Who is running 18x10 front and rear?
12-26-2008, 08:34 PM
#18
Rennlist Member
The ET value from the front wheels has to stay close to the original, ET45 to ET 50 for a late offset car. Otherwise you will ruin the geometry of your front setup, and break the carcas (if that is a correct word) of your tires. Dunlops are most sensitive to this, Michelins the most resistant.
Rear it does not matter, you can use spacers to your hearts content.
Rear it does not matter, you can use spacers to your hearts content.
What does the OP want to do with the car as well?
12-27-2008, 08:59 PM
#19
Rennlist Junkie Forever
The ET value from the front wheels has to stay close to the original, ET45 to ET 50 for a late offset car. Otherwise you will ruin the geometry of your front setup, and break the carcas (if that is a correct word) of your tires. Dunlops are most sensitive to this, Michelins the most resistant.
Rear it does not matter, you can use spacers to your hearts content.
Rear it does not matter, you can use spacers to your hearts content.
Hans,
As another data point, I run a late offset suspension setup and run a ET 55 factory 9" Cup 2 wheel (275 tire) on the front with no problems on the track with R compound tires.
And, I'm about to have those widened to 10" and run a 1/2" spacer (to maintain the same relative offset) or evel 11" and run a 1" spacer to maintain the same relative offset (I run a 1" wider fiberglass front fender, but the 275's fit fine on the stock fender).
TonyG
12-28-2008, 04:51 AM
#20
Rennlist Member
Thread Starter
333 the car is going to be a DE/track toy. I'm debating about kitting it out for one of the cup classes but am leaning away from that at the moment.
TonyG, I have those cup wheels on the back of the car at the moment (I believe; just bought the car and think there's a 55et back there - I'll have to go check)
TonyG, I have those cup wheels on the back of the car at the moment (I believe; just bought the car and think there's a 55et back there - I'll have to go check)
12-28-2008, 07:52 AM
#21
Rennlist Junkie Forever
333 the car is going to be a DE/track toy. I'm debating about kitting it out for one of the cup classes but am leaning away from that at the moment.
TonyG, I have those cup wheels on the back of the car at the moment (I believe; just bought the car and think there's a 55et back there - I'll have to go check)
TonyG, I have those cup wheels on the back of the car at the moment (I believe; just bought the car and think there's a 55et back there - I'll have to go check)
I have rear cup 2 wheels on the front (9") and widened rear cup 2 wheels on the rear (widened by 2").
TonyG
12-28-2008, 11:25 AM
#22
I have a different point of view...
I have a hard time believeing that people need to go that wide in the front of a properly set up car.
Let me preface that comment by saying my car only puts out about 200HP to the rears but my braking with the S4 calipers is as good as anyone else I've ever run against and in the corners my limiting factor is the rears. (as I like it that way) I can currently run 2:17-19 at VIR for a speed reference...
That's why for next year I'm going from 245's all around to 245/275's.
As a point of reference the CUP cars don't run 285's in front and the 944 series has the benefit of having the engine in the front for added weight transfer upon braking that makes very wide tires irrelevant. If your car is understeering that badly you need to adjust your set up first.
Remember, the added mass of those wheels and tires is not a good thing....
Flame suit is on...
I have a hard time believeing that people need to go that wide in the front of a properly set up car.
Let me preface that comment by saying my car only puts out about 200HP to the rears but my braking with the S4 calipers is as good as anyone else I've ever run against and in the corners my limiting factor is the rears. (as I like it that way) I can currently run 2:17-19 at VIR for a speed reference...
That's why for next year I'm going from 245's all around to 245/275's.
As a point of reference the CUP cars don't run 285's in front and the 944 series has the benefit of having the engine in the front for added weight transfer upon braking that makes very wide tires irrelevant. If your car is understeering that badly you need to adjust your set up first.
Remember, the added mass of those wheels and tires is not a good thing....
Flame suit is on...
12-28-2008, 11:43 AM
#23
As you get more power, more rubber makes sense. Seems like you need the rubber where the weight is, the 911's all run staggered setups because they have more weight in back.
West is someone I've watched on track who is very fast on the square setup, the suspension can be adjusted to make it neutral. I'm going with the square setup for next year as much to get cost down as anything else. If you can rotate tires you can get more out of them.
West is someone I've watched on track who is very fast on the square setup, the suspension can be adjusted to make it neutral. I'm going with the square setup for next year as much to get cost down as anything else. If you can rotate tires you can get more out of them.
