Rubbing issue on track (FD)
02-04-07, 07:57 PM
#1
Rubbing issue on track (FD)
Anyone seen this issue before?
For the record, I'm running 18x10 CCWs. As you can see, I have the M2 lower links. (Yes, I installed the spacers in the right direction.) The wheels do not rub under normal street driving. I am running zero toe and camber in the rear. The tire pressures were a little low--a few psi--due to cold ambient temps. I'm running 285/30 Michelin PS Cups. They are new and have been heat cycled.
The car is lowered on Zeal coilovers, but I'm not running nearly as low as some FDs.
You can see that there was rubbing on both the well and the trailing arm.
The wear pattern was nearly identical on both sides of the car. The car is straight and has never been in a wreck.
-ch
For the record, I'm running 18x10 CCWs. As you can see, I have the M2 lower links. (Yes, I installed the spacers in the right direction.) The wheels do not rub under normal street driving. I am running zero toe and camber in the rear. The tire pressures were a little low--a few psi--due to cold ambient temps. I'm running 285/30 Michelin PS Cups. They are new and have been heat cycled.
The car is lowered on Zeal coilovers, but I'm not running nearly as low as some FDs.
You can see that there was rubbing on both the well and the trailing arm.
The wear pattern was nearly identical on both sides of the car. The car is straight and has never been in a wreck.
-ch
02-04-07, 08:35 PM
#2
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Those rub marks seems to come from the tires.
During hard cornering, tire deflects. And these deflection could go up to .3-.5 inch. Check out these photos at the Bay Area Autocross forum: http://www.baautox.com/forum/index.p...&start=0&rid=0
haven't seen you at the autocross for a while now.
During hard cornering, tire deflects. And these deflection could go up to .3-.5 inch. Check out these photos at the Bay Area Autocross forum: http://www.baautox.com/forum/index.p...&start=0&rid=0
haven't seen you at the autocross for a while now.
02-04-07, 08:59 PM
#3
Well, I was surprised to see rubbing from the CCW setup. Is this common among FDs?
Reza, I haven't been to an autoX for about 1.5 years because that's how long it took me to do my LS1 conversion!
Are you still running your FD in the bay area?
-ch
Reza, I haven't been to an autoX for about 1.5 years because that's how long it took me to do my LS1 conversion!
Are you still running your FD in the bay area?
-ch
02-05-07, 12:07 AM
#4
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If you got that set of wheels of Alex, then yes that wheel was on my car, and at Atwater those Kumho V710 rubs the inner fender.
We did a test with masking tape, and it rubs due to the tire deflection. Did you see the link to baautox?
Oh yea, the CCW did not rub, if its the CCW that rub, then you will have very thin marks, the rubbing definitely off the tires.
Yes, I am still running. They have a new class now, XP = it is X-whatever Prepared..... something like that.... you should be able to put your LS1 FD in there.
We did a test with masking tape, and it rubs due to the tire deflection. Did you see the link to baautox?
Oh yea, the CCW did not rub, if its the CCW that rub, then you will have very thin marks, the rubbing definitely off the tires.
Yes, I am still running. They have a new class now, XP = it is X-whatever Prepared..... something like that.... you should be able to put your LS1 FD in there.
02-05-07, 12:28 AM
#5
Hah! I bought those wheels from Jason who I think got them from Alex. They've been on quite a few bay area FDs!...
I haven't measured them, but I'm assuming they are the +50mm offset that John at CCW uses for all FDs? (In other words, this happens often with the 285/30/18 combo?)
I'm planning on bringing the car out but running it on street tires--the PS Cups take about 1-2 laps to heat up so they'll be useless at the AutoX.
-ch
I haven't measured them, but I'm assuming they are the +50mm offset that John at CCW uses for all FDs? (In other words, this happens often with the 285/30/18 combo?)
I'm planning on bringing the car out but running it on street tires--the PS Cups take about 1-2 laps to heat up so they'll be useless at the AutoX.
