RS steering problem

[Computerbob]

As some of you know, I spent some time recently riding Matt's GS and (of course) fell in love with the GS, but more importantly discovered something about my bike that I never would have known had I not had the chance to ride a somewhat similar bike for an extended period. I've ridden a few other people's bikes, but mostly just around the block or in a parking lot. Not for a couple hundred miles, or couple weeks like I did Matt's.

 

I've always complained about the RS and how it made my back hurt right between the shoulder blades and thought it was the seating position. I've discovered that it's actually the steering. It's just enough off-kilter that I have to constantly push against the bar with the left hand or pull against the bar with the right hand to keep the bike going straight. I guess I'd ridden it so long that I had grown accustomed to it and just forgot all about it until I spent time on another bike.

 

Recently, I replaced the front fender and in the process I messed up mounting the front axle and didn't get the wheel square with the bike which made the steering problem even more exaggerated. Matt helped me figure out how to remedy that, but it's still not 100% back to being straight.

 

I stopped by TonUp today and talked to their wrench on duty and he said without even batting an eye that the next step is to pull the forks and make sure they are true. He said that if I pulled them off and brought them to him, he'd check them and straighten them (if possible) for around $25-40 depending on how long it took.

 

My questions are, has anyone else ever experienced something like this? If so, does this remedy sound right? Also, as a semi-novice home-schooled guy with a barely stocked garage of tools am I getting in over my head trying to pull these forks or should I take him up on his offer to do it for me for $100?

[Paul Mihalka]

I suggest take the whole job to your technician. It is not a small job and that way if something is not right you know it is not something you did.

[mneblett]

I had a '99 R11RT which pulled to the right pretty strongly. Solution in my case was to shift the swingarm 2mm to the right -- I put a 2 mm shim (a large washer) under the head of the right swingarm pivot, and screwed the left pivot bolt 2mm farther in.

 

Beware: If you don't properly heat up the right pivot bolt, the thread locking material BMW uses will literally strip the threads out of the side of the transmission case.

[dirtrider]

Morning Bob

 

A LOT of BMW bikes of the era yours is has a thing called pull-to-the right. It has nothing to do with bent forks, it's mainly a weight off set & a tracking issue not bent forks.

 

Bent forks seldom cause a bike to pull one way or the other it's way more likely that bent forks cause seal leaks & binding on compression. That can give you harsh ride or fork sticking.

 

[Trullion]

Yes, my RS is the same. Some advocate removing the spacer between the rear wheel and FD, or using a thinner one. I would leave your forks alone.

[Computerbob]

Yes, my RS is the same. Some advocate removing the spacer between the rear wheel and FD, or using a thinner one. I would leave your forks alone.

 

I just did a google search for "RS pulls to the right" and found many articles saying "it just does that, deal with it" or others that say "they all do that, until you pull the spacer from the rear wheel."

 

I can't believe that people actually enjoy riding a bike that they constantly have to force to keep it going straight down the road. Within an hour of riding like this, my back and shoulders are throbbing. Maybe mine is more severe than others but I'm dead tired of it.

 

I'm going to try pulling the spacer tonight and see what that gets me. Thanks for the heads-up. Even if that doesn't fix it, at least I can skip the fork work that probably would have been a waste of time.

[Paul Mihalka]

A simple trick, put anything you carry in the left saddle bag, or if you are packed, everything heavy in the left bag.

[NCStephen]

My experience is with a K12RS. Perhaps some of this might still be relevant for you.

 

When I got the bike with low miles I noticed the pull right. This was notable and discovered when using the cruise and finding I was always having to correct the steering. I now have a bike that tracks straight. Here are thing things I discovered.

 

 

(1-TIRES)

 

The tire brand and model matters. I don't know why but it is what I found.

Metzler Z6 while the tire that kept the bike straightest on slab, heavy in twisties was the tire that exhibited the most pull to the right.

Michelin PR2s not as solid straight line tire but the tire with the least pull to the right

Roadsmarts 2s in between those to.

Dunlop Q2s the most sporting feeling tire, only moderate pull to right.

 

(2-Body Position)

 

I use a low sport shield so shoulders and upper torso in the are in the wind.

