wheel spin...

Started by MELK-MAN, January 04, 2003, 09:08:31 AM

0 Members and 1 Guest are viewing this topic.

MELK-MAN

recently had my forks done by Traxxion. Worked out GREAT. Took a full
second off my lap time that day after being stuck on lap time for 4 track
days. Best of 1:22.2 at NFMP/Jennings GP.. many high 1:22s..
question, i have a penske rear double clicker (that took 1/2 sec. off prior
to the 1 second off with the forks). I have a 2000f4 and have had track days
every other weekend since march 02. with a michelin s2 tire front and rear,
i am getting alot of wheel spin comming out of the corners, and if i roll on
even somewhat aggressivly IN the turn, i get some slide too. No real big
deal as the soft tire slides better than the m2 michelin, but if it would
hook up comming out im sure i could go faster..
front forks are as you sent them back-i set sag at 35mm. Rear shock has a
850lb spring (i weigh 175 with gear).  compression is 1 click toward hard
from middle. rebound was 4 clicks in from middle toward hard but i backed
off 4 clicks back to middle. sag is 30mm, and ride height is as i have had
for many months, put a 5mm spacer on the stock shock to get additional 1.2
inches or so. ... new shock is same length as the stock as a result as i
left the spacer in rather than take out and lengthen the penske. There are
what frank kinsey described as cold tire tears... the sides of the tires
have rubber rolling off, not just  a narrow strip eigther, but the whole
side of the tire..(29lb of air-ft & rear). it did not do this as bad with
the medium tire and i realize the soft is good for only 6-12 laps at race
pace, but i hope the medium will slide less too.
should i change ride height or rebound on the shock or both??? what about
adding links to extend the wheelbase??
thanks
(long but i figured id put all the variables in now..)
2012 FL region & 2014 South East overall champion
Pro Flow Tech Performance Fuel Injector Service
MICHELIN, EBC, Silkolene, JenningsGP, Engine Ice

thetireguy

What was the air temp? Track temp? Did you have them on warmers? How long did it take to start tearing the Soft?

I would give the Pilot Race H2 rear a try. You'll also save $50.00. The H2 is the Medium/Soft and a very good race tire. Quick to come up to temp and durable.




BC61

#2
Were you spinnig the tire before you took rebound out? If not why did you back off the rebound? If so, after you're spinning problem did you try to go back to original rebound setting? Taking rebound out should have made it worse. As long as the bike continues to turn try adding a little rebound or taking some compression out. Try to keep a little weight on the rear tire.

MELK-MAN

QuoteWhat was the air temp? Track temp? Did you have them on warmers? How long did it take to start tearing the Soft?

I would give the Pilot Race H2 rear a try. You'll also save $50.00. The H2 is the Medium/Soft and a very good race tire. Quick to come up to temp and durable.

I do use warmers. the air time was in the 60s-70, track temp im not sure about but it was sunny. The soft was "tearing" after 3-4 sessions. I started out on h2 fronts and rear. The h2 front was just plain dangerous after my times came down. the Medium rear has been GREAT and i decided to try the soft as they are the same price as the m2. However, they are great for about a session or 2. i need a little more life out of a tire given the budget and am going back to the m2.

Talking with Max Mccal. i discovered i had "0"  free sag.. none, the shock was topped out with me off the bike, even with nearly 30mm rider sag. Increased the free sag to about 9mm and will give this a shot...
later

2012 FL region & 2014 South East overall champion
Pro Flow Tech Performance Fuel Injector Service
MICHELIN, EBC, Silkolene, JenningsGP, Engine Ice

MELK-MAN

QuoteWere you spinnig the tire before you took rebound out? If not why did you back off the rebound? If so, after you're spinning problem did you try to go back to original rebound setting? Taking rebound out should have made it worse. As long as the bike continues to turn try adding a little rebound or taking some compression out. Try to keep a little weight on the rear tire.

as posted above, i discovered with talking with Max Mcl. of Traxxion, i had NO free sag. I am going to try the bike after backing preload off nearly 2 turns to get 9mm or so of free sag. Sag with me on the bike is still pretty close to 30mm..
 I talked with frank kinsey at the track the day i was having this difficulty and he and others suggested decreasing the rebound dampening would allow the wheel to rebound back to the track, that it may have been not rebounding fast enough and thus spinning as it was unweighting...i backed the penske off 4 clicks, still was doing it some. went back to mid setting and still.
With the free sag set, im going to see how it does on 1 more soft tire... (had 1 more). then after a session, work on preload up and down again..
thanks..
2012 FL region & 2014 South East overall champion
Pro Flow Tech Performance Fuel Injector Service
MICHELIN, EBC, Silkolene, JenningsGP, Engine Ice