Friday, July 3, 2009

Unchain My Heart

The chain drive that I put on my bike has lost it's luster. It rattles, flops around, stretches and slings chain lube. It's time to switch back to a belt. I'm looking at the Gates Eliminator belt. It comes highly recommended. It is supposed to be stonger than any belt on the market, including the Gates GTs that Boss Hoss uses. As with all of the available belts, it is only available in finite lengths. Right now I am looking at running a 40/72 tooth sprocket ratio which will give me around 2500 RPMs at 73 mph with a 25 inch diameter tire. Doing some quick and dirty calculations,I think I will need a 44 inch belt. The closest that Gates has is about 46 inches, so I will end up with another inch of wheelbase. Not bad. I was aiming for as short a bike as possible when I began this conversion. I am at 79 inches right now, so I can live with 80. The pulleys for this belt are different than the stock BH pulleys. The have, what is known as, an RPP pattern. Reinforced Parabolic Profile, whatever that means. The countershaft pulleys are no problem. They are held on with the QD bushings, same as stock. The rear is a different story. All that is available is a large, heavy cast iron unit. It weighs about 40 pounds. I'm not a chassis guy, but I do know that unsprung weight is important and you want to keep it as low as possible. I don't know why, and maybe it's no biggee. One guy that I correspond with says he has no problems with his, so I may just go ahead and run one and see how it goes. I may try to cut an aluminum one later. I have a horizontal mill and a dividing head, but not a hell of a lot of experience. I would cut one from MDF first to see if my skills and math are up to snuff. I have a bit more research to do before I begin. I can't afford to screw up and start again. Money is too tight right now. I still have my Nesco to sell for additional funds, but I wanted to wait until I'm sure that the Ranger was the right choice (it was) and for the market to go up a bit so I can get the best price.

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