high speed wobble

ive got 1999 st 1100 jus bought new metzlers for the bike! ive had it up to speed on different roads and not had any problem,but last week i went on a diff tollway and was getting some shake!! i have read posts about recomended air pressure in front and back tires, so i filled them at 36 front and 42 back. if that doesnt cure it,and i have to take it back to that stretch of road to verify,id like to inspect verify front fork oil, rear swing arm bearing. any suggestion?? thanks!!

Try 41/41. Shake at what speed? What do you consider high speed?

Besides tire/wear could there also be worn wheel-bearings, damaged head-bearings, too soft/worn down rear shock, worn fork bushings, a barn-door sized windscreen, too large/heavy top-box, tail-frame fixings loose or named suffered a crack...
Some items could be determined/checked while stationary, others require trial & error runs to circle down...

speeds in excess of 95mph

and they are new tires, less than 1k on them or there abouts

the thing is ive done those speeds on other roads and its been smooooth sailin!!

Did you torque the front wheel on properly when the tire was replaced. I have ST13 and it makes a big difference on it. My ST13 had a slight wiggle at 50 mph after tire removal. I torqued it again following the Honda manual to the tee and it went away. I had my concerns that it would reappear at a higher speed and it would be severe. No problem at any speed now with 11000 miles on that tire.

MATTK said:

the thing is ive done those speeds on other roads and its been smooooth sailin!!

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maybe it just the road,,, if other roads are good

Al st1100 said:

maybe it just the road,,, if other roads are good

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I was thinking the same thing... if all other roads are fine... then avoid the bad one...

There is a road near me where the entire thing has been chip/slipped (like many others) but this chip material is either bigger or not adhered to the road surface properly, I always feel like the rear is going to slip out on the slightest curves... eventually I had to ask myself why in the heck do I keep going down this thing???

It ain't the tire. Run 38 front - 42 rear.

ST1100Y said:

Besides tire/wear could there also be worn wheel-bearings, damaged head-bearings, too soft/worn down rear shock, worn fork bushings, a barn-door sized windscreen, too large/heavy top-box, tail-frame fixings loose or named suffered a crack...

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Yeah, I agree with Martin, I don't think your problem is with the tires, I think it is with something else, for example, one of the things Martin mentioned in his post.

I have a 2001 ST, I've always used Metzelers (the Z series), it has 170,000 km on it now and a lot of those kms have been on the German autobahns at speeds that North Americans can only imagine - for example, steady cruise at 160-180 km/h (100-115 MPH), with the occasional burst up to 230 km/h (140 MPH). I've never encountered any kind of instability or shake, ever, although I do note that the front end gets kind of light above around 220 km/h (130 MPH). I use the same pressures you do (what Honda recommends): 36 front, 42 rear.

Once, I got a 'bad tire' when I had the tires changed - it had a wobble in it, like a tire that was not properly balanced. I took the bike back to the shop the next day, and they gave me a new tire. They said that they have problems with perhaps 1 in every 100 moto tires, but such problems are usually immediately apparent to the rider. The tire will balance OK on the dynamic machine, but wobble when riding at speed. So, if your tire is new, that might be the problem.

Michael

I wonder if its the road surface? I've found that the Michelin tires on our suv sound very noisy on some asphalt roads and sooooo quiet on others (not talking about the difference between new asphalt and grooved concrete, but visually similar surfaces). If you don't experience it on all roads at the critical speed (say onset at 97), then it might be external to the bike (but a combination of tires, or suspension and the road surface).

In addition to the items mentioned by Martin, you can add tire balance, shock preload/dampening settings, and even wind turbulence.

Ok, we have all been tossing out possible causes, now its time to start real troubleshooting, and as always, it begins with the simple things. Have you checked for steering head looseness? Wiggle or looseness in the front forks (with the bike on the center stand and someone holding the rear end down)? Did the shake (and I assume you mean head shake, as distinctly different from high speed weave caused by turbulent air behind semis and/or rear shock adjustments) appear immediately after you got the new tires?

This is what I would do. First, since someone wrenched on the front wheel, I would loosen the axle bolts and go through the procedure once more, torquing, bouncing the front end, etc. to set the forks/axle properly. Read the manual for this info. Then I would set the tire pressure to Honda's specs and take it for a ride. Vary the pressure up or down a few pounds and take different runs. I'd do static tests on the bike (like I mentioned in the last paragraph), and check the rear shock preload and dampening settings - maybe here a tweak, a test ride, and there a tweak and another test ride. No change? I'd consider trying a different front tire before I jumped into the front forks, either by borrowing a front wheel from another website guy or simply buying another brand. You have to eliminate the simple things first.

Chicago area? North of 95mph? You might consider dumping all those tickets you've collected from the gendarmes - they might be unbalancing the bike and causing the shake.

Last idea, if it goes away at say 99, then just ride a bit faster or slower.....

If it is just happening on one particular road why blame the tires?

I have been on roads that change the riding characteristics of the bike significantly, for example a lot concrete roads have a textured surface that can steer the bike a little and the harder you try to keep it going dead straight the worse it gets. On a road like that it is best to relax and let the bike pick it course.

Gerhard

I HIGHLY recommend 42psi. both front and rear tire. If that doesn't resolve the issue, the roller ball type steering head bearings need to be replaced with tapered roller bearings. This change totally resolved this issue with my ST1100. Paved road surfaces or concrete road surfaces have absolutely no affect on bike handling at speed......unless there is steering head bearing issues going on. A simple diagnosis and easily remedeed.

BTW, the stock roller type steering head bearings IS a common issue with these particular bikes!

MATTK said:

the thing is ive done those speeds on other roads and its been smooooth sailin!!

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I'm just spit balling here but what about road surface? I would occasionally get death wobble on my Nighthawk bad enough to make me inspect forks, wheel, etc. Eventually I figured out it was a 'rippled' road surface. The fact that your only seeing it on certain roads leads me to wonder...

Brant said:

I HIGHLY recommend 42psi. both front and rear tire. If that doesn't resolve the issue, the roller ball type steering head bearings need to be replaced with tapered roller bearings. This change totally resolved this issue with my ST1100. Paved road surfaces or concrete road surfaces have absolutely no affect on bike handling at speed......unless there is steering head bearing issues going on. A simple diagnosis and easily remedeed.

BTW, the stock roller type steering head bearings IS a common issue with these particular bikes!

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Thumbs up on this. Changing to the roller bearings in the steering head is a must-do on the ST1100. Also do not allow the rear suspension height too low. I see owners lowering the rear suspension because its hard to hold up the bike at a stop. Bad move, but if you insist on lowering the rear suspension, then you must also lower the front tubes as well.

i think your correct w road surface!! ill test when i get back to tollway !!!

i could see the weight of my tickets unbalancing the bike....good point!!

ill check thanks!!

checked the neck bearing the other day. it had some tightning needed, and it improved wobble this time at 100. think i have to remove and inspect races and bearings including swing arm...