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Oddball Tire Wobble

R

rvedder3

Tricycle
I've got an 86 that I just recently purchased that needed some tires. I bought and had installed a set of metzler lazertecs and now for some reason at approx 50-55mph and only at 50-55mph if I let go of the handle bars or even loosen my grip to much the front tire wobbles and shakes like crazy. What could cause this to happen only at this speed range 50-55mph above it its fine and below as well.
 
Rudy, Since you just had your new tires professionally mounted, I'll assume that they are not worn, are properly inflated and mounted, balanced and rotating in the proper direction. That likely leaves a couple of things - steering head bearing adjustment or worn wheel bearings. With the bike on the center stand, jack the bike up slightly so that the front wheel is just barely suspended. With the front end in this position, it should freely travel from side to side with very minor resistance. If the front end "flops" from one side to the other, your steering head may need to be tightened up or the bearings replaced. The adjustment nut is located under the top triple tree. Consult a manual on how to get to it and make the adjustment. Check the wheel bearings, with the front tire suspended, by pulling up from the top of the tire looking for any movement at the bearing, particularly side to side. With the wheel rotating on its axle there should be no loud noises, grinding or roughness. BTW, if the fellow that mounted your tires was observant, he should have noticed any issue with the wheel bearings when he was balancing the tire. One more simple thing you should also check is the tightness of ALL the nuts, bolts and connectors associated with your suspension and front end. HTH and let us know what you find. Hank, 16HP Craftsman Lawn Tractor
 
If it is only doing it if you let go of the bars while decelerating then it may be head bearing. This bike is real sensitive to it being loose. A change in tire can change how it acts. If it is shaking with your hands on the bars then I would look into wheel bearings, balance, defective tire... All things the installer should have noticed except maybe a defective tire. It happens. Photos[/url]
 
After playing around with it some more its doing it slightly on acceleration but still only from 50-55mph but on deceleration its really bad. Also if I don't grab the bars or tighten my grip it'll continue to wobble down lower then 50 and gets progressively worse the longer I let it shake. It's the weirdest thing since it's only at that particular speed range. Thanks for all the input so far you guys are great. I'll look into that head bearing the previous guy mentioned.
 
If you didnt have a problem b-4 you changed the tires, it's probably the tire. Had the same exact problem with my 86. put on dunlop radials, terrible headshake at 50-60 mph during deacceleration. took dunlops off and installed Bridgestone bias ply tires, problem gone.I have been spinning wrenches on bikes for 30 years and experience has taught me not to put radial tires on bikes engineered for bias ply tires anymore. For what its worth I wont sell metzlers at all.Dont discount other variables that may have aggravated a underlying problem, But I have always been maintainance neurotic and the chance of a variable on mine was zero.I.E. if it walks like a duck and quacks like a duck.
 
Head bearings are loose. Period. Not the tire, not the rider, it's the bearings or one of a few other things. I have never seen the tire be at fault, tho if balanced and mounted correctly. 30 yrs, and you haven't figured this one out? Stop on over, I hear even old dogs can learn new tricks. :) I can make your bad tires do what they're supposed to by fixing what's wrong on the bike. There are entirely too many 'bad tires' out there, and no one NO ONE has taken me up on my offer yet. What are people afraid of?! No one has sent me a single set of these evil tires yet either....hmmm...I'm starting to think they don't exist except in myth and imagination. :gasp: Rudy, I've got the wrench if you need to borrow it. We can also put some time into an inspection of sorts, find out what else you might need tweaked/torqued. You may get put to work in the sandblasting cabinet, tho. :eg: http://www.millerized.com I'll be in the garage
welder.gif
COG 6425, CDA 111 a through g
 
Miller I might just have to take you up on that offer and swing on through one of these days. Sandblasting huh? sounds fun but I'm sure its only fun for a bit. As for junk yard thanks for the input man but the metzlers are bias ply tires and I read a lot of good things about them before I bought them. I basically had it narrowed down to these and the Avon storm/azaro combo. The shop I ordered through couldn't get the avons in for a week and I needed tires asap. The bike is my daily driver rain or shine so I didn't have time to wait around. Also wouldn't a bad tire shake and wobble at more then just a small speed range like I'm having issue with? Not being a smart ass I just really don't know.
 
Well... I had no problems to speak of on my '06 with the stock Dunlops. The second set of Dunlops were a nightmare; almost instant front end wobble, particularly at around 45 mph, if I took my hands off the bars for a split second. Thanks to recommendations about tires on this forum I went to Avons for the third set . Problem gone!!! For good measure I installed a Motorcycle Larry fork brace. The combination of the Avons and the fork brace has made my Kawi rock steady and stable at all speeds. I take my bike in for regular maintenance at the dealer but if I had the time I'd rather do it, myself. I'd love to go to some wrench sessions...
 
