2002 ezgo txt pds speed issues

[Ezgo808]

Hello everyone I’m new here to these forums.

I have a 2002 ezgo txt with a 36 volt pds system.

The problem I’m having is after installing a freedom chip (top speed) and lifting my cart with a 6” axle drop lift and 25” tires I am not seeing the speed I was expecting. A friend of mine has the exact same cart and batteries with the same lift and speed chip only difference is he has smaller 23” tires but has a higher top speed then I do.

When going down hill I have clocked my cart at 26mph before the regen brakes kick in. But I am only able to get 20-21 mph on a flat straight. Could it be my motor is just worn out and not able to achieve higher speeds or could it be because the tread on my tires are really aggressive? Or maybe something else I could check? My batteries are brand new and were fully charged when testing.

Any info is much appreciated


Thanks!

[JohnnieB]

The freedom mode ups the motor's speed limit to about 4400RPM, which is roughly 18.5MPH on stock height (18" tall) tires and mathematically 26.3MPH on 25" tall tires. However, along with the 38.9% speed increase, you also get a 28% loss in torque, so the cart will not reach the theoretical speed.

In addition, you mentioned your tire had an aggressive tread pattern, which takes more torque to turn than a smoother tread pattern. I also suspect they are low pressure (less than 10PSI max inflation pressure) off-road (TV) tires, which take a lot more torque to turn. If so, I'm surprised the cart does 20MPHG on level ground.

Since the regen braking is kicking in at 26MPH going downhill, I'm pretty sure the actual height of your tires is only about 24", or less. The numbers on the sidewalls are approximate at best and actual height can vary by an inch or more in either direction.

The stock PDS controller and stock PDS motor are not going to survive very long turning 25" ATV tires, so when they go replace the controller with an Alltrax XCT-48500-PDS and the motor with one a standard speed one having about 30% more torque. Also, add one or two more 6V batteries to get 42V or 48V, a 36V system doesn't play well with 25" tall tires.

[scottyb]

The stock motor will not survive 25" tires for long either. Basically 25 is just too much tire for the stock components and most aftermarket stuff except the extreme upgrades.