drop with 20's....front clearance issues?

[Jerryrig]

Im possibly going to pull the trigger in ordering my 5.5/7 drop for my 70 c10. Im planning on running 20" rims. My only question is will my front wheels rub while turning to the max of my steering?
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[Smoothride]

depends on tire size

[RRR18]

You wanna know about the WHEELS or the TIRES rubbin? I'm guessin we might need more info on your planned setup.

[Jerryrig]

Just over all....the rims i want to run come in 4 different widths...20x8.5, 20x10, 20x12 or 20x15.

My drop will be static. 2.5 drop spindals, 3in drop springs in front and rear axel flip kit and 2in drop hangers

Not sure of the tire size becauae i dont have the rims yet. This is the reaon i am asking so i dont end up spending money on useless parts...lol
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[Smoothride]

but thats the thing, its your tire size that will rub not your wheel size.... you can rub with a 17 wheel with a big tire and you may clear with a 20 wheel with low profile tire

get a tire size to get the total height of the tire to see if you clear

[CC69Rat]

Jerryrig -- First, Welcome to the board! We'll help you get it figured out.

Things we need to know in addition to your drop specs:

Year of the truck (I'll explain later)
Intended use (show, running cones and road racing, or daily driver)
Future drop specs? Will you bag it eventually?
Fleetside bed, or stepside bed?

Which wheel are you looking at? Do you understand and/or need help with backspacing?

[Jerryrig]

Originally Posted by CC69Rat

Jerryrig -- First, Welcome to the board! We'll help you get it figured out.

Things we need to know in addition to your drop specs:

Year of the truck (I'll explain later)
Intended use (show, running cones and road racing, or daily driver)
Future drop specs? Will you bag it eventually?
Fleetside bed, or stepside bed?

Which wheel are you looking at? Do you understand and/or need help with backspacing?

Thanks!!!
My truck is a 1970 c10 with rear leaf springs
I will use the truck for shows and occasional cruising on nice days
I want to keep it just a static drop....no bags for this truck.
Its currently a stepside. But im buying a fleetside bed to swap it very soon

And i am looking at the raceline static 6 rims.....and il need some help with the backspacing

Hopefully this helps....
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[CC69Rat]

Are you going to put discs up front ? Does it have them already?

[Jerryrig]

Originally Posted by CC69Rat

Are you going to put discs up front ? Does it have them already?

Im ordering the disc conversion for the front when i order my lowering parts......only front disc on the truck and rear drum is how the truck will stay. And im keeping it 6 lug
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[CC69Rat]

Now, we need to know which rear end housing you have in the truck. Being a 70 model, it could be either.

1967-late 1969 these trucks had a more narrow rear end housing in them. In 70 up through 72 GM widened the rear end housing a bit to adjust for the front discs that came out in 71.

How do you tell which one you have? As I mentioned, the 70 model trucks could be either and this measurement WILL cause you issues if you don't know it. For example, if my truck is a 70 with a LATE rear end housing, and I'm running a 20x10 with 5.5" Backspacing .. it may or may not work for you. IF your rear end housing is .75" more narrow on either side, the wheel fits completely different.


Here's how you tell:

Lay down underneath the truck (in the back of course) Measure from the inside of one brake backing plate to the other side. If this measurement is roughly 55.5" long, you have the early rear end housing. If this is 57" you have the later rear end housing. In 70, the GM people building the trucks basically used whatever they could find, or had available. My 70 = late rear end but I have seen them both ways.

My next concern is the leafs -- before I give you measurements I'm hoping Keith will chime in. I'm not sure the 20x10s will work on a fleet with leafs ..

lolife99 .. where you at.. ?

[Jerryrig]

Originally Posted by CC69Rat

Now, we need to know which rear end housing you have in the truck. Being a 70 model, it could be either.

1967-late 1969 these trucks had a more narrow rear end housing in them. In 70 up through 72 GM widened the rear end housing a bit to adjust for the front discs that came out in 71.

How do you tell which one you have? As I mentioned, the 70 model trucks could be either and this measurement WILL cause you issues if you don't know it. For example, if my truck is a 70 with a LATE rear end housing, and I'm running a 20x10 with 5.5" Backspacing .. it may or may not work for you. IF your rear end housing is .75" more narrow on either side, the wheel fits completely different.


