The Money Pit

I am toying with the idea of trimming the rear frame in the T-arm pocket area for additional tire clearance. I know this has been done before by others, and so what I'm asking is if you did the mods, how much clearance did you gain, and if you have any pics can you post them. I am now starting to look for a shop that can do the work, and I want to have good pics so they will know what I'm wanting to have done.

The plan is to keep my 295 55 15 drag radials, but swap to a 15x10 wheel with a deep enough backset to get as much tire under the fender as I can. The last mod I did got them within 1/2 inch of all under, but the frame is the limit,.....so it's got to be nudged some.

69ttop502

Search BeeJay as he had a thread in which he did this. I don’t know if I could bring myself to do it. I am sure it could be made to be strong, but that is right in the spot where GM thought they neede to reinforce the frame so I would just probably stay away from it. I think in the thread, there were links to others who have done it. I do remember a ton of pics.

Bill

The Money Pit

I found the BeeJay thread. Lots of pics of the welding, not sure what the end result was as far as clearance.

I am nervous about the frame strength too, and probably only am after 1/4 to 1/2 inch more room. If the cost is off the charts to do the mod,.....I'll live with where i'm at now.

Doesn't make sense to spend a fortune for 1/4 inch more room especially if it compromises the frame strength.

Sky65

Can post a link please? I can't find it.

Thanks
Tom

Metalhead140

There was a thread on this only a few days ago, with a link to the beejay thread: https://www.corvetteforum.com/forums...clearance.html

Sky65

Thanks! I saw that thread the other day but missed the link to beejay's.

Tom

jim2527

Ridetech put something like 315's? with a stock frame. 18's but still.... With proper backspacing and offset trailing arms is there a reason the same wouldn't work with 15's?

The Money Pit

I have the stock frame,offset T-arms, no flares and can tell you the frame near the T-arm pocket will hit if I try 5 inch backset with my 295 tires, I had to have a custom adaptor made to clear, and it's only .710 thick, so less than 1/4 inch made the difference.( My Welds have 5 1/2 inch backset) I saw a recent post where a forum member put 15x10 on with 5 1/2 inch backset, which makes sense since mine are 15x9s, and he did the frame clearance mod I'm asking about in this post. I did ask him to send pics of his work, and haven't seen any as of yet.

It's tough to measure without actually fitting the tire to the wheel and trying it, as smaller diameter tires may fit where my 28 inch tall drag radials are tight, not to mention the wheel width changes how much tire bulge you have.

69427

I've been running 10 1/2 inch wheels on the rear without frame interference issues for years, and I was a bit puzzled by your fitment issue until I read how tall your tires are. My track tires are noticeably shorter radius than yours.

69427

Pretty much every picture I've seen of that car shows some decent size flares on the rear fenders.

69ttop502

Here are two threads where stock fendered cars are running 315’s. In addition, the Ridetech car did in fact have 315’s square before they flared it. Now I don’t know the diameter of the tires but suspect they are smaller than 27, which is definitely a help in avoiding that reinforced part of the frame. Both cars are running the Ridetech rear, but frames are the same. They say you can run 5.5 inch backspace with their system and that certainly appears so on my chassis. Not sure what the variable is one car to the other. One could look up the diameter of the tires in these threads as they are listed.
https://www.corvetteforum.com/forums...p-install.html

https://www.corvetteforum.com/forums...ch-system.html

69ttop502

What backspace, and are they 15’s or the wheels in your sig pic?

3JsVette

To get max room without frame modifications and/or offset trailing arms you need at least an 18" diameter wheel.
I'm pretty sure there is also someone on this forum running if memory serves me right 18X10 with 295s front and rear.

3JsVette

Found it. https://www.corvetteforum.com/forums...4-corners.html

69427

The wheels I had mentioned are some C5Z items that I use frequently on track days (the wheels in my avatar are 16" wheels I was using until decent tires stopped being available in that size). I was commenting on the spatial issues in the rear fenderwells, I'm running a wider wheel than the OP discussed, but the diameter is shorter, so no fitment issues in the trailing arm pivot area. (I'm also running a C4 suspension, so the normal trailing arm interference issue isn't a factor for me.)

Metalhead140

I run 18x10 with 295s all round as my track wheels.

v2racing

I think Money Pit's problem with clearance to get tires under the fenders has more to do with big 15" having a much larger cross section than a 18" or larger 295 would have. I have 285/40/18's under mine and could probably get 295's without hanging out much. 295/55/15's would be a different story.

Although I'm a drag racer at heart, I chose 18" wheels for the handling. I like pushing it hard through corners, but I know I'm giving up straight line traction from what big 15 drag radials would give me. Have to compromise, you just can't have everything.

Money Pit, did you have traction problems with the 275/60/15 drag radial you were running or do you just want the 295's just because?

Mike

The Money Pit

I never ran 275 60 drag radials, but prior to my 295 55s I ran 295 50 street tires and could over power the tires with not much trouble after the second gear shift. I got tired of having to pedal the car to keep it straight, so I went to the 295 55 drag radial.

I do like the fat tire look, and at one time ran 275 60 street tires and felt they were too narrow, but filled the wheel well nice. When I went to the295 50, they were wider, but I felt they looked too short,.....Then MT came out with the 295 55 drag radial,.....ewe la la,...the perfect size, or so I thought. The Welds I run are not made to fit the car,...had to use an adaptor to clear the brakes, and coupled with the drag radial extra sidewall bulge,...they stuck out past the fender more than I would have liked. A decade later, I'm looking to make it work to my liking.

The easy solution,.....smaller tires,.....but that isn't happening for me. I will find a way to make it work. Already half way there now. Just need to come up with a quarter to half inch...…..