18" or 19" rims on GT4
#151
Hi all. Subscribed, as this will be my GT4 fun till delivery in June.
For SCCA street class, we can go 1" down but no wider, and currently
a GT4 would have to, because the stickiest 200tw tires (that's the minimum
tw allowed) such as the RE-71R don't come it 20" at all...
So unless things change, I'll be in the market in June for a 19"x8.5"
and 19"x11" ideally. The drop in overall diameter would help a lot
because we'll be in second mostly, and that's awfully tall.
For SCCA street class, we can go 1" down but no wider, and currently
a GT4 would have to, because the stickiest 200tw tires (that's the minimum
tw allowed) such as the RE-71R don't come it 20" at all...
So unless things change, I'll be in the market in June for a 19"x8.5"
and 19"x11" ideally. The drop in overall diameter would help a lot
because we'll be in second mostly, and that's awfully tall.
19" X 8.5" front wheels (up to 6mm less Offset would be OK)
19" X 11" rear wheels (up to 6mm less Offset would be OK, but might get tight on fitment with fender)
I have seen 19" BBS, and HRE wheels clear the PCCBs. Does anyone know if the 19" X 11" rears clear with no changes to Toe Links?
Last edited by jpgunn; 12-20-2015 at 10:47 PM. Reason: Clarity
#152
Former Vendor
I am in the market for SCCA Street class legal wheels (that clear PCCBs) as well:
19" X 8.5" front wheels (up to 6mm less Offset would be OK)
19" X 11" rear wheels (up to 6mm less Offset would be OK, but might get tight on fitment with fender)
I have seen 19" BBS, and HRE wheels clear the PCCBs. Does anyone know if the 19" X 11" rears clear with no changes to Toe Links?
19" X 8.5" front wheels (up to 6mm less Offset would be OK)
19" X 11" rear wheels (up to 6mm less Offset would be OK, but might get tight on fitment with fender)
I have seen 19" BBS, and HRE wheels clear the PCCBs. Does anyone know if the 19" X 11" rears clear with no changes to Toe Links?
#153
Rennlist Member
Tire data I pulled together. Let me know if you want to be able edit to update/edit google sheet.
Attachment 997814
Attachment 997814
Thank you for posting the above chart. I was doing the math on some tire choices before you posted the chart and boy that chart made it allot easier. However, I want to point out that in the R7 tire columns there is an error. The rear tires all have the same height with different tires. The first R7 column has the rear tire at 315/30-19 with a 26.1" height and the second R7 Column has a 295-30-19 Rear at 26.1 on the same size wheels. The 315/30-19 Rear in the first R7 column actually has a height of 26.44 , which deviates from the front to rear aspect ratio of the stock tire and wheel combo. The 295/30-19 R in the second R7 column has a height of 25.97 vs its front 25.5" height(235/35-19), the closest to stock aspect ratio. So a good choice, if no adjustments are to be made to the suspension, is 235/35-19 Front and 295/30-19 rear. I did see that you mentioned changing the suspension height to better suit the wider front tire for the third R7 column choice.
Last edited by acropora157; 12-21-2015 at 09:31 PM.
#154
Thank you for posting the above chart. I was doing the math on some tire choices before you posted the chart and boy that chart made it allot easier. However, I want to point out that in the R7 tire columns there is an error. The rear tires all have the same height with different tires. The first R7 column has the rear tire at 315/30-19 with a 26.1" height and the second R7 Column has a 295-30-19 Rear at 26.1 on the same size wheels. The 315/30-19 Rear in the first R7 column actually has a height of 26.44 , which deviates from the front to rear aspect ratio of the stock tire and wheel combo. The 295/30-19 R in the second R7 column has a height of 25.97 vs its front 25.5" height(235/35-19), the closest to stock aspect ratio. So a good choice, if no adjustments are to be made to the suspension, is 235/35-19 Front and 295/30-19 rear. I did see that you mentioned changing the suspension height to better suit the wider front tire for the third R7 column choice.
FYI - All the other specs in the table are from the manufacturer - not calculated from the labeled sizes.
UPDATE: I spoke with Hooiser today, they said the sizes are correct. 26.1 on both the 295 (mounted on 10" rim) and 315 (mounted on 11" rim).
Last edited by ShakeNBake; 12-22-2015 at 11:20 AM.
#155
Rennlist Member
I need to take some pics - but we got it all setup now. 265 will work on the front, as will a 11" on the rear. Forgeline got it dead on. To get -3 in the front with adjustment for the tire size in ride height (rake), -5mm, and get all the clearance maxed out, you will need BGB;s toe kit, and Tarret thrust-arm pucks to get the caster close to stock (9 degrees). John at BGB helped me get it dial'd in with advice and parts, soulspeed in austin maniacally perfected the alignment.