-ch
02-05-07, 08:36 AM
#6
My 10 +50's rub a bit in back like that too. It's very close (a compromise for the front really).... in fact, it's down to alignment. You're running 0 camber, and that's the problem. Put a degree or so in, and it won't rub anymore. I actually snagged a 5 mm spacer (apparently made by CCW) from Fritz to help out.
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02-05-07, 11:23 AM
#8
Glad to see it's not totally unusual. I'm going to call CCW about some spacers for the rear.
Does anyone have a recommendation on how best to cover up the exposed steel in the fender well? My inclination is to mask off a 1" border and spray it with Krylon, but if there is a better approach I'd like to hear it.
I'm also going to re-verify the toe settings with my toe gauge. I'm pretty sure the alignment shop got it right, but you never know.
-ch
Does anyone have a recommendation on how best to cover up the exposed steel in the fender well? My inclination is to mask off a 1" border and spray it with Krylon, but if there is a better approach I'd like to hear it.
I'm also going to re-verify the toe settings with my toe gauge. I'm pretty sure the alignment shop got it right, but you never know.
-ch
02-05-07, 02:33 PM
#13
Thanks for the kind words on the car! Great to see another LS1 conversion--and running 10s! That's fast. I really like your oil cooler setup. I have that LG adapter but haven't gotten around to installing it because I can't decide if I'm going to stay with an wet sump (and add an Accusump) or just bite the bullet and go with and LS7.
Back to tire issues: I'm still working out the setup and am running only -1 deg in the front. It's a street alignment; anything more and the car hunts like a 19-year-old at Panama Beach. If I were track only I'd go -2 in the front and -1 in the rear with a bit of toe in on the front.
At Laguna--where my tire pressures were wrong and it was cold as hell--my water temps never went above 180 F the whole session. I was getting a bit of turn-in understeer but you could manage the attitude with throttle/brake pretty well. On power the T-2R diff was very progressive but in 2nd or 3rd it wasn't too hard to get wheelspin if you really provoked it. You could make turn 11 look fun to the observers.
My brakes were shot too, do I didn't push too hard. I'm going to run it again in the Spring when it gets a little warmer.
As far as hamming out the wheel well, I could definitely make room with the 5lb persuader but I'm also rubbing on the M2 trailing arm as well which is already offset inboard.
-ch
Back to tire issues: I'm still working out the setup and am running only -1 deg in the front. It's a street alignment; anything more and the car hunts like a 19-year-old at Panama Beach. If I were track only I'd go -2 in the front and -1 in the rear with a bit of toe in on the front.
At Laguna--where my tire pressures were wrong and it was cold as hell--my water temps never went above 180 F the whole session. I was getting a bit of turn-in understeer but you could manage the attitude with throttle/brake pretty well. On power the T-2R diff was very progressive but in 2nd or 3rd it wasn't too hard to get wheelspin if you really provoked it. You could make turn 11 look fun to the observers.
My brakes were shot too, do I didn't push too hard. I'm going to run it again in the Spring when it gets a little warmer.
As far as hamming out the wheel well, I could definitely make room with the 5lb persuader but I'm also rubbing on the M2 trailing arm as well which is already offset inboard.
-ch
02-05-07, 02:48 PM
#14
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I recently spoke to a fabricator about hammering out the wheel wells. He said the most problematic area is tied into the end of the frame rails and will not move. I believe that is where the scuff marks are in the pictures above.
I wonder how difficult it would be to cut it back a bit and seam weld it. The trailing arms could be curved around the tire to provide more clearance. Obviously it would be a lot of work, but if it would provide enough room for 315s without doing any exterior sheet metal work it might be worth it.
Hyperion. What's the meaning behind your name? Any relation to structured finance?
I wonder how difficult it would be to cut it back a bit and seam weld it. The trailing arms could be curved around the tire to provide more clearance. Obviously it would be a lot of work, but if it would provide enough room for 315s without doing any exterior sheet metal work it might be worth it.
Hyperion. What's the meaning behind your name? Any relation to structured finance?
