will stock rear end hold up with drag radials?

Discussion in 'Got gears?' started by puddle, Nov 9, 2014.

  1. puddle

    puddle Silver Level contributor

    Planning on going to a 1/4 mile track this spring (finally!) My truck has a completely stock truck 12 bolt posi that has the C clip axles. I will be installing 275/60R 15 drag radials. RPM's go to 1600 with a foot brake launch before I can't hold it with the brake any longer. See my signature below for the rest of combination. Will the stock rear end hold up OK or am I looking at an axle upgrade with C clip eliminators?
     
  2. mltdwn12

    mltdwn12 Founders Club Member

    I ran a stock 12 bolt in my GS for for 28 years. I ran at the drags with slicks running low 12's back then and never had a problem. In 2008 when I rebuilt the whole car the only thing I did was add a set of Moser axles with a C-Clip Eliminator kit.
     
  3. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Your combo might be a little much for that rear with off the line traction. Not only are the c-clips a concern but for some reason the General made the truck 12 bolt rears weaker than the car 12 bolt rears by giving them smaller pinion. If I remember correctly I think the car pinion is 1.625" and the truck pinion is 1.437" diameter. Not sure why they did this to the trucks, seems like the trucks should of got the stronger parts back then like they do today.:Do No:

    Anyway something you might want to look into. GL


    Derek
     
  4. Jim Jones

    Jim Jones Wretched Excess

    Bolt in axles are a good idea in the event of axle breakage. The C clips only retain the inner end of the axle, leaving the outer end to separate from the car should breakage occur. But quite frankly, I have never seen a failure caused directly by the C clips, it is usually the axle shaft that fails. Moser makes forged axles for the 12 bolt that are retained by C clips, and I have used them with good results on a hard launching car with drag slicks. If you are on a tight budget, this may be a good option.
     
  5. puddle

    puddle Silver Level contributor

    Thanks for the replies. I will look into an axle upgrade, but maybe the week link is the pinion shaft? At any rate, I may go with 255/60R-15 drag radials instead to leave a bit of a "fuse". It wouldn't take much to improve on the 215/75R-15 street radials with fairly hard rubber that I have on there now.
     
  6. sean Buick 76

    sean Buick 76 Buick Nut

    Do the drag radials, enjoy the truck, and if you have an issue with the rear end then rebuild it properly with a good possi unit, rebuild kit, new gears, and Moser axles... If the rear end stays happy then leave it alone.
     
  7. puddle

    puddle Silver Level contributor

    Thanks Sean. I like the "if it ain't broke don't fix it" advice! Sturgis Drag Way is a little 1/8 mile track just down the interstate and I will try the drag radials there and see how it does before venturing further to a 1/4 mile track Looking forward to reading your book.
     
  8. Mark Demko

    Mark Demko Well-Known Member

    Im going down the same road with my 350 GS. Going to purchase 275/50/15 DR's, to use instead of the TA's.
    Im not one bit concerned about my 12 bolt, and if it does break (highly unlikely) that will be cool:Brow:
     
  9. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    I ran two Drag Week's with a stock GM 8.5" with stock axles and just the TA diff cover and 235/65R15 drag radials (narrower than yours), and with a manual transmission. I always launched relatively soft and the second Drag Week it lunched the left rear axle bearing, but otherwise survived low 12's.
     
  10. 71skylark3504v

    71skylark3504v Goin' Fast In Luxury!

    I blew the spider gears out the backside of my K10's stock 12 bolt while abusing the truck off road a few years ago. Honestly, you need to be looking at 67-72chevytrucks.com for advice on this rear end. Quite a few guys running 5-600 HP through this rear, not in stock form though.
     
  11. Da Torquester.

    Da Torquester. Platinum Level Contributor

    I'm still using my original 10 bolt 8.2 axle. It's never been apart or messed with. It has the bolt in axles of which I replaced from a parts car I have. Car weighs 4100 lbs with me. I use full slicks. The stock rear end is strong, just depends which one you have. The old 10 bolt bop style I've been told is stronger than a 12 bolt. ( Just what I''ve heard ) And lighter. Mine has held up through some tough use over the years. I would find out what specific 8.2 rear end you have first before using a real sticky tire. John.
     

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