Wide rear rallyes
 

Hello, I am starting over on a 71C10 build I started 10 years ago. Trying to figure out rear rim backspace because they need to be special ordered. I have the stock 12 bolt rear and I have added the wide Tubs. My plan is to go with 12inch wide US Wheel Rallye's in the back. They will do a custom backspace for me. I want to run the Hoosier Pro street 29x15x15 tires. I have been trying to figure it out but don't want to make a mistake on the rim backspace. So far i'm coming up with a 8.5in back space ? Has any one done this same tire and wheel combo on the wider rear axle like mine ? Based on my homemade Jig going off the drum face, I would have 8.5in in and 4.5in out. (13"overall rim width) Any help would be appreciated. Thank you

Re: Wide rear rallyes
 

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See if this thread will help you any.

http://67-72chevytrucks.com/vboard/s...d.php?t=736143

I never followed through with mine but I was thinking 7.5 BS

LockDoc

Re: Wide rear rallyes
 

Thanks Leon, I'll check it out. I know the earlier trucks have a shorter axle . I just want the tires to look centered . The Hoosiers have a 15.3in center width. I hope some one with my setup has done it and will chime in. At $300 a wheel , mistakes are bad lol. Appreciate your help !

Re: Wide rear rallyes
 

Mine is a 69 CST 10. I sent my center sections to Stockton California. They welded the center into a 12x15 inch blank wheel with 7 inch back spacing. If your keeping the drums, you will have no problems. I put 31x16x15 Mickey Thompson Sportsman on them. So far, works great. The only issue is if your going with steel wheels, is the weight. Their heavy.

Re: Wide rear rallyes
 

If you go to the forum Lockdoc posted, you can see my truck with the 29x15x15 Mickey Thompson tires. Lots of clearance.

Re: Wide rear rallyes
 

Appreciate the reply. With the 7in bs do the tires stick out on the sides ? My truck is lowered 5in in the rear. I'm sure your tubbed ? Is the tires centered in the wheel well ? Do you have coils or leafs ? Thank you

Re: Wide rear rallyes
 

subbed for info

Re: Wide rear rallyes
 

My truck was lowered also 2 1/2 front and 4 in the rear. I have room for 14 inch wheels. I have coil springs and still have the bump stops. If I go with 14 inch wheels, they would need to be removed. If I go with 14, I would use 8 inch back space. Check the thread LockDoc has high lighted and you can read and see about my truck.

Re: Wide rear rallyes
 

So on your truck , found a group of 4 pics. What is the setup on there. 15x12 or 15x14 ? I made up a jig to try and measure for backspace. It looks like I have to go like 8" in or the lip will be to close to the outside ? Totally confused. I know the hoosier tire in 15x15.5 has a 15.3 in tire width with a 12" tread width. Going 29" tall . If I have to come down more? just want to make sure it doesn't hit . Appreciate the help

Re: Wide rear rallyes
 

The pictures have the 15x12 with the 29 inch high tires. These wheels have the 7 inch back space. There is lots of room. This set up never once hit the bed sides or the frame or closer yet, the bump stops. If you go with the 8 inch back space, you might hit the bump stops. Check that to make sure. Now I'm still using the same wheels (15x12) with 31 inch tires. They too, have not hit any thing. I felt the 29 inch tires were to small. They didn't seem to fill the wheel well enough for me. I raised the front back up to factory height. The front tires would hit the fenders on big dips or speed bumps. I got tired of that. The back is still lowered with no issues.

Re: Wide rear rallyes
 

Yours looks good. I am planning on the 29's but I was worrying about them being small ? My truck has the 3.5/5 lowering kit I put on 12 years ago. My plan is a 496 BB with TH400. . My rear end ratio is 3.42. Not sure how much 2inches changes much on gearing ? ( 29 verus 31" ) Wheels and tires are expensive , so i'm trying to do it one time lol. Thanks again!

Re: Wide rear rallyes
 

29" x 3.42 @ 40mph= 1585rpm
@ 60mph= 2377
@ 70mph= 2774

31" x 3.42 @ 40mph= 1483rpm
@ 60mph= 2224
@ 70mph= 2595

Stock 'truck' ralley wheels are a common wheel to run. These 15x8's have 4" of back spacing. Widening to your specs would yield 8" of BS to keep things consistent as far as the spacing between the outer bedside lip & the edge of the wheel/tire.

Your proposed 8.5"BS would work. You might need to remove the bumpstop; might not.

FYI.... US Wheel might offer the wider/custom wheels but getting them can be an entirely different ordeal. I purchased 2qty 18x8" wheels & they were available/in stock via Summit. I placed a 2nd order for 2qty 18x9" wheels after verifying the fit of the 8" wheels. Five months later I still did not have my 2nd pair of wheels. I could not (nor could Summit) reach ANYONE @ US Wheel. Calls went to VM's after eventually going through & you never got a call back. The kicker? I had to 'eat' a penalty fee from Summit to return the 2qty 18x8" wheels because w/o the rear 9" wheels, the fronts were kind of useless.

Not my fault. Not Summits fault but they could have waived the fee since the wheels just sat around in a box for 6months. Be ready to possibly wait.....

Re: Wide rear rallyes
 

Thank you, That really helps me out!

Re: Wide rear rallyes
 

OneBad71, you have the exact set up I'm running. Big block 454, 400 trans, USA 3:42 gears. A real gas guzzler. I installed a Gear Vendors overdrive and one piece drive shaft. Now it's a lot fun to drive on the street and still race it at the drag strip. Runs low 12's. Still can't get the slicks to bite.

Re: Wide rear rallyes
 

Cool, Quick question. Without the Overdrive, can you still run a one piece drive shaft ? I have a short bed. Thanks, Dan

Re: Wide rear rallyes
 

I don't know. Mine is a long bed. A shop here in Pa who builds rear ends and transfer cases for truck pullers built mine.

Re: Wide rear rallyes
 

Short bed trucks can run either a 1 or 2pc drive shafts.

Re: Wide rear rallyes
 

Thanks !