Miller said: "Head bearings are loose. Period. Not the tire, not the rider, it's the bearings" Yep, in over 40 years of riding it's always been the head bearings.
 
Millerized is probably right, you must have inadvertantly loosened the stem nut when you changed the tire if the problem didnt exist before you did.or maybe it had a set of magic tires on it that automatically identified problems and compensated for it and you took them off. Millerized probably knows where to buy a set of them. And lord knows no company has ever produced a bad tire, just ask firestone (ford explorer) or dunlop(Muliple AMA riders on the deack after rear tires dissintegrated at 150 mph plus at daytona a few years ago).And I didnt Say unequivicably the tire itelf was positively to blame. there is a good reason Mcy. Mfrs. specify certain tires for their bikes but I bet Honda, kaw, Zuke,etc could just fire all their engineers and get someone on the internet to make tire choices for them.And you could probably go to any AMA,Wera, or wsbk event and the teams will all tell you it doesnt matter what brand of tire or tread pattern you use, there is no such thing as chatter, bad harmonics, etc. that stuff is all caused by loose head bearings. Ancient chinese proverb: Better to keep your mouth shut and let people think you are a fool then speak and prove their suspicions.
 
Diffrent tires even of the same brand and tread can have different "harmonic vibrations" that could cause a wobble if the head bearings are a tad loose. That is why the wobble only shows up at certain speed ranges. Any variable will change the vibration. "If it hasn't killed me yet, it's runnin out of time" COG # 8062 AMA # 1084053 ROMA or Scarlet harlot acording to my wife
 
Nevermind. Obviously being new to the Concours you have it all figured out. We're all ears.
 
Folksies, I'm with Millerized on this one. The C10 is blessed with wimpy steering head bearings. Few people realize that they should be tightened after the first 500 to 600 miles, and that the procedures outlined in the factory manual for detecting slop in the bearings are ineffective. If you don't get after the stem bearings in a timely fashion, you risk the races becoming notched and resistant to your steering inputs - a dangerous situation. You also might be surprised how snug stem bearings will reduce vibration in the handlebars. I tighten mine at each valve adjustment.
 
I brought this post over from another tire thread. Most replies recommended tightening steering head. However, why would the shimmy go away after changing back to the OEMs if I didn't tighten the steering head? I can ride with no hands for miles and not have a problem with it pulling either way. Last year I replaced the OEM Dunlops with the Avon Azaro/Storm combo. I loved the grippiness but didn't like the new shimmy in the steering after having them installed. I took the bike back 3 times for rebalancing - shimmy persisted. I had the combo replaced based on a hypothesized "manufacturer defect" - shimmy was worse with the new set. After yet another rebalancing (and nearly three weeks later) I requested a new set of Dunlop OEMs and guess what NO Shimmy! I was told that the Concours is the first bike this mechanic has seen in 40+ years to require the OEM tires. Any thoughts??
 
My thoughts... The bike is prone to do this and any small thing can set it off. I have put on new tires and had no shake and had it come back when tire gets old. Every thing you change only changes the situation and does not FIX it. My real solution: STOP TAKING HANDS OFF THE BARS 50<40 at least, if not all the time. It never shakes when you hold on unless the tire or bearings are bad. Photos[/url]
 
I've basically decided to just hold on until I can tighten the head up I found the wobble more or less by accident as I don't always go riding around with no hands and decided it probably wasn't supposed to wobble like that. The tires are great so far only slipped once and it was more my fault on slick wet pavement. So if I have to deal with a slight shake at a small range of speed I'm ok with that.
 
Bent wheel. Mine that is. Was on a 600+ ride a couple weeks ago (Cascade Loop) and the front wheel was wobbling? Wasn't bearings.... this time. I rode Skate CR Rd near Packwood WA a week prior and hit a sink in the rd and bottomed out the supension sending a shock into my body. Not the first time over years of riding and did not think about it again. Until I ckecked the wheel today and there is defintely a slight dent in the wheel to produce a wheel hop.
 
smithr, I appreciate the advice, but my point (slightly exaggerated) was the bike doesn't veer off center as described as a symptom of bad bearings. I was hoping to rule that out as the cause :) My real solution: STOP TAKING HANDS OFF THE BARS 50<40 at least, if not all the time. It never shakes when you hold on unless the tire or bearings are bad.
 
You want to make those evil tires work with your broken bike, follow these suggestions: http://forum.concours.org/index.php?topic=57639.msg212909#msg212909 If done correctly, it WILL work. It ain't the tires, it's the bike. Period. Anyone willing to lay money on it, stop on over. If it is the tires, I'll pay you what my procedure costs you. (I should edit to add that I'm knee deep in the project bike, but once it's done and delivered, just stop on over...Towards the end of July would be best) http://www.millerized.com I'll be in the garage
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COG 6425, CDA 111 a through g
 
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