12-28-2008, 05:16 PM
#24
Rennlist Member
The ET value from the front wheels has to stay close to the original, ET45 to ET 50 for a late offset car. Otherwise you will ruin the geometry of your front setup, and break the carcas (if that is a correct word) of your tires. Dunlops are most sensitive to this, Michelins the most resistant.
Rear it does not matter, you can use spacers to your hearts content.
Rear it does not matter, you can use spacers to your hearts content.
12-28-2008, 05:18 PM
#25
Rennlist Member
333 the car is going to be a DE/track toy. I'm debating about kitting it out for one of the cup classes but am leaning away from that at the moment.
TonyG, I have those cup wheels on the back of the car at the moment (I believe; just bought the car and think there's a 55et back there - I'll have to go check)
TonyG, I have those cup wheels on the back of the car at the moment (I believe; just bought the car and think there's a 55et back there - I'll have to go check)
01-05-2009, 07:04 PM
#27
Rennlist Junkie Forever
Why would that be?
Let me preface that comment by saying my car only puts out about 200HP to the rears but my braking with the S4 calipers is as good as anyone else I've ever run against and in the corners my limiting factor is the rears. (as I like it that way) I can currently run 2:17-19 at VIR for a speed reference...
With respect to your lap times at VIR.... I've never run VIR. But with 200RWHP running a 245/275, no matter the weight of your car... you'd get killed (lapped) out here at the tracks in southern California.
The super fast 951's run a 295 or a 315 on the front and either a 315 or 335 on the rear. These are cars that run in 996 cup car range (both with very fast drivers).
As a point of reference the CUP cars don't run 285's in front
Comparing what a cup car runs on the front to what a 944 runs is silly. I don't even know where to begin to address that.
Have you put a cup car on the scales? If you did, then you'd see why they don't run a 285 on the front.
Go read "how to make your car handle" by Fred Puhn.
TonyG
01-05-2009, 08:40 PM
#28
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Why would that be?
OK. Nice, but I'm not sure it means much. You haven't said a single thing about the weight of your car, nor the aerodynamics, nor the tires you run, etc.
With respect to your lap times at VIR.... I've never run VIR. But with 200RWHP running a 245/275, no matter the weight of your car... you'd get killed (lapped) out here at the tracks in southern California.
The super fast 951's run a 295 or a 315 on the front and either a 315 or 335 on the rear. These are cars that run in 996 cup car range (both with very fast drivers).
Yeah so?
Comparing what a cup car runs on the front to what a 944 runs is silly. I don't even know where to begin to address that.
Have you put a cup car on the scales? If you did, then you'd see why they don't run a 285 on the front.
Go read "how to make your car handle" by Fred Puhn.
TonyG
OK. Nice, but I'm not sure it means much. You haven't said a single thing about the weight of your car, nor the aerodynamics, nor the tires you run, etc.
With respect to your lap times at VIR.... I've never run VIR. But with 200RWHP running a 245/275, no matter the weight of your car... you'd get killed (lapped) out here at the tracks in southern California.
The super fast 951's run a 295 or a 315 on the front and either a 315 or 335 on the rear. These are cars that run in 996 cup car range (both with very fast drivers).
Yeah so?
Comparing what a cup car runs on the front to what a 944 runs is silly. I don't even know where to begin to address that.
Have you put a cup car on the scales? If you did, then you'd see why they don't run a 285 on the front.
Go read "how to make your car handle" by Fred Puhn.
TonyG
01-21-2009, 04:48 PM
#29
Rennlist Member
bump.
I'm going through this debate at the moment and would like some more input from anyone with experience. My tire guy is reluctant to go up to a 285 on my car but these guys are so used to having cars with a staggered setup. His point about the wider front tire misbehaving under braking could be valid though no?
Tony, I'll try to phone you on the weekend.
I'm going through this debate at the moment and would like some more input from anyone with experience. My tire guy is reluctant to go up to a 285 on my car but these guys are so used to having cars with a staggered setup. His point about the wider front tire misbehaving under braking could be valid though no?
Tony, I'll try to phone you on the weekend.
01-21-2009, 07:04 PM
#30
I run a power rack without power with big blacks. I run 17x9.5 or 18x10 on the front and have NEVER had any wierdness with braking. Believe me, with that setup, if it was wierd, I'd know it. I suppose it's possible to have an alignment that causes it to be a problem under braking. OTOH, in my experience, most mechanics are dead set against doing anything they haven't done before, especially if you read about it on the web! :-) Which is one of the reasons I do my own work.
West
West