Hooplehead Posted June 24, 2011 Share Posted June 24, 2011 Running back from asheville a week ago 2-up, I noticed at about mile 60 of the trip; my bike began to shudder while maintaining 120mph. I know its not tire balance, and its definately not that fine machine of mine. Has anyone else noticed that as their tires wear, they become less speed rated? Was this caused by the heat of the road not being properly disapated with a thinner tire? My rear pirelli is damn near new, but my front pirelli is just now getting into the wear bars on the edges. Has anyone experienced this? As my speed decreased, the vibration went away. The longer I maintained a decent speed, it got more violent. When I first noticed, I pushed up to 130's and it got worse. Figd, I'd see if maybe faster would help... it didnt. Tire pressure is fine, me and the wife weigh 150 per. Any suggestions, other than slow down? I have a new front tire, but am waiting to see if someone thinks its the actual tire brand thats at issue. Heres a pic of the front, anyone think I waited too long to change it, or should I wait longer? NO THEY AINT CUPPED EITHER!!! Quote Link to comment Share on other sites More sharing options...
The Krypt Keeper Posted June 24, 2011 Share Posted June 24, 2011 Ever take a look at your wheel bearings? Might have one going bad in the front causing this shutter. I had one going bad a few yes ago while at WVXXT but it was telling me something was wrong on the corners when it would shutter when leaned over hard. Quote Link to comment Share on other sites More sharing options...
Redbird Posted June 24, 2011 Share Posted June 24, 2011 How do you know it's not the balance? Only reason I ask is just today in another thread you recommended someone balance a wheel using the axle and a couple blocks. That doesn't work as well as some think. Quote Link to comment Share on other sites More sharing options...
Mekanix Posted June 24, 2011 Share Posted June 24, 2011 I've never noticed problems with old tires in a straight line, but twisties can be harrowing. Maybe balance as well. I have noticed air pressure had a big difference on new tires, but I can't verify old tires. Wish I was more help. Quote Link to comment Share on other sites More sharing options...
Hooplehead Posted June 24, 2011 Author Share Posted June 24, 2011 I cant be perfectly sure about the balance. I know that axle balance trick is slightly better than nothing, but if it was a balance issue, woudnt it present itself at speeds of 30,60,90 and 120 ect...? Anyhow, I KNOW how cars react to imbablance, That, and the bike only diid this the one time recently. Im going to replace the tire just to be sure. Ill check the bearings, prolly just think about getting some just for for good measure. Hell, maybe its the chain that has a couple of tight links? Ill replace it and the rear cush's too. Thanks for replies guys. Quote Link to comment Share on other sites More sharing options...
Warp11XX Posted June 24, 2011 Share Posted June 24, 2011 Tires not well balanced will do what you describe without being consistent at other speeds. Worn tires even more so. Check the head bearings and brakes while you're at it....they can contribute unwelcome heebie jeebies as well. Quote Link to comment Share on other sites More sharing options...
Hooplehead Posted June 24, 2011 Author Share Posted June 24, 2011 Good advice, had nearly forgotten to check the headset too. I wish there was a speed balance shop near me, but I havent located one. I'll do some callin around. Quote Link to comment Share on other sites More sharing options...
Chewtoy Posted June 24, 2011 Share Posted June 24, 2011 Just swapped from Pirellis to Bridgestones and the difference was unbelivable. IMHO, the tire can get out of balance as it wears. Worth checking if you think there is enough meat on the tire to keep it. Quote Link to comment Share on other sites More sharing options...
Dotetcher Posted June 26, 2011 Share Posted June 26, 2011 Running back from asheville a week ago 2-up, I noticed at about mile 60 of the trip; my bike began to shudder while maintaining 120mph. I know its not tire balance, and its definately not that fine machine of mine. Has anyone else noticed that as their tires wear, they become less speed rated? Was this caused by the heat of the road not being properly disapated with a thinner tire? My rear pirelli is damn near new, but my front pirelli is just now getting into the wear bars on the edges. Has anyone experienced this? quote] I've experienced this with two blackbirds of the same year ('97's). Bike was loaded up with rider and gear 1st time and just lot's of gear 2nd time. For me it was more of a harmonic vibration and never was all that violent. Was a little nerve wracking the first time. Heading through Utah 2 up doing the same kind of speeds and first noticing the vibration made me a bit nervous. Not the plade I wwanted mechanical troubles. The vibration stayed (at higher speeds) till we got back to New York. Next time was last year on my 2nd '97 loaded with enough gear for a 1 month trip. I figure with the xtra camping gear I was carrying the same weight as the first trip. The vibration started about 4000 miles into the trip. First trip was on Metzler Z6's. Second trip was on PR2's. Quote Link to comment Share on other sites More sharing options...
tomek Posted June 26, 2011 Share Posted June 26, 2011 KISS , keep it simple , stupid . Re-balance the wheels , it should help unless they are significantly out of round , but when they are on balancing stand you`ll be able too see it . I`ve had couple of sets that needed balancing after couple of K miles , some sort of midlife crisis . Quote Link to comment Share on other sites More sharing options...
Hooplehead Posted June 27, 2011 Author Share Posted June 27, 2011 After unmounting the old tire, its O SO OBVIOUS how little rubber is left. The casing is very light and incredibly weak. Im guessing this didnt help matters. Found a shop with a spin balancer. Let me balance my new diablo myself. I checked my rim and tire for runout, all looks good. Didnt take too much weight to get her -zero-. I havent had a chance to get it warmed up, or up to speed yet, but It had much easier turn-in, and vastly softer ride. Gna have to wear the new off her before I check the edges, but soon enough we'll ride and check for that vibration. Just got wife that new qwest helmet with resized cheekpads. Hopefully thatll buy me some touring time. Thanks for all the replies, Ill let ya know if the problem comes back or not. O' btw, all wheel bearing and heaset checked out fine. :icon_thumbsup: Quote Link to comment Share on other sites More sharing options...
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