front end wobble

[SUNNYBEAR]

Hi folks...

I am getting a little "wobble" in the front when driving at lower speeds, say 35 mph city streets...I have new tires on front and back.

I have tried adjusting the steering damper on the '84 R100RT, but this does very little...

Could it be that I need to replace the bearings in the steering tube?

 

[shire2000]

Usually, bad steering head bearings will cause a very stiff feeling to the steering. Sometimes if the bearings are not set correctly (to loose) you will get movement when you jerk the bars forward and back and can get bad wobbles as well. But those wobbles usually just get worse the faster you go.

Most causes of wobbles at low speeds is an out of balance wheel or tire. Also check the wheel bearings and the preload on them. If not set correctly, you can burn up those bearings which will cause you to come to a very abrupt halt.

 

[20774]

I've heard people mention the rear shocks as a possible cause of a front end problem. This bike doesn't still have the Nivomats on them, does it? Not sure if it came with those... Also, make sure that the swingarm is centered in the frame.

But if it's just started with the new tires, then I might look there first. Are the new tires properly seated on the rims? Check to be sure that the rubber mold like is uniformly spaced from the rim on either side.

 

[jforgo]

I would start with cleaning, regreasing, and adjusting your steering head bearings. There are good threads in here about how to do this. In the process you also wind up realigning the forks.
I suspect the crisper, narrower profile of the new tires has manifested what was already a creeping, incipient problem.

 

[BRICKRIDER]

Hi folks...

I am getting a little "wobble" in the front when driving at lower speeds, say 35 mph city streets...I have new tires on front and back.

I have tried adjusting the steering damper on the '84 R100RT, but this does very little...

Could it be that I need to replace the bearings in the steering tube?

Steering head bearings which are properly adjusted but have gone bad (frozen / rusted / aged without grease) will cause a stiff feeling in the steering as you ride. However, your bike is in a group in which a distressingly high percentage of steering stems were improperly machined (oversize) by whomever this component was outsourced to by BMW, causing some very serious handling problems. The most prominent symptom is front-end wobble and a "loose" feeling in the handlebars. If you listen carefully while doing about 35, hit a bump or two purposefully and you may hear a "slam" or "bang" in the steering head area. Or you might feel the abnormality in your hands right through the grips as the gaps slam together.

A great deal has been written about this subject by myself and others. Please feel free to search my username for posts on "steering head bearings" or "SHB". (I owned a 1983 R100RT for 16 years and 117,000 miles. This bike had the problem big-time, and I learned about this subject the hard way and without any dealership help. If it wasn't for my late friend Sam the Machinist, I might never have discovered the cause and would have given up on the bike.) You might also contact the Forum user "grumpyone", as I coached him both publicly and privately through the process of getting the problem resolved "the right way". His bike needed machinework in order to properly repair.

My comments are based upon the presumption that you have mounted the correct spec tires for your bike, that they are balanced, and that other serious issues like fork springs and rear shocks are in good shape. "Good shape" does not mean that they clean up well and look good with a coat of wax. It means that they are not too old to work as they should.

If the fork springs in your bike are originals, they should have long ago been replaced, preferably by an aftermarket brand, as OEM Airhead fork springs & rear shocks are very poor by comparison.

No, the steering head damper won't even begin to alleviate the problems which are beginning to show on your bike. You have begun correctly by asking in this Forum. This needs to be addressed before you ride much this season, as front-end wobble is a serious safety issue.

Ride Safely,
BrickRider

 

[JANMILLER]

Did the wobble show up immediately after mounting the new tires???

Might not be seated correctly, spin 'em and watch for wiggles in the tread.

Also, some tires have an inherent wiggle, though usually not noticable at speed. I just put Avons on, and there is a little wiggle I don't like at all just as you come to a stop, in the last 3-4 feet.

 

[sumran]

You mentioned you have new tires but did not say whether the wobble was there with the old tires. I see you are a newer member, but don't know how long you have owned the bike. Have the tires been changed since you got the bike?

 

[ABE456]

Zero in on the steering bearings. They are notorius for causing steering wobble. Also, if Brickrider is correct, your bike's steering stem will need minor surgery by a local machinist. Search the posts and you will get plenty of hits on this issue.

 

[SUNNYBEAR]

wow!

thanks for this information so far

yes, the problem was there before the new tires...