 

If you take your left hand off the grip and place it on your leg or tank your torso takes on a slight twist so that it becomes a rudder pushing the bike to the right. I didn't think this would be much of a factor but with the cruise control on I can cause a drift to the left or right based upon just which one hand is up on a grip. This will also be affected by if you are tired and are shifting your butt in the seat to give yourself a rest.

 

 

(3-Loading bags)

 

I ride nearly all the time with bags on. The K12RS has a nasty shaped, small limited left bag. I was putting all my daily stuff in the right bag. In the end it was about 3-4 lbs heavier than the left. I reversed this and it changed the drift a lot.

 

 

(4- Spacer ring on wheel)

 

I heard about removing this as well. My wheel is the 5.5 inch one and I run a 180/55 tire. As it is, it will sometimes just barely brush the swing arm. If I take out the spacer ring, that moves the wheel closer to the swing arm where space is already at a premium. I have a bike that runs true now so did not do this one.

 

 

(5- Using reposition of Washers/spacers in swing arm mount)

 

I had read that you can disassemble the swing arm and remount it so that you can move it a few mm to the right by use of washers and that this will correct the drift to the right. I considered this option but I have a bike that runs straight now so never pursued this.

 

 

(6-Load on rear rack)

 

I discovered that things I had on the rear rack magified things. I can't say this shape or that shape. Just that I noticed that when something was back there, the drift might show up more or less than when it wasn't. Wind does move around behind the rider and put some pressures on that load. The shape, placement and wt of the load impacts this as well as the position of the rider.

 

(7- Suspension settings will make it better or worse)

 

Worn suspension might be another issue but having your suspesnion set to ideal for the bike and rider does matter. My OEM suspension was 'fiddled' with and it did help get the drift better.

 

(8-exhuast system)

 

If you have an aftermarket, light exhaust, where in the center line of things did it save weight. Did it make one side a little light than the other?

 

SUMMARY

 

So what I have and makes the bike feel solid and straight is

 

I better balanced the load in the bags. I actually have the left bag a few lbs heavier than the right. My rainsuit, a few extra tools and my lunch stuff usually go in the left bag. The right is pretty empty most of the time. The bike ran straighter this way. (if you use a lighter exhaust you have perhaps made one side of the bike a bit heavier as a result)

 

I switched tire brands. The pressure in the tires didn't seem to effect it much. The PR2s were the easiest to have running straight. The Q2s do very OK now.

 

I set the preload so it had appropriate 1/2-3/4" no riders sag and about 1 1/4 inch sag with me aboard with gear and bags with daily load.

 

It wasn't just one thing but with the above things now the bike runs true. I can tell the balance in the bags because of a drift left or right that I can predict with my loading. I can easily ride straight for miles without having to feel a tense forearm from constant pressure on the bars.

 

So change of tires and start with recommended pressures ( I actually run a bit less than that now and monitor heat of tire as indicator of correctness for load, mileage is still great)

 

Use brands that seem to run better than others in correcting this bike character.

 

Set your suspension correct as possible using known techniques. This is for preload and rebound

 

I didn't have to removed spacer in wheel

I didn't have to adjust swing arm mounting

I didn't have to have excessive wt in one bag to compensate

I do keep things in bags as close to center line as possible, esp when only a few items. Wt bias in bags is so the left is heavier.

I know that my body will add input into steering in small but noticable ways

I do have a bike (NOW that is)that is sweet to ride on slab or twisties and seldom deal with any drift right or left.

I have switched suspension but the drift was fixed with the OEM ones before the switch

If I do have a drift one day I look to the variables that I can control, body position, load in bags, load on rear rack. Those can often explain it and even help to nullify it.

 

I hope this helps.

NCS

 

[BmKev]

I read somewhere that one cause of the RS drifting to the right is that the fuel tank is not symmetrical, so you have the extra weight of the tank + fuel + all the internals on the right.

(so it should drift a little less when nearly empty? )

Kev

[dan cata]

Now where is that topic where this rider made a frame from the front to the back of the bike and measured that the rear wheel was not in a straight line with the front one, so he made some spacers to compensate that (and some rear caliper mount mods too).

 

Dan.

[tallman]

I had an RSL for about 40,000 miles.

