Drilling Holes in the Sides of Wheels

[1reason]

Is there a reason not to drill holes in the sides of wheels? I've been able to cut out a lot of weight and I have a wheel balancer so I can balance them.

But I'm also not seeing cars on youtube with holes in the side and I can't be the first person to try it. I don't have the ability to test track the cars so I don't know if wind and or other factors have a greater influence on the car's speed as a result.

I haven't noticed by eye that the wheels have lost structural integrity, but maybe when they are spinning something happens???

 

[DerbyDad4Hire]

Tested it and they were slower. Fan blades. At least as far as bearing cars go.

 

[Guest]

Is there a reason not to drill holes in the sides of wheels? I've been able to cut out a lot of weight and I have a wheel balancer so I can balance them.

But I'm also not seeing cars on youtube with holes in the side and I can't be the first person to try it. I don't have the ability to test track the cars so I don't know if wind and or other factors have a greater influence on the car's speed as a result.

I haven't noticed by eye that the wheels have lost structural integrity, but maybe when they are spinning something happens???

DD knows.

I can picture it working in my head with the highest levels of precision (like 3D SLA prints that are contoured inside the holes to channel air certain ways) all balanced to within an inch of it's life.

However, here on earth I have not seen this yet.

 

[GravityX]

I think for the ultimate aerodynamic designs or shapes for something like this, I would look at world of racing bicycles. I am sure they have spent countless hours researching and developing the ultimate aerodynamic design to try and give the cyclist the biggest aerodynamic advantage. I could see this possibly working with the razor wheels, but not other wheels like the ones used in the SS or SP classes.

 

[bracketracer]

It would be interesting if we could duplicate the surface finish of a bicycle TT disc wheel on a PWD razor wheel, but the wheels are scaled down, the air molecules aren't!

It probably wouldn't make any improvement, though. The disc wheels need to be moving at around 30 mph before they release the air, our cars might not be moving fast enough for the effect to function.

 

[1reason]

Tested it and they were slower. Fan blades. At least as far as bearing cars go.

"Fan blades" - Thanks, that makes sense. I'm guessing you tried large, small many and few holes to really dash my hopes.

I'm guessing that for the fourth raised wheel it may still be advantageous? The Chinese wheels I've been testing start at 44 grams and between holes and scraping out the inside of the tread I can get them down to about 22 grams. If I don't care about balance etc.. I'm guessing I can take it down to under 20 grams. That's weight I can move to the rear (obsessive I know and fully admit)

 

[1reason]

I think for the ultimate aerodynamic designs or shapes for something like this, I would look at world of racing bicycles. I am sure they have spent countless hours researching and developing the ultimate aerodynamic design to try and give the cyclist the biggest aerodynamic advantage. I could see this possibly working with the razor wheels, but not other wheels like the ones used in the SS or SP classes.

Thanks, that's a good point about bikes.

I'll leave the holes out, except for maybe the raised wheel, not sure about that one yet.

 

[bracketracer]

Tested it and they were slower. Fan blades. At least as far as bearing cars go.

"Fan blades" - Thanks, that makes sense. I'm guessing you tried large, small many and few holes to really dash my hopes.

I'm guessing that for the fourth raised wheel it may still be advantageous? The Chinese wheels I've been testing start at 44 grams and between holes and scraping out the inside of the tread I can get them down to about 22 grams. If I don't care about balance etc.. I'm guessing I can take it down to under 20 grams. That's weight I can move to the rear (obsessive I know and fully admit)

All the wheels pass through the air. Holes in any of them (even the large one on the backside), will slow you down.

If your wheels are showing 44 grams on your scale, it's time for a new scale!!!!

 

[1reason]

Tested it and they were slower. Fan blades. At least as far as bearing cars go.

"Fan blades" - Thanks, that makes sense. I'm guessing you tried large, small many and few holes to really dash my hopes.

I'm guessing that for the fourth raised wheel it may still be advantageous? The Chinese wheels I've been testing start at 44 grams and between holes and scraping out the inside of the tread I can get them down to about 22 grams. If I don't care about balance etc.. I'm guessing I can take it down to under 20 grams. That's weight I can move to the rear (obsessive I know and fully admit)

All the wheels pass through the air. Holes in any of them (even the large one on the backside), will slow you down.

If your wheels are showing 44 grams on your scale, it's time for a new scale!!!!

I'm headed out to the garage again and will double check, but I think they did start at 44, what should they be. (I have a 5oz test weight and will double check the scale also)

 

[GravityX]

I'm with BrackeRacer, check your scale! All four of my wheels don't weigh that much collectively. At 44 grams that is about 1/3 the weight of the car.

