Wheel & Tire Size with a 3.5/5 Drop?

[Taylor21293]

I have a 1971 GMC C1500 Long bed, rear coil suspension. I’m looking into getting the ECE 3.5/5 Drop kit, but I’d like to run 20x8 smoothie wheels from Detroit Steel Wheels. I’m not quite sure if I could get away with running 20x9s, or if 20x8s will work. I’m also torn between what size tires I should go with. I definitely like the “low profile” look, but I’m not sure if a 40 profile tire will be too little. I appreciate any pictures/help with this!

[Taylor21293]

This is the most recent picture I have of her, I’m not even entirely sure what level of drop the truck has (I bought it like that), and it’s been sitting up in Sacramento for the last 4 years since I moved to Southern California. I was rented the opportunity to finally bring it down here with me, so I got the muscle bug workin inside of me and I’m getting everything lined up so when I DO a get it here, I can jump in and start getting her back on the road

[rjs53]

A lot of people on this site are running 20x10 rear and 20x9 in front. The rears easy to find. Put jack stand under axle, pull the wheel put a straight edge on the drum and measure from face of drum to outer wheel well lip and to frame. Remember 3/4” is about the least amount of clearance you want from rubbing.
This will help with backspace, don’t forget section width of tire also

[88gtstreetrod]

I have a 71 gmc. Has a 5/5 drop. Running 20x10 5.5 backspacing with 1 inch spacer on rear and 20x9 4.5 backspacing. I have plenty of room

[Taylor21293]

Originally Posted by 88gtstreetrod

I have a 71 gmc. Has a 5/5 drop. Running 20x10 5.5 backspacing with 1 inch spacer on rear and 20x9 4.5 backspacing. I have plenty of room

So you didn’t have to run your rear end, correct? Do you have any pics by chance?

[Taylor21293]

Originally Posted by 88gtstreetrod

I have a 71 gmc. Has a 5/5 drop. Running 20x10 5.5 backspacing with 1 inch spacer on rear and 20x9 4.5 backspacing. I have plenty of room

Never mind haha, just found your introduction thread you posted, that thing is badass!

[Dwyert4]

I have a 70 long bed that has 22x9 transport wheels. I have a 3.5" on front and 4 in rear. 1" spacers for the rears. Tires are 265/35 and have plenty of room. I did 2 1/2 drop spindles disc brake conversion on front plus 1" drop spring and 4" coil in rear. Drives great and no rubbing.

[Dwyert4]

Thinking of going 5" in rear.

[Taylor21293]

Originally Posted by Dwyert4

I have a 70 long bed that has 22x9 transport wheels. I have a 3.5" on front and 4 in rear. 1" spacers for the rears. Tires are 265/35 and have plenty of room. I did 2 1/2 drop spindles disc brake conversion on front plus 1" drop spring and 4" coil in rear. Drives great and no rubbing.

Beautiful truck! That’s awesome that you can fit 22s in there, they fit nicely on that truck

[Dwyert4]

Thanks man I appreciate it. Now what color and finish.

[saon]

Dwyert4
what did you use for a drop kit and a brake swap?
im looking to buy something soon and cant decide who or what or if I want to do a 73+ swap then piece it together.

[Dwyert4]

21/2 western chassis kit. Comes with everything needed. Springs also western chassis. Kit came with the truck when I bought it. I just had it done a couple months ago. Its my daily and i love the ride.