TADT

The cure is to ride in more curves and fewer staightaways.

 

I always packed bags to weigh close with a smidge more heavy left side low.

Never was an issue for me.

YMMV

[Computerbob]

I did some more googling and found this article with an enclosed piece by Paul Glaves, Tech Editor from BMW Owner's News. In it, he said, "Some owners and dealers have found that omitting the flat, washer-like spacer from between the rear wheel and final drive output flange (where the wheel bolts on) lessens both pull to the right and left side front tire wear. This has the effect of moving the rear wheel a few millimeters to the right, more under the weight so to speak, which would lessen the effect. This is not a recommendation, and if you do it, be careful that you have maintained tire clearance from the swingarm."

 

I happened to be at a gathering of like-minded individuals last night and mentioned my problem and several people suggested loosening all the connections to the forks, letting the bike rest on the wheel and 'untweak' themselves by applying pressure repeatedly against the front forks (compressing them) and then tightening everything down. They said that sometimes things just get out of whack and need to be untweaked.

 

I've had no shortage of advice on how to fix this problem running the gambit from "it just does that, get used to it," "pack heavier things in your left bags," to "take it to the dealer, they'll fix it." and everything in between. I'm not sure where I'll go, but apparently it's not an easily diagnosed or fixed problem, so I'll have to make a list of all the possibilities and work my way through starting from the easiest/least expensive fixes. When I do figure out what it was, I'll be certain to post it here.

 

I do plan on selling this bike soon, but don't want to just pass on this problem to the next person.

 

 

[chrisolson]

Now where is that topic where this rider made a frame from the front to the back of the bike and measured that the rear wheel was not in a straight line with the front one, so he made some spacers to compensate that (and some rear caliper mount mods too).

 

Dan.

Straight from the BMW factory repair manual for a '99 1100S. Note that the offset is a design feature.

Interesting that their example gives a negative result but the actual spec calls for a positive value.

[dirtrider]

Morning Bob

 

Something to keep in mind on your PTTR.

 

That track offset is nothing new or strange to the BMW boxer bikes. Some Harleys run a lot more track offset than the BMW boxer for rear drive belt clearance.

 

In the past we have set the Harley's up to run with a straight offset (like the BMW) IE both wheels tracking straight ahead just an off set in the wheel placement.

 

We have also set them up with an angled rear wheel so the rear wheel follows the front wheel track but the bike frame then goes down the road a bit crooked.

 

In neither case would that bring on a pull to the right or pull to the left.

 

So that tells me the PTTR on the BMW isn't due to the wheel offset & tracking offset but more due to the weight placement from the bike center line being different because of an off set tire center patch. Moving the rear wheel over can help that weight offset a bit. Moving the swing arm & wheel can help even more.

 

Same with the front forks being loosened then wiggled around & re-tightened. To believe that is to also believe that the front axle is being bent by the fork position. Seeing as that large diameter front axle passes through net fit holes on both sides of both fork bottoms then is tightened securely between the fork lowers would mean that it would HAVE to be bending to allow fork angling.

 

Definitely the fork position as it relates to the lower axle (distance between the lower fork tubes) can cause fork binding & some stiction but very difficult to believe it can actually lean the tire in relation to the road to cause a PTTR.

 

 

Find a cut away of your transmission & look where the majority of the shaft & gear weight is. Same with drive shaft center line & some of the fuel placement.

 

[tallman]

So, TADT unless you tinker?

Maybe going through 6 sets of tires in 2/1/2 years kept mine tweaked.

 

Never had an issue, was much easier than the GT to get around a bend, but a better rider could even that playing field, IMO>

[dirtrider]

Afternoons Tallman

 

As far as I have been able to determine they don't ALL do that but most do. I had one oilhead RT with a radio & had the least PTTR of any oilhead I owned, don't know if it was the added radio weight on that side or just coincidence.

 

I never plotted the rear wheel position against PTTR but some come from the factory with the rear wheel farther right than others. Just look at the spec +/- 9mm & that is desired spec-- some builds can be off more that that.

 

 

Most of my 1100 & 1150's had PTTR to some extent, it never bothered me so I didn't address it until I was working on the rear wheel or final drive.

