I am new here but i have owned my g-bodies. but for the first time i am buliding a pro touring 79 gp and would like to run 16 0r 17 inch rims with the widest rear tire in the wheel wells that i can. without notching the frame . Up front the same size but 7in width rim . anyone with and expreince with these larger rims and tires backspacing and sizes would be greatly appreicated.
79 gp wheel and tire size
- Thread starter taab123
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hey, welcome
on my GP, I am running 16" IROC-Z wheels. They are 8" wide, with different backspacing (BS) front to rear.
Front: 4.75" BS
Rear: 5.25" BS
To avoid shearing/breaking studs, I opted to use "Front" wheels in rear, and "Rear" wheels in front. I added a 1" adaptor infront, so that it would not hit the tie-rod. In the rear, I used a 3/8" spacer just to be safe.
(to avoid this ofcourse... you can find yourself four "Front" marked wheels)
using IROC 16s on a Gbody is not really the greates setup, as it causes alot of headache. For example, to use a 3/8" spacer in rear, I had to upgrade to extended studs (2-7/8" long), which no longer worked with normal lugnuts. I had to source open-end lugnuts, which are tough to find with a deep conical seat.
I used these raised Gorilla, open-end, lugnuts: http://www.summitracing.com/parts/GOR-90087/
For upfront, it was tough to find a decent 1" adaptor. I would avoid any cheap ones like this: http://www.summitracing.com/parts/TRD-7070/
This adaptor is made from cast aluminum and has been known to shatter at extremes.
On my wheels, I am running 245/50R16 tires, front & rear. A tire this size gives plenty of grip and handling, and you'll find that US brands like Goodyear or BFG are wider than foreign brands, even in the same size. If I could do it again, I would find a taller tire for the rear (as 50series tires look small in the back), and a skinnier tire for the front (the 245 does rub at full lock).
I hope all this info helps,
if you have any questions, feel free to ask...
on my GP, I am running 16" IROC-Z wheels. They are 8" wide, with different backspacing (BS) front to rear.
Front: 4.75" BS
Rear: 5.25" BS
To avoid shearing/breaking studs, I opted to use "Front" wheels in rear, and "Rear" wheels in front. I added a 1" adaptor infront, so that it would not hit the tie-rod. In the rear, I used a 3/8" spacer just to be safe.
(to avoid this ofcourse... you can find yourself four "Front" marked wheels)
using IROC 16s on a Gbody is not really the greates setup, as it causes alot of headache. For example, to use a 3/8" spacer in rear, I had to upgrade to extended studs (2-7/8" long), which no longer worked with normal lugnuts. I had to source open-end lugnuts, which are tough to find with a deep conical seat.
I used these raised Gorilla, open-end, lugnuts: http://www.summitracing.com/parts/GOR-90087/
For upfront, it was tough to find a decent 1" adaptor. I would avoid any cheap ones like this: http://www.summitracing.com/parts/TRD-7070/
This adaptor is made from cast aluminum and has been known to shatter at extremes.
On my wheels, I am running 245/50R16 tires, front & rear. A tire this size gives plenty of grip and handling, and you'll find that US brands like Goodyear or BFG are wider than foreign brands, even in the same size. If I could do it again, I would find a taller tire for the rear (as 50series tires look small in the back), and a skinnier tire for the front (the 245 does rub at full lock).
I hope all this info helps,
if you have any questions, feel free to ask...
Thanks for the advice btu i am putting a 650 horse poncho stroked 400. wheel spacers are not an option. i am going to buy new rims with mickey thompson drag radials of some sort. i just want the wheels and tires in the rear to stay in the wheel wells i dont want them hanging out i will roll the lip if i have to. i like the look when the wells are full of tires but i dont want to mini tub it. any other ideas on the sizes. thanks
there are plenty of options for wheels and tires out there... as long as you don't drive a G-body... ha ha
... just kidding...
If you're going to 17" tires, I would recommend using atleast 8" wide in front. With a low-pro tire, you will have a hard time finding anything wide enough on a 7" wide rim (you're looking at sizes like 195 or 205/55R17). With a 8" rim, a 245/45R17 tire will sit nicely upfront.
The rear is a tougher situation as there is limited back space. Factory wheels came with 4" backspacing, while you may be able to stretch that to 4.5" BS. I believe brands like American racing offer wide wheels with small backspacing. Generally you want to look for wheels with a big lip...
I think anything past 4.5" BS you will need to look into spacer, or frame notching.
And at 4.5" BS, and let's say a 9.5" or 10" wide rim, you may need to consider folding the wheel well lip. But at a 9.5" wide rim, you can comfortable fit a 275/45R17 tire...
I would not be too afraid of spacers... You can always upgrade to stronger wheel studs.
If you're going with drag radials and are concerned about utilizing maximum traction, I would recommend sticking with 15" or 16" wheels. At 17", the tires will simply not flex enough to grab the road properly. Unfortunately though, I am not familiar with drag radial sizes available in 16"... but feel free to ask about 15"s
Hope that helps...
... just kidding...
If you're going to 17" tires, I would recommend using atleast 8" wide in front. With a low-pro tire, you will have a hard time finding anything wide enough on a 7" wide rim (you're looking at sizes like 195 or 205/55R17). With a 8" rim, a 245/45R17 tire will sit nicely upfront.
The rear is a tougher situation as there is limited back space. Factory wheels came with 4" backspacing, while you may be able to stretch that to 4.5" BS. I believe brands like American racing offer wide wheels with small backspacing. Generally you want to look for wheels with a big lip...
I think anything past 4.5" BS you will need to look into spacer, or frame notching.
And at 4.5" BS, and let's say a 9.5" or 10" wide rim, you may need to consider folding the wheel well lip. But at a 9.5" wide rim, you can comfortable fit a 275/45R17 tire...
I would not be too afraid of spacers... You can always upgrade to stronger wheel studs.
If you're going with drag radials and are concerned about utilizing maximum traction, I would recommend sticking with 15" or 16" wheels. At 17", the tires will simply not flex enough to grab the road properly. Unfortunately though, I am not familiar with drag radial sizes available in 16"... but feel free to ask about 15"s
Hope that helps...
Yes that helps alot , there are only a few drag radials in 17 in so maybe i will try to stick with 16in wheels because traction will be a big concern. but i like the larger rim look. thanks for all of your help. If any one has pictures of there gp with 17 or 16 custom wheel feel free to send would love to see them. thanks again
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