Loosing the rear...

VetteRacer · 06-22-2005, 10:57 AM

For some reason it feel like my rear tire is slipping out when turning. Notice it mostly at low speeds, has me scared to hit high speed turns. I got new tires ago, but did a few rides on them without problem, my pressure is good, and the wheel has no play in it.

I will have to check what tires I am running, not sure if this is what people talk about tires warming up?
Plan on going out this afternoon and seeing what I can find out at higher speeds.

Thoughts?

Matt

JonyRR · 06-22-2005, 11:06 AM

check the paralever pivot bearings. any play there will translate to that 'spooky sensation' you're experiencing...and don't overlook the pivot bearings at the FRONT of the swingarm. When I did my clutch, I greased these bearings also (there's a bearing shield on the OUTSIDE of the bearing races at the front of the swingarm, but not the inside, so a finger will reach.

Rapid Dog · 06-22-2005, 11:07 AM

ditto dat

DanGreene · 06-22-2005, 11:14 AM

Yep. I bet a dollar it is the rear pivot bearing. Put the bike on the center stand and sit in the cow milking position on the left side. Grab the rear wheel and move it back and forth. You will notice some movement and there should be none at all.

VetteRacer · 06-22-2005, 11:57 AM

Dan.
I did this yesterday and had no play at all. I will dig out the Tq wrench and check it all over again (did a driveshaft replacement few months ago). But I dont think thats it, cause it felt solid..

It has a mild simularity to when I got a flat tire, but only when turning.

Dr. Curve · 06-22-2005, 12:36 PM

Vette, did you replace the two sets of paralever pivot bearings when you did your driveshaft? Always replace them if you are already to the point where the rearend is off the bike. Replace the Piviot Pins as well if any scaring is observed. Don't reback with the BMW silver crease that they come with but instead go to a high quality ultra stickey grease like you might get from Ring Power. Movement here can be hard to detect. It may only show up under load and not seem to move with just your hands. Good Luck, but the way you describe the problem sure sounds like piviot bearings somewhere in the Paralever. You would really needs some miles on the bike before play show up in the crown wheel bearings so that only leaves those other four.

roger albert · 06-22-2005, 12:43 PM

Ditto the Dr. and other folks' input.

Also carefully check for play in the rear carrier bearing.
(it can be felt most easily by having someone rock the wheel back and forth a bit while you hold a fingertip bridging the gap between the brake rotor and rear drive housing.

From the rider's seat, both of those problems give the same vague kinda slipping feeling.

The pivots suggested are far more likely, but I've seen both.

Merrimac · 06-22-2005, 01:09 PM

There is another possibility. It seams to me that some tires are designed in a way that can create a feeling simular to slipping when leaning over into a turn i have noticed this feeling when the tires are new.

What I think might be happening is caused by a difference in the tire diameter from the center to the outside of the tire. When the bike is leaned into a corner the back end begins to oversteer by having the rear tire change its turing radius.

I mention this because of the reference to "new tires." After the the tire wears a bit the feeling goes away. I have noticed this mostly with Metzler tires.

Again, this may be a possibility.

pwillikers · 06-22-2005, 06:50 PM

Roger and I just replaced my paralever pivot bearings. Prior to replacement, whilst milking the cow, there was about a barely perceptible play discernable betwixt the paralever housing and rear disk in the manner the Rog suggests above. The sensation on the road was quite unsettling. Felt like I was riding on rain groves around turns. 'specially chicanes, the left-right or right-left manuvers really manifested the loooooosenessssss. With the new bearings, asses be a kickin' an' shiit.

On the other hand, I find that if I eat Mexican food, the rearend loosens up unexpectedly.

What tires did you choose?

VetteRacer · 06-22-2005, 08:12 PM

Didnt get a chance to do anything on it today. Started raining

. And been prepping the dorm room for the 53" TV thats being delivered tommorow (hehe). So not sure on tires.

What do the bearings cost? Do thay have to be pressed in? Any idea what a shop would charge to do it?
IF thats what it is, any damage to be done by riding it? I was planning on taking it back home this weekend (240 mile each way, dead straight). Since I am loaning my car to my friends who just arrived in the area and are car shopping.

Matt

steve abella · 09:28 PM

do you run Metzler Z6 on the rear
I had that feeling to so I changed tires and it went away

JonyRR · 06-22-2005, 09:45 PM

vetteracer, doesn't an air force base have an auto shop you can use anymore? if thats wrong what it is you MIGHT be able to get away with just tightening them. You'll need the wrench to fit the big jam nut on the inside (I think 36MM or CAREFULLY use a biiig crescent wrench) and the allen, 10MM I think, for each side pivot pin. ya need a heat gun, ideally. In a perfect world, also a torque wrench.
the hack way to do this would be to pull the rear wheel, heat the jamnut somehow (yes, I know you're gonna use a propane torch so be careful) back the jam nut off, carefully heat the inner pin, then loosen it a bit, use some loctite on the threads at the end by the swingarm, then thread it back in just a bit tighter than it was....a light drag like a tapered wheel bearing on a car as you move the rear end housing up and down. loctite the jamnut, tighten it down while makins sure the pivot pin doesn't move, and that should see you through until you can get it done right.
Many a night I spent in auto shops keeping my beaters running whilst in the army......

Dr. Curve · 06-23-2005, 06:07 AM

Sorry RR, but that is some of the worst tech ever written to a fellow R11S rider concerning the subject.

Tightening would make no difference, A crescent wrench won't work, ect. ect.'' Please don't tell us you have done this job to your bike.

I have done the pivot and bearing job front and rear on a R11S and its not a casual, light weight, or quick job, if it is performed to spec.

You must have been pulling a joke or something, surely.

VetteRacer · 06-23-2005, 06:20 AM

I do have access to the shop, just no time. Head back to Cali on the weekends for various things, wedding this weekend. And work during the week.
I have the tools needed to do the job, I went and bought them all when I was in MaryLand and had to do the rear shaft splines. I will hit them really quick checking tightness and all that. Have a delivery coming today so get a few hours off. We are allowed to do minor repairs in the parking lot...

I am running Dunlop 208s. Wasnt able to check profile cause it was dark, had to use the cell phone light to read it

Curve, as he said, the hack way of doing it...

Matt

JonyRR · 06-23-2005, 08:04 AM

It's nice to have every tool known to man and a perfect shop to do the job in, but not everyone can do stuff the 'approved' way. Sometimes ya have to (insert Gunny Hiway's hoarse whispered 'adapt,overcome' speech here) improvise. The true measure of a technician is NOT when in the perfect shop with no distractions and all the parts, but at midnight, in the ditch by the side of the road, with a bic lighter for a flashlight, some bailing wire, 5-minute expoxy and ingeneuity. The label of 'hack', depending on circumstance, can be a badge of honor

dannyleo · 06-23-2005, 11:39 AM

Mine's been feeling the same way, and I just thought it was me. Due for the 30k check in two weeks, I'll make sure and let them know.