Austin peeps - highly recommend Soulspeed for setting up your car.
Forgeline knows their ****....wheels for the RS were perfect, and now they have the formula for the GT4..not to mention the lightest wheels you can buy that are not carbon.
Austin peeps - highly recommend Soulspeed for setting up your car.
Forgeline knows their ****....wheels for the RS were perfect, and now they have the formula for the GT4..not to mention the lightest wheels you can buy that are not carbon.
Where did Soulspeed move to? I used them years ago when they were off Burnet, but I thought they went out of business?
#156
Rennlist Member
Interesting. I took these directly from Hoosier's website. That is the mounted diameter they published for both sizes. I checked with tire rack - same deal. Both 26.1. It's probably wrong, I will contact them.
FYI - All the other specs in the table are from the manufacturer - not calculated from the labeled sizes.
UPDATE: I spoke with Hooiser today, they said the sizes are correct. 26.1 on both the 295 (mounted on 10" rim) and 315 (mounted on 11" rim).
FYI - All the other specs in the table are from the manufacturer - not calculated from the labeled sizes.
UPDATE: I spoke with Hooiser today, they said the sizes are correct. 26.1 on both the 295 (mounted on 10" rim) and 315 (mounted on 11" rim).
Last edited by acropora157; 12-22-2015 at 04:44 PM.
#157
It's entirely possible the GT4 Clubsport wheels will be available in 2016 from the Porsche Motorsport catalog. Obviously pricing is another issue, but I would expect them to be in line with what BBS's wheels run on their website.
Pretty sure these wheels are 18", which would be cool because tires would be a bit cheaper, and they clearly fit over the front BBK.
Pretty sure these wheels are 18", which would be cool because tires would be a bit cheaper, and they clearly fit over the front BBK.
#158
It's entirely possible the GT4 Clubsport wheels will be available in 2016 from the Porsche Motorsport catalog. Obviously pricing is another issue, but I would expect them to be in line with what BBS's wheels run on their website.
Pretty sure these wheels are 18", which would be cool because tires would be a bit cheaper, and they clearly fit over the front BBK.
Pretty sure these wheels are 18", which would be cool because tires would be a bit cheaper, and they clearly fit over the front BBK.
#159
I don't think it's that easy. The club sport is running pfc racing calipers that are very low profile, and has a different upright with slightly different geometry. I don't think you can put an 18" wheel on it without at least going to better, low profile caliper like a stop tech or pfc.
#160
I had 18" wheels on my .2rs with 380mm brakes and they were specially designed to clear - so I get why you are asking - but it had totally different calipers (lower profile with a removable bridge) and different suspension geometry which didn't get in the way. If the 991 gt3 guys are running 18" wheels then you have a chance, at least in front.
#161
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I believe the rear suspension on the GT4 is also different than the Clubsport race car in the same way, and the rear toe arm knuckle is not going to clear an 18" rim. The Clubsport rear suspension is spec'ed on the Porsche site as a "modified wishbone from the 911 GT3 Cup," so the suspension clearance in the rear may be just as problematic on the GT4. The mods necessary to fit 18s on the GT4 may be more extensive than most folks can justify. I haven't heard of anyone doing it successfully yet.
TT
#162
Nordschleife Master
Originally Posted by Mvez
Here's the deal guys, 18's can fit, but they require specific offsets and widths.
For example, Finspeed's F14 wheel will fit. He has already confirmed the 18" front wheel clears the 991 GT3 brakes, so they will clear ours.
The rear will fit easily, but requires a 18x10.5" wheel, ET44, if you want to avoid using alot of rear camber to clear the toe-link.
For example, Finspeed's F14 wheel will fit. He has already confirmed the 18" front wheel clears the 991 GT3 brakes, so they will clear ours.
The rear will fit easily, but requires a 18x10.5" wheel, ET44, if you want to avoid using alot of rear camber to clear the toe-link.
I've emailed finspeed and PM'd mvez several weeks ago, but no response yet
#163
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#164
#165
Rennlist Member
They just moved to Austin, and I was at winding road looking at a vette that had a bbk with their 18's on it. I've never seen wheels with a stepped barrel designed that way, but I have no doubt they can get one in 18 to fit after seeing that. One of you Austin members that already has your car please drop it off for them to design around!
Last edited by nxfedlt1; 12-25-2015 at 01:19 AM.