I had the bike serviced (by Touring Sport in Greenville, SC...great folks, btw) before I brought it to its new home with me here in Raleigh, NC...they went through the bike, told me what it may need as well as things to keep an eye on...that is where I hpurchased and had the new tires mounted...as I wsa talking to the mechanic and going over the bike, he said that when he test drove it that the front springs seemed sort of soft, but to ride it for a while, dust the cobwebs off, and see where I wanted to take this issue...could soft springs cause this wobble?

 

[TGHSMITH]

sunnybear I sent you a pm

 

[SUNNYBEAR]

thank-you

 

[BRICKRIDER]

wow!

thanks for this information so far

yes, the problem was there before the new tires...

...could soft springs cause this wobble?

In the mid-80s, a friend of mine and I were riding down the freeway at about 70 mph. I was on a Suzuki GS850 shaft drive and he was astride an R75/5 of someone else's that he intended to repair.

The front springs were soft as mush, and that /5 went into an uncontrollable tank slapper. He went down, separated from the bike, and they both skidded a loooonnngggg ways before coming to a stop while I watched helplessly. The top of the headlight even had roadrash on it.

Gotta give him credit - after the cop left he righted the bike and rode it back to the garage.

Sooooo yes, front fork springs can cause a wobble.

Ride Safely,
BrickRider

 

[SUNNYBEAR]

hey!!

I had a Suzuki GS 650 shaft drive at about that time!!!

My parents still had their beemers...I couldn't afford one then...

thanks

 

[BRICKRIDER]

hey!!

I had a Suzuki GS 650 shaft drive at about that time!!!

My parents still had their beemers...I couldn't afford one then...

thanks

That's why I owned a rice burner at that time - did not think that I could afford a Beemer.

But it was false economy. I babied that Suzuki with all the necessary maintenance and then some, but at 53,000 one or two of the exhaust valves had receded so far into the head that no more shims were available to correctly adjust the gap. The only solution was a new head. Cost (for just the head and nothing else) -$300. Value of the bike at that time -$300.

So in 4 1/2 years my $3,000 investment dwindled to the point where I felt lucky to get $300 out of it.

That's one mistake I have not repeated in Life.

Wish I could say the same about other mistakes made!

Ride Safely,
BrickRider

 

[The_Veg]

While you're examining the rear suspension, do not ignore the preload setting. If the back end sags too low, you can get a wobble.

 

[jforgo]

While you're examining the rear suspension, do not ignore the preload setting. If the back end sags too low, you can get a wobble.

Does it help if the passenger eats salads instead of fries once in a while?

 

[JAMESDUNN]

Question.

Does it wobble with your hands on the bars or when you take them off? I recall reading in a mag that a wobble at around 35 mph is common when riding "hands off". My RS does that but does not wobble at greater speeds when I take my hands off the bars. Just a thought.

 

[81twins]

I have an '81 RT that developed a sudden/severe wobble that would occasionally occur when I slowed... checked rear shocks, ensured rear swing arm was centered and correct torque (had done shocks earlier), checked and changed fork oil (had newer springs installed earlier) and still had the wobble. I had read of a similiar problem diagnosed to be tire related.. they had been using a "round" tire vs the tall "oval or V style of tiresthat came with the bike. I was running metzler marathons and noted the front was not wearing evenly... changed it to "old style" metzler ME33 and similiar vintage rear and wobble has not returned. As well... noted the heavy feel that I noticed when I moved the bars quickly from side to side was gone as well. Perhaps tire related... even if new?

 

[SUNNYBEAR]

well, I need to report that my wobble issue has been resolved thanks all to tghsmith who was very generouds and supportive of his time and knowledge..

come to find out that the problem was that the front tire was not seated in the bead properly...the tire was wobbling from being unbalanced!

I am a little disheartened that I left the dealer and they did not mount the tire properly...I know simple mistakes can occur but this seems fairly basic to me...

I did not notice this I think because the tires that were on the bike when I first rode it were in shabby shape...

but anyway had a nice couple hours learning about my bike...aforementioned member went through the bike...torqued the engine bolts, checked the exhaust valves for wear, checked the charging system, synced the carbs...and really went out of his way to help me..

As I am a newb (sort of) to the ownership of an airhead, I am so very grateful for his help, and one day hope to repay his efforts by sharing what I learn with someone else..

again, thanks!!!!

 

[mitchell0481]

I had the same problem, Loose steering bearing. It was a bear to take apart. Once I tighted it up the wobble went away.