Cub Cadet 122 transmission

Does anyone have any experience modifying/overspeeding the cub cadet 122 transmission? I would like to know how it holds up to overspeeding and offroading. The driveline of the 122 is completely straight shaft with no belts, so if the transmission could hold up it seems like it would be very capable.

Surprisingly, exact info on that trans is very scarce but apparently it should have either a 3 speed w/reverse or a 6 speed w/reverse and a creeper gear. Anything Cub Cadet from that era is ridiculous strong and desirable in the tractor pulling community so you know it's strong!

If it's like other shaft driven Cubs where the driveshaft is coupled off the flywheel of the engine then there's no way to overspeed it without internal gear changes which I'm not sure how possible that even is. I definitely wouldn't recommend overspeeding the engine because Kohler K series are known to break connecting rods but they are an excellent engine!

Although it's built like a tank and a really awesome tractor maybe it's not the best choice for an offroader, could make one heck of a pulling tractor though!

Times like this  @Mister_Studabaker's knowledge would be good.  Keiser was a force of nature.
https://www.atltf.com/t6058-keizer-the-little-cub-cadet-122-is-growing-up


Maybe some info there?

Brianator wrote:

Surprisingly, exact info on that trans is very scarce but apparently it should have either a 3 speed w/reverse or a 6 speed w/reverse and a creeper gear.

I believe the setup is a 3 speed transmission, and an optional creeper gearbox that had 2 gears that would turn it into a 6 speed. I do agree that they were built very well, they are more like tractors than lawn tractors are now. I guess that's the reason I'd like to build one for offroad, along with the fact that they just look good. I think the best thing to do with the 122 that is available to me is to get it running and keep it stock as a vintage tractor, and try to find a different tractor that is more suitable for offroad use.

it is completely possible but as @Doug said you can achieve amazing speeds out of them it's just going to cost ya. Some Cub Cadet gearing on the inside are interchangeable so if you can find a Cub Cadet transmission that's compatible and geared higher you can pull the gears out of it you can swap around and speed it up. Also a higher RPM engine is the only other way I can think of

Could you put some sort of overdrive gearbox in between the engine and transmission to get more speed out of it (Like gears or a chain)?

You could probably run some sort of gearbox or a Jack shaft me personally I would opt for the Jack shaft

There's no doubt it would have decent offroad capability but if it were mine I'd be happy with whatever speed the biggest tires I could fit under the fender pan and a couple hundred extra rpms could get me (probably 8-10mph). Something about speeding up an old Cub without major work doesn't sit right with me, I'm sure it would be a blast with a good set of tires and a few other small goodies though and gives you something to play with!

The only ways that I know of to overspeed the cub gear drive transaxle is to

# 1‐ remove the governor to gain higher engine rpm.
# 2‐ swap out the ring an pinion in the transaxle to a higher gear ratio.

( there is an older car model that fits in real good with little machine work - 【it think it's dodge dart but I could be wrong】-    or with more work I think the Ford 9in stuff will fit too.)

There is alot of info on this in some garden tractor pulling forums and I think there are even companies that sell the setups.

I just wanna say that that tractor in your avatar looks incredible. I have heard of the pinion gear swap method, and from what I have seen online that seems to be the only way to do it outside of something on the outside of the transmission.