Here's how you tell:

Lay down underneath the truck (in the back of course) Measure from the inside of one brake backing plate to the other side. If this measurement is roughly 55.5" long, you have the early rear end housing. If this is 57" you have the later rear end housing. In 70, the GM people building the trucks basically used whatever they could find, or had available. My 70 = late rear end but I have seen them both ways.

My next concern is the leafs -- before I give you measurements I'm hoping Keith will chime in. I'm not sure the 20x10s will work on a fleet with leafs ..

lolife99 .. where you at.. ?

I will check my rear end when i get home in 30 min
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[CC69Rat]

He said Rear end..
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[CC69Rat]

( jus messin with you man..)
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[Pro Performance]

Originally Posted by CC69Rat

He said Rear end..
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^^^^Nice.... that was a good one.... made me laugh.

That is very good info that CC69Rat has given, and the rear end definitely will determine what backspace to run. Now, for my plug... lol... we are a Raceline dealer if you need some pricing and can also help you with backspace as well.

The 5.5" backspace (10" wheel) on a wider rear end fits well for the fleet side trucks. Up front, a 5.25" is good for a 8.5" wheel, running a respectable tire, such as a 245/45/20.

[CC69Rat]

^^ 5.5 BS on the wider rear end housing,.. but will it work ok with leaf springs? I know coils would be fine, just not sure about the leaf springs.

Should he do 5.5" BS up front too because it will be that low?
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[Jerryrig]

Lol! I got a good laugh out of both of those! Hahaha

Cc69rat.....i just measured it and it is 57".

Properformance, thanks for plug and added knowledge. As soon as i get this figured out, i may be buying a set from you
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[CC69Rat]

20x10 rear with 5.5" backspacing ( just make sure on the leaf spring thing)
295/40/20 tire

20x8.5 up front with either 5.25" backspace OR 5.5 will give you an extra little bit of room on the outer fender lip. It would be less likely to scrub when you turn. Im doing 5 3/8 just to split the difference.
245/45/20 or 255/40/20 tire.

You should be all set. Buy from ProPerformance if you can, we try to support the forum vendors as much as possible..

Good luck man!
Chad
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[Pro Performance]

^^^ Thanks for the support Chad.

Yeah, should be good with leaf springs. If you have appx. 6.25"-6.5" from the drum mounting surface to the leaf springs, that will be enough room. That is accounting for a .5" tire bulge & wiggle room, which is a good amount.

For the front, 5.5" would work too and give a little more clearance for the 5.5" drop. I didn't notice the 5.5" drop vs. 4.5". This is where it sort of depends on personal preference where you want the front wheel to sit. The .25" isn't much though.

Here is a picture of a customer's truck (and board member) running a 10" wheel on the wider rear end and 8.5" up front. 5.5" backspace for the rear and 5.5" up front.

[buckskins4ever]

Two things one has been covered already.....I run a 20x8.5 front with 245/50 and 20x10 rear with 275/45. Plenty of room to clear and full turn.......NOW, make sure when you drop it you buy the adjustable panhard bar for the rear (if running trailing arms not leaf springs in the rear). With trailing arms your axle will shift over about 1 1/2 inch to the left side.

[72BlckButy]

Opinions are like ********, everyone has one.

IMO... I wouldn't go lower than a 4.5/6" drop with 20's. Any lower I would install bags front and rear.

Now, speaking from experience, I would order your disc brake upgrade and lowering kit, install them and then measure your truck for the wheel/tire specs. Reason being.... all trucks are different. CPP modular spindle, wide/narrow rearends (esp. in 70), etc. You don't know what all has been done to the truck prior to your acquisition.

If you're going to order wheels (w/ custom BS) then install the suspension and custom fit the wheels/tires to your application.

Check out my build thread "Project Blank Slate" (click below) and go to page 15. It will give you all the height changes etc. I experienced on my install from start to finish.

[CC69Rat]

That black truck is perfect..
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[CC69Rat]

Nate has a good point too..
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[Jerryrig]

Originally Posted by CC69Rat

That black truck is perfect..
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Thats the look i want!
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[sprint_9]

Originally Posted by Jerryrig

Thats the look i want!

Me too, that thing is sweet

[screaminchevypickup]

That black truck sure is sweet!!
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