faster start on old railless track

[stay at home dad 13]

This is my son's second race and need some more speed info. We haven't started building yet
Here's last year,
Track is an ancient wood track with no rails, only sides to keep cars in their lanes. Car was at 5 oz. with canted wheels and extended wheel base in a thinned body style. Axles were polished and wheels lightly sanded. COM very small in front of rear axles. Due to no rails we set up the car on 3 wheels to run as straight as possible. We did pretty bad. I noticed that it ran pretty staight all the way down and really did lose much speed. The one thing I did notice was that we had one of the slowest starts and couldn't catch up.
This year
He wants a tank design so the amount of weight I will have to add won't be as much as last year. Still going to cant the axles and run as straight as possible. I'm going to play with the com to move it forward a tad.
Any tips on how to get a faster start? Stick with 3 wheels or because of the track run 4
Thanks

[Vitamin K]

Hmm, I would think that a 3 wheeler should start faster than an equivalent 4-wheeler all of the time, due to less initial energy needing to be invested in getting the wheels spinning.

How's your rear alignment? Are you canting with bent axles, or with drilled cant? If you do the former, do you have a way to align axles independently? If the latter, are you using a tool to ensure that the axles have zero toe-in or out? For either way, what does your testing procedure look like?

Also, what are you doing for lubrication and bore/axle prep?

[Speedster]

I think Vitamin K has answered your question. It sounds like you did almost everything correctly. The one thing I see lacking is prep, prep, prep the wheel bores. If you do not have a concentricity gauge, and are unable to build one, do not sand the wheels. There is a good chance of making them worse. All you are concerned with is the inside edge of the wheel which is all that will ever touch the track. Hob-E-Lube is a very popular graphite. Are you allowed to use oil? The "Search" function will give very good information on how to prep a wheel and also good information on how to lube a wheel. If your scout is after speed, I would not build a tank (stay with a Hershey bar shape) and do not move the COM forward. Exactly where is your COM now?

[stay at home dad 13]

We haven't starting building yet. We get it on Friday. He's more interested in the shape and I'm more interested in speed. Last year we rode with bent axles, and probably this year too. We were aligning the rears first, just rolling on a flat surface and making sure the wheels migrate out, nothing fancy or scientific. Then measuring the amount of drift per foot. Last year was about 2 inches per 7 feet. I thought about buying pre-finished wheels and axles from maximum velocity, that's where the kits came from last year. Something tells me I did damage to the wheels and made them worse. We can only use dry lube, so graphite. Although I thought about using dry spray silicone lube this year

[Vitamin K]

We haven't starting building yet. We get it on Friday. He's more interested in the shape and I'm more interested in speed. Last year we rode with bent axles, and probably this year too. We were aligning the rears first, just rolling on a flat surface and making sure the wheels migrate out, nothing fancy or scientific. Then measuring the amount of drift per foot. Last year was about 2 inches per 7 feet. I thought about buying pre-finished wheels and axles from maximum velocity, that's where the kits came from last year. Something tells me I did damage to the wheels and made them worse. We can only use dry lube, so graphite. Although I thought about using dry spray silicone lube this year

I'd stick with graphite, if you have to run dry lube. Use a quality brand, like Max-V or Hob-E-Lube.

For aligning the rears, if you're using bent axles, check out Stan Pope's alignment method. It's been very helpful to me for verifying and correcting rear axle alignment.

[whodathunkit]

Speedster touched on a point about wheel and wheel bore prep.
Before I start any wheel bore prep work I use a good dish soap and warm water to wash the wheels.
Vitamin k and Speedster are on the right track.


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