still feels strange compared to the OEM Z6's even when they were new. I can't imagine that changing tire brands would make that much difference. Your thoughts, please.

 

I put Z8's on my 2004 RT a couple of months ago and had a nearly identical experience. In my case, I commute every day on the bike round trip of about 55 miles on multi lane roads, and when my Z6's needed replacement they were seriously flat in the middle of the tire.Putting nicely rounded new tires on the bike madeit feel like a sport bike the way it dropped suddenly into a turn - or at least, that is how it felt.

 

I took me a couple of hundred miles to feel fully secure entering turns, but once I got used to it I want new tires ALL THE TIME!!!!

 

 

Dermot

 

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Peter Parts

There is no correct tire pressure. For a given tire, it is always a trade-off of handling versus comfort. Simple as that. Your choice.

 

You lower the pressure till you can feel the squigglies in places where you'd rather not, then raise it a bit.

 

Different tires differ a lot, of course. But the principle is the same.

 

I find the Battlax BT-23 can ride at a lower pressure before the squigglies are present for me, as compared to other tires. That's a great tire.

 

Ben

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You lower the pressure till you can feel the squigglies in places where you'd rather not, then raise it a bit.

Could you define "squigglies"?

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From Urban Dictionary: ;-)

 

Squigglies:

 

Scrambled adult movies found on the upper cable channels during the 80s and 90s. The audio was not distorted and often it was possible to make out a nipple for more than 5 seconds.

 

"Dude, my mom threw away my stack of playboys, so I spent the night watching squigglies in my room."

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