My usual year's riding consists of a bunch of short trips amounting to a couple of thousand km plus a 4000 km Blue Ridge Parkway trip, so a total of around six or seven thousand km per year. My past 2 front tires were Avon Azaro AV45 120/70R18 which I religiously kept at 42 psi. What I find is their life is limited by cupping down to the tread base, they don't wear uniformly down to the wear bars.

The first of these lasted 12689 km (2 BRP trips plus sundry). The second lasted 20427 km (3.5 BRP trips plus sundry) and died in Asheville NC.

I think the difference is that when I installed the second tire, I also installed a steering damper to control wobble. Now I confess, much of my riding on the BRP is around the 50 mph wobble resonance point. But to me it looks like wobble causes front tire wear and a steering damper cures wobble.

What did you use for a steering damper?

Sprint, about 16.5" long
http://web.ncf.ca/ag136/steeringDamper.htm

Nicely done. George. I wonder how long until one of enterprising members makes a kit for us?

There hasn't been a lot of take-up, many others think the answer is to crank the steering head bearings a little stiffer.

There hasn't been a lot of take-up, many others think the answer is to crank the steering head bearings a little stiffer.

An alternative answer it is..... Same end result but with different meds!

I swore by the steering damper I fitted to my 72 CB750 as to make the bike handle faster I dropped the front end through the triples by half an inch and while it surely turned in faster it could cause the bike to go into a full blown tank slapper if you chopped the throttle to abruptly. The damper cured that and made open road riding so much easier to have the bike want to track in a straight line even though wind gust.

If you had offered up a kit I know that I would have tried one; and might yet still.

I've read all the threads about the wobble and understand why tightening the bearing nut down works. But so would welding it tight. Wouldn't turn too good though. I can't believe that while tightening will work, why should it be required?

I've also wondered if the wobble which seems to be particularly strong in Avon tires (mine does it a little more on slabs that are grooved concrete than those that are ungrooved asphalt) is not related to longitudinal grooving in the slabs and the size/direction of the tire sipes combined with a soft compound tire moving at a particular rate of speed.

I am no engineer, but I can imagine some distortion at tread level occuring as the sipes try to follow the running grooves, then recover, the follow the grooves, then recover, over and over creating a standing wave effect in the tire like happens when water is pushed ahead of the tire when it rains and you go too fast. A harder compound tire might not distort so much (not follow the grooves at the microscopic level) and therefore not wobble or wear as fast (or stick as well).  This rolling distortion seems to be what wears off corners of the tread and what happens when tires are repeatedly forced into a curve, stood up, laid over, etc. The corners wear off and the tire cups the tread.

Since the wobble most always seems to happen at 40-50 mph, that makes me think it's a frequency problem like how waves in the water can "pile up" or cancel out depending upon frequency and wave length when an outside force causes them. Think ripples from two rocks thrown in a pond. You also hear frequencies "pile up" or "cancel" in music when an instrument is out of  tune and the sound goes "wah, wah, wah" while playing the same note as another identical, but differently tuned instrument. The term I think that is correct is "harmonics." If it is a harmonics problem, it should duplicate again at twice the frequency (speed?) since harmonics and waves tend to occur in "multiples" again like an instrument playing a particular note in different octaves.   A dual compound Avon might fix the problem so long as kept inflated properly because the center of the tire would "carry"  the softer sidewalls down the straight.

I don't know, but I suspect neither grooving nor this tread design were around in 1984-85 when the Connie was being designed for 1986. I was working in the asphalt grinding business in the mid 80's and diamond grinding of grooves was "the next great thing" but for concrete.  Connie (or the Avons) might not be designed for grooved highways.   

Or, it might just something off the wall.
Ron

I am an engineer and I put together a little blurb on wobble
http://web.ncf.ca/ag136/frontWheelWobble.htm

VERY interesting George, thanks. Has this information been available on the forum before or did you just do this? It explains a lot of what I was guessing about. I was particularly interested in the reference to bias ply tires. What is not addresses is the apparent sensitivity of the Avons. I'm (again or still) guessing that the construction specifications and possible compounding/thickness of the tire carcass may play a role.  Thanks for the info.
Ron

Yes, it's here
    * The Kawasaki Concours Forum >
    * Wiki-FAQ >
    * C-10, the 'classic' Concours, info >
    * Suspension

Compared to a 130/70-18 bias, I think the radial Avon 120/70R18 is not as thick and massive and therefore absorbs less energy, i.e. damps wobble less. The bigger thicker tires are a pig to steer, but they do absorb wobble better. So far, I'm sticking to radial fronts, although now I'm sporting a Michelin Pilot Road 2, because I like the more responsive steering.

. . . If you had offered up a kit I know that I would have tried one; and might yet still.

One kit coming up:

Shindy 17-015 150mm stroke so you wouldn't need to shim the steering stop and the steering lock would still work
http://www.amazon.com/Shindy-LIGHT-STRING-DAMPER-17-015/dp/B000WNSEK8

41mm bracket
http://www.ebay.com.au/itm/Steering-Damper-Fork-Mounting-Stanchion-Bracket-41mm-/320413153323

Fabricate a bracket to attach to the frame per
http://web.ncf.ca/ag136/steeringDamper.htm
click on the bracket for dimensions

Compared to a 130/70-18 bias, I think the radial Avon 120/70R18 is not as thick and massive and therefore absorbs less energy, i.e. damps wobble less. The bigger thicker tires are a pig to steer, but they do absorb wobble better.

I ran a 130/70-18 Bias AVON VENOM on the front of my Concours and when it started to wobble I "snugged" up the stem bearings and it went away. The stem bearing were not overly tightened at all as once nudged past center the bars wound still free fall from side to side with the front wheel off the ground.

Then I installed a ZRX front end complete with a 17" x 3.5" rim and a 120/70-17 Radial SHINKO 005 ADVANCE with this install there was not so much as a hint of wobble at any speed under any condition. But now that there is some miles on this set up the wobble has returned that same as before; to which I've not tried to snug up the stem bearings as of yet.

Oddly the wobble I've had only appears when I'm slowing down through the 50 to 40 MPH range never going up through 40 to 50 MPH and will only be noticed if I have one hand lightly resting on the bar or less (no hands) if I've got a firm one handed grip or have both hands on the bars it is never to be seen.

I believe that any tire can wobble if given the opportunity and something induces it.

One kit coming up:

  Copy that George....I smell a winter project, thank you!

George I see there is now a Michelin Road Pilot 3 tire available in the 120 70 18 size.

What size are you running with the Road Pilot 2 you have?

What are you running for a rear tire?

I have the ME 880 tires, on when I got the bike, and they ride like a lumber wagon plus take forever to warm up. Brutal in mountain riding for sure.

I'm real happy with  both Avon AM41 & AM42   from compacc.com   for 277.88
or
http://www.swmototires.com/index.php?option=com_virtuemart&page=shop.browse&category_id=94&Itemid=53&vmcchk=1&Itemid=53

. . .
What size are you running with the Road Pilot 2 you have?
What are you running for a rear tire?. . .

The front is a Road Pilot 2 120/70R18. I would have tried a 110/80R18 but they didn't have one is stock. The rear is a Michelin Commander bias ply 150/80-16. The combination seems to work fine.