Wheel width and speed?

MoHasAFastCar Sunday, 12/6/2015

I'm not thinking about skinny wheels.  Just normal wheels which have varying widths.  I would suspect that wider wheels would be slower.  That there's more track contact probably isn't much of an issue since it's mostly rolling.  I did, however, have some corgi juniors as a kid that despite being very light and having pretty small wheels were very fast.  The only notable difference I see in them is that the wheels have a ridge stripe in the center which is the only thing making track contact.  Like a lot of the MB/HW knobby tires. But then those wheels, despite that small stripe of track contact don't generally perform well.

What I would suspect makes wider wheels slower is the greater amount of axle contact and hence friction.

Anyone have any thoughts or experiences or testing to share on the subject?


Discussion

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fordman 12/6/15

some redlines and early johnnies had a raised ridge along the inside edge...

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72_Chevy_C10 12/6/15
Event coordinator

I think that wheel diameter has a lot more to do with speed than width. A wheel has a maximum rpm that it will reach based on the friction with the axle. A smaller diameter wheel will hit the maximum more quickly, so it would be better on a short track. A larger wheel will take longer to reach maximum rpm, and it will be a faster speed, but it will be better suited for a longer track.

As for a wider wheel having more friction on the axle...on an fte wheel, the 'hub' is the same size no matter the width. The only disadvantage for a wider wheel is a bigger contact patch with the track. And, if you wheel has any wobble, it might be more exaggerated on a wider wheel.

Just my 2 cents :)

  • Are you sure about the hub being the same...just eyeballing a couple in blister I'm skeptical — MoHasAFastCar
  • My mistake, the wider hubs are a little wider :) But, the biggest thing is that they run true, whatever size they are :) — 72_Chevy_C10
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redlinederby 12/6/15
Site manager

First, a quick lesson from our old friend Mr Wizard

https://www.youtube.com/watch?v=vJ0_UHLtxhE

...not sure that helps much but it's great seeing that old show...

A larger diameter wheel will go faster but not by much. It contributes less to rolling friction that will slow a car down, but that also coincides with other factors...but I guess it all adds up.

In my pea-sized brain, larger wheels go around less over the same distance as small wheels. It's equal force making them all go (gravity) so the other factors are then friction of moving parts and the ground. 

For wheel width think about real race cars. The wider the more grip, more skin touching the track. But that's a balancing act. Too wide and you get too much friction, too narrow and there's not enough to get you going. I'm sure there's some formula to match the car size to the tire width.

What I have yet to experiment with is wheel weight. What if I add weight to my wheels? They're hollowed out, right...fill that in with something heavy and does that matter. Weight makes a huge difference in our sport so, in theory, that could make a difference. More weight spinning weight could create more energy going forward?

  • but you have to be sure to balance them. otherwise, wouldn't it be fighting — CrzyTrkrDude
  • itself the whole way down the track, and want to stop with the heavy spot pointing down? — CrzyTrkrDude
  • Increasing wheel weight will increase the wheels inertia (reluctance to spin), so greater force/energy needed to spin wheel, so car goes slo — Skuxmobile
  • On the other hand, greater inertia will allow the wheels to act like a flywheel and keep speed longer — Skuxmobile
  • I think you have to balance acceleration with keeping momentum — Skuxmobile
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