 

[bracketracer]

Tested it and they were slower. Fan blades. At least as far as bearing cars go.

"Fan blades" - Thanks, that makes sense. I'm guessing you tried large, small many and few holes to really dash my hopes.

I'm guessing that for the fourth raised wheel it may still be advantageous? The Chinese wheels I've been testing start at 44 grams and between holes and scraping out the inside of the tread I can get them down to about 22 grams. If I don't care about balance etc.. I'm guessing I can take it down to under 20 grams. That's weight I can move to the rear (obsessive I know and fully admit)

All the wheels pass through the air. Holes in any of them (even the large one on the backside), will slow you down.

If your wheels are showing 44 grams on your scale, it's time for a new scale!!!!

I'm headed out to the garage again and will double check, but I think they did start at 44, what should they be. (I have a 5oz test weight and will double check the scale also)

The Chinese wheels are around 2.6 grams more or less, each. They're generally about .1-.2 grams heavier than the USA made BSA wheels out of the box.

 

[down4derby]

If the holes are the correct size and spaced apart at a certain distance the wheel won't lose structural integrity. If you could cover or fill the holes with material lighter than what you removed it might be possible to negate the aero disadvantage. Also if you drilled from the inside out on a BSA style wheel without going all the way through leaving the area of the hole on the outside paper thin. Probably over kill though.

 

[DerbyDad4Hire]

Balance was also a serious issue. I CNCd the holes in but when I tried to cover them I could not get it perfect.

 

[OPARENNEN]

Is there a reason not to drill holes in the sides of wheels? I've been able to cut out a lot of weight and I have a wheel balancer so I can balance them.

But I'm also not seeing cars on youtube with holes in the side and I can't be the first person to try it. I don't have the ability to test track the cars so I don't know if wind and or other factors have a greater influence on the car's speed as a result.

I haven't noticed by eye that the wheels have lost structural integrity, but maybe when they are spinning something happens???

I did try it on ELIM wheels, using a set of old Jewkes wheels that I felt were obsolete.
I timed it first with no holes.
Then I created a jig to make = spaced holes, and added a bet of compensating weight.
With holes was slower, but so long ago, I forget the time diff.

I also still have a very old set of DerbyWrx razor wheels with holes (and another set w/o holes) that I could never get to be anywhere near competitive times, even a set with their small pins for axles. The pins were faster than .090 DerbyWrx wheels, but nowhere near as competitive as todays ELIM times.

incidentally, when my own sons were cubs, the wheels were different, maybe some of the old-timers may remember their shape. Somewhat like RR's. I put hole in them, and also balanced them. The increase was significantly faster. But it doesn't work on fatter wheels we use today.

 

[1reason]

Checked my scale, yeah it wasn't grams, not sure what it was as the scale LCD print is kinda small and even with my reading glasses it's small (it reads in oz, grams and two others)

I took a pair of scissors and scraped out the inside tread (actually my son did) and took them from about 2.5 down to 1.8 grams. we have a magnetic wheel holder and uses that to balance them, but the tread is kinda thin.

Not sure if we shot ourselves in the foot as we also have about 2.5ish deg cam on the rear wheels.

 

[chromegsx]

Checked my scale, yeah it wasn't grams, not sure what it was as the scale LCD print is kinda small and even with my reading glasses it's small (it reads in oz, grams and two others)

Probably grains. shows 'gr' on my scales. Grams just shows a 'g'. working from memory there, so I might be off. Grains are usually used for things like reloading ammo or sizing bullets for reloading.

1 gram =15.4323584 grains... according to google

 

[Kinser Racing]

Checked my scale, yeah it wasn't grams, not sure what it was as the scale LCD print is kinda small and even with my reading glasses it's small (it reads in oz, grams and two others)

Probably grains. shows 'gr' on my scales. Grams just shows a 'g'. working from memory there, so I might be off. Grains are usually used for things like reloading ammo or sizing bullets for reloading.

1 gram =15.4323584 grains... according to google

+1

That sounds like it!

 

[Guest]

It would be interesting if we could duplicate the surface finish of a bicycle TT disc wheel on a PWD razor wheel, but the wheels are scaled down, the air molecules aren't!

It probably wouldn't make any improvement, though. The disc wheels need to be moving at around 30 mph before they release the air, our cars might not be moving fast enough for the effect to function.

Hold On BR!
Isn't that what people used to say about aero on these little cars too?

 

[1reason]

Balance was also a serious issue. I CNCd the holes in but when I tried to cover them I could not get it perfect.

What do you use to measure balance? I have a rod pointed at both ends that spins on two magