[d.b. cooper]

Would anyone, off-hand, happen to know the approximate weight difference between a 7.5" 10-bolt and a 12-bolt (or 8.5" 10-bolt for that matter).

i'm assuming(?) there is a weight difference because the 7.5" has an aluminum center section while the 12 bolt's is iron. Also the 7.5"s axle tubes are 2.5" diameter vs. the 12 bolt's 3" and the 7.5's tubes have a slightly thinner wall.

i know a 12 bolt or 8.5" 10 bolt is much stronger than a 7.5, but the car is light--1940 lbs and i'm not making big time power. i'm trying to make it lighter.

i know there are variables such as type of brakes, bracketry and width, but i'm wondering in general, what is the weight difference if any?

 

[big gear head]

All of them have a cast iron center. The 7.5 is not aluminum.

 

[64nailhead]

The grunt factor says I can carry a 7.5 without brakes installed on my shoulder - begrudgingly. I can move the 8.5 around by bending over. A 12 bolt is heavier than both. I'll guess 75-90 lbs heavier than the 7.5.

How's that for a guess

 

[cerial]

10 bolt is around 200lbs.
12 bolt is around 275lbs.

Close weight without drums.

If you feel your power needs require you to run a 12 bolt then run one. Throw disc on it to knock down the weight.

Lots of areas to loose unsprung weight. Lighter suspension arms/springs, lighter rims, brakes, and tires to name a few.

 

[curtis73]

IIRC, the 8.5 is within a few pounds of a 7.5. I would personally rather have beefy and 10 more lbs than wimpy and 10 lbs lighter. I'll just stop eating fast food and save that 10 lbs somewhere else

What is your torque going to look like? Power doesn't kill it, torque and traction do. Also, manual or auto. Big difference. A nice firm 1-2 shift in a TH350 is nothing compared to grabbing 2nd in a manual and re-engaging the clutch.