Increasing rear tire clearance in a '70 Charger.

[Mark Erwin]

Hello again!
Like many of you, I wanted to fit the widest tires that I could in my car. When my Charger was toward the end of bodywork and paint in 2003, I measured carefully and ordered tires and wheels that allowed free movement without rubbing the outer body.

The look that I wanted for this car was a sort of NASCAR-esque appearance where the body was laid over the widest tires I could fit and afford.
The goal was to look sort of like these cars:

View attachment 1235831

View attachment 1235832

Aside from the larger diameter wheels, I think the wide tire look was met.

View attachment 1235830

Your car looks really great !!!

 

[nativefx]

Hello again!
Like many of you, I wanted to fit the widest tires that I could in my car. When my Charger was toward the end of bodywork and paint in 2003, I measured carefully and ordered tires and wheels that allowed free movement without rubbing the outer body.

The look that I wanted for this car was a sort of NASCAR-esque appearance where the body was laid over the widest tires I could fit and afford.
The goal was to look sort of like these cars:

View attachment 1235831

View attachment 1235832

Aside from the larger diameter wheels, I think the wide tire look was met.

View attachment 1235830

Always loved the way you were able to squeeze the widest tire on your car Kern. I've been searching to find correct backspacing to hopefully run the same size wheels & tires. I haven't bought wheels yet, so I was hoping you could tell me if I ran 18 x 10 wheels but went with 5.5" backspacing, could I avoid having to cut out that bulge for now in the outer wheel housing? Going from your 4.75" bs to whole wheel/tire would move inward 0.75". Is there enough room to the stock leaf spring location and inner wheel well to do this, or would I need to go with a narrower tire? thanks

 

[Kern Dog]

Always loved the way you were able to squeeze the widest tire on your car Kern. I've been searching to find correct backspacing to hopefully run the same size wheels & tires. I haven't bought wheels yet, so I was hoping you could tell me if I ran 18 x 10 wheels but went with 5.5" backspacing, could I avoid having to cut out that bulge for now in the outer wheel housing? Going from your 4.75" bs to whole wheel/tire would move inward 0.75". Is there enough room to the stock leaf spring location and inner wheel well to do this, or would I need to go with a narrower tire? thanks

I’ll check for you but if I recall, my 4 3/4” BS left me about one inch to the inner tub at the sidewall. Not a lot of extra room there!

 

[Bighouse]

You could stuff a fiberglass welding blanket in there from the trunk side to protect your quarter panel.

 

[Kern Dog]

I was hoping you could tell me if I ran 18 x 10 wheels but went with 5.5" backspacing, could I avoid having to cut out that bulge for now in the outer wheel housing? Going from your 4.75" bs to whole wheel/tire would move inward 0.75". Is there enough room to the stock leaf spring location and inner wheel well to do this, or would I need to go with a narrower tire? thanks

Hello again...
I did measure the clearance today. The wheels do have the 4 3/4" BS as I wrote. From the mounting surface of the wheel to the inner wheel tub is 6 1/4". The tire sidewall sticks out 1/2" past the edge of the rim so I was actually correct when I wrote that I have one inch of tire clearance to the inner tub. A 5" backspace would work but personally, I'd not go any more than the 5 ".
This wheel tub ridge is a problem for lowered cars with wide tires. If you're going to stay at stock height, you might be okay. I've had 1" lowering blocks in the car for several years because I like the look of being a bit lower than stock.

 

[Kern Dog]

I decided to weld instead of using the panel bond stuff.
The initial reasoning was my concerns about putting too much heat near the quarter panel. I got around that by doing short bursts and blowing compressed air afterwards. I'm having trouble with the welds though. They look terrible. I have a MIG with a 75/25 Argon-CO2 and am using .030 wire. The wheel tub sheet metal is thinner than the Charger wheel tub. I either get tall welds or I burn through. I've tried numerous wire speeds and can't seem to get consistent welds. I'm lucky this job will be covered in seam sealer and undercoating but crap...I wanted it to look better than this. I'm going to try some thinner wire, something like an .023 or similar.

 

[1 Wild R/T]

.023 should help..

 

[eldubb440]

I decided to weld instead of using the panel bond stuff.
The initial reasoning was my concerns about putting too much heat near the quarter panel. I got around that by doing short bursts and blowing compressed air afterwards. I'm having trouble with the welds though. They look terrible. I have a MIG with a 75/25 Argon-CO2 and am using .030 wire. The wheel tub sheet metal is thinner than the Charger wheel tub. I either get tall welds or I burn through. I've tried numerous wire speeds and can't seem to get consistent welds. I'm lucky this job will be covered in seam sealer and undercoating but crap...I wanted it to look better than this. I'm going to try some thinner wire, something like an .023 or similar.

do you "hover" over the weld?

I've seen guys do that and the wire pushes their hand around and it sucks

all I weld is thin metal.....because I only weld for a second or 3, I always rest my nozzle on the work, the control is superb...... I don't even use a helmet, I close my eyes and kind of "hide" behind the gun. Without my hand moving around. I can "hear" the weld. I let off for a second or 2, move a little, and get right back into while it still a little red. I've welded several cars together with my eyes closed, that how I roll lmao

oh, I use .030 for everything

 

[Kern Dog]

do you "hover" over the weld?

