Thread: Electrathon - A Different Kind of "Hotrod"

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Originally Posted by RestoRod

If I correctly understand, you are saying that gearing is a trial and error attempt to get the highest speed at the lowest current draw? Do you change gears during a race or do you fix the gearing for each race track and essentially run a single speed vehicle? I didn't notice a gear change lever in the car being built even though I think Jim used a derailier unit.

That is essentially correct. With the limited battery power we are allowed in a race, we need to make the batteries last for the entire hour while still running fast enough to outdistance everyone else. After a few races we begin to get a "feel" for what gearing is necessary for a certain type and length of course. It's a trade-off between speed and longevity; we have to find that happy medium.

My orange car had a 6-speed derailleur in it, but I never found the right primary gear reduction to make it work effectively. Dana ("The Bat") put a 6-speed derailleur in his car and it seems to work very nicely. My team's cars now all have single-speed drive including the one I just built in this thread. I try to make an educated guess on gear ratio before a race and select the sprockets accordingly. It ain't high tech, but it's reliable.

As for 5 or 6 speed gearing,having the chain come off in a race will make you fail badly,or a flat tire or any kind of brake down mostly just takes too long to fix,so if your not super up on how to control chains,it's a bad idea to used 5 or 6 speed derailers and bike sprockets that are designed and made to jump chain so they can shift.
Yes I use this set up,but take note,I'm taking a risk doing so,even though I have super know how on bike racing over many years. One gear is better if it is the right one!
For those that think they'd like to look at some of my bike racing;
http://www.wisil.recumbents.com/wisi...ge/default.htm
I think any one would also call these bikes ac kind of hot rod.

Originally Posted by J. Robinson

I try to make an educated guess on gear ratio before a race and select the sprockets accordingly. It ain't high tech, but it's reliable.

If it's not a racing 'secret,' what ball park are you in with regard to gearing? I would guess you make changes by swapping the front or motor sprocket as it would be much easier than changing the one on the drive wheel.

What RPM are these motors designed to run at most efficiently?

Jim
I posted this under a different thread, but wondered if you've heard or seen this


The Hot Rod Hybrid, crafted by Braille Battery to compete in the Hybrid and Electric Class of the Redline Time Attack Series, also features a roof-mounted solar panel, according to the report. The owner plans to compete in the One Lap of America race series with the car, which is claimed to be making 440 hp and can supposedly tick off quarter-mile runs in 12.9 seconds at almost 110 mph.