Michelin Pilot Slicks - High Speed Instability (600RR)
Hello All, I need some advice regarding Michelin Pilot slick geometry/tire pressures for a 06 600RR. This last weekend I switched from Michelin Power Race DOTs (Rear: 180/55/17 Med; Front: 120/70/17 Med) to Pilot Slicks (Rear: S1847 18/67-17; Front: S1246 12/60/17) and made no changes to the bike geometry/suspension. It was surprising how different the bike behaved -- huge loss of stability at high speeds. Subsequently lowered the front tubes 4-5mm (raised the bike) which helped a little but there's still too much instability coming out of a corner and the straights. Further, I notice that my corner entry and exit have also been adversely compromised by raising the bike (front). Thus far, no changes have been to the rear shock height.
The wear on the rear and front look fine so I think the suspension settings may be ok. I was running 30/28psi. I was also using tire warmers set on high temp.
I went to the Michelin website and couldn't find any info on the tire circumferences, etc., for the 2 types of tires.
I haven't run those slicks, so don't have good answers for you. I'd suggest calling Dale Kieffer of Racer's Edge, who is a Michelin rep and should know the answers you seek: Dale Kieffer Phone: 702-257-3808 Fax: 702-257-3810 Email: racersedge1@earthlink.net
They're in Vegas, so it's Pacific Time Zone for them.
Can't really help you either as I never ran Michelin. I know that some Michelin runs on reallllllly low pressure, not sure about the slicks.
When I traded my DOTs for slicks (Dunlop) last year I noticed a BIG difference in bike handling though, but it was a good one. The bike was harder to initiate into turn but once it was the corner speed was greatly improved over DOTs
A few years ago I changed from DOT race tires to slicks on my SV, and it was a rude awakening.
I didn't compare the height of the tires before I bought them, and later found that the Dunlop slick was significantly taller in the back and somewhat shorter in front. This made my stable-as-a-truck SV jump around alarmingly on the straights. This is partly due to the change in geometry, but also because slicks aren't made to be stable in a straight line and lack the belting that keeps them from deforming at high speeds, narrowing your contact patch on the straight.
My Ohlins shock had ride height adjustment, but it was already at the lowest setting without modifications, so I lowered the forks in the tubes 3 mm. Didn't do shit. I tried to pass a bike on the outside of the back sweeper at Grattan, found that bump that everybody talks about, and the bars shook out of my hands as I headed for the grass. I'm thinking, ' this has to be the first tankslapper in the history of SVs.' I loosened my grip, got on the gas, and it went away. I bought a steering damper the second I got home.
Then I lowered the tubes 4 more mm, putting the top caps of the tubes slightly below the top triple clamp. That helped appreciably, and though I still got some dancing and occasional head shake, I learned to ignore it, because when I got on the brakes or started to turn the bike, it settled down immediately and gripped with power.
Last year, Dunlop changed the profile of their front slick, raising it about a half inch. Huge difference. Steady as she goes, now.
Good luck.. and by the way, 'Whip's right: call the rep! The reps are there to tell you what is up with the tires, applications, fitment, and pressures - all of them will be happy to talk to you because they want you to tell your friends how good they are at customer service.
A few years ago I changed from DOT race tires to slicks on my SV, and it was a rude awakening.
I didn't compare the height of the tires before I bought them, and later found that the Dunlop slick was significantly taller in the back and somewhat shorter in front. This made my stable-as-a-truck SV jump around alarmingly on the straights. This is partly due to the change in geometry, but also because slicks aren't made to be stable in a straight line and lack the belting that keeps them from deforming at high speeds, narrowing your contact patch on the straight.
My Ohlins shock had ride height adjustment, but it was already at the lowest setting without modifications, so I lowered the forks in the tubes 3 mm. Didn't do shit. I tried to pass a bike on the outside of the back sweeper at Grattan, found that bump that everybody talks about, and the bars shook out of my hands as I headed for the grass. I'm thinking, ' this has to be the first tankslapper in the history of SVs.' I loosened my grip, got on the gas, and it went away. I bought a steering damper the second I got home.
Then I lowered the tubes 4 more mm, putting the top caps of the tubes slightly below the top triple clamp. That helped appreciably, and though I still got some dancing and occasional head shake, I learned to ignore it, because when I got on the brakes or started to turn the bike, it settled down immediately and gripped with power.
Last year, Dunlop changed the profile of their front slick, raising it about a half inch. Huge difference. Steady as she goes, now.
Good luck.. and by the way, 'Whip's right: call the rep! The reps are there to tell you what is up with the tires, applications, fitment, and pressures - all of them will be happy to talk to you because they want you to tell your friends how good they are at customer service.