I've seen guys do that and the wire pushes their hand around and it sucks.

oh, I use .030 for everything

Yeah, I have the nozzle about 1/2" from the car when I'm welding. Is that wrong? I thought you need some space or the wire will weld to the tip.

 

[eldubb440]

Yeah, I have the nozzle about 1/2" from the car when I'm welding. Is that wrong? I thought you need some space or the wire will weld to the tip.

i edited my post a little after you read it....... anyway, my tip is down in the nozzle a little, I rest the nozzel on the work at a bit of an angle........ make a weld, drag the nozzle back a little (1/8-3/16") and make another..... repeat as needed

 

[eldubb440]

the only time I "hover" is if I'm running a bead on thicker metal...... I use a helmet/shield for that

 

[nativefx]

Hello again...
I did measure the clearance today. The wheels do have the 4 3/4" BS as I wrote. From the mounting surface of the wheel to the inner wheel tub is 6 1/4". The tire sidewall sticks out 1/2" past the edge of the rim so I was actually correct when I wrote that I have one inch of tire clearance to the inner tub. A 5" backspace would work but personally, I'd not go any more than the 5 ".
This wheel tub ridge is a problem for lowered cars with wide tires. If you're going to stay at stock height, you might be okay. I've had 1" lowering blocks in the car for several years because I like the look of being a bit lower than stock.

View attachment 1238578

View attachment 1238579

View attachment 1238580

Thanks for the info Kern. I like the lower stance and tire width as well, so this helps me tremendously to figure out what I may do. Eventually I'll remove the inner and outer tubs to widen and then also cut out that hump to give me as much clearance as possible. I'm just trying to figure out what I can do in the meantime to get some decent rubber back there. Definitely appreciate all your informative threads!

 

[Kern Dog]

I switched to the .025 wire and had better luck avoiding burn through spots but the welds still don't look great. Working overhead and in a cramped space with an axle in my neck and the welding hood on sucks!
Weld, grind....weld, grind...
I used compressed air but even without it, I never felt the outer body get hot. Maybe because I welded in short bursts.
Both sides are welded. No warpage.

I spread seam sealer on the edges and the welds where I "pie-cut" the patch. Tomorrow, Undercoating!

 

[747mopar]

I did this mod when I built my car, with no other changes I easily run 305's with no rubbing but my rims are exactly centered.

Probably to late now but if I were doing this on a completed car as beautiful as yours I'd cut the whole area completely out then hammer out some patches that would overlap enough to plug weld in and seam seal them. Safe and clean.

 

[Kern Dog]

A 305 would surely fit. I was hoping to find a 305-40-18 Nitto NT 05 for my next tire. I was hoping to see some offered since the Challenger Demon used that size. I could only find Drag radials. Are those good for cornering? I don't drag race.

 

[747mopar]

A 305 would surely fit. I was hoping to find a 305-40-18 Nitto NT 05 for my next tire. I was hoping to see some offered since the Challenger Demon used that size. I could only find Drag radials. Are those good for cornering? I don't drag race.

Here's what it says about the Nitro drag radial, I highlighted the part that might answer your question.

 

[Grabbergreendream]

Hey Kern, your doing a great job!
Out of curiosity, what are you running your gas regulator at on your welding tank?
I just welded in USCT subframe connectors and had the opposite problem & had to turn my pressure as well as my voltage up to get the weld to "dig" in. I always have to when welding overhead, but always forget till the first sputter & have to crawl back out & adjust. You may need to turn things down. Just a thought...

 

[Kern Dog]

I have a Lincoln unit, comparable to a 175. Mine was bought used but still fairly new. I had to convert it to use gas. I run it at 13-15 psi as suggested by a local welding supply house. Wire speed is sort of hard to determine since the knob on mine seems to not be linear. from 1-2 it barely changes. From 2-2 1/2, it is finicky.
My welds are much better laterally or when the work is below me.

 

[Kern Dog]

The job is done and it seemed to work out well.
I took a drive today along a road where I usually get tire rub and it was as smooth as if I had stock tires on the car.

Now for a little contrast, look at the stock ridge:

In some twist of irony, the left side turned out better and has more clearance.....The right side was the one that rubbed the most. No matter. I gained enough room to drive with 3/4 tank on a bumpy road and have no contact. I could probably have a couple of robust buddies ride in the back and still be okay. It isn't just the matter of sidewall scuffing that worried me. It was that hard contact could buckle the quarter panels at the wheel opening edge when the wheel tub gets pushed up on contact.
I barely had enough of the spray on undercoating to do both sides. I bought 2 gallons from Resto Rick awhile back and used some on a couple of cars. I have had trouble here with some stuff going bad in the can. No matter how well I think that I sealed the can, some stuff stays good, other stuff hardens in the can. I've lost primer, body filler and half a can of undercoating to early "hardening".

Total cost?
Hmm.....Probably $40 for the wheel tub sections that I got from the self serve junkyard, $40 for welding wire and tips. I already had the grinder discs and saber saw blades. The 1/2 gallon of sound deadener/undercoating maybe cost $50...?
For less than $130 I have the clearance to drive the car without worry.

SCORE !

If you have wide tires in your car and want more clearance than the stock setup allows, this wasn't all that hard to do.

 

[beanhead]

Nice work dude! I like the concept for getting that little bit of extra clearance; not as involved as the 'ol stretch the wheel tub trick, and definitely better than the high-school "just cut a hole in that bulge and leave it" method.