 

[tallman]

Some posit that we (the riders) make a subconscious adjustment

so we don't notice it.

Perhaps.

If I straddle that era boxer, no weight on saddle, and twist throttle, we all know which way the bike moves.

 

I think this is venturing into politics now.

[dirtrider]

---If I straddle that era boxer, no weight on saddle, and twist throttle, we all know which way the bike moves.

 

 

 

Afternoon tallman

 

That only matters while free revving the engine (the old action/reaction thing). When bike is in gear & riding down the road the engine is pulling against the drive train so there is no measurable twisting torque on bike axis. It moves to the tire to pavement interface. You just can't get the engine to revv fast enough in higher gears to feel the engine torque reaction.

 

At a very quick throttle up while riding in a low gear there is a very slight twist but as soon as the RPMs stabilize it is all gone again.

 

 

 

 

[tallman]

Agree.

Your quick throttle up is my twist...

[Michaelr11]

I happened to be at a gathering of like-minded individuals last night and mentioned my problem and several people suggested loosening all the connections to the forks, letting the bike rest on the wheel and 'untweak' themselves by applying pressure repeatedly against the front forks (compressing them) and then tightening everything down. They said that sometimes things just get out of whack and need to be untweaked.

When installing my front wheel after a tire change I tighten the axle bolt and leave the pinch bolts loose. Then sort-of like you describe above, I compress the front end several times. No front brakes; just rear brakes and compress the front end a bunch. Tighten up pinch bolts and calipers. Been doing this for the last 3 or 4 tire changes. I have no PTTR that can be felt on the bike. Tire wear on the left side still occurs but it is significantly less pronounced than it was before. The wear is now center and left, before there was a left side wear band.

 

Photo is from my last tire change. Total miles comparisons don't work because road surfaces are so different. I don't know how people get 10K miles from a sport touring tire.

[Computerbob]

As I mentioned in the fork thread, I took everything off and put it all back together (and even put fresh fork oil in) and nothing changed.

 

Today, I did the most simple thing anyone mentioned. I put my bags on and left the right one empty and put 16lbs of weights from my scuba belt in the left bag. I did 200+ miles today and the bike tracked straight down the road. There were times I was able to completely take both hands off the bars and just sit there with my hands on the tank (although I'm not really comfortable doing that) and keep going down the road without leaning off the left side of the bike to keep it going straight.

 

Is this my permanent solution? Maybe, maybe not. But it's the one I've found for now. 16 extra lbs sure seems like a lot of dead weight to drag around. Plus I sometimes like to ride without any bags and can't do that anymore.

[Paul Mihalka]

Now that we stopped going in so many directions, it is determined that you have a bit extreme case of the well known "they all do that" PTTR (Pull To The Right) caused by uneven weight over the line of the wheels. One primitive solution is putting weight in the left bag, as you did. The real solution is moving the wheel line to the right to get +/- even left to right weight.

I had a extreme PTTR R1100RT. First step was removing the shim between the rear wheel and the drive. Mild improvement but not enough. Next step: Put a 2mm spacer under the right hand swing arm pivot bolt and adjust the free play by tightening the left pivot. Don't do more than 2mm, as you run out of clearance and adjustment. Result: Running straight.

Note: I sold this R1100RT after 175K miles with no ill effects of this mod.

[Computerbob]

OK, I pulled the shim out of the rear wheel and put the wheel back on. I was able to pull 6lbs of weights out of the left bag, leaving 10lbs still needed to keep the bike going straight. If moving the wheel over 3mm allowed me to get rid of 3/8's of the balance weight (6 of the 16 lbs)... do you think that making your suggested 2mm change is going to make the rest of the difference I need?

[dirtrider]

Evening Bob

 

Probably not but it sure will be closer to going straight.

 

To get the rest you need to change all the money in you wallet to $1 bills then move it to your left pocket.

 

Seriously maybe try putting a bit of weight in the L/H storage box & maybe bolting some weight under the muffler area. The farther out you get the weight the less you will need.

[Paul Mihalka]

Simply removing the wheel spacer and moving the swing arm over 2mm was all I could do. It was enough to improve handling and eliminate left side wear on the front tire.