Wheel Offset

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Cabrzama
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Wheel Offset

Post by Cabrzama »

I feel silly asking so many basic questions, but this one I tried to find more on and couldn't.

I wanted to raise one of my front wheels so that the car has less friction (running on 3 wheels). How far should I raise it off a flat surface--the width of a sheet of paper, the thickness of a dime, or more?

Does it matter which front wheel is raised?

Will I need to cut the axle slot deeper or just try to place the axles on the other three wheels in the middle of the slot, and the raised wheel at the top of the slot?

Also, my axle slots are very tight. Is it advisable to sand them slightly wider and then just glue the axles/wheels into place? I was planning to glue them anyway.

Thanks in advance, everyone!
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MaxV
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Re: Wheel Offset

Post by MaxV »

In my opinion, the 'silly' people are the ones that don't ask questions!
I wanted to raise one of my front wheels so that the car has less friction (running on 3 wheels). How far should I raise it off a flat surface--the width of a sheet of paper, the thickness of a dime, or more?
We always raise one wheel 1/16". You don't have to raise it that high, but that distance makes sure the wheel is off the ground.
Does it matter which front wheel is raised?
Not really. Just make sure to place the worst wheel (as determined by observation and spin tests) on the raised axle.
Will I need to cut the axle slot deeper or just try to place the axles on the other three wheels in the middle of the slot, and the raised wheel at the top of the slot?
I suggest inserting the raised axle at an angle. Alternately, you can slightly bend one axle to get the wheel off the ground. Unless you have good woodworking equipment and/or a lot of practice, messing with the slots is generally not a good idea.
Also, my axle slots are very tight. Is it advisable to sand them slightly wider and then just glue the axles/wheels into place? I was planning to glue them anyway.
They should be tight. Before shaping the car, insert the axles from the side of the car, using a hammer if needed. Then pull them out with a pair of pliers. This makes them easier to install later on. By the way, there is a tool to create pilot holes in the slots; you can read about it in the "Derby Products and Services" section of this forum.

Even though they are tight, you still want to glue them in place after all the wheel aligment is complete. We just apply some wood glue on top of the axles near the center of the car. Make sure to keep the glue away from the wheels.
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Darin McGrew
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Re: Wheel Offset

Post by Darin McGrew »

Cabrzama wrote:I wanted to raise one of my front wheels so that the car has less friction (running on 3 wheels). How far should I raise it off a flat surface--the width of a sheet of paper, the thickness of a dime, or more?
It needs to be high enough that it doesn't touch the surface of the track during the race, but low enough that it still keeps the car from leaving the center guide rail.

On a very smooth track (e.g., aluminum or plexiglass), the thickness of a dime might be plenty. On a very rough track (e.g., unsanded plywood), you'll need a lot more than that.
Cabrzama wrote:Does it matter which front wheel is raised?
No.
Cabrzama wrote:Will I need to cut the axle slot deeper or just try to place the axles on the other three wheels in the middle of the slot, and the raised wheel at the top of the slot?
Most of the raised front wheels I've seen just used the full depth of the slot for the raised wheel and put the other wheel further out (no closer than the middle of the slot).
Cabrzama wrote:Also, my axle slots are very tight. Is it advisable to sand them slightly wider and then just glue the axles/wheels into place? I was planning to glue them anyway.
How accurately do you think you can sand the slot?

At our workshops, we have a drill press that we use to press the axle holes before cutting the block. We put a spare axle in the drill press, turn on the drill, and drive the axle into the axle slot. This expands the wood in a controlled manner so the axle can go in straight later, when the car is finished. But there's still enough "spring" left in the wood to grip the axle without glue.

Don't glue the axles until you're satisfied with their alignment, because it's hard to adjust them after they're glued in.
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