Biggest tires and keeping the back seat

[postal]

Assuming you did all the correct frame rail and wheel tub modifications what would be the largest rear tires you could fit up inside the wells w/o having to lose the back seat. I plan on setting my nephews car up with a four link / coil over setup. I want to run the biggest tires I can but I do not want to run huge wheel tubs that force me to get rid of the stock rear seat. If you dont know what the biggest are I would atleast like to hear of what people know for sure will fit.

TIA: Jason

 

[John Wilde]

Jason,

The bigger problem is the frame.
Are you going to keep the frame?
There are a couple ways to look at this.
Let me know!

 

[postal]

I'm looking at a 4-link back half welded up assembly. It would be the frame rails, 4 link bars and brackets welded in, ford 9" housing, QA-1 adjustable coil over shocks, QA-1 springs, link / panhard bar, and built in drive shaft loop.

So the frame will not be a problem, I'm just worried about retaining the back seat.

This is probably the one area of my nephews car that I plan on going over budget. I know I could spend some money here and some money there and build up a stock style rear suspension. The problem is that stuff all adds up, and the stock style set up isn't very much cheaper. Reguardless of what I do a 9" ford will be going into the car, and now is the time to decide on how its going to be hung in there.

TIA: Jason

 

[Louie L.]

Although I cannot give you any info on tire size, I think that you have to come up with a reasonable tire size before you move on this project. I helped a friend build a early 70s chevelle with a 4link subframe. I dont think that you can do anything like a 33 in tall slick and keep the back seat. The main issue is that most if not all rear subframe assemblies made for a 4link set up make a sharp up swing to hang over the rearend and suspension. That coupled with the big tubs makes it almost impossible. I say almost because ive seen several big tubbed cars with rear seats . But they have shortened the seat bottom or narrowed the seat back and even laid the seat fabric right over the tub.Also the lenght of that car helps.

Another option is to use the stock frame and remove the whole tire side of the frame leaving just the back. Lay back and box the rear part of the frame(right over the tail pipes) and even it up with the front. Install mini tubs. With the right wheel and spacing and frame height you can probably fit a 30 x 10.5. We have a similar set up with a 11 in rim and a just 28 in tall tire and there is bunches of space for a much bigger tire. Then you could keep that back seat. :biggrin:

 

[broke1]

My brother runs 29x15.50 Sportsman's on his LX coupe that retains the back seat.His car also still has the stock length 8.8" with the wheels offset bringing the tires inside the fender(15x12 Drag Lites,not sure of the BS)

Ladder bars or 4 link will have to be premeasured to make sure they do not interfere with bottom rear seat area....and trimming of the seat foam will most likely have to happen to fit the seat over the wheel tubs.

No problem

 

[turbodave231]

You might want to look at S&W race cars for your welded frame assembly. They offer a 4 link and a ladder bar version designed specifically for G-bodies that retains the stock trunk floor and most of the back seat floor. I think the frames even use the stock locations for the body mounts. As far as I know, they offer these frames in Mild Steel only.

The tallest tire I can fit in an unmodified wheel well/frame is a 29X9 on 8" rims. I tried a pair of 30X9's but they contact the wheel lip.

Dave

 

[chevyII]

most of the front link systems for ladder bar or 4 link need to be 8-9 inches up from the groung to work properly. The four link will be taller because of the upper bar.

 

[Twin70BB]

When I had my 86 GN I install a ford 9 inch that was shorter on both sides by
3/4 of an inch on both sides.I pushed the inner frame in about 3 inches and
cut the inner wheel well in half and added a filler piece between the cut wheel well.The tire/rim was a 15x10 convo pro with 5 inch bs and tire was a
29x10.5. This setup looked good and the tires were tucked under the wheel lip.If you are careful with the filler piece and placement the back seat fits in there.
Tony

 

[Twin70BB]

When I had my 86 GN I install a ford 9 inch that was shorter on both sides by
3/4 of an inch on both sides.I pushed the inner frame in about 3 inches and
cut the inner wheel well in half and added a filler piece between the cut wheel well.The tire/rim was a 15x10 convo pro with 5 inch bs and tire was a
29x10.5. This setup looked good and the tires were tucked under the wheel lip.If you are careful with the filler piece and placement the back seat fits in there.
Tony
P.S. I install a 4 link with this setup and all you have to do is slice the floor
were the upper 4 link tube will ride.

