[Jeremiah H]

<These are my thoughts, some suggestions from my experience, if some of my hypotheses are no good, please correct me>
If you want to shoot for 15 fps and your team has a good driver, I'd say go for it. Last year, we put our bot up on blocks to find its freewheeling speed, and high gear was around 14 fps. Once we got the bot on the ground, we never actually clocked it very accurately, but our rough figures said that it was running about 12 fps. You may not lose as much speed as we did, depending on the efficiency of your drivetrain and the type of wheels you use. (We ran a six wheel #35 chain drive with 4 go-cart tires and two pneumatic Skyway look-alikes. If you use smaller wheels I wouldn't think your bot would slow down as much as ours did) Ours seemed blistering fast, it was fine for '06 (the field was open and our driver was great), but I wouldn't recommend it for a playing field that has a lot of obstacles like it was in '05.
Also- two things we learned the hard way-
-make certain that the key for your output sproket/pulley is TIGHT. We had problems with shearing, yes shearing, keys off on our output because they were too lose and were getting slammed back and forth a lot due to our defensive strategy (ram, back off, repeat, etc.)
-try not to shift when your motors are under power, it tends to be hard on the dog. when we took our gearboxes apart this summer, the dogs' corners were worn worse than they should've been. Just try to shift only when the motors aren't running at full power, and I think you'll be alright.
As for the clearance, I know exactly what you are talking about, but I can't remember what ours was. I'll check the bot tomorrow and get back to you. I would reckon that 1/8 would be plenty, but I honestly can't remember.
Good luck!