Wheel Spacer Advice for NB 996
07-18-2011, 10:19 AM
#17
Burning Brakes
That is correct..I should have said with stock wheels you can't go wrong with the 15mm spacers. The GT3 wheel has a little more aggressive offset in the front bu the rears are about the same as stock. Thant having said I am running the spacers with the BBS REs adn they are fine.
07-18-2011, 11:22 AM
#18
Nordschleife Master
07-18-2011, 11:49 AM
#19
Instructor
Thread Starter
pterfloth.....the best example is to use Jake's picture. I'm guessing he is saying for you to add 15mm spacers to get the look he has. Why? The wheels on his car are GT3 wheels which have the following specs (8.5 et40 and 11 et63). I run the GT3 wheels on my 2000 CAB and they are perfect.
Here's how much "theoretical" spacer they have compared to your 7.5et50 and 10et65 wheels.
Front difference 7.5et50 --> 8.5et40 equates to adding a 22.5mm spacer to your 7.5 wheel.
Rear difference 10et65 --> 11et63 equates to adding a 14.5mm spacer to your 7.5 wheel.
Putting on 15mm spacers front and rear would be just fine. I would NOT go more than 15mm in the rear as that is about as maxed out as you can go without putting the tire at risk from compression. The biggest problem you have is the 7.5et50 was the least aggressive of the 18" wheels that were on the 996. FYI....Porsche sells a 17mm spacer that does not require longer bolts. It is a spacer with studs built in. I have a set that I ran on my Turbo with narrow body wheels. Here is what they look like LINK
Here's how much "theoretical" spacer they have compared to your 7.5et50 and 10et65 wheels.
Front difference 7.5et50 --> 8.5et40 equates to adding a 22.5mm spacer to your 7.5 wheel.
Rear difference 10et65 --> 11et63 equates to adding a 14.5mm spacer to your 7.5 wheel.
Putting on 15mm spacers front and rear would be just fine. I would NOT go more than 15mm in the rear as that is about as maxed out as you can go without putting the tire at risk from compression. The biggest problem you have is the 7.5et50 was the least aggressive of the 18" wheels that were on the 996. FYI....Porsche sells a 17mm spacer that does not require longer bolts. It is a spacer with studs built in. I have a set that I ran on my Turbo with narrow body wheels. Here is what they look like LINK
07-21-2011, 04:35 PM
#22
Instructor
Thread Starter
I was all set to order a set of 15 mm H&R spacers and bolts when a pair of the 17 mm OEM spacers you referenced came up on EBay, which I bought. Are these going to be too wide for rear with a 265 tire?
07-22-2011, 12:52 AM
#24
Instructor
Thread Starter
The 265's on the back are too narrow and have no bulge at all on the 10" rim, but they were brand new on the car when I bought it last summer. When they are in need of replacement I will go for a 285 or 295 and review the wheel spacer fitment at that time. I put 12,000 km on them in the last year, weekend pleasure driving only, so that probably will be next summer.
07-22-2011, 09:11 AM
#25
Nordschleife Master
I'd go with the 285 for the 10" and the 295 for the 11".
It's different, but not drastically different with the 265 in the rear, compared with the 285.
It's different, but not drastically different with the 265 in the rear, compared with the 285.
07-22-2011, 09:25 AM
#26
Race Car
I love excuses to dig up old picturs. This is my old C2 with 15mm spacers front and rear on Sport Design wheels.
Couple of notes not that it makes much difference, my fronts were 8" not the standard 7.5", but I think the effective offset was not much different.
Car is pictured on H&R springs with M030 dampers. When it got lower on coilovers the fit was even better.
Couple of notes not that it makes much difference, my fronts were 8" not the standard 7.5", but I think the effective offset was not much different.
Car is pictured on H&R springs with M030 dampers. When it got lower on coilovers the fit was even better.
07-22-2011, 10:25 AM
#27
Pro
I don't think it's the same as bump steer if that's what you're referring to...
Last edited by sandersd; 07-22-2011 at 12:12 PM.
07-22-2011, 08:35 PM
#28
Nordschleife Master
Sanders......
You are confusing nouns and verbs and the terminology used in the racing/DE engineering world.
Bump steer is the change in geometry (more specifically toe) when the car is under compression
Bump (also called compression) is the when the damper compresses from load
Rebound is when the damper releases back from from said compression.
Adjustable dampers (ala Moton, JRZ, etc) have settings to adjust bump and compression so you can the change in direction of the rod inside the damper can be dialed in for a specific direction of travel rather than equal both directions
You are confusing nouns and verbs and the terminology used in the racing/DE engineering world.
Bump steer is the change in geometry (more specifically toe) when the car is under compression
Bump (also called compression) is the when the damper compresses from load
Rebound is when the damper releases back from from said compression.
Adjustable dampers (ala Moton, JRZ, etc) have settings to adjust bump and compression so you can the change in direction of the rod inside the damper can be dialed in for a specific direction of travel rather than equal both directions
07-23-2011, 01:23 PM
#30
Pro
Sanders......
You are confusing nouns and verbs and the terminology used in the racing/DE engineering world.
Bump steer is the change in geometry (more specifically toe) when the car is under compression
Bump (also called compression) is the when the damper compresses from load
Rebound is when the damper releases back from from said compression.
Adjustable dampers (ala Moton, JRZ, etc) have settings to adjust bump and compression so you can the change in direction of the rod inside the damper can be dialed in for a specific direction of travel rather than equal both directions
You are confusing nouns and verbs and the terminology used in the racing/DE engineering world.
Bump steer is the change in geometry (more specifically toe) when the car is under compression
Bump (also called compression) is the when the damper compresses from load
Rebound is when the damper releases back from from said compression.
Adjustable dampers (ala Moton, JRZ, etc) have settings to adjust bump and compression so you can the change in direction of the rod inside the damper can be dialed in for a specific direction of travel rather than equal both directions
My point was the comment didn't seem relevant since spacers don't change the suspension geometry, if indeed the reference was to bump steer. In regards to bump (i.e. compression and rebound), although one could argue the increased width would act like a longer lever arm and affect interaction with the spring (rate), I suspect it would be nominal and somewhat independent from the action of the dampers. Still, calculations could be done to verify...
Not trying start anything - I'm just explaining myself since my sense of humor doesn't always come across as I intend it on the forum. ( I'm still not sure what you meant since you didn't explain how spacers and compression are an issue.)
I put the 18mm's on and I think they look fantastic.