02-05-07, 05:43 PM
#16
so you run -1 camber in front and you get hunting? what is your caster? mine was too hight at 7 and would hunt like crazy. i put it to 6 and all is good now. FWIW this was with the looped rack.
i have -2 camber in front currently and its great for street. you said you get understeer; i would bet its because you ain't running enough neg camber up front.
in the rear, you have zero camber. did you do any slaloms? i would think the transitions would be really difficult because of oversteer if you had enough speed with the zero camber. but also keep the rear shocks set to softest setting, and put -1.5 camber in the rear. and don't use high psi. in my v700's in back, i was running 25 psi. never ran michelin PS so can't advise.
re: oil cooler. not necessary for autocross, but if you open track the car, i'd do it. even with accusump. getting LS7 is not a bullet to bite, its more like a cannonball. i personally think thats way overkill in the HP and tq dept's and damn, its dangerous on a road course with that much power. especially on stiffly sprung FD. keep the shiny side up
i have -2 camber in front currently and its great for street. you said you get understeer; i would bet its because you ain't running enough neg camber up front.
in the rear, you have zero camber. did you do any slaloms? i would think the transitions would be really difficult because of oversteer if you had enough speed with the zero camber. but also keep the rear shocks set to softest setting, and put -1.5 camber in the rear. and don't use high psi. in my v700's in back, i was running 25 psi. never ran michelin PS so can't advise.
re: oil cooler. not necessary for autocross, but if you open track the car, i'd do it. even with accusump. getting LS7 is not a bullet to bite, its more like a cannonball. i personally think thats way overkill in the HP and tq dept's and damn, its dangerous on a road course with that much power. especially on stiffly sprung FD. keep the shiny side up
02-06-07, 11:21 AM
#20
Yeah, I run 265/35/18 PS2s on 9.5 SSRs for the street...but even those can get a bit nervous over uneven pavement.
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
-ch
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
-ch
02-06-07, 12:16 PM
#21
Probably a combination of less-than-ideal alignment and isolation/complient bushings.
Thoe cars are also heavier, so they'll not be as sensitive.
Thoe cars are also heavier, so they'll not be as sensitive.
Originally Posted by hyperion
Yeah, I run 265/35/18 PS2s on 9.5 SSRs for the street...but even those can get a bit nervous over uneven pavement.
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
-ch
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
-ch
02-06-07, 12:47 PM
#22
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Originally Posted by hyperion
Yeah, I run 265/35/18 PS2s on 9.5 SSRs for the street...but even those can get a bit nervous over uneven pavement.
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
Yeah, I run 265/35/18 PS2s on 9.5 SSRs for the street...but even those can get a bit nervous over uneven pavement.
Last edited by CMonakar; 02-06-07 at 12:53 PM.
02-06-07, 02:51 PM
#23
Originally Posted by hyperion
I'm very curious to understand what people like Chevrolet do to make such wide tires work predictably on the 'Vette.
02-06-07, 03:06 PM
#24
Cmonakar, I'm not sure what you mean...I'm pretty sure the 265 is the ideal tire for the 9.5" rim.
Mahjik, I drove a C6 Z51 recently and I didn't notice much hunting, even on the ultra-crappy California freeways. But then again, I wasn't paying much attention to it...
-ch
Mahjik, I drove a C6 Z51 recently and I didn't notice much hunting, even on the ultra-crappy California freeways. But then again, I wasn't paying much attention to it...
-ch
Last edited by hyperion; 02-06-07 at 03:30 PM.
02-06-07, 03:28 PM
#25
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My only point was that the 255 with an overall diameter of 25" is closer to the stock overall diameter of ~24.8 than the 265 which is .5" larger than stock. As far as being ideal for a 9.5" rim, they're both within .25" of the middle of the range.
255 8.5-10" (9.25 mid point)
265 9-10.5" (9.75 mid point)
If a choice is going to be made based on width, isn't it better to be on the upper end of the rim size spectrum?
-Chris
255 8.5-10" (9.25 mid point)
265 9-10.5" (9.75 mid point)
If a choice is going to be made based on width, isn't it better to be on the upper end of the rim size spectrum?
-Chris