Axle rework

kidd1

New member
I have a older ultramax champ kart and it has a long axle in it that sticks out to about the end of the rim and I was thinking about cutting it of and putting a new snap ring groove in it. Can I do this or am i missing something that I am not thinking threw. I know the less turning weight the better.
Any advise is greatly appreciated!
Thanks
 

alvin l nunley

Site Supporter
unless there is some pressing need to cut it, I wouldn't worried about the turning weight. don't let the turning weight be the reason for the cutting.
 

kidd1

New member
unless there is some pressing need to cut it, I wouldn't worried about the turning weight. don't let the turning weight be the reason for the cutting.

I have always heard that a pound of turning weight equaled to 10 pounds off of your racing machine in power. Don't know if this is a hundred percent true.
 

PD Power

New member
I few inches of extra axle length does not add a measurable amount of turning weight.
Turning weight only becomes relevant if the weight is added a considerable distance from the center of the axle.
Even then, if there was measurable turn weight, that same weight would be relevant only in helping keep axle
speed up, during times of resistance.....namely on turns. That is a good thing.
 

JPMKarting

Site Supporter
Nothing wrong with cutting it. We run the shortest axles we can in our karts. On an older Ultramax champ, your going to want some axle sticking out the RR so you have adjustment in and out
 

Outrider

Member
What PD and JP said. When they're talking rotating weight they're talking the effects of polar moment of inertia of the rotating assembly. It doesn't make much difference when it's 5/8" from the center of the axle - it makes a difference out toward the outer edge of the rim and the tire. And since you're removing length from the axle, not diameter, none of that's going to change anyway. You will, however, reduce the total weight of the axle which will, in turn, have a minute effect on momentum, as has already been pointed out. Cut it and don't worry, but don't expect any big difference in the way it turns, just a slight overall weight reduction.
 

harrym

Member
Take an equal amount off of each end and make sure you have enough key way. Snap ring groove can be done easily on a lathe. Diameter is so small that rotating weight is not a factor.
 

kidd1

New member
Thanks guy for all the help. I am a machinist and have a lathe so I think I can take care of it but was just making sure I wasn't overlooking something that said don't do it or that's a big no no. Thanks again.
 

jhucks03

Member
The axle could probably stand replacing if its been in there any length of time. Just buy a shorter one and put it in. Keep the long one for a spare.
 
Top