I’ve posted several times on this site, mostly in order to buy parts. Now I hope I can get some expert advice with bike setup issues. I have a 2005 Kawasaki ZX6RR which is a dedicated track bike. I’ve made upgrades to the suspension with a Penske 8987 triple and Ohlins internals in the forks. The upgrades have given me more adjustability but I’m still not close to having the set up right. It’s cause me quite a bit of frustration but I realize that it may take a while before I find what works for me. What has really thrown a monkey wrench in process was when I upgraded to Michelin slicks, 1247A front and 2788R medium rear. The new tires actually caused the front to wobble at high speed in the straight. I raised the triple back to stock height and set the shock higher as well. This helped but the problem remains. Has anyone encountered this? What could be causing the issue? Thanks in advance, Paul
What tires were you running before you switched over the to slicks? Not familiar with the Michelin slicks, but is the front more triangluar?
I balanced the tires myself at first then had them balanced again at a local shop. A friend of mine and I bought 2 sets of these tires. He has a 748 and when he did his first track day with them yesterday, he had the same issue whereas before he was one of the fastest guys on the track. I was running Bridgestone BT-002 RS before. Sorry, can't say for sure if the profile is more triangular...they're definitely not as tall. Thanks!
Should have gone with the Bridgestone slicks, that's what I run, they have the same profile as the '002's. You could possible try increasing your rear ride height in small increments, not really sure what could be causing it. I take it you didn't have these issues with the '002's.
I may end up making a switch to the stones...probably the easiest solution at this point but would really like to figure out the issue. We got the tires from eBay at a real good price. One of the local racers here even vouched for the seller.
Just to add to this, I'm the guy that PJED references above with the Ducati, that's having the same problem. I immediately started experiencing nasty headshake a mere 100 yards out of the track entrance...it was immediate. Down straight aways, over bumps, etc, etc. If I was in the power, that front end was gonzo. So, I raised the rear ride height significantly, and noticed an immediate improvement...but still got bad headshake at times, which was definitely hindering confidence to push/go faster. I was told by the local shop that profile of the rear tire is smaller, but he profile of the front is taller (than bridgestone). So by raising the rear, I think things improved some, but in order to really get the bike back to where it was prior, I also need to lower the front (because the front tire is taller profile than what I've been running previously). Regardless, the situation has been really frustrating, and will likely just go back to Bridgestones, what I should have done to begin with. Get's a little old having to spend your entire track day making adjustments in an effort to make the bike track straight! Surprising that the differences between the two manufacturers are so significant! Anyway, that's my rant for the day.
Try a Michelin DOT Power1 rear with the 1247a or 1246a or even a 16.5" front power1 slick. What has occured with my bikes when trying slick rears is without the rear end set up perfect, you get too much grip that has the front wheelie a bit, and the front then starts to shake. With the DOT rears, it will spin more on exit keeping the front end planted. This season i tried the new 16.5" front/rear power 1 slicks. The big 6" rear hooked up too much, was actually having to roll off throttle on my r6. threw the dot rear 190/55 and fixed the very next session. Can try both a 190/55 or a 180. I have found i like the extra side grip of the 190 at some tracks, but will try the 180 at tracks like VIR where flicking from side to side is paramount. The 1246a is a GREAT front tire..
You bring up a good point melk-man...but there has to be another way of solving this issue other than having less grip in the rear. That sounds more like a band-aid fix. With so much extra grip could it be a wheel base needs to be lengthened?
I did start getting some head shake while on the throttle coming out of corners...so melk-man's diagnosis make sense. I still don't undertand why I would get the headshakes in the straight, with the bike straight up. Raising the front did help but I still felt the shake suddenly come on after shifting to 5th at full throttle...a little scary to say the least. I think the solution can be got by making a whole lot of changes which will take a lot of time through trial & error. I want to make the most of the remaining track days this season so I'm going to go back to Bridgestones. Anyone interested in a very lightly used pair of Michelin slicks? LOL.
While there may be other ways, without a good suspension tuner and spending some money revalving, trying springs, etc.. put the DOT tire on the rear. I wouldn't call it a band-aid fix if it works as good or better than before, and the 1246a slick front is one of the best tires Michelin ever had/has. Wears forever, and grips till the cows come home. Good solid feel as well as the carcass is firm. The 190/55 Power1 dot tire has MAJOR side grip, and is a very good rear tire. Spin does not always mean "loosing speed" kind of spin, like on ice or wet pavement. You will be moving forward.
just a quick question that I haven't seen addressed yet.. what pressures are you running? I've experienced this w/ the new power one front (just jacked up my steering dampner a click) but never with the slicks. Pressures from my Michelin vendor for slicks is (cold) 28 front, 26-27 rear (hot) 31-32 front, 30 rear
I just did a trackday this Saturday with a new set of BT-003s DOT Race tires. Had the fork seals replaced as well. I didn't have time to set sag or mess with the suspension and just ballparked everything. It felt like I was on a different bike...totally awesome. Still can't believe the different manufacturer with a different height/profile could affect handling so much. As suggested, I will stick with Bridgestones from now on.
