Dream Car, No Rules

[dbc1218]

I'm entering a derby at work and there are very few rules. The car dimensions, Less than 7" long and 2 3/4" wide. Weight less than 5 ounces. Also a ground clearence of at least 1/4" and 1 3/4" inside width of the wheels. I think this is pretty standard, but I haven't been in a derby for years. THe only other rules are the body must be mostly wood, and no propulsion system. So it keeps with the spirit of a PWD but anything goes for construction. My question is If you could build a car using anything to make it go fast, how would you do it and what would you use? I don't know anything about the track yet, but hopefully I'll find out soon.

[DerbyDoc.com]

If you have no rules stating that the wheels in the kit must be used then I would at least go with the 1.8g wheels from derbyworx.com or my choice would be to use the derbyworx RS wheels with extended wheelbase and hob e lube. Keep your car long and lean, Keep it right at 6 15/16 long so when you paint it, it should still be no longer than 7 in. Keep most of your added weight towards the back,I like to put about 1 oz to 1 1/2 oz behind rear wheels and the rest of the added weight within an inch in front of rear wheel. Work on your alignment and use plenty of lube. I hope this helps. Good luck

[dbc1218]

I can use any Wheels I want. I know the RS wheels would be fast but I thought about a smaller diameter custom wheel, but it could never be built as well as the RS. Also with the alignment, I thought about using some smaller guide wheels mounted horizontal so that they would follow the side of the center guide. Anybody ever done anything like that?

[ProQuest]

Hey dbc:

I'm not the resident authority, but I can answer your last question. Yes! Randy Davis, of Maximum Velocity, recently did a study in which he tested the technique you are taking about. However, as was later pointed out by another respected expert in this field (whose identity escapes me at this moment), most if not all pinewood derby rules prohibit any moving parts other than the four wheels, and the "guide wheels" would violate this rule. If your rules do not prohibit moving parts other than the four wheels, then what you have described could, if done properly, be very effective. It is important to note that in the study that Randy performed, he used bushings (or it might have been bearings, again, I'm having a senior moment and can't recall) and for comparison purposes he also used a guide system that did not turn -- something like a small rod that kept the center rail from coming into contact with the wheels. The car with the bushing outperformed the same car without the any guide system, but the car with the non-turning device/rod performed worse than the same car without any guide system. If this isn't clear, post more questions, I'd be glad to try to clarify.

ProQuest/Steve H.

[dbc1218]

I'm pretty sure the rules will allow it, I check though. Does Randy have a post or any other info on his results.

[ProQuest]

dbc:

Go to Maximum-velocity.com, sign up for the news letter and in one of the back issues is the study he did. Once you sign up for the news letter and get your first one, the links to the back issues will be there.

ProQuest/Steve H.

[gimpypaw]

dbc1218 said:

I'm pretty sure the rules will allow it, I check though. Does Randy have a post or any other info on his results.

Did I read your first post right, or are you working with a 1/4" clearance rule? Most guide strips are only 1/4" high, so for your guide strip roller to be effective it's clearance will need to be around 1/8" from the track.

[DerbyDoc.com]

Good point Gimpy. Unless your gonna be competing against top builders then I wood just go with a set of RS. I would even use the big axles since their easy to work with. You could really punish the other cars if they all show up with stock wheels. The RS wheels alone with good axles could give you a huge advantage.

[dbc1218]

I took a look at the Maximum-velocity.com post on the guide rollers and with the RS wheels actually slowed the car down, slower than with no guide system. Once I build the car I'll decide if its worth it. So has anybody got any other interesting ideas for speed?

[gimpypaw]

from looking at the rules you posted, your basically building for a mod division car. Just build with thin wheels, machined axles, extended wheel base, 3 wheels on the track, and rear weighted. If you have time and ambition, alignment should be rail rider.

[dbc1218]

I just found out the track is 28ft long, so any special tips for a short track?