2014 EZ GO RXV Unstable at Speed

[casey344]

Just purchased this 2014 RXV this evening. I test drove it and it seemed unstable. We fell in love with the 'look' of the cart. Seller said I'd get used to how it handled so this thread 'may' be premature.

Over 20 mph it seems very unstable. The body rolls quite a bit and my wife isn't enjoying the ride. To be honest I was white knuckled a few times. At one point I drifted into the other lane because I was afraid to over-correct too much. It seams that if I stiffen my arms and keep both hands on the wheel I can keep it more steady. Fun but not very comfortable.

We chose the RXV because we live in a very hilly neighborhood. The cart GPS'd at 29 mph and has dropped to 12 mph climbing a hill.

I need this cart safe but ideally want speed too so I can keep up with traffic. Is that possible? Where should I start? I thought these AC motor carts were designed to maintain speed while climbing hills?

FWIW the seller is a custom cart builder. This was his personal 'show' cart. He was very nice to work with and I'll be talking to him tomorrow. I'm just hoping to learn a little more about the possible issues with this build before we talk.

[rockfordpi]

Originally Posted by casey344

Just purchased this 2014 RXV this evening. I test drove it and it seemed unstable. We fell in love with the 'look' of the cart. Seller said I'd get used to how it handled so this thread 'may' be premature.

Over 20 mph it seems very unstable. The body rolls quite a bit and my wife isn't enjoying the ride. To be honest I was white knuckled a few times. At one point I drifted into the other lane because I was afraid to over-correct too much. It seams that if I stiffen my arms and keep both hands on the wheel I can keep it more steady. Fun but not very comfortable.

We chose the RXV because we live in a very hilly neighborhood. The cart GPS'd at 29 mph and has dropped to 12 mph climbing a hill.

I need this cart safe but ideally want speed too so I can keep up with traffic. Is that possible? Where should I start? I thought these AC motor carts were designed to maintain speed while climbing hills?

FWIW the seller is a custom cart builder. This was his personal 'show' cart. He was very nice to work with and I'll be talking to him tomorrow. I'm just hoping to learn a little more about the possible issues with this build before we talk.

That is this cart lifted is never going to be stable at the speeds you referenced because it was never designed to be. If you completely re-did the suspension, you might be able to make it so.

A lifted RXV above 20 MPH starts to get SCARY fast. We build a lot of these. We put 14" wheels with low profile street tires which handles better at higher speeds.

I have dealt with a guy that converts these to street legal LSV's that are DOT approved. However, to be DOT approved, at least with his design, he can't go over 19.5 MPH (though cart is capable of that), he can't lift the cart, and he must use US DOT Rated tires. The cart in the pic has very nice tires, but I am almost certain those are not US DOT street legal tires made/rated for higher speeds.

In terms of uphill speed, you might be able to get a little more with upgraded higher amp controller. However, our experience has been the higher amp controller does wonders for top end speed, but very little for low to mid range torque. The motor has a max horsepower level (which may be higher than the rated, but not infinitely so) and at that point there is nothing else it can do.

[jkredman]

Nice Cart.

In looking at your front profile pictures, I don’t think the Front Suspension is anything close to stock. It looks like it has a lot of flex. Great for off roading, but allows the cart to roll side to side on the suspension.

The stock controller would be a Curtis controller rated at 235 amps. There is a 350 amp Curtis controller that can give you more torque and acceleration with the proper programming. That’s done with a Curtis handheld programming unit, or a computer. However, unless the cart has been ‘Freedom Mode’ enabled, both controllers will cap you out at 17.5 MPH on standard tires. Freedom Mode maxes out at 19.5 on standard tires. So with your oversized wheels & tires I can see how your easily getting close to 30.

How is your braking?

The RXV uses the motor for braking. It also has a ‘motor brake’. However the motor brake functions mainly as the parking brake.

Typically anything larger than a 12.5 in wheel starts adversely affecting the braking.

Final thought is a question about the rear springs. I can’t tell from the pictures, for sure, but I think they are the stock springs. You may need the heavy duty springs. If they are stock, and you have weight in the rear seat, that will also adverse affect the ride, as in my case the stock springs would bottom out and allow the axle to hit the frame.

[BobBoyce]

People tent to lift carts and throw on huge tires/wheels for the look, without giving a single thought for the consequences.

First, as you mentioned, you lose much needed torque for hill climbing ability. The RXV regulates speed by regulating motor RPM, and that goes out the window when the motor no longer has the torque to maintain RPM because it is spinning MUCH SLOWER THAN IT WAS DESIGNED TO OPERATE AT. On top of that, it damages the controller, because in the long run, the motor turns into a power hog because the AC controller is no longer able to properly map the current required to maintain the RPM throughout the motors tuning range that was programmed. So the controller cannot perform the calculations required, and performance suffers in several ways. Regenerative braking is greatly affected, and that is the only service brakes on an RXV. Relying on the motor brake to TRY to lock up the rear axle when you depress the brake pedal hard is not how the brakes were designed to be used. The electric motor is supposed to smoothly slow you down and stop you, safely.

I am an engineer, and I designed electric vehicles for EV manufacturers. It concerns me deeply to see what people do for looks with no concern whatsoever for the outcome.

Now for the biggest issue. Lift kit manufacturers care only about the looks. Any time you lift a vehicle, you are raising the center of gravity. You are taking an already unstable, narrow track/short wheelbase vehicle, that is already handicapped for stability due to a higher than usual CG (Center of Gravity), and raising that CG by several inches. Not only is it unsafe, it is also illegal in many jurisdictions. You not only put yourself at risk, you are risking the safety and lives of everyone around you and everyone that rides on your cart. There is nothing that can be dore, short of returning the suspension back to factory stock, to undo this issue.

UNLESS!

You would have to hire an engineer to design you a new suspension, one that widens the track and lengthens the wheelbase, lowers the battery pack to lower CG, and reduces the ride height of the vehicle. This means a vehicle that you ride in, not sit on top of... no high roof either. Not too practical, is it?

My suggestion is to return the cart to the seller and buy one that is not a "show cart". Stick with real DOT legal road tires, not tires stamped with DOT that are fakes, if you intend to operate it on the roads. And stick to tires no larger than 20.5" diameter, no lift kit required. Both from a safety and ride height perspective, and to keep the controller happy with the motor. You really want an RXV of 2012.5 or newer, one that has the Curtis controller.

Performance can be had by reprogramming a stock 235 Amp Curtis controller to give you faster acceleration (If that is what you want), top speeds in excess of 30 MPH on the road with those 20.5" DOT tires, and regen braking with the feel of disc brakes. I do this Curtis RXV performance upgrade programming for free for forum members. It is my way of showing that lift kits and large tires are not the only way to go fast, AND to be safer doing it.

If you want to see what can be done with an RXV, check out my RXV chassis based road car build project. A 45+ MPH vehicle with low CG and NO lift kit. Of course, it'll have wider tires and a higher powered controller than the stock 235 Amp Curtis, but it will be cramped to ride in. Built for one person. It's been on hold for a while, but I intend to get back to it soon. The welding shop that I was expecting to do some aluminum fab work is closed and there are no others in the area that work with aluminum. My new welder does not have the spool gun required to work with the aluminum wire. Getting the spool gun ordered from my "local" Home Depot has proven difficult, at best. They don't mind selling stuff, but ordering accessories for what you buy can be a challenge at times.

http://www.buggiesgonewild.com/road-...-road-car.html

Bob

[basshawk84]

You need to do a front end alignment, both caster and toe adjustments. I've done a bunch of lifted RXV's and they will be a very unstable ride if out of alignment. I set the camber as close to zero as I can get and the toe in to 1/8". It takes me a long time to adjust both because every time you change one it affects the other. I also have to move the cart at least 20' or so after an adjustment and re-measure. The main thing is to be patient.

[Buggieman18]

What Bob and 'Hawk says.

Regarding alignment:

First, stop driving so fast until you know if your wheels are properly aligned. My poorly aligned wheels made me feel like I was about to drive off the road at medium speeds, especially after recovering from a turn. Very scary. I know I wrote out my alignment method for the RXV; I will find and post it shortly. Be very patient and be very anal with your measurements. Beyond that, you'll have to decide if you wish to drive around in a cool looking cart that is not designed to go that fast.

Nice cart, BTW.

[pootie316]

Originally Posted by BobBoyce

People tent to lift carts and throw on huge tires/wheels for the look, without giving a single thought for the consequences.

First, as you mentioned, you lose much needed torque for hill climbing ability. The RXV regulates speed by regulating motor RPM, and that goes out the window when the motor no longer has the torque to maintain RPM because it is spinning MUCH SLOWER THAN IT WAS DESIGNED TO OPERATE AT. On top of that, it damages the controller, because in the long run, the motor turns into a power hog because the AC controller is no longer able to properly map the current required to maintain the RPM throughout the motors tuning range that was programmed. So the controller cannot perform the calculations required, and performance suffers in several ways. Regenerative braking is greatly affected, and that is the only service brakes on an RXV. Relying on the motor brake to TRY to lock up the rear axle when you depress the brake pedal hard is not how the brakes were designed to be used. The electric motor is supposed to smoothly slow you down and stop you, safely.

I am an engineer, and I designed electric vehicles for EV manufacturers. It concerns me deeply to see what people do for looks with no concern whatsoever for the outcome.

Now for the biggest issue. Lift kit manufacturers care only about the looks. Any time you lift a vehicle, you are raising the center of gravity. You are taking an already unstable, narrow track/short wheelbase vehicle, that is already handicapped for stability due to a higher than usual CG (Center of Gravity), and raising that CG by several inches. Not only is it unsafe, it is also illegal in many jurisdictions. You not only put yourself at risk, you are risking the safety and lives of everyone around you and everyone that rides on your cart. There is nothing that can be dore, short of returning the suspension back to factory stock, to undo this issue.

UNLESS!

You would have to hire an engineer to design you a new suspension, one that widens the track and lengthens the wheelbase, lowers the battery pack to lower CG, and reduces the ride height of the vehicle. This means a vehicle that you ride in, not sit on top of... no high roof either. Not too practical, is it?

My suggestion is to return the cart to the seller and buy one that is not a "show cart". Stick with real DOT legal road tires, not tires stamped with DOT that are fakes, if you intend to operate it on the roads. And stick to tires no larger than 20.5" diameter, no lift kit required. Both from a safety and ride height perspective, and to keep the controller happy with the motor. You really want an RXV of 2012.5 or newer, one that has the Curtis controller.

Performance can be had by reprogramming a stock 235 Amp Curtis controller to give you faster acceleration (If that is what you want), top speeds in excess of 30 MPH on the road with those 20.5" DOT tires, and regen braking with the feel of disc brakes. I do this Curtis RXV performance upgrade programming for free for forum members. It is my way of showing that lift kits and large tires are not the only way to go fast, AND to be safer doing it.

If you want to see what can be done with an RXV, check out my RXV chassis based road car build project. A 45+ MPH vehicle with low CG and NO lift kit. Of course, it'll have wider tires and a higher powered controller than the stock 235 Amp Curtis, but it will be cramped to ride in. Built for one person. It's been on hold for a while, but I intend to get back to it soon. The welding shop that I was expecting to do some aluminum fab work is closed and there are no others in the area that work with aluminum. My new welder does not have the spool gun required to work with the aluminum wire. Getting the spool gun ordered from my "local" Home Depot has proven difficult, at best. They don't mind selling stuff, but ordering accessories for what you buy can be a challenge at times.

http://www.buggiesgonewild.com/road-...-road-car.html

Bob

Hi, just picked up a 2014 RXV. Can I send you my controller for the upgrade you mention, or do you have to do it in person?

Thanks.

[4mula1fan]

Yes! Alignment and lower tire pressures. I run 7PSI or so in front and 14PSI or so to carry passengers and loads. The alignment is tricky to get right, and it sounds like yours is off.

[4mula1fan]

Oh and those aren't the greatest street tires.

[BobBoyce]

Originally Posted by pootie316

Hi, just picked up a 2014 RXV. Can I send you my controller for the upgrade you mention, or do you have to do it in person?

Thanks.

Yes, it can be sent by mail. You'll need to make 4 more posts so I can send you a PM (Private Message) with the information on how and where to send it. It takes 5 posts to be able to use PM.