Some buds of mine have been tinkering around for the last couple years with mower racing in a backyard setting. After last fall, I decided it was time to throw my hat in the ring. I had a couple mowers that I played around with when we did tractor pulling, so I thought that would be a good start. The leauge does have a few rules for building...nothing over 13 hp and the total investment must be less than $100.
Well, I was at a community auction this last weekend, and picked up a Dynamark "Central Park" mower for next to nothing. I would say that it's from the 70's. It has a 3 speed trans w/reverse and a 12hp Briggs I/C engine(not original). The rearend/gearbox looks really beefy compared to the other mowers I had looked at(Murrays). I believe that it has 18x9.5-8 rubber on the back and ribbbed balloon-type tires on front. One of the other mowers I have is basically the same mower, only in the 8hp variety. It has a 3-speed trans which is chain driven to the axle.
On to the build: I had figured on welding the front axle beam to the frame and "tightening-up" the steering...it's got some play. Also considered lowering front end of frame and moving beam forward when I weld the axle solid...probably about an inch down on frame and nearly 2 inches forward. I have considered that I will have to do some minor modifications to the steering when I do that.
Have a few questions, first is this a good mower to use? I had talked to one of the guys that runs a mower and he said that I need a mower that has a 5-7 speed trans on the fender, that way you can "slam through the gears".
Second, what type of front tires would be best to run on a short dirt track...the original ribbed balloon type tire or a shorter, narrower turf tire. The ribs on the originals are only about 1/8" deep, so I figure the front end grip would be minimal with these. However, they would have more sidewall flex.
Last of all, what would be a good start to throwing different sized pulleys on this mower. I know that the guys that were racing last fall were probably topping out around 30-35 mph(not on the track). I figure on a short track, a person probably needs more torque coming out of the corners than just all-out speed.
Any advice would be greatly appreciated. Look forward to getting started.