Back spacing
 

Looking to possibly run rocket racing attack titanium wheels. It's a 70 c10 4/6 drop wheels will be 18"

Not sure if I can run a 10" up front or not, front is stock arms, here are the options for back spacing... I do own a angle grinder if need be ;)

Front
18x10 5", 5.5"
18x9 4.5", 5"
Rear (no tubs or bed floor) I believe I have the later rear end, I remember my axle shafts were 31.313", I don't have the rear end with me, it's being rebuilt.
18x12 6", 5.5"

Re: Back spacing
 

Anyone?

Re: Back spacing
 

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I'm not a wheel guru but I would say probably not a 10" on the front.

It may take a while to get an answer on that one, especially on a weekend.

LockDoc

Re: Back spacing
 

I figured on the 10in, pretty sure 9.5 is the widest I can run. Mainly interested in the rear at 18x12 with a 6in bs on the late model rear end. Originally I was going to just run ramblers until I found the rocket racing attack titaniums listed on summit. Truck is on jack stands right now so I'm not all that worried, won't need wheels until the start of next year. Waiting on my rear end to get done so I can finish up the kore3 rear brakes and start on the front.

Re: Back spacing
 

I have 14" wide tires for the rear of the panel truck and I figure I will need 7 or 7.5 BS for those, with 12" wide rims. My wheel tubs are already widened. Mine has the '67 rear which is a little narrower than the later stuff so I'm not sure 6" will be enough on yours. I have a gauge I am going to put on mine to double check it before I order wheels.

LockDoc

Re: Back spacing
 

I'll most likely be running a 305 in the meantime, next motor I'll put 335s, a/r between 30-40.. I know the narrow guys run a 7in bs typically.. I'm sure the 6bs would fit its mainly a matter of how flush it would be for me.

Re: Back spacing
 

I'm really just trying to find out if someone knows how flush it would be since the truck doesn't have the bedsides on it yet, I'll have to pick those up early next year once I finish up my rear setup so I don't really have anything to measure off of.

Re: Back spacing
 

I'm thinking that the 6" might rub on the outer wheel wells/quarter. Dunno'

LockDoc

Re: Back spacing
 

The alternative is an 18x11 also 6bs

Re: Back spacing
 

18x12 6", 5.5" or 18x11 6", 5"

Re: Back spacing
 

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Hopefully others will chime in on this.

LockDoc

Re: Back spacing
 

Alright, after a lot of research and sifting through some older builds, 18x12 with a 6bs likely won't fit. Most guys on the wider rear end tend to run a 7bs, now the question is will a 18x11 with a 6in bs fit.

Re: Back spacing
 

Considering the cost of new wheels, this measuring tool is cheap.
Better than relying on other people’s guesses, measure it precisely yourself.
https://www.summitracing.com/parts/php-01201

Re: Back spacing
 

That is the same one I have. A friend of mine gave it to me when he was done with it. I haven't used it yet though.

LockDoc

Re: Back spacing
 

I'm running 19x12 with 6"bs on the earlier 67-70 rear, that has been narrowed an additional 1" on each side (2"overall). 7" rear drop. I run a 345/30 and the outer tire tread is barely inside the outer fender well - and that's with me trimming most of the rear fender lip. Granted, i have a step side bed, but with a 6"rear drop, you might have some rubbing, as the tire will almost definitely stick out past the fender. you are better off waiting to get it all back together and measuring your setup. Most people don't want to hear that, but it's a costly mistake to make if you order custom wheels and they don't fit the way you hoped. Ive always run the widest tire i can in all my 'hot rods/toys' and the only way is to do your own measuring. Plenty of info on the site of guys trying to run 12" wide rear wheels, don't know if you tried the search function or not.

Re: Back spacing
 

I answered in the Suspension forum but I'll add a little more here....

Typical trucks w/a 4/6 drop & factory 6-lug pattern can run 4x4 15" truck Ralley wheels in back w/o issue. They have 4" back-spacing. There might be a little wiggle room going out-board but not much.

Using that as a starting point helps do the math quickly....

8" wheel w/4" back spacing fits no-problem.
9" wheel would need 5"BS to fit no problem.
10" = 6"BS
11" = 7"BS
12" = 8"BS

Given those numbers for a 'no-problem' fit to the outside sheet metal, you can WAG how much wiggle room you have before it requires a different number/combo to work (ex: 12" wide w/6"BS is going to stick way outside the body & will require narrowing the rear end or flaring the wheel opening; 12" wide w/7-7.5"BS might work but would be close).