Rail ride with weights only?

[tanczosm]

I've been reading this forum a lot and trying to help introduce concepts into my son's car that still meet the district rules.

My son's district competition requires 4 wheels, no axle modifications (other than polishing), no canting, must use slots.. My question is this.. is it possible to rail ride entirely using uneven, off-center weight distribution or is the force needed to do that simply not there with weights alone?

 

[TRE]

You are gonna have to bend or cant a axle

 

[tanczosm]

Thanks. My question was based on some type of research paper which had mentioned that an off-center weight difference of as little as a half ounce could impact steering but I can't seem to find the link anymore.

 

[Prozach2]

Thanks. My question was based on some type of research paper which had mentioned that an off-center weight difference of as little as a half ounce could impact steering but I can't seem to find the link anymore.

Aside from rail riding thing, what else are you thinking about doing to the car?

 

[txchemist]

So if a Cub uses a hand drill into the slots, without any mechanical guide- and doesn't get it perfect, it will have some cant to it. If he drilled a bunch of bodies, some of them would have both back wheels at a 1 degree cant. That same body with almost perfect front axles will none the less have a drift. No matter how you try, with weights in the back of the car- both front wheels will not weight the same. Do all 4 wheels have to touch? even then you can not get both front wheels to weigh the same. One will be heavy like 20-25 grams, and the other about 2.8 grams. With some luck, you can now mess with it to get the drift causing and the DFW to be the same wheel, and then move some weights to improve the balance and you have a legal rail rider that will have all 4 wheels sit flat when not moving. At any rate- that is what the district winner will run.

 

[TRE]

If you dont narrow the front and it does ride the rail the back wheel is gonna ride it too

 

[TRE]

Now if your front axle is bent and your rears are canted that is just enough from keeping the rear off the rail...the car wont be centered on the rail but it wont hit either

 

[tanczosm]

So if a Cub uses a hand drill into the slots, without any mechanical guide- and doesn't get it perfect, it will have some cant to it. If he drilled a bunch of bodies, some of them would have both back wheels at a 1 degree cant. That same body with almost perfect front axles will none the less have a drift. No matter how you try, with weights in the back of the car- both front wheels will not weight the same. Do all 4 wheels have to touch? even then you can not get both front wheels to weigh the same. One will be heavy like 20-25 grams, and the other about 2.8 grams. With some luck, you can now mess with it to get the drift causing and the DFW to be the same wheel, and then move some weights to improve the balance and you have a legal rail rider that will have all 4 wheels sit flat when not moving. At any rate- that is what the district winner will run.

Here is the rule:
Wheel bearings, washers, bushings, and hubcaps are prohibited. All 4 wheels must make contact with the track surface. (This is tested by free-rolling the car). And this is implied that the full wheel must make contact. Therefore the axles be in straight and the full wheel must be making contact with the surface.

I think this explains some of the difficulty I've had getting every wheel to touch perfectly. I've wrestled with all sorts of adjustments and probably ended up drilling the slot for the front wheel a bit deeper than the other just to get some type of four-wheel touching flat-ish. Getting four flat probably has been the hardest part of the build so I ended up taking over for my son to try and "fix" his axles.

I really wonder how much they would enforce the flatness aspect of it.. because it would be tremendously easy for a winning car to include some cant by accident perhaps.

I'm going to reply to the other posts but I wanted to say something here first. Thanks for the comments guys.

 

[tanczosm]

If you dont narrow the front and it does ride the rail the back wheel is gonna ride it too

We have a rule that states:
The minimum width between the wheels shall not be less than 1 ¾ inches, so the car will clear the center guide strip on the track. The maximum overall width (including wheels and axles) shall not exceed 2 ¾ inches.

Does anyone ever shim a real wheel with an extra 1/16in in circumstances where the front can't be cut narrower? If you can somehow get some minor wheel tweaks to get the steer you want would that achieve the same goal?

 

[Thinkin'Bout Racin]

We have a rule that states:
The minimum width between the wheels shall not be less than 1 ¾ inches, so the car will clear the center guide strip on the track. The maximum overall width (including wheels and axles) shall not exceed 2 ¾ inches.

Does anyone ever shim a real wheel with an extra 1/16in in circumstances where the front can't be cut narrower? If you can somehow get some minor wheel tweaks to get the steer you want would that achieve the same goal?

Take 1/16" off the DFW side. Then add 1/16" to the NDFW side. You did not change the overall width and meet your rules while still accomplishing your goal of keeping the rears off the rail.

Make a template with a straight axle thru a wheel. Lift the axle on one end until the wheel is still just flat. Mark your template. This is how much angle you can drill and still have your flat wheels. Then pick some of your not so straight axles and prep them. Use these up front. Turn them to get your desired steer. Use the one that is most off on your DFW. There is no way they can enforce an entirely flat wheel. The question is what will be allowed. I have heard that some with this rule use a sheet of paper to check how flat the wheels are.

If you can't get enough steer, I might be inclined to lightly scuff the DFW edges to provide more steering bite. Clear as mud?

 

[Jupiter 2.9]

The rule says wheel, not hub.
If you want to explain that to the inspection guy on race day.

 

[Thinkin'Bout Racin]

The rule says wheel, not hub.
If you want to explain that to the inspection guy on race day.

I agree it says wheel and not hub. However, the argument can be made that the hub is part of the wheel, so it all depends upon how they interpret and enforce the rules .....

I have actually seen it enforced both ways at different district races.

 

[Charles Studer]

Wow! Lol. Ok in regards tobthe original concept question. The answer is yes. Biasing the weight can and willmimpartva steering effect. Will it help you win a race? Probably not at the level you are currently running. My zero steer car uses this principle among a few others to run sub 3 on the 42' Bestrack. It is more of a supplemental technique than a sole function.

Out of yhe box scout axles are not straight. Find the worst one and use it to impart steer on a well cross weighted car. It Will be faster than a huge biased set up. Just saying...