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New Michelin PR4s - Twitchy at Speed, And...

6K views 16 replies 13 participants last post by  Black Rhino 
#1 ·
A little over two weeks ago, I got a new set of PR4s mounted up. Quickly noticed that the bike handled much more ...lightly for lack of a better word. Kinda pleasant.

Then I noticed that at speeds approaching 90, the handling became downright twitchy. OK... I don't ride at those speeds much, anyway.

Then I got on the interstate, and found myself closing on a semi ahead of me. When I got to within maybe 400 feet, the bike started a nasty bob-and-weave head shake. :yikes: Took all my attention to keep it pointed in a straight line while I got around the semi. And the next. And the next. The bike had never exhibited any such decrease in stability with the OEM Trail Wings.

I can't see where anyone else has reported anything similar here. So I guess I'm the only one. Suggestions are appreciated, but I'm not going to install a fork brace to solve a problem that didn't exist with the OEM tires.

Thanks!
 
#2 ·
I suspect that new Trail Wings would be similar- New tires have smaller radii cross-sections (some say "rounder"). I had similar experiences when my bike was new, but over time it diminished. Your windscreen and bags greatly affect what is going on as well- did you put them on after a couple of thousand miles on the TW's after they had been worn flatter?

You could also play with tire pressure. I like to run 35 in my Shinko 705's, but a bit less with the TWs.

You need a fork brace anyway. I noticed a significant improvement immediately and I ride the slab every day. Don't be a denialist.:green_lol:
 
#3 ·
Such handling issues at speed can involve the aerodynamic angle of attack, loose steering head bearings and/or wonky front tires. Fork braces help. Lower the front by raising the fork tubes in the triple clamps 10-15mm. Check the steering head bearings.
 
#4 ·
I've got about 650 miles on my PR4s, and have had occasion (and I'll deny it if pressed) to slightly exceed prevailing limits by a couple of mph... (or more). I've hit triple digits once or twice for the express purpose of checking handling (open highway, no traffic, certainly no trucks around). It stayed planted, straight, and true like it was glued to my line.

That being said, I have my forks raised 19mm to match my 3/4" links, and there was a noticeable increase in stability both at speed and in cornering. So, I 2nd greywolf's suggestion... At least as a checkbox...
 
#5 ·
The Glee is a different beast. It doesn't have the plastic ramp under the headlights that causes lift and its longer shock already lowers the angle of attack. Vees and Wees have significant lift on the front at speed that is even worse with headwinds or being in the slipstream of large vehicles. I feel it is important to at least try lowering the front. It's not that difficult, free, and reversible if it doesn't help.
 
#6 ·
Although new tires can feel twitchy, the only things that have changed are the tires, mounting, ballencing and installation. I'd double check that the tires are mounted in the correct direction, rear sprocket alignment is correct and adjusters are tight, axles and pinch bolts are torqued, visually inspect tires for defects and ballencing weights, and manually rotate tires while on centerstand while looking for abnormalities.
Then raise the fork tubes and install a fork brace. Both of which are needed on this bike anyway for stability reasons
 
#7 ·
Thanks, guys. I'll do the suggested checks in a day or two and see what I can find.
 
#8 ·
I got to say my new P4 are great . No wobble at 100 MPH on a private road of course . Slight road noise but al in all a great ride. Tyre Pressure 34F 36R
 
#10 ·
I ride 34/37 w/ the PR4s. The Pilot Roads always seemed to like an extra lb. That's solo. I'm 185-190lbs. (depending on dinner the night before).
 
#11 ·
Hi , Tyre Pressure 34F 36R is riding solo . I am 216 pounds. I am still experimenting as New Zealand Roads are generally "B Roads" and are not smooth concrete but road chip and quite often dips and bumps etc where the road has been repaired.
 
#12 ·
I've always been a big fan of "V" shaped tires that give a sharper turn in feel at the expense of some straight line sensitivity. When leaned over in a corner, a "V" shaped tire will get more rubber on the ground and be more stable in a turn.

Michelin has always been what I call a "U" shaped tire. More rounded thereby making it more stable in a straight line and slightly harder to push down into a turn. "V" shaped tires "fall in" to a turn very quickly.

With the new Pilot Roads, Michelin had made them more "V" shaped than previous versions. They make the bike feel lighter, more nimble, and turn in better. If you're not used to it, the it might feel a little twitchy. Just remember, you have a lane designed for a car, you can use it all. If you move around a foot or so (which would be extreme), you're got plenty of room.

Of course, you can always do the old "Adopt a Highway" and widen the lanes like Kramer. :)

 
#14 ·
90 mph is twitchy on my DL1000 with Tourance tires, add some rough cross wind coming off a semi truck and it becomes a DANCE.

It's not the PR4 tires. It may be the new tires are actually round and turn into a lean quicker. Even with Tourance EXP tires my bike dances around once over 85 mph. Its much better since I added stiffer springs and a fork brace, but the old Strom is much less stable than my KTM 950 ADV above 80 mph, no doubt about it...

Occasionally I'll run 90 mph on two lanes with no big issues, but it gets real light on the front running higher speeds on the interstates with all the cross winds. My thumpers feel the same, so I've gotten accustomed to the "dance", when I get on a FJR it makes the Strom feel like an old 1980's F250 4x4 with 36" ground hawgs.

Upgrading the rear spring so the bike doesn't squat under acceleration so much helps, the Strom likes a nose down stance. :green_lol:
 
#15 ·
MRV, what tire pressures are you running? Start with the recommended pressures on the sticker on the swing arm & owner's manual. If you want, work up from that. The Michelin customer service telephone rep might have some pressure info, also.
 
#16 ·
No problem on a Wee

I put a set of PR4s on my wife's wee about 2k miles back. The tires have been very nice so far. No stability problems such as described. I have the suspension setup stock height and do have a fork brace installed. High speeds are not a problem and the bike about steers itself through the turns.

I would look into suspension very carefully, wheel alignment, balancing, head bearings, and proper inflation. I don't think there is anything inherently unstable with these tires. Proper weight distribution is important too.
 
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