1983 GS1100ED - Michelin Pilot Activ - Speed wobble. :(

[CCM911]

As the title says, I have a 1983 GS1100ED that I just re-shod with a new set of Michelin Pilot Activ tires. But now I have a horrible speed wobble as soon as hit 80 mph or so.

So far, I have removed the front tire and had the balance checked by another shop. We also checked for runout, and out of round. All looked OK. While I had it up on the jack, I determined that there was no slop in the steering head bearings, and nothing appeared to be loose.

I am running about 26 pounds in the front tire.

Is this just a bad tire choice? Can it be a bad tire?

It sucks having a dast bike that can not go over eighty mph.

Thanks for reading.

 

[TxGSrider]

Hi and welcome to the site.

Was there any wobble before the new tires? Sometimes the head bearings don't have any "slop" but they may still need to be snugged down a little.

 

[trevor]

26lbs is low imo...I run around 32 in mine....as for a"sloppy" feeling...if your head bearing is going you feel a "notch" in the steering when on the centre stand a front wheel off the ground.
Cheers and welcome to the site

 

[Nessism]

What size are the tires?

Those tires should be run at 32/36 (front/rear) according to the Michelin website. 100/90-19 front and 130/90-17 rear are the correct sizes.

 

[CCM911]

Thanks for the welcome, guys! I thought I was a member, but then I had to re-register, LOL.

I will try 32 PSI.

My bike has only 14k on the clock, so I am not convinced my steering bearings are on their way out.

I really appreciate the input.

And before these new tires, the wobble came on at 120 mph, so 80 mph is 40 less, or in other words, a lot.

 

[BigD_83]

I'm on team low tire pressure...but there might be something else contributing to the wobble.

 

[Nessism]

The question about tire sizes was not answered.

Regarding "team low tire pressure", that may have been a good team back in the 1980's, but today it's best to listen to the tire manufacturers on what pressure their tires are designed to run with. In the case of those Michelin's the pressure is 32/36psi.

BTW, if the steering head and swingarm bearings haven't been serviced lately (or ever), now is a good time. Fresh grease is a wonderful thing.

 

[Cipher]

If not steering bearing maybe the swingarm bearings?

 

[trevor]

Thanks for the welcome, guys! I thought I was a member, but then I had to re-register, LOL.

I will try 32 PSI.

My bike has only 14k on the clock, so I am not convinced my steering bearings are on their way out.

I really appreciate the input.

And before these new tires, the wobble came on at 120 mph, so 80 mph is 40 less, or in other words, a lot.

Miles don't matter all the time...after all it is a 30+ year old bike. Things dry up.

 

[BigD_83]

The question about tire sizes was not answered.

Regarding "team low tire pressure", that may have been a good team back in the 1980's, but today it's best to listen to the tire manufacturers on what pressure their tires are designed to run with. In the case of those Michelin's the pressure is 32/36psi.

BTW, if the steering head and swingarm bearings haven't been serviced lately (or ever), now is a good time. Fresh grease is a wonderful thing.

I think you misunderstood my position. I am on the team that believes the low tire pressure is potentially the cause of the wobble, but not the only cause as the PO has stated that he had a high speed wobble at high speed previously.

 

[Wingsconsin]

Do not neglect the rear tire as well...
That can also affect the bike as it 'wags' the entire frame -
Low pressures in either tire can manifest as a wobble

 

[CCM911]

Tires are stock sizes. I will try 32/36 and report back.

The question about tire sizes was not answered.

Regarding "team low tire pressure", that may have been a good team back in the 1980's, but today it's best to listen to the tire manufacturers on what pressure their tires are designed to run with. In the case of those Michelin's the pressure is 32/36psi.

BTW, if the steering head and swingarm bearings haven't been serviced lately (or ever), now is a good time. Fresh grease is a wonderful thing.

 

[hannibal]

Ed, where did you find the recommended pressure info?
I don't see it on Michelin's site. I'm trying to find the suggested pressure for the Shinko 230s i just bought. The FSM says 25/28 which seems a bit low.

 

[TiiMuch]

rear wheel alignment?
sight down a long straightedge place ideally onto the outside edge of the rear wheel, one side, then the other.
Inexpensive, quick, easy test.

 

[bonanzadave]

The whole thing sounds pretty familiar. I have speed wobbles going from Dunlops to Avons. Front @36,rear@38 religiously. And yes, I have changed, tightened, or adjusted everything you're going to suggest. No difference. Still wobbles. Cant go over 100mph.

 

[CCM911]

32 front/36 rear. My first pull to 100 on the way to work was fine. Then the wobble came back!!!

This is driving me crazy!! So am I limited to under 100 on this bike? I may as well just ride my Ninjette 250 instead.

 

[Cipher]

So did you check the swinging arm bearings? Wheel alignment? Steering bearings?

 

[TxGSrider]

I'm not sure what the problem is... but I can tell you that I am envious of you guys that have a place to do 100+mph on your way into work. lol

 

[dantodd]

I'm not sure what the problem is... but I can tell you that I am envious of you guys that have a place to do 100+mph on your way into work. lol

You'll notice he didn't say "legally" go 100mpg.

 

[posplayr]

Well something is wrong. Did you ever drain the forks and replace the fluids. Differential damping rates can cause uneasiness.
When my bike was modified but with stock suspension I always has a low speed 30-35 mph wobble on the front steering with hands off but nothing about 50mph.

The main thing I had added was Ohlins rear shocks, Racetech emulators, progressive F springs and fork brace. Other than that went through everything.