Hi from New Zealand

[eyeguy]

Hello,
I'm writing from New Zealand. I was looking for information on the rear axle drive for a go cart. Here is the reason why. My son recently brought home a go cart that he built in high school. About 30 other students built the same machine. Anyway, the drive hub, brake hub and both wheel hubs were secured to the 16 mm rear axle by sheer pins in the form of 5 mm bolts. Needless to say, the go cart operated for just about 10 minutes before sheering a bolt. I, being a mechanical guy, was not pleased with the design. This go cart had cost $700 to build in the high school workshop.
As an improvement we keyed the shaft and hubs and tried again. The engine is a 49cc machine imported from China. Chain drive to the axle. No problems there so far. The keys were holding out well, but the torsional stresses put on the axle because of the fixed rear wheels and the sharp turning involved. Well, I'm sure you know what happened. The axle sheered clean through where a key way met a sheer bolt hole. Not happy. It's only afterward when I think about the torsional stresses, that I feel a bit stupid continuing with a skinny axle. All history now. So, probably the most important question is- Is it normal for a go cart to have both rear wheels keyed hard to the axle?? I see that some carts have a small differential, which will ease the torsional stresses on the axle, but they COST!
Anyway, Normally, are both wheels keyed onto the axle or does one wheel idle and the other drive? If both wheels are keyed to the axle, what is a good size to make the axle?
Any advice is welcome.
Thanks
Eyeguy

 

[jr dragster T]

Most live axle karts have a 1" axle and both wheels are locked to the axle full time.

 

[eyeguy]

Thanks very much. I'll redesign, build and let you know how I get on. Thanks again.

 

[jr dragster T]

No probelem!

 

[Benjo]

which part of NZ are you from

 

[eyeguy]

Hello Benjo. I'm in Hamilton.

 

[Benjo]

im from the naki if you couldnt tell allready

 

[Rickracer]

Most race kart have at least 1 1/4" axles, no point in going smaller, also, lots of used parts for that size axle available, sprocket hubs, brake hubs, wheel hubs, etc.

 

[eyeguy]

Hello guys. Here is an update on my sons go cart. We thought about putting in a larger axle but the changes would have needed a machine shop. The cost could not be justified for such a light go cart frame. So we made a new 16mm axle. What we did though was drive only one rear wheel. We left the option of driving both rear wheels just in case the go cart was going to be used on grass. Anyway, the go cart goes really well and going round sharp corners where the driven wheel is on the inside allows great wheel spins. That's on concrete! We tried the go cart on grass with single wheel drive then two wheel drive. The single wheel drive goes so much faster and the cart turns so much sharper too. Anyway, we are so pleased with the way the go cart runs. Thanks to all who replied to my axle question.