Rear independent suspension axle

[Jeremiah Froese]

Hey everyone Im wanting to do rear independent suspension on my next go kart. I found some pictures on online of how it’s done just like regular with double a-arms and CV joints. I was just wondering though if I could possibly use u-joints instead of CV joints and make my own axle? The picture attached is what I’ve been thinking of making

 

[redflash]

no reason why not.....awful lot of work...google up " how to build mx5 differential chain drive differential " go Kart.....see what I did !

Da Flash

 

[madprofessor]

I sure do hope you try the U-joint build for it, but not with driveshaft joints for a big pickup truck.
I've looked carefully at the common steering U-joints sold by gokart parts dealers, and wondered if they could hold up to the stress of being used for transmission of motor power. All I figured out was 2 things:
#1 would be that the left/right axles would need to be quite long (wide kart) to reduce the angle of the joints at full extension/compression.
#2 would be that the steering U-joints with splines that match splined steering shafts would be preferable, to avoid having to weld smooth-bore joints. Would of course require using steering shafts for the axles.

 

[madprofessor]

Addendum to previous post: I was imagining how to make a locked-axles drive for a kart with IRS. No differential, for the purpose of doing it all on the cheap. Keep us apprised of your progress if you do a build with IRS.

 

[Jeremiah Froese]

madprofessor, the universal joints that I had in mind are one from Princess Auto with 1in. inside diameter. They are good for 1000 rpm’s, and 400 inch pounds of torque. I plan to make the kart a two seater so getting the axles wide enough shouldn’t be too big of a deal

 

[Denny]

I think you would be better with a CV joint. The CV joint was developed for front wheel drive cars to compensate for the extreme angles encountered when steering or using short drive shafts. They also allow for the slight length adjustments through the arc of travel without having to use some type of slip yoke or joint. Not to mention having to keep the slip joint sealed to reduce wear and play. You could save your self a lot of trouble and heartache by using already engineered pieces from a front wheel drive vehicle. It would also be cheaper in the long run also. Less or no custom machining would be needed then.

 

[madprofessor]

They also allow for the slight length adjustments through the arc of travel without having to use some type of slip yoke or joint.

That's very cool, would like to see how that's done. Had to deal with that length slip in the steering of ShizoBallz, as the shafting utilizes 3/4" threaded rod coupling that physically screws the shaft back/forth as the wheel is turned, as opposed to a simple bushing.
Ended up using a hexagonal quick-release steering wheel hub as the slip yoke, with the insert sliding back/forth without locking into it.

 

[Denny]

They usually have some travel built in on the inner (transmission side) joint. Usually less than an inch is all that is needed.

 

[Jeremiah Froese]

I think you would be better with a CV joint. The CV joint was developed for front wheel drive cars to compensate for the extreme angles encountered when steering or using short drive shafts. They also allow for the slight length adjustments through the arc of travel without having to use some type of slip yoke or joint. Not to mention having to keep the slip joint sealed to reduce wear and play. You could save your self a lot of trouble and heartache by using already engineered pieces from a front wheel drive vehicle. It would also be cheaper in the long run also. Less or no custom machining would be needed then.

Any ideas where I could find some ATV type CV joints for a decent price?(online?). Also wondering how I would do it if they’re splined… I was thinking with the universal joint thing that I would just be running a 1 inch shaft out from centre with jetway and set screw but with splined CV joints it would be different. By the way, our farm shop has a lathe and milling machine, and my grandpa is an experienced machinist, so some machining would be no big deal.

 

[Denny]

Buy an old ATV or go to a junkyard. Me, I myself would use old car parts for that bullet proof factor.

 

[MTScott]

I think through this a lot for how I might do my next buggy (which I'm hoping to do IRS).... I'd just use CV axles from the auto industry. They're likely cheaper than ATV/UTV parts and should be plenty stout. I doubt you could actually make them cheaper yourself by the time you're done buying shafts, U-joints, flanges, splined adapters, etc... CV axles for small passenger cars run 50-75 bucks, and they're already figured out.