Luke Huxham

Hey guys,

First time poster due to finally purchasing my own 997.1 GT3 recently. Anyway I live in Japan and will be picking up my new car next week and the previous owner put some horrible 20inch wheels on the car which need replacing immediately along with some equally as bad coilovers. Now I know my way around Japanese cars and have been drifting / racing them for 6+ years but when it comes to Porsche its a whole new ball game for me. I'm unsure of the limits when it comes to wheels hitting coilover struts or not clearing brake caliper. Obviously i know the standard offsets and size to roughly go by but would like to double check with some people on here that have more knowledge than myself. I have some Bilstein ClupSport lined up to dropped in as well.

I have some good relationships with Japanese wheels makers and tyre makers here in Japan and with that being said I will be looking at moving down to 18 inch wheel from the original standard 19 inch wheels and I will also be going to widths of 18x9 and 18x11 with very sticky Advan Neova AD08r tyres for street and track.

These are the sizes and offset chart of the wheels I would like to get... Is there any guidance you give me as to which 18inch / offset setup will work best? PCD will be custom to 130 but I'm a little unclear with disk clearance etc..
http://www.ssr-wheels.com/wheels/whe...=500&width=700

With tyres the 18x11's would be wrapped in a Neova AD08r 295/30 and then for the front I'm thinking a 18x9 with 255/35's. I don't foresee the extra 5mm upfront in tyre profile being a huge problem but still advice is always welcome. One thing is very clear though, I'm not wanting to run 19's for daily and track use and current apartment in Tokyo has no room for multiple stacks of daily / circuit wheels.

Many thanks in advance for any help.

Best regards,


Luke.H

These are the SSR wheels.

Spyerx

Gt3 run 12" rears with 305 rubber
Do you have steel or pccb? If steel most wheels should clear
If you will run an 11" rear you need an aggressive offset or it will look weird
I've seen this with volks on gt3


These are bbs 18" specs:
9" ET + 50.0
12" ET + 64 w/o factory 5mm spacer

Luke Huxham

Hey Spyerx, your car looks great!

My GT3 is steel, didn't want the PCCB hassles. Yep I know the GT3 runs a 12" 305 standard thanks. My previous experience with cars makes me no stranger to low offset wheels. My old AE86 drift car use to run wheels with sizes around 14x9.5 -38, this was for getting wider track and making a shorter wheel base car more stable when throwing it sideways. This of course is not something I want to do with my Porsche but I do know like you said I will have to run a lower offset. Running a 18x12 is not a problem it's finding street radial tyres to fit because most most tyre makers in Japan at least make no bigger than a 295/30/18 street radial.

As far as grip is concerned when running a 295 street radial compared with the standard Porsche shipped Michelin 305 tyres, I'm not really that worried. The Nevoa AD08r is light years aheads of those 305 Michelin's. It's just trying to figure out what exact offset I should run to keep the 18x11 wheels and tyres nice and flush around the guards and also not to mess up the geometry too much and to keep it balanced. 19inch is just not for me unless I'm doing more damage than good by going with the 18inch setup I'm talking about in here.

I'm think offset along the lines 18x11 +56 for the rear will be safe, then I can add or subtract the 5mm depending on fitment but just not too sure.

CosmosMpower

Go 18X9 18X12 I like CCW

Luke Huxham

Sorry I think you're missing the point, I'm not going to go 18x9 and 18x12 because you or someone else simply likes them I also can't find 18inch street radial rubber in a 305 width and don't want to stretch 295's over a 12inch wheel. I want a nice 18inch street radial friendly setup.

The tyres I plan to run Neova AD08r, feel almost like a semi slick but with radial lines cut into them. These tyres I can also get at very good rate.

r6elmo

i run AD08R street/track with 255/305. The 255s in front work and don't rub. If you go 255/295 then it should make for a more over-steer happy setup. I would adjust the sway bars accordingly, but really depends if you push the car or not.

are you going 295 in rear mainly b/c advan only makes it in 295 for 18s? Consider Nitto NT01? I believe they have 305 in 18s.
OEM the GT3 runs 305 over a 12" wheel, i believe the 997.1 Turbo runs 305 over a 11" or 11.5" wheel so not as stretched.

Luke Huxham

You have these mounted to 18" wheels or are you talking about 19" as my whole thread is about using an 18" setup but I noticed you said 305's which are only available in 19".

Cheers for input.

r6elmo

correct it's on my 19s. just giving you feedback as to tire width.
as cosmos said most running 18s go for a 235/245/255 + 305/315 setup or the like.

Luke Huxham

Was going to run Advan Neova because I will basically be getting them free and if or when I have pay for them they will be extremely cheap. That's why I was trying to adopt my car to a 255 / 295 setup, I have used Neova's for over 6 years and can't find a better street radial tyre. They also seem to not get as greasy as other tyres do when pushing them hard lap after lap on circuit from my experience.

Spyerx

You seem to have decided your path so not really clear what your question is at this point.

Nt01 is a decent tire for the street until the tire is down to 4/32 and only has center grooves.

It is available in 18 in 305. I run this exclusively with 245 front. Street and track.

Can you post the outside mounted circumference for the tires you are considering? These cars are very sensitive to rake and f/r tire circumference ratios.

Luke Huxham

Do not know the outside mounted circumference sorry.
Guess I'm just trying to find a nice offset that will allow me to run 18x11 rear and if someone else has info about this as well.

Spyerx

You need to find that. If you want your car to work when pushed and not screw with your ABS.

The offsets are easy. I posted the bbs e88 specs for a narrow body. Plug those into a calculator with the change in rim widths and you can get the equivalent. Bbs fit very flush and look perfect.

If I did the math right a 51 offset 11" wheel will sit same on the outside as a 12 at 64. You will have a bunch more more inner clearance obviously.

CosmosMpower

NT01

MC 968CS

Hello. I run Yokohama AO50 18" track rubber and its works very well. On my 997.1 GT3

I don't suggest your sizes. I'd go normal 235 front and the 295.35 rear if available.

Re narrower rear you are spot on. The r spec Neova rubber will be far more grippy than other Oem type rubber, it's nothing to worry about.


Re offsets.....just copy what's known to work. Look up Advan racing and their 18" light weight race wheels for 997.1 GT3, in Japan. Look up their website and grab the offset. A couple of mates run them and it's sorted for you. Or just buy them.

Enjoy.

Luke Huxham

Thanks Spyerx, ABS was also my concern but one of my friends said if you keep the offsets correct with the right tyre sizes it should all me fine. Cheers for the offset info as well!


Thanks MC 968CS, this was exactly the info I was looking at just to reassure me. Yep I was looking at the Advan offset and originally was going to get Advan wheels but I quite like the look for the SSR's more so just have to make sure the centre disk does not cause any issues because they offer 4 difference centre disk styles.

One things I seen on the web regards 235's was someone saying it triggered their tyre senosors and that's why he changed to a 245. No issues with yours running 235?