Looking for advice, Just picked up a used 31 spline axle as a spare for my lightning sprint. Decided to throw a dial indicator on it to check run out, it's about .030" is this too much or still useable?

Depends on where it's bent, but it can be straightened, .030 I don't consider bad! Bob

I got the .030 measurement with the outer ends supported, checking run out in the center of the axle, it's just a spare guess I will leave it as is. Thanks for the reply!

Kart

.030 isn't too far off. AJ Felker has an axle straightener in house and should be able to dial you in a little closer.

We use him all the time for both rear and front axles.

Honest Dad himself

Thanks for the info, I will keep that in mind!

Put it in V blocks and measure the ends and where the birdcages sit. .030 isn't horrible.

it helps to know which end is bent and how much run out there is at the birdcage.

On dirt, you will not feel .030" in the car. Axles are not perfect when new. Most have .005 - .010" run out, depending on how and where you check. The wheels will have even more run out. You don't want to know what the tires have.

You will notice it if it's much more and depending on where the bend is. A axle can be straight at the bearing shoulder and out 30 thou at shoulder and it can be bent at shoulder and less on the end. An axle can also be twisted in the splines. A quick and dirty in the car is to watch and make sure the cages aren't walking