Triumphrat

c_marcus3 · 03-22-2010, 02:50 AM

Just had a weekend away - approx 750 miles done. Early on I finished bedding in a set of new tyres - ContiGo's. Great tyres...around left hand corners!

Going around right hand corners the front end shimmys / wobbles slightly - very unsettling. In left turns a super planted, faster steering (than with OEM Metzler Lasertecs), lovely handling Bonnie, whereas in right turns I get a wobble? What the heck???

Checked the forks - ok. Checked the rear shocks - ok. Checked the chain adjustment - ok. Checked the tyre pressures - ok. Checked the tyres for bulges or bits - ok.

Did more riding...found that:
- Two-up with no luggage - the issue is almost non-existent.
- Solo with about 10kg (22lbs) luggage in a pack on the rear of the seat and preload on my normal 4 of 5 - it happens most right hand corners (unless they're very smooth).
- Solo with same luggage but preload upped to 5 about 3/4 of the wobble goes away.

I've checked alignment as best I can and searched the threads on this forum without coming across this problem anywhere.

Any help or ideas would be greatly appreciated...

Forchetto · 03-22-2010, 07:09 AM

Check alignment of the tyre and rim. There's a moulded line all round the tyre about 1/4" from the rim's edge. See that this is equidistant all the way round. You can see that line in this example:

c_marcus3 · 03-22-2010, 08:11 PM

Thanks Forchetto
Have checked the alignment for both tyres and on both sides - all equidistant.

Forchetto · 03-22-2010, 08:31 PM

I can only think of inspecting the front forks. See that they protrude the same through the triple clamps, oil quantity the same on both legs, the springs are the same length, that sort of thing.

Rocket59 · 03-22-2010, 08:45 PM

Maybe your forks are racked slightly to the right.

NITES · 03-22-2010, 08:47 PM

I know this might be a stretch, but one issue could be the rear wheel bearings are wearing or dirty. I had a similar problem with a friend's honda. Mechanic suggested we pop wheel off and clean out bearings and reinstall. Surprisingly it fixed the problem. His logic was if the front tire wobbles during left & right turns, it's the front bearings. If only in one direction, it's usually the back. The back bearings don't get as much attention and sometimes get alot of grime and blacktop goo in there. I'm not sure if that's the solution but hope it helps.

PAAS · 03-22-2010, 08:52 PM

Assuming you didn't have this problem before you changed tyres, didn't alter your fork set-up at the same time, and although you've "checked alignment as best I can", I would have a closer look at your wheel alignment.

Flaco · 03-22-2010, 08:58 PM

A+
What paas said...

c_marcus3 · 03-22-2010, 11:24 PM

Thanks, that gives me some things to go on with. I hadn't altered the fork setup but will check them anyway and look at the wheel bearings and alignment. May have to go back to the shop for that...

fat frank · 03-23-2010, 08:52 AM

If it wasn't noticeable with the old tire, I'ld have another look at that front tire. There could be blems there that are hard to see. Or, maybe just a bad install.
Good luck and let us know what you find.