PhilT3 (PT3)

(Dismissing the BBS magnesium wheel here)

So it looks like the lightest wheel on the market is the BBS FIR.

Here's a question for the smart guys out there.

With tires, will a 'light/racing-duty' (forgeline, HRE, BBS) 19'' wheel and tire package be:
1. Lighter than the FIRs
2. Heavier...
3. About the same.

What say you?

TRAKCAR

Have 19" been done on track?
What tires will you run and will SC TC and the RWS / electronic variable diff still be happy?

I've posted this elsewhere but I haven't read about anyone seriously tracking a different wheel / tire package.

nwGTS

Way too many variables to give a 'correct' answer but consider this...
The two major variables in like tires and like wheels going from 18 to 19 is aluminum, rubber and then less but still a variable is the steel/nylon/kevlar or whatever else is used to reinforce the belts and sidewall.

The difference in mass from 18 going to 19 with like tires and wheels in negative. So a 19 wheel package will be lighter. (Rubber has more mass than the aluminum replacing it in the step up in size).

This is just for aluminum. Metals with less mass (magnesium) will have even greater delta. Wheels with more mass (steel) will have lower or even positive delta depending on how much more mass.

Note: this is for commonly available consumer street/R/slick tires. Specialty rubber is extremely light (F1 for example). In that case you can toss the above out the window.

PhilT3 (PT3)

Hey bud. Your questions are 100% valid.

I believe GMG has had a couple of customers running 19's.

As for the technical concerns....again...valid and something to consider.

I'm hoping the smart guys can weigh in on that.

PhilT3 (PT3)

Thanks for this information, nwGTS..!!

Though, I'm not sure I completely follow. Do you have any thoughts on running 19's on the RS? I ran 19's on my GT3 with no issue/concern. However, the RS is running a 21" rear and so I take more pause as it's a greater delta from 19".

Your thoughts?

Thanks again.

Jamie@dundonmotorsports

As long as tire choice is chosen based on overall diameter to match the 21" rears (meaning 35 or 40 series aspect ratio for a 19" wheel), then the DSC and RWS should be fine.

Also if we keep the differential between front to rear close it will be fine. I did this with the 19" 265/325 hoosiers on my GT3 and it's been stellar...

PhilT3 (PT3)

Thanks Jamie.

I too had great success with my 19's on my GT3. Its the difference between the 21 and 20 that make me take pause.

Jamie@dundonmotorsports

So just looked into it...

Stock Front 265 35 20 with diameter of 27.3"
Stock Rear 325 30 21 with diameter of 28.7"
difference of 5.1% front to rear


Closest 19" R7
265 35 19 with diameter of 26.1"
325 30 19 with diameter of 26.8"
Difference of 2.7%

It may work out but ideally would want someone to just bolt the wheels and tires from my GT3 on to their RS and see if the car freaks out...

Anyone on in the Seattle are just stop by the shop and we can give it a shot!

PhilT3 (PT3)

Thanks Jamie!

Looks like I'll be waiting to make a decision on aftermarket wheels.

Forgeline GA1R's in 19" weigh (on avg)
19x9.5 - 19 lbs
19x12 - 21 lbs

BBS FIR in factory RS sizes are:
20x9 - 17.4 lbs
21x12 - 23.5 lbs

Seems like a 'wash' from a weight perspective. So now it comes down to the overall height difference and the delta between the fronts and rear. Too much science/math for me!

mooty

on RS, run oem size
other size... u will find out the hard way

PhilT3 (PT3)

Yeah....that's what I'm thinking...

Was hoping to have more tire choices.... oh well.

mooty

^ no real tires choices, to fix that i bought another car hahah

PhilT3 (PT3)

Oh man...that's a nice option to have!!

SupremePower

Ofcourse you did!

mooty

it's nothing spectacular trk use only. no luxury leather and such
coming jan
rolls on bbs of courses