Wheel & Tire size for Flat out C4 Build

[jeremywrags]

Hi All,

I came across a smoking deal (it caught fire) on an 86 corvette for $200. Good news is that the suspension is perfect and the car only had 80K miles on it. Based on this find I am going to go with the Flat Out Engineering front & rear suspension setup for my 1959 Apache

Admittedly I am new to all of this but Jerry at Flat out seems super helpful so I think this is the direction i'll go.

That said, the vette has no wheels so I am going to start looking for a set of wheels and tires. I have a couple of questions.

1. What size wheel & tire would work\ look good with this setup?
2. Anyone have pictures of this setup? I want to know what the rake looks like. I do not like the stinkbug look, I like it more close to level
3. Is there a way to level it out with this setup?

Thanks

[CountofMonteCarlo84]

Well I can tell you I have 215/55/18 in front and 265/50/20 in the rear on my 57. I can't see getting any bigger of a tire in the front without some mods and my fenders are already rolled. I won't post a picture though because its dropped some in the front beyond that kit and the rear has air ride.

[Dan in Pasadena]

My ‘55.2 has Flat Out front cross member and Corvette IFS up front. The rear is a Mustang 8.8 rearend flipped on top of the stock leaf springs. The bed isn’t on so the rear height will be adjusted after that.

The vintage Torq Thrusts are 15” with 235/75 tires. Can’t use them because 15” won’t fit over the Corvette calipers, gotta have 16” at least.

The shiny wheels are 17x8 Boyd’s Smoothie II’s I got cheap via OfferUp. Tires are 235/55’s.

[bobinbc]

Dan what year is the C4 front end and what is the backspace of your wheels please?

[BIGglaSS]

Originally Posted by jeremywrags

1. What size wheel & tire would work\ look good with this setup?
2. Anyone have pictures of this setup? I want to know what the rake looks like. I do not like the stinkbug look, I like it more close to level
3. Is there a way to level it out with this setup?

Thanks

I did C4 in the back. In my opinion, the flatout kit gives the back the stinkbug stance. You can probably modify the mounting height to get the stance you want. Or, if you use the transverse spring, longer bolts will get it lower, though geometry may not be optimum. I made my own back-half frame, and tucked the rear end up higher than the flatout mounts.




C6 wheels w/2" adapters: 19x10, 285/35r19

[Dan in Pasadena]

Originally Posted by BIGglaSS

I did C4 in the back. In my opinion, the flatout kit gives the back the stinkbug stance...

Only if the front is too low in relation to the rear.

I’ve seen a number of TF’s with the Flat Out conversion and they looked great. Mine (dark red above) has their IFS and I’m actually worried it’ll be too low in the rear once the bed is back on.

[clegg]

Originally Posted by BIGglaSS

I did C4 in the back. In my opinion, the flatout kit gives the back the stinkbug stance. You can probably modify the mounting height to get the stance you want. Or, if you use the transverse spring, longer bolts will get it lower, though geometry may not be optimum. I made my own back-half frame, and tucked the rear end up higher than the flatout mounts.




C6 wheels w/2" adapters: 19x10, 285/35r19

Nice job on the back half and I see you can use the sway bar.

OP, I have a home brew C4 suspension front and back (not flat out), used 275/35/18 and 325/30/19 C6 Grand sport wheels. I had to use 1/2" spacers on the back, concentric style. 1955.2 truck.

I would attach pics but the truck is in body and paint a bit of a distance from me.

[jeremywrags]

Originally Posted by clegg

Nice job on the back half and I see you can use the sway bar.

OP, I have a home brew C4 suspension front and back (not flat out), used 275/35/18 and 325/30/19 C6 Grand sport wheels. I had to use 1/2" spacers on the back, concentric style. 1955.2 truck.

I would attach pics but the truck is in body and paint a bit of a distance from me.

I have not bought the flat out kit yet but I have a C4 donor. Can you share details of your diy build? Was it heavy fab work? I would love not to pay $300 shipping for the front and rear crossmember but I am a newbie when it comes to fab skills and my toolset is growing but a little limited... I like the idea of a simple weld\bolt in kit but if I can save about $2000 total I’d love it.

[BIGglaSS]

Originally Posted by jeremywrags

I have not bought the flat out kit yet but I have a C4 donor. Can you share details of your diy build? Was it heavy fab work? I would love not to pay $300 shipping for the front and rear crossmember but I am a newbie when it comes to fab skills and my toolset is growing but a little limited... I like the idea of a simple weld\bolt in kit but if I can save about $2000 total I’d love it.

I would say moderate skill. A plasma cutter is a BIG help, plus you will need a solid welder capable of 3/16-1/4". If you're not confident at welding, or short on time, then I would suggest the flatout kit. The hardest part is planning, and figuring out the geometery. Since you have the donor car, be sure to get the measurements and geometery from the donor. I have seen a few builds that use the stock c4 front crossmember, but I can't help you there.

Only if the front is too low in relation to the rear.

Dan, in the back, the difference is 10" ride height, or 7-8" ride height (measured at the rear of the rockers).

Here is a well-done truck that uses the flatout kit, probably the best build thread out there with a C4 swap. He posts lots of pictures, and measurements. This will give you a good idea of what is involved.
https://www.trifive.com/forums/showthread.php?t=97044

[svr]

I used c4 running gear from an '88 pn my '57. The '88 and later versions are slightly wider than the earlier ones. Something to think about when ordering tires and wheels. I made my own brackets and cross members kinda copying the flat out style. I used the original corvette front cross member to measure and align all the mounts. I am just about to order wheels and tires. I kept the original '88 tires and rims for rollers while i worked on the frame ect. The original wheels are 9.5x17's with a plus 56mm offset or 7.5" backspace with 285/40x17 tires both front and back. When i put the cab and box back on the frame after the suspension was mounted i found the corvette wheels had to much offset and i had to put 1.5" spacers on the rear to clear the bed sides and with those on i barely had clearance on the outside on the fenders, i could get my fingers in there but it was tight. In the end i made some mini tubs for the bed sides to make the sway bar clear the bed floor and make some additional room for tire choices in the future wothout haveing to have special rims made. So my wheel choices are torque thrust classic ll's with gray 5 spoke centers, 9.5x17's for the rear and 8x17's for the front, plan on 285/40x17 tires on the back and 225/50x17's on the front, the rears will have 6.5 back space and the front will be 4.5 back space. Look at my build and if you have any questions ask away.

[CountofMonteCarlo84]

I'm not sure what qualifies as a "stinkbug" stance, but I like the way mine sits.

[JDarby]

CountofMonteCarlo84, I really dig the stance of your truck!
Can you please tell me how does it handle, meaning:
Twisties
FlatTrak
Hwy
Saturday Cruising
Thanks!

[BIGglaSS]

^^Nicely done!!! I guess I like them lower in the back with less rake. But that is opinion.

[OKGMC4]

Old thread but thought I'd share in regard to the original question of wheel and tire with C4 suspension. I started with stock corvette wheels but they didn't look right and I had to use spacers to get them placed correctly. I ended up with Rocket Racing Booster wheels 18x10. They are the modern muscle version meant for the rear on 93-02 Camaro. The 35mm offset requires no spacers and I am running 275/40R18. Can move to a 295 later with the 10" width.