HELP WITH WHEEL AND TIRE SET UP

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Dave777

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I have a 1985 c10 long bed, I lowered the back 4inches (but seems more like 3) and put a 15x8 wheel with a 275/60r15 on it. Did not fill up fender as I hoped it would, so figured I would put it on the front, which I'm in the process of installing 3-inch drop spindles on. I thought about going with a 10-inch wheel on back with a taller tire but running into issues with what tire size and back space to get. I'll post some pictures of my truck asap. Would appreciate any suggestions
 

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Here she is with only rear lowered and new wheel and tire on rear
 

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Soundmound

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I'm dealing with backspacing questions as well. From my research it seems like the factory rally wheels I have are 8" with a 0 offset or 4" BS and have 31 x 10.50 x 15's mounted, no rubbing. The C10 "specific" Halibrand Sprints I purchased come in 4.5, 4.75 or 5.25 BS and moving to a 20" x 8.5" I went with a 4.5" BS assuming I'll be using CPP modular spindles which narrow track width and it will be a 4/6 or 5/7 drop. It seems all other spindle manufacturers either retain your stock geometry or move the center line out up to 1/2 inch. I have seen that if running 15-17" wheels you should not have less than 4.5" BS or you may need to clearance the lower control arms and maybe roll the fender lips.

Probably isn't helpful, but it's what I got. I'm just hoping I don't need to get the 5.25 backspacing wheels since it seems like that's what most of the trucks I see on YouTube are running regardless of lowering method or amount.
 

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The kid bought one of these with his buddy.
It has not been used just yet, but will tell you what you want to know for size and backspace.
I like visual indicators for myself and this will be great when I need to do the figuring for my own cars.


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Dave777

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Thanks for responses. Now I'M very confused, I installed 3-inch drop spindles from QSA this morning and lowered truck onto shop floor and measured. Stock was 20-inches from floor to fender, and 18 1/4 inches with drop spindles, this is not a 3-inch drop. This is the first truck I've done this to, but I do work on vehicles. I've looked at all kinds of pictures of trucks that did a 2 1/2 on front and 4 on back and look good. Could it be the company I ordered this from? I need help!
 

Soundmound

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Thanks for responses. Now I'M very confused, I installed 3-inch drop spindles from QSA this morning and lowered truck onto shop floor and measured. Stock was 20-inches from floor to fender, and 18 1/4 inches with drop spindles, this is not a 3-inch drop. This is the first truck I've done this to, but I do work on vehicles. I've looked at all kinds of pictures of trucks that did a 2 1/2 on front and 4 on back and look good. Could it be the company I ordered this from? I need help!
MOST spindles are rated for 2.5" of drop. I spoke with Suspension Specialists, Western Chassis, Belltech, McGuaghy's and CPP. It would appear that almost all "manufacturers" use a single foundry and casting - CPP being the exception as they offer 3 types of spindle for our trucks. Springs can also make a difference. I have seen a lot of posts where the drop is more than advertised due to worn springs or uneven side to side for the same reason. Some of the pics you saw may have had some coils removed and not detailed it in the write up if there was one. I also believe you should be measuring the drop from spindle center to fender lip for a true measurement if I recall correctly.
 

Dave777

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Sorry, I wrote that wrong, the measurements were from fender to center of spindle.
 

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What are shooting for? You have to keep in mind, every one of these trucks is like a fingerprint. They’re all different. So some trucks drop more than others with the same parts. My truck took a total of 5/8 (and some weight in the bed to boot) to sit the same as some of my buddies trucks at 4/6. Normally, a 4/6 or 5/7 with a 245/60/15 and 275/60/15 tire combo looks awesome

Here is a ~4/6 with 2.5” McGaughys spindles, stock springs with 1 coil cut and a flip kit out back. 245/40/20 and 275/45/20 tires on 20x8 and 20x10s.
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Now here’s ~5/6 with a fresh rebuilt front end with the same 2.5” spindles but OE front springs trimmed 1/4 coil at a time until I was happy with it. Same flip kit out back and 20x8 and 20x10.5 wheels with 255/40 and 315/35 tires.
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Now here’s ~5/8 with the same front setup but added 2” shackles to the back flip kit. Same wheels/tires.
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Finkaire

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Did the K series have 10” wheels? If they did, are they 5 or 6 lug? Something I’ve wondered. I think 10” ralley’s in the back would look nice.
 

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This is what I'm hoping for
 

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Radiohead

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I wish more guys were slamming 3/4 & 1 tons. I want to lower the c20 some and still keep the usefulness of a truck. I am sick of lifting everything up higher than my decrepitness allows, plus it would be nice to improve handling too. This truck won't be seeing 20's or anything so fancy, but it will be interesting to see how wide I can go in back.
 

Catbox

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I wish more guys were slamming 3/4 & 1 tons. I want to lower the c20 some and still keep the usefulness of a truck. I am sick of lifting everything up higher than my decrepitness allows, plus it would be nice to improve handling too. This truck won't be seeing 20's or anything so fancy, but it will be interesting to see how wide I can go in back.
I wanted to lower my 3/4 ton, but my wife asked if I would rather put that money into another vehicles rebuild.

My truck looks just fine at stock ride height for me now.
:happy107: :happy107: :happy107: :happy107: :happy107:
 

TotalyHucked

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Did the K series have 10” wheels? If they did, are they 5 or 6 lug? Something I’ve wondered. I think 10” ralley’s in the back would look nice.
K series trucks were all 6 lug, so that wouldn't work on a C series. Nothing came from the factory with 10" wide wheels, 8" rallies were as wide as it got. But you can buy 10" wide ones in the aftermarket or get stock ones widened.
 

TotalyHucked

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This is what I'm hoping for
How did you lower the back of your truck? Spring hangers? When you did the drop spindles, did you drive the truck around before measuring? You've gotta move the truck around to settle the suspension, it will definitely be high if you just drop it off the jack and measure right then.

The blue truck you posted looks to be ~3/5 maybe with 295/50/15s all around and the silver truck I would say is a 5/7 but I can't tell the tire size.

Here's a truck I saved pictures of a long time ago. This is a 2.5" spindle, 2" drop springs and a flip kit for a 4.5/6 drop and 15x8 and 15x10 rallies. Tire size is 245/60/15 and 295/50/15. This is what I originally was shooting for on my truck
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Dave777

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That looks perfect! This is my first lowering experience and I wish I would have done more research before starting. I purchased a 4-inch drop kit off Amazon( Tuningsworld), came with bracket for the front of leaf spring and shackle in the back, I also replaced the leaf spring bushings. I put a 8-inch wheel with 275/60r15 tire on it but it seems way too small. I purchased the 8-inch wheels for the front but have not put tires on till I can figure out size I want to go with, was thinking I might want to go with 10-inch wheel on rear. For the front, I ordered 3 inch drop spindles from QSA, I'm installing them now with new ball joints and tie rod ends.
 

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