The contact numbers are on the web sites.
Yep...saved me the typing. Check your heights, but slicks are inherently less stable by design. Get the recommended pressures, and check your gauge against a calibrated one.
"It's not debt per se that overwhelms an individual, corporation, or country. Rather, it is the continuous increase in debt in relation to income that causes trouble." --Warren Buffett
Here's the latest after speaking with the Michelin Tire guys, Ohlins, and Traxxion. Unfortunately, there is no common agreement on what geometry changes should be made to reduce instability at high speed.
Tires: Michelin does not publish the tire specs (circumferences, etc) but they 'think' that there's very little difference between the Power Race DOTs and the Pilot Slicks. Bottom line, they've recommended leaving the front height where it was and lowering the rear 1mm.
Its amazing how difficult it is to get tire dimensions from the manufacturer. If anyone out there has a set of Michelin Power Race DOTs mounted (120/180) and you can get the tire circumferences, please let me know.
Supension: Mixed info. Some say in leu of changing the bike's geometry, that you need to soften compression, others say the opposite. It seems reasonable that softening compression may cut down on the bike's jerkiness at high speed because you're allowing the sticky rubber to grip rather than skip around.
Here's the latest after speaking with the Michelin Tire guys, Ohlins, and Traxxion. Unfortunately, there is no common agreement on what geometry changes should be made to reduce instability at high speed.
Tires: Michelin does not publish the tire specs (circumferences, etc) but they 'think' that there's very little difference between the Power Race DOTs and the Pilot Slicks. Bottom line, they've recommended leaving the front height where it was and lowering the rear 1mm.
Its amazing how difficult it is to get tire dimensions from the manufacturer. If anyone out there has a set of Michelin Power Race DOTs mounted (120/180) and you can get the tire circumferences, please let me know.
Supension: Mixed info. Some say in leu of changing the bike's geometry, that you need to soften compression, others say the opposite. It seems reasonable that softening compression may cut down on the bike's jerkiness at high speed because you're allowing the sticky rubber to grip rather than skip around.
Bridgestone slicks state the size on the tire (ie 190/645/17 645mm tall), Dunlop has most of what you want online
Maybe your next set needs to be another brand
If everything tastes like chicken..... what does chicken taste like
Its amazing how difficult it is to get tire dimensions from the manufacturer. If anyone out there has a set of Michelin Power Race DOTs mounted (120/180) and you can get the tire circumferences, please let me know.
Getting actual meaurements are the best way to do it. Depending on mold, how well they control the process, and any mid-year changes, the dimensions could be different than published. I would trust my own measurements before published data from the manufacturer, though their information is good for pointing in the right direction.
Good luck with the setup, and note that things like tire weight (% of unsprung mass), tire spring rate and damping, and a few other things will dictate how you make adjustments. I would start with "how are these tires different" and then make changes to compensate. Oh, and one change at a time
Reality is merely an illusion, albeit a very persistent one.
Albert Einstein
Getting actual measurements are the best way to do it.
This has really been a learning...but I'd like to stay with the slicks vs. race DOTs because of the more ridged feel and larger contact patch.
After measuring the circ and diameters the race DOTs were quite a bit taller than the slicks. The other learning was that the race DOTs were not the legitimate PRCs but rather a street/race tire. This may be part of the reason why I lost the rear end coming out of the corner. I need to have a word with the dealer on this one.
So, all of changes I made to the front (lower the tubes thru the upper triple) prior to the race may have been in the wrong direction. It now appears as though the front forks need to be raised at least 5mm which will improve corner entry & exits. As for the instability in the straights....the rear is too high and it needs to be lowered 2mm.
Thanks everyone for all the great advice. We'll see what happens at the next race.
I hope that term 'lowering the tubes' wasn't confusing. I was trying to indicate that the front of the bike would be raised up by clamping the tubes at a higher point.
Do you have ride height adjustment on that bike in the rear?
I hope that term 'lowering the tubes' wasn't confusing. I was trying to indicate that the front of the bike would be raised up by clamping the tubes at a higher point. Do you have ride height adjustment on that bike in the rear?
No confusion...we very much appreciated your help. What we didn't know at the time was that the slicks may actually be the taller of the 2 tires. If so, the front of the bike will need to be lowered by pulling the forks up thru the triple tree.
It’s taken 2 days and bunch of phone calls to get tire diameters from Michelin. Now that we have some data, I’ll go back and do a few more measurements and make the necessary changes to both the front and rear.
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Originally Posted by fearj
That looks great! Glad to hear you're liking it. 
It seems reasonable that softening compression may cut down on the bike's jerkiness at high speed because you're allowing the sticky rubber to grip rather than skip around.
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