Transmission Gearing

Gene-C · Post by **Gene-C** » Thu Dec 01, 2005 9:14 pm

I have a friend re-building his swing axle tranny and while it was apart, the mechanic asked him if he wanted to install close ratio first & second gears. Is there any great advantage in this modification?? The buggy is used for general off road, trail and some duning. Jimbo

newmanx59 · Post by **newmanx59** » Thu Dec 01, 2005 11:33 pm

That would be a close 2nd and 3rd. Close 2nd and 3rd will enhance off road performance provided the ratio, tire diameter and engine size are factored into the equation. Close 2nd & 3rd can be a chore to drive on the road (lots of shifting). Depending on the usage and the terrain he will be driving the buggy in, he might want to change the ring & pinion ratio instead.

Lee · Post by **Lee** » Fri Dec 02, 2005 1:28 am

I'm with Jerry. My buggy has 28.5" tall rear tires, and the 1600 Dual Port provided decent power in first and second gear with the 4.12 ring and pinion. I did have to get the RPMs up a little in first gear before taking off from a standing start, or the engine would bog down. We won't even talk about third and fourth, other than to say they were too high. I had Rancho rebuild the transmission as a "Pro Street" setup with a 4.37 ring and pinion. It was much better in first and second gear, but still a bit weak in third, and fourth was still only good for level or down hill roads. I recently had Rancho install a lower third gear (replaced stock 1.26 with a 1.31) and also fourth gear (replaced stock .89 with 1.04). Third gear is now perfect. I can continue to accelerate on those uphill freeway onramps. Mind you, it's not pin-you-to-the-seat acceleration, but at least it doesn't fall on its face anymore. Fourth gear has lots of power now, maybe a little too low. Fourth gear is also noisey, so the trans is going back to Rancho, where they will try to locate a (hopefully quiet) 1.00 fourth gear. That should put the RPMs where I want them If I want anything more out of the car I will need to install a five speed or build a bigger engine. The third and fourth gear ratios I mentioned work great on the street (the 1.04 would be perfect if I had larger rear tires - it tachs 3,500 RPM at 60 MPH now). If the buggy is to be used off road only, lower ratios can be used, but I wouldn't go any lower if there will be any amount of street driving. First and second pull real well off road with the 4.37 ring and pinion, even with a stock engine and a fully loaded buggy. Sand dunes might be a different story, possibly requiring an even lower ring and pinion (or a bigger engine).

Gene-C · Post by **Gene-C** » Fri Dec 02, 2005 6:55 pm

Thanks for the imput, guys. I will print this all out and give it to my friend for his decsion Jimbo

fubar · Post by **fubar** » Fri Dec 02, 2005 10:50 pm

My friends just put together a long travel four seat buggy. The used a turbocharged efi ford 2300. The trans axel was out of a newer watercooled bus. I told them that the gearing was probably going to be too tall and their thoery was that with the turbo it would overcome that. The test drive proved otherwise. I guess it was a turd even in first gear. That is with something that should be pushing 200hp. That max power probably is unachievable if the turbo can't spool up. The right ring and pinion is the cheapest way to go fast in the sand, next to a rental car.