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Discussion Starter · #1 ·
Hi

I am ordering a set of 18" wheels for my Cayman S gen2. Most common combo I have seen is 18X8.5 front with Et50 and 18X10 with Et 36. Champion Rg 5 etc..

I am thinking going with 18X9 front and 18 X10.5 on the rear for my track setup. I will be using stock suspension with PASM to start with. so running aggressive negative camber to fit wider tires up front is not an option until the make some changes. Plan is also to use 245/ 40 front and 275 / 40 rears. with an option to go with wider sizes in the front and rear at a later date. Idea is to keep the ratio on front and back in line to avoid understeer issue.

Looking for suggestions on the offset and any pro and cons on the rim width ? I have seen some threads with 18X10.5 et 38 as a combo that worked. Can someone confirm this. Any suggestions on the front. Will 18X9 with Et 51 work with a 245 or 255 tire on the front ?

Thanks
 

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In the front you can use 8.5 et51 down to 44. We spec most of our wheels with the 44mm offset, but also sell Champion one piece wheels with et51. We have fit a 9.0 et 45 on the front with a 245. That car had lots of negative camber but had plenty of room. If you go with a 9.0 51 and you find it tight on the strut you can always use a thin spacer. With camber you can get without stock suspension you can use either the 8.5 et51 or 8.5 et44

On the rear the 10 et36 is popular as that is what the Champion one piece wheels are. We have built 10.5 et38, 11.0 et38, 10 et36.

If you are going to go with a one piece wheel you are a little limited in choice, but the Champions fit will and will work with your 245/275 tire choice, we run the RG5 on our Cayman with those widths in 19 inch. In a multipiece wheel you have a few more options.

Cheers
 

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Discussion Starter · #3 ·
Thanks for the quick response.

I realize that going with 18X9 with et51 will reduce inner space by 6MM compared to 18X8.5 with Et50..if I stick with 18X9 et50..wheel will stick out more...will it hit the fender without negative camber..? I dont want to use spacers..I am thinking ET50 is better since it does not chnage inner dimension. You said you have seen fronts go to ET44 ...on 9 " width will wheel not stick out a lot..?

I guess I could do 18X10.5 at the rear with 36 or 38 and both would work right? BTW these are multi piece wheels. So I have the flexibility to with custom width / offset

Thanks again
 

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Here is a pic of a 9.0 et45 wheel with a 245 tire. This car has -2.5 degrees of camber mind you at that makes a big difference..... but we could have put a 5mm spacer in there still on this car....

Let us know if we can help with your multi piece wheel needs. We are dealers for Fikse, HRE and Forgeline for multipiece.

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And a 10 et36 with a 275 (19 inch this time) the front wheels are 8.5 et51 with a 5mm spacer netting an et46 with a 245 tire...
 

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Thanks for the quick response.

I realize that going with 18X9 with et51 will reduce inner space by 6MM compared to 18X8.5 with Et50..if I stick with 18X9 et50..wheel will stick out more...will it hit the fender without negative camber..? I dont want to use spacers..I am thinking ET50 is better since it does not chnage inner dimension. You said you have seen fronts go to ET44 ...on 9 " width will wheel not stick out a lot..?


Thanks again
The 1mm will likely not make any difference.

When I say spacer, I mean shim. A 3-5mm spacer (shim) still allows the wheel to be hubcentric and causes no issues what so ever. If you use an 8.5et51 or a 9.0 et51 the centerline of the tire is still in the same location. Yes the shoulder gets pulled out a little more on the wider wheel, but not the full extra width of the wheel. We fit the 8.5 et44 with stock suspension and 245 tires with no issues. That wheel has the same "front space" as a 9.0 et51...

If you plan to go to coil overs in the future, and remain under 2.0 degrees of camber, I would use the 8.5 et44.

Cheers
 

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Discussion Starter · #8 ·
thanks Jeff.

I am waiting on the wheel weight info before deciding on 18X8.5 ET 46/ 18X10 Et 36 vs. 18 X9 et 48 / 18 / 10.5 et 38

if the weight increase due to wider wheels is significant I will stick with first combo. I see that you fit 18X9 with ET45 on a car with a lot negative camber..I will go more conservative and stick with Et 48.

can i use stock 235 / 265 width on 18X9 / 18X10.5 respectively without issues?
 

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Hi

I am ordering a set of 18" wheels for my Cayman S gen2. Most common combo I have seen is 18X8.5 front with Et50 and 18X10 with Et 36. Champion Rg 5 etc..

I am thinking going with 18X9 front and 18 X10.5 on the rear for my track setup. I will be using stock suspension with PASM to start with. so running aggressive negative camber to fit wider tires up front is not an option until the make some changes. Plan is also to use 245/ 40 front and 275 / 40 rears. with an option to go with wider sizes in the front and rear at a later date. Idea is to keep the ratio on front and back in line to avoid understeer issue.

Looking for suggestions on the offset and any pro and cons on the rim width ? I have seen some threads with 18X10.5 et 38 as a combo that worked. Can someone confirm this. Any suggestions on the front. Will 18X9 with Et 51 work with a 245 or 255 tire on the front ?

Thanks
In terms of the wheel size I plan on going with 9' fronts 245/18 and 10" rear wheels with 275/18. This will give you extra tire you want and will leep the 1" width difference between front and rear wheels.

Have driven some race cars that have much wider rear wheels than fronts and don't like the balance. Like many things this is a personal choice.
 

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The 19 inch 987 wheels were 8.0/9.5 so adding and inch would give your 9.0/10.5 in 19 which works well in 18 as well.

Typically weight goes up about 1 pound for each inch of width. So plan about a half a pound for a half inch on the same wheel.

Cheers
 
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