| Author | Message | ||
     Kw1125r |
Just put on a new Angel GT front tire which was installed/balanced at a local shop. Immediately noticed a slight handlebar shimmy at virtually any speed - slower or faster depending on speed. Took wheel/tire back to shop to recheck balance and was told it was spot-on and the wheel/tire seems to run straight and true. Re-installed and still have the slight shimmy. Nothing (no suspension settings, etc.) else changed other than the new tire. Have about 1500 kms on the tire now and still the same. The bike never did this before the new tire. Any ideas? Bad tire? What should I look at now? | ||
| Jimustanguitar |
Is it affected at all by braking? Could be a tweaked rotor that just surfaced when you took it on and off. Check your pressure. The PSI required to pop the bead is usually much higher than what you'd roll down the street with. Do you have the equipment to spin balance the tire on the bike? My father in law had a tire that did this on his Viper, and they had to balance it on the car to get it right above a certain speed. | ||
| Kw1125r |
Not affected by braking at all (I have had the tweaked rotor thing in the past). Checked tire pressure and tried everything from 35 to 38 psi with no change. The shop did the 'dynamic balance' with the wheel/tire off the bike - don't know of anyone around here that can do it on the bike... thanks for the suggestions though! | ||
| Sparky |
It seems as though there is a heavy imbalance out from the centerline of the wheel and the wheel weights were not applied properly to balance this out correctly. It could be that this shop's dynamic balancer is not sensitive enough or is not calibrated for this type of situation. If it were me I'd remove all the wheel weights that that shop put on and take the wheel to a different tire shop for a better balancing job. | ||
| T_man |
I actually had a pretty bad shimmy as well, but between adjusting the suspension and swapping out to pilot powers (rounder profile) I eliminated it completely. | ||
| Azxb9r |
It is most likely the tire. I stopped using the Pirellis due to the shimmy/wandering feel that I got from them. | ||
| Ratbuell |
It could also be a tire-height change. A taller or shorter tire will alter the stance of your motorcycle. Front-low equals faster turn-in and more twitchy steering. Front-high equals slower steering. Try dialing in more rear sag and see if that helps any. | ||
| Kw1125r |
Thanks for the suggestions/ideas so far everyone! I'm thinking more the tire than any suspension setup but not hard to try a few clicks. Steering is not really affected, just have a small, consistent to speed, movement on the handlebars which you can see with a very light (or hands off) touch on the bars... | ||
| Froggy |
I have Angel ST and GT tires on my R and CR, never had any shimmying issues. | ||
| Sir_wadsalot |
Been running every Diablo variant except the Angel (but I ran the old Stradas)for eight years and have never had or heard of them causing a shimmey. It could be a one-off manufacturing defect.... It seems more likely to me that the forks are tweaked than "Pirellis just wobble". I've heard people describe Corsas and Supercorsas as feeling "unstable" because of the super sharp turn in, but the Angel profile isn't that sharp. Don't pull the weights, but do take it to another shop to recheck the balance. If you pull the weights you won't know if the other shop screwed it up. I doubt it wasn't balanced "dynamically" enough. I've never had my wheels anything but cone balanced by hand and never had a problem on a bike. If one wheel "has" to be balanced on the car, that's usually because it's mildly bent, and the dealer makes more money off of you "super duper ultra" balancing your wheels every time, than on you just replacing it the once. (Or them replacing it under warranty!) Subaru's big on it....they don't tell you that all wheel drive cars just don't track quite as straight as two wheel drive cars and that's normal. They tell you "normal" 4-wheel alignment is inferior to their "super-ultradooper on-car high speed" alignment and balancing system, at twice the price! What was your old tire? Does it do it while it's cranked over? Did you pull the wheel, or did the shop? Any chance you over-torqued the bearings? Did you put everything together hand tight, and then bounce the forks to seat them before torqueing the axle? Does it smooth out at speed? If you come to the decision that Pirellis just "wobble" I'll be more than happy to relieve you of that burden  (I'm not discounting the "wondering/unstable" thing, Diablos do indeed tend to hunt around on the highway, but not the Strada/Angels, and definately shouldn't feel like a shimmey.) (Message edited by sir_wadsalot on September 11, 2013) | ||
| Jimustanguitar |
Time for some balance beads? | ||
| Kw1125r |
Let's see... to answer Sir_wadsalot: The old tire was a Shinko - I went with a new Angel on the back and really liked it wet or dry so wanted to put a match on the front. The shimmy is there, all the time - doesn't smooth out with speed. I pulled the wheel myself, both times. Unless my torque wrench suddenly quit working it was torqued to spec - I am very careful about this as I had issues at a local shop once where things were over-torqued. Yes, hand-tight first then bounced to center/seat things before torquing. Jimustanguitar - tried balance beads in the front once... probably just my imagination but I didn't like the turn in feel. I have been in touch with where I purchased the tire so hoping to work out an exchange - it would be my luck to get the only 'bad' one out of a production run. | ||
| Sir_wadsalot |
Idunno what else would cause that....sound like a bad tire. Seems like you know what you're doing. | ||
| Spike240sx |
The short wheel base is the majority of the cause. Proper suspension tunning can remedy it. It does not matter if the the weights are not in the center of the rim. DO NOT use balance beads. They are for cruisers only on bias ply tires. Head bearings may also add to the issue. | ||
| Kw1125r |
So just to see what would happen I made some suspension changes as suggested and went for a ride and yup, no change... I can send the tire back to the place I bought it but they aren't guaranteeing a credit until they send it to their distributor and I can guess how that'll go but not sure I many other options. Thanks for all the feedback though - the best and most useful forum I know of! | ||
| Dannybuell |
who did you buy the tire from? | ||
| Spike240sx |
Sounds like motorcycle superstore. I deal with it all the time. It does pay to buy your tires local. | ||
| Kw1125r |
Purchased and installed a new tire on the bike today and the problem is gone. So a 'bad' tire... | ||
| Sir_wadsalot |
Are you sending the screwy one back, or just gonna eat it? | ||
| Kw1125r |
The screwy one was sent back (they provided the pre-paid shipping label) along with all the information about what was happening with it. Hopefully they credit me, if not, they will have to send the tire back to me and I eat the cost I guess... | ||
| Thefleshrocket |
Spike, the Dyna Beads work just fine in radial bike tires--I've used them in every tire I've personally mounted. That said, it's been my experience (see my other thread) that a tire needs to be balanced with weights and then augmented with the beads, not just have the beads as the only balance. |
