Odd noise with front brake -- pulling to side

[John844]

I have 2 issues that might be related. When I use the front brake, there is a slight noise coming from it. It sounds like something is touching the groved abs area. One pad is worn past the visible indicator on side of pads, but other 3 look brand new. The noise starts with very little pressure of the brake, and does not get worse with additional pressure.

 

I have not pulled the pads off to inspect further yet. I think I will also look to see if there is anything touching the groved abs area.

 

I also have a significant pull to the right. This pull is there all the time, not just when braking. I have to lean my body about 45 degrees to the left to track straight down the road if I let go of the bars.

 

I have heard that the wheels being out of line with each other can cause pulling to the side. Are there other causes that I should check out, and how would I correct the alignment if it is off? In the old days, I would just adjust the tensioners on each side of the back wheel, but that will not work with a single sided swingarm.

 

Thanks, John

[Tipover_Bob]

John:

Don't use the brakes until you have replaced the worn one. Those disks (rotors) are expensive. You may have ruined one, but I expect you can just replace the pads. Possibly the worn pad is not releasing due to corrosion. It may be correctable once you get some new pads.

 

Regarding pulling to one side, I believe that is caused by different things including tire wear and misalignment. I do not believe in trying to adjust alginment of a shaft drive bike with the rear wheel. All alignment must be accomplished at the front wheel. I'll bet your uneven brake pad wear and pull to the side may be related. Not that a brake could cause a pull. It sounds like a caster problem, cause 45 degrees is a lot of body lean.

Tipover Bob

[John844]

Thanks Bob. I will pull them off now and inspect closer. How smooth should the rotors be? Each of them have a little unevenness to them, but no groves or obvious scoring.

 

I'll post back after I inspect further.

 

How do you adjust caster? Is that sideways tilt in layman's terms?

[Edgar]

Check this previous discussion. Link

[Tipover_Bob]

How smooth should the rotors be? How do you adjust caster? Is that sideways tilt in layman's terms?

John:

Sounds like your rotors are in good shape.

I don't know any thing but layman's terms. Think about what causes pull (right or left). It is misalignment, uneven tire wear, road crown or uneven weight distribution. These here beemers were not designed to be pieces of crap, so if everything is good they should go down the road straight as an arrow. Generally I expect road crown would lead to wear on the left side of the tires and a tendency to pull to the left. However, tires wear in different ways. I like to think that either crash damage or improper front end assembly can lead to a tendency to pull to the right. Anyway, I had the same problem as you when I got this bike four months ago. I worked on it and it's doing pretty good now. I'll tell you what I did shortly.

Tipover Bob

[Boffin]

RTs pull to the right. They all do that to one degree or another. From the M/C FAQ at the top of the page: PTTR

 

My personal opinion is that the biggest culprit is the asymmetric fuel tank. On the left hand side of the bike is a glove-box/radio box/authorities battery depending on the options on the bike. On the other side of the bike in that space is fuel. Lots of it. I suspect the RT-P will have less PTTR because the second battery weighs a lot and will counterbalance the fuel.

 

My bike tends not to PTTR because I never let go of both bars, that said I have often intended to put a plastic bag full of water into the glove-box to see if my theory is correct. that will have to wait for me, as I am off the bike due to an ongoing cat-related injury.

 

In short, I would not be overly concerned about the Pull To The Right. They All Do That.

 

Andy

[boatzo]

John, Check your front axel and see if it slides freely from one side to the other. I had a fork mis alignment on my 1100rt and when I corrected it the PTTR almost went away. I also agree with Andy on the fuel/weight distribution. When I have a full tank, I have no PTTR. When near empty I have a very slight PTTR.

 

Check this link and read the linked article in the post about tire wear. Very interesting in deed.

 

http://bmwsporttouring.com/ubbthreads/sh...true#Post943332

[PapaJ]

It sounds to me as if you have a dragging caliper. I've experienced the same thing in the past (on a car) where the caliper wouldn't retract or release due to corrosion. The other caliper will grab when brakes are applied and cause a swerve to the side opposite the dragging caliper. I'd check to make certain that the cylinders in the brake caliper with the most worn pads will slide in easily (and to replace the pads) if not it will need to be rebuilt.

[T__]

It sounds to me as if you have a dragging caliper. I've experienced the same thing in the past (on a car) where the caliper wouldn't retract or release due to corrosion. The other caliper will grab when brakes are applied and cause a swerve to the side opposite the dragging caliper. I'd check to make certain that the cylinders in the brake caliper with the most worn pads will slide in easily (and to replace the pads) if not it will need to be rebuilt.

 

 

Greg, sorry but that can’t happen.. The bike only has one front wheel so any brake or brakes on that wheel assembly will only apply stopping torque to the single wheel then to road surface.. If that wasn’t the case every motorcycle out there with only one front brake rotor (& there are many) would pull while stopping (that just doesn’t happen)..

 

Twisty

[flars]

My R1100RS pulls to the right until the tire gets seriously worn on the left side, and it has done so for the last 80,000 miles.

Every R1100RT and R1100RS pulls to the right, and I don't care if 10 people say "Mine doesn't" - they are either in denial, or lying or their butts are seriously misshapen, or their left boob is bigger than their right.

Don't worry about it. And be prepared for the left side of your front tire to wear much faster than the right side of the tire. They all do that, too, although I have heard that SOME people claim to have a specific brand of tire that doesn't wear unevenly.

And also - replace the brake pad before you hurt something expensive.

[John844]

I pulled all of the brakes off and inspected them last night. All of the pads are in good shape. I am not sure what I was looking at when I saw one much thinner. It must have just been the angle I was looking at it. The thinnest pad is still about half the thickness of the rotor.

 

The abs sensor has plenty of clearance and is not rubbing.

 

There is nothing dragging when I spin the wheel by hand, and I don't hear anything odd when spinning by hand.

 

The wheels apear to be out of line from front to back. I stretched a string from each side of the rear wheel forward. The front wheel is about 1/2 inch closer to one string. I would have to adjust 1/4 inch to get them lined up if this test is valid.

 

My tires are in good condition. The front looks brand new, and the rear shows a little wear, but nowhere near the wear indicators.

 

The pull is almost scary. The first time I let go to zip up my jacket, I almost ran off the road. If I don't hang off the side of the bike, I have about 2 seconds before veering off the side of the road.

 

I will try adding weight to one of the bags, but I would guess it would be 30 lbs or more to straighten it out.

 

This has been a learning experience. This is my first BMW, and I have only had it a few weeks. BMW seems to have a different way of doing everything. Thanks for the information everyone.

[John844]

In the link Edgarr posted, tipover_bob says

I tightened the crossover bolts while holding the front wheel to the right against the stop with slight pressure.

What are the crossover bolts? I am familiar with the axle bolts and the pinch bolts, but this suspension design and term is new to me. Google was no help

 

Can someone help direct me to them?

[Tipover_Bob]

John, Check your front axel and see if it slides freely from one side to the other. I had a fork mis alignment on my 1100rt and when I corrected it the PTTR almost went away.

 

John:

I had the same experience as Bill, I got my R1100RS and it pulled so hard to the right that I couldn't lean enough to hold it straight. The tires were wore slam out too. I took the front end loose including the axle bolt, clamp bolts and cross-over brace. I then shimmed the right side of the cross-over brace with two pieces of a beer can. I also held the front of the front wheel firmly to the right (against the stops) while retightening the crossover brace, axle bolt and clamp bolts. The result was the pull to the right was very significantly reduced and I was able to balance the bike with less lean to the left. I then replaced the front tire and the bike is almost perfect.

 

I believe what happens is that when the front tire is normally replaced the mechanic holds the front of the front wheel while tightening appropriate bolts. This could have a tendency of cocking the front wheel to the left resulting in an increased pull to the right normally expected due to the crown in the road.

Tipover Bob

[John844]

Bob, is the crossover brace the first connection to the bike above the wheel. It looks like a plate attached the forks with 2 allen screws holding each fork?

[boatzo]

Bob, is the crossover brace the first connection to the bike above the wheel. It looks like a plate attached the forks with 2 allen screws holding each fork?

 

John, You are correct about the brace.

 

I did not go as far as Bob went with the shims. I simply loosened all 4 allen bolts on the cross over brace and then (with the wheel removed) slid the axel through both forks and aligned the forks until the axel slid smoothly into both forks. Then I tightened the cross over brace bolts and checked the axel again to make sure the alignment was correct. Re-installed the wheel and went through the bouncing and loading routine prior to tightening the pinch bolts. Bike rides well within acceptable limits now with only sligt PTTR.

 

BTW, I test rode an 07 R1200GS and an R1200RT recently and neither one had any PTTR at all. May be due to the balabced crank in the new ones.

 

Keep us posted.

[Tipover_Bob]

Bob, is the crossover brace the first connection to the bike above the wheel. It looks like a plate attached the forks with 2 allen screws holding each fork?

John:

Yes. By shimming beneath the right hand side of the cross-over brace, I was trying to put a very, very slight camber to the front wheel to the right. Anyway, all in all, I was successful in reducing my pull to the right to pretty much nothing. The handling of these bikes is so good and so neutral in the turns that there was no way I could be happy with the initial, heavy pull to the right that I was experiencing.

Tipover Bob