Lifted Diesel Cart 8:1 or 6:1 ratio gears?

[rbraden4]

A few years ago I built a 96 EzGo, it’s lifted with 28” tires, powered by a Kubota D850 and I think I’m ready to change the gearing. It jumps up to top speed pretty much right out of the hole then cruising the motors just reving.
I’m looking for opinions on the ratio. Ide like to load the motor down pretty good, it’s usually a pavement queen and doesn’t see much if any hills.
I was thinking and about to hunt down a 6:1 set but I thought ide ask in here before.
Thanks.

[kgsc]

Factory rear ratio is around 12:1. 6:1 with 28” tires is pretty steep but the diesel might have enough torque to pull it off.

[scottyb]

I agree 28" tires are greater than a 50% increase vs stock tires so I would not go with too big of a change, Unfortunately common gearing available is 8:1 which would another 50%.
It may or may not handle that.
My BB Ezgo kinda does the same thing with 25s and 15:1 gears but I'm not sure I want to go any faster, Actually eyeing up some 22s stacked in the shed to improve off road use. But I enjoy the cushioned ride of the 10x25x10s


Keep us posted.

[slonomo]

What's is your current max rpm? What is MPH at that point?

Most diesel engines max out at around 3k, some even lower. They don't rev high, obviously you know that lol. If this engine has tons of torque the gearing may not even matter, to be honest. Especially if you aren't pulling anything or climbing hills. I don't know the specs on that engine to give an opinion on if the engine will handle the gearing increase. If the engine is in tip top shape and it pushes 50 lb ft, then it might be good to go.

As the others have already pointed out 28" tires are pretty tall, but is that the "size" on the side of the tire, or is that "actual" height? That makes a difference here. I've seen 25" tires measure out to 23.5" and I've seen 22" tires measure out to 23". It all depends on the rim width and the tire itself, they are all over the place size wise.