THE WHEEL BACKSPACE dilema!

[MisterE72]

Greeting folks. I'm ready to make that all important decision: which wheels and what size. I know I want 20 x 8.5 fronts and 20 x 10(9.5) rears (255 & 275 40 series tires). My problem is I dont know how much BACKSPACE I can get away with without having rubbing issues on the inside or outside of the wheel wells. The truck has a 4-6 drop that may change down to a 5-7 soon. Its a 72 deluxe with stock discs and drums on a 12 bolt posi. Thanks for the help. Mr.E
PS These are the kind of wheels I like.

[lolife99]

I'd say 5.25"-5.75" BS (on a 8.5 inch front),... and 5"BS (on a 9.5inch rear) and 5.5"BS (on a 10 inch rear). But you better measure for yourself.

[MisterE72]

Originally Posted by lolife99

I'd say 5.25"-5.75" BS (on a 8.5 inch front),... and 5"BS (on a 9.5inch rear) and 5.5"BS (on a 10 inch rear). But you better measure for yourself.

Thanks for the quick response. I'm very limited in the measurements I can make because I don't have the bed or fenders mounted on the truck right at this time. Thats why I was hoping to get feedback from other board members who have already been through this. I found a website that explains a lot about wheel measurements. It really clarifies much of the vocabulary in wheel fitment https://www.rsracing.com/tech-wheel.html#backspace
Keep those responses comin' and Thanks again. Mr.E

[72BlckButy]

MrE, over on SCOTI's post about the spacers for the Coys wheels, he posted info on the BS specs for his Coys. Link....

Hope this helps...

[TotalChevy1]

Originally Posted by MisterE72

Greeting folks. I'm ready to make that all important decision: which wheels and what size. I know I want 20 x 8.5 fronts and 20 x 10(9.5) rears (255 & 275 40 series tires). My problem is I dont know how much BACKSPACE I can get away with without having rubbing issues on the inside or outside of the wheel wells. The truck has a 4-6 drop that may change down to a 5-7 soon. Its a 72 deluxe with stock discs and drums on a 12 bolt posi. Thanks for the help. Mr.E
PS These are the kind of wheels I like.

If you chose the second rim, I would go with disc all the way around. I don't like the look when you can see 70% of the drum makes the rim look out of place.

[SactoJim]

Here's mine.

18x8 with 4" bs and 255/50's
18x9.5 with 4.5" bs and 275/55's

Not exactly sure on the drop but gotta be close to a 4/6.

No rubbing at all and I think I have room to go a tad lower.

Hope this helps.

[MisterE72]

Originally Posted by 72BlckButy

MrE, over on SCOTI's post about the spacers for the Coys wheels, he posted info on the BS specs for his Coys. Link....

Hope this helps...

I think that particular truck is a 74. If I recall correctly the front suspension is a little different from the 72's. I'm not sure if that would affect the available backspace. Those Coys sure look nice on his truck. Thanks.

[MisterE72]

Originally Posted by SactoJim

Here's mine.

18x8 with 4" bs and 255/50's
18x9.5 with 4.5" bs and 275/55's

Not exactly sure on the drop but gotta be close to a 4/6.

No rubbing at all and I think I have room to go a tad lower.

Hope this helps.

Your rim/tire combo fills in those wheel wells nicely. I imagine the ride is smoother with that little extra tire sidewall too. Thanks SactoJim

[70c10]

Originally Posted by SactoJim

Here's mine.

18x8 with 4" bs and 255/50's
18x9.5 with 4.5" bs and 275/55's

Not exactly sure on the drop but gotta be close to a 4/6.

No rubbing at all and I think I have room to go a tad lower.

Hope this helps.

One of my favorite trucks here!

[67_C-30]

Originally Posted by 70c10

One of my favorite trucks here!

Mine too!!

[BigSky71]

Originally Posted by 67_C-30

Mine too!!

Plus one to that... when I am bouncing around town on my 315/35s I sometimes wish I was running a smaller wheel / taller tire, but I got my mall crawl down so it evens out. BTW, there are no malls in NW Montana, but I try .

[MisterE72]

I went to a wheel shop and was quoted $2150 out the door for the Foose Nitrous wheels with 255/35 F and 275/40 R. The only problem was that he told me the Hanook front and rear tread design would be different. Is this common when you go with different height tires? Thanks Mr.E

[PipsC10]

Thanks for starting this thread Mr E, I plan on running the same rim/tire size and have seen 7,000 different back spacing ideas. I look forward to seeing how yours lays out with a 5/7 drop with those rim sizes and whatever back spacing you choose.

On a side note, I have a friend in Hughson with a 71 that is running a similar set, although I'm not sure of the backspacing. I know he had to use spacers in the back because he did not figure in using drum brakes. He said when I'm ready I can throw his rims on temporarily to check fitment and backspacing. If you have not purchased anything by then, I will let you know what spacing works best. I am also looking for clearance so when I air out my bags the tires wont rub.

[72BlckButy]

Hey MrE, since you've mentioned that you're thinking about going to a 5/7, how are you going to accomplish this? I figure that you'll run a shorter drop spring up front, and maybe blocks in the rear???? Inquiring minds want to know...

[MisterE72]

Originally Posted by 72BlckButy

Hey MrE, since you've mentioned that you're thinking about going to a 5/7, how are you going to accomplish this? I figure that you'll run a shorter drop spring up front, and maybe blocks in the rear???? Inquiring minds want to know...

That's how it will be done...Great minds think alike..

[72BlckButy]

bump for some more responses for MrE

[buffle]

Have a 1999 2dr 2wd Tahoe 2" front & 3 1/2 rear drop. Does anyone have any experience withe backspacing on one of these?

[Mondo]

I have 1 inch spacers on the back and the tires look about the same track as the front now...

Looking at Sacto"s specs am I correct in thinking he has a similar set up?

[SCOTI]

Originally Posted by MisterE72

I think that particular truck is a 74. If I recall correctly the front suspension is a little different from the 72's. I'm not sure if that would affect the available backspace. Those Coys sure look nice on his truck. Thanks.

The wheels in the pics were actually purchased for my 68. They fit the 74 w/no issues because the suspensions are the same (disc vs. disc set-up). I just had them on my 74 for the weekend burger joint.

Lolife99 is accurate on the back-spacing suggestions IMO: 8.5's w/5.25"BS; 9.5's w/5.0"BS or 10's w/5.5"BS.

[Ackattack]

I just ordered wheels (20x10 w/ 5.75" BS and 20x8.5 with 4.25" bs)

[steelhorse]

I think project Copperhead had 4.5 backspacing but those were 17s.

[SCOTI]

Originally Posted by lolife99

But you better measure for yourself.

Notice how many different possibilities that have been suggested? This is the only way to go. Use the provided info as a starting point & measure your vehicle to be sure.

[whatnow123]

Originally Posted by SCOTI

Notice how many different suggestions that have been suggested? This is the only way to go. Use the provided info as a starting point & measure your vehicle to be sure.

I happen to agree since everyone want the wheels to sit in the wheelwell a little different. I for one don't like the "tucked" in look that increased backspacing has.

[SCOTI]

Originally Posted by whatnow123

I happen to agree since everyone want the wheels to sit in the wheelwell a little different. I for one don't like the "tucked" in look that increased backspacing has.

Unfortunately it is sometimes a necessary evil the lower you go (unless you can narrow the track width).

[Hart_Rod]

I bought one of these:

http://musclerodzstore.com/index.asp...ROD&ProdID=148

Well worth the investment considering the cost of new wheels nowadays.......