 

[Dusty Bradford]

I've got a 29.5x10.5 non W on my 85 regal with a 15x11 bogart with 6 inch bs. I cut away all of the outer frame back to where the spring perch is welded to the top of the frame and welded an insert inside the frame to box it back. Then mini-tubbed the stock wheel wells to clear the tire. My backseat fits back in place but the bottom sits slightly out towards the bottom but is not noticable if you don't know what to look for. If I would have went any further in then my seat would not have fit.

 

[John Wilde]

I think the bottom line is that anything taller than 30inches will give you problems.

 

[John Wilde]

When I had my 86 GN I install a ford 9 inch that was shorter on both sides by
3/4 of an inch on both sides.I pushed the inner frame in about 3 inches and
cut the inner wheel well in half and added a filler piece between the cut wheel well.The tire/rim was a 15x10 convo pro with 5 inch bs and tire was a
29x10.5. This setup looked good and the tires were tucked under the wheel lip.If you are careful with the filler piece and placement the back seat fits in there.
Tony

What happened to your car???

 

[Twin70BB]

I sold the car to a guy in NJ.He put a chevy motor in it and juice.The car was For sale a couple of months ago.I beleive OTTO knows who has it.
Tony

 

[John Wilde]

I sold the car to a guy in NJ.He put a chevy motor in it and juice.The car was For sale a couple of months ago.I beleive OTTO knows who has it.
Tony

A chevy n20 motor!
Your car deserved more than that!
How fast did you go with that thing?

 

[Twin70BB]

The car went 9.40`s@145-147 mph.
Took the motor out and added a glide to the blue car and it`s gone
8.49@159mph.
With the old car it would 60ft in the low 1.30`s.In the blue car and a 15 psi launch has gone 1.24 60ft.There is also other things I changed in the combo before the blue car build.
tony

 

[John Wilde]

Tony,

Could you please hook us up with pictures of the blue car???
Thanks in advance!

 

[postal]

Hoosier Drag Slick
29.5'' x 11.5'' - 15'' W
Wide Tread Design
Stiff Sidewall Construction
D05 Compound

Tire Compound: D05
Tire Overall Diameter: 30.6''
Average Roll Out/
Circumference: 96''
Tire Tread Width: 13.5''
Tire Section Width: 15.2''
Wheel Diameter: 15''
Required
Wheel Width: 12'' - 14''
Tire Weight: 30 lbs.


With the tire diameter of 30.6" of this 29.5x11.5w, do you guys think the back seat would have to go? I'm not sure why but I kind of like the specs on this tire and it seams like it would be a good one to run.

thanks for all the inputs: Jason

 

[Twin70BB]

John ,did you get those pics I sent ya.
Tony

 

[John Wilde]

John ,did you get those pics I sent ya.
Tony

Tony,

Yes I did thank you.
I am getting back to you now!

 

[postal]

Maybe this one:
Hoosier Drag Slick
29.0'' x 12.0'' - 15''
Tire Compound: D05
Tire Overall Diameter: 29.3''
Average Roll Out: 92''
Tire Tread Width: 12.0''
Tire Section Width: 13.7''
Wheel Diameter: 15''
Required Wheel Width: 10'' - 12''
Tire Weight: 26 lbs.

I think that is a good bit of tire and should not cause me to lose the back seat. Another bonus is that I have a set of 10' rims (I'll have to measure to make sure), if I don't have to spend money on wheels that would be good.

What do you guys think of this tire?

TIA: Jason