72V TXT - Tire question

[BAC5.2]

I should be getting a 2017 Cushman Shuttle 6 very soon, and was curious about whether or not anyone had any experience with the 72V AC powertrain in that car. As far as I know, the Shuttle 6, and the Express L6, are both lengthened 72V TXT's.

It comes with 18" tires, and a claimed top speed of 16.5mph. The EZGO Express L6 version of the car comes 23" tires. They, too, claim a top speed of 16.5mph with the same stated rear ratio (17:1), motor power, and controller specs. I'm not sure what's different in the programming that limits the speed of the EZGO version of the car. The Freedom claims 19.5mph with a 20" tire, and the same 17:1 drive ratio, motor, and controller. It sounds like the Cushman programming might be the "Freedom mode" programming, with a smaller tire.

Does anyone have experience with this powertrain, and have run a 23" tire with the "Freedom" programming? The math should put it around 21mph. I've seen several threads suggesting that the electric powertrains can struggle with that size tire, but I don't think any of those were with the 72VAC powertrain.

Would I be OK running a 23" tire, or should I stick to a 20" tire?

I'm leaning towards the Street Fox tire, and I'd use a 14" wheel (3:4 offset - maybe the GTW Pursuit or the Vortex). The car will be used almost exclusively on-road and year-round (rain/snow included). It's pretty flat, but there are some short hills. Ideally I'd like to avoid lifting, which I believe is possible with the 20" tire.

[JohnnieB]

The motor's RPM is limited by the controller to whatever RPM that yields the speed published for the stock height tires for that model cart.

The stock tire height is also part of the speed/torque curve programmed for the motor, so changing the tire height very far from stock height is going to require reprogramming the controller at a very basic level, programming levels below what can be accessed by the hand held programmers.

From what I understand, which isn't all that much, going from 18" to 20" may be within the tolerance, but 23" isn't.

Hopefully Bob Boyce will see this and respond.

[BAC5.2]

I was reading some Bob Boyce threads, and it definitely sounds like he's the expert on these things. It almost looks like the Cushman programming is the same as the Freedom mode, so maybe a 20" tire gets me 19.5mph and I don't really need to do any worrying. If Bob is ever out west, I may be interested in some tweaks to hit 25mph.

[BobBoyce]

Originally Posted by BAC5.2

I was reading some Bob Boyce threads, and it definitely sounds like he's the expert on these things. It almost looks like the Cushman programming is the same as the Freedom mode, so maybe a 20" tire gets me 19.5mph and I don't really need to do any worrying. If Bob is ever out west, I may be interested in some tweaks to hit 25mph.

I would stick with the E-Z-GO vs the Cushman if you are ever planning on upgrading it. Even though both are made by Textron, they are very different from one another in parts used and how they are implemented. You certainly would not like the lack of programming options... They are not golf cart controllers, and not all modern 72V are AC drive.

Pretty much every 72V cart I've seen has had 23" or 25" tires. The AC motor maps were written for 23" tires. 25" tires are within those AC motor maps range.

I've done my one and only western route trip. I still have the pneumonia that resulted from that trip. I drove nearly 7,000 miles and reprogrammed 12 controllers on that trip. Too many miles driven for the number of controllers reprogrammed. I enjoyed meeting the members visited for sure, it was just too much for me in my state of health.

Bob

[BAC5.2]

Thanks for the info Bob! I'm sorry to hear about your health.

The deal on this cart is so good, I can't pass it up. I've confirmed it's a 72VAC, with the same powertrain as the L6/Freedom, and it has 18" tires.

I tried sending you a private message, but it looks like your inbox is full. I had a couple of questions.

[BobBoyce]

Originally Posted by BAC5.2

Thanks for the info Bob! I'm sorry to hear about your health.

The deal on this cart is so good, I can't pass it up. I've confirmed it's a 72VAC, with the same powertrain as the L6/Freedom, and it has 18" tires.

I tried sending you a private message, but it looks like your inbox is full. I had a couple of questions.

It'll likely be full for some time. If you've ever hooked a programmer up to a Cushman, you would understand why it's not the same. Good luck with it if you get it because nobody will be able to help you.

Bob

[BAC5.2]

I appreciate the insight, Bob. This will be my first cart, so I've got very little experience with the differences between cushmans and EZGO's, and their programmers. If the Cushman proves to be more trouble than it's worth, I may just resell it and wait for a deal on an L6 instead.

Have you had luck in tuning the 72V AC L6's and 72V Freedom cars?

[BobBoyce]

Originally Posted by BAC5.2

I appreciate the insight, Bob. This will be my first cart, so I've got very little experience with the differences between cushmans and EZGO's, and their programmers. If the Cushman proves to be more trouble than it's worth, I may just resell it and wait for a deal on an L6 instead.

Have you had luck in tuning the 72V AC L6's and 72V Freedom cars?

I've reprogrammed literally dozens of them. But the Cushman version of the controller lacks the E-Z-GO VCL (Vehicle Control Language). No VCL means nothing can be changed or tuned. You are stuck with the way it comes. You can't even remap the motor to turn 23" or larger tires!