tractorleo
New member
I am trying to find a way to turn a hydrostatic transmission craftsman riding mower into a racing mower. Any ideas of how to increase the speed are helpful.
Increase speed
- Thread starter tractorleo
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CincyFlyer
Veteran Member
#1 is to increase the speed of the input pulley on the hydrostatic transmission, by either making the drive pulley larger or the driven (transmission) pulley smaller. Note that there is a limit, at which point you haven't enough power to spin things that fast. Also, you may find the limits of the transmission, in a rather rude way. That will get you the biggest gain (short of replacing the transmission with one with higher internal gain.) One other way is to increase the speed of the engine, which is typically limited to 3,600 rpm. There is also a limit to this, but with OHV engines (yours may or may not have it) you can get them to spin a lot faster. You'll need some upgraded internal parts to do so.
I used to know some folks that did tractor pulls with lawn tractors; some cost more than my car.
I used to know some folks that did tractor pulls with lawn tractors; some cost more than my car.
muddstopper
Veteran Member
I aint going to comment on speeding up the transmission. I will tell you that if your Craftsman hydrostatic is a k46 model, you are doomed to a very fast failing transaxle. Those things have a bad rep even when used as intended. You may have better luck if your mower happens to have the k66 transaxle, and it might hold up a little longer if you change out the transaxle pulley for one a little smaller in dia.
As for more info, the k46 transaxle is considered non-serviceable. Replacements start at around $600, but if your handy with tools, you can buy enough parts for a rebuild.
As for more info, the k46 transaxle is considered non-serviceable. Replacements start at around $600, but if your handy with tools, you can buy enough parts for a rebuild.
crazyal
Super Member
I think you'll find you want a gear box transmission. I have a backup MTD mower that uses a belt system (like a snow machine) that would also handle an increase in speed. But I think you'll find that the hydro gear box is going to over heat if used for racing. Also it's not as efficient as a geared or belt system. Racing is all about getting the most amount of power to the wheels.
CincyFlyer
Veteran Member
You can get cheap geared axles such as this: 3 Speed Peerless MST2 3-569 Transaxle | Mechanical Transaxles | Transaxles | Power Transmission | www.surpluscenter.com
Fallon
Super Member
I'm a big HST fan for tractor usage, but this is probably a case where it's not the right tools for the job. A HST is 15% less efficient in power transmission & racing is all about efficiency of power transmission.