# Golf cart rear axle, how fast could it go?



## todayican (Jul 31, 2008)

I am brainstorming a small, light, cheap, highway capable, 1 seat trike (1f2r)

In a nutshell, here is what I am thinking, fairly stout forks from a 600 or so cruiser bike up front additional rake, lightweight frame, and a golf cart differential and axle in the back on light leaf springs. and either going with a higher rpm motor mounted directly to the diff, or running a pulley from the motor to the diff to get the right gearing for the highway.

anybody have any comments, or experience with golf cart axles being pushed to those speeds? will the bearings hold out, brakes?

Thanks for the input.


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## Coley (Jul 26, 2007)

The Dana rear axle that a lot of them have would probably hold up, but won't give you much over 45 mph.
The motor is mounted on the differential and is about a 4:50 ratio.
I would go with a small street legal car's rear end. 
Easier to gear the motor to a lower ratio for higher speed.


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## wvomike (Sep 30, 2016)

I was thinking of doing a similar thing, as I already have a Club Car 48V motor on a transaxle. But I don't think my differential is the same type of Dana you are referring to.

I will try to attach a pic of what I have.


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## rmay635703 (Oct 23, 2008)

If you can find a post 1980 comutacar or comutavan in derelict condition, they have axles that are more competent up to about 55mph depending on your motors max rpm and power curve. My c-car can hit 55mph on 72volts


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## galderdi (Nov 17, 2015)

Get a small front wheel drive gearbox and drive shafts from any bone yard. There is no reason why it can't be run in the rear driving the rear wheels. It will be light weight. It also give the added bonus of giving a full range of gears. So top speed should no longer be an issue. The hardest part will be sorting out gear linkages. But you could even run an automatic and then gear linkages are nolonger such an issue.


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## Sunking (Aug 10, 2009)

I have built 3 racing golf carts, so I have a fair amount of experience with them. Fist a little background. By Law a Golf Cart can go no faster than about 14 mph. There is a loophole in the Law that makes provisions up to 19/20 mph for PEV's. 

So how do manufactures limit the speeds. Simple physics, they do so mainly by the differential ratio. Depending on manufacture and motor type Differential Ratios range from 20:1 to 12:1. So with say a motor with a maximum 5000 RPM, tire diameter of 18 inches, and a differential ratio of 14:1, 20 mph is as fast as possible. No way to go above that.

So how in the heck do I get a golf cart to go 70 mph? You change out everything including batteries. 

You start with a motor. Golf Cart motors rum 3 to 5 Hp with a RPM limit of roughly 5000 RPM. That motor has to be changed to at least 16 HP where peak torque and HP happen at 5000 to 7000 RPM. I used a HPEV AC15 motor operating at 96 volts. 

Next I have to lift the cart 3 inches to make room for 22 inch tires. While I am at it, front wheel disc brakes must be added if I plan to live.

Get rid of the 450 pound Pb battery and replace it with a 120 pound LFP battery with a large enough AH capacity to deliver 500 amps peak, 100 amps continuous.

If that were not expensive enough, I finally have to change out the Differential Gear to a SPEED Gear to give me somewhere between 7:1 to 4:1. That gear is some $500. 

What did I end up with? A $10,000 used golf cart that is dangerous as you know what. At 7000 RPM motor gets me 70 mph with 22-inch tires, a 6:1 ratio speed gear. That motor has to produce 60/ft-pound of torque from 0 to 6000 RPM which is roughly 70 HP peak, and 16 hp continuous.


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## TerryH (Jun 9, 2012)

Ancient thread resurrection alert.  Original thread from 2009. 

BTW...we went 101.81 mph with a 6:1 gear in our Club Car/Graziano golf cart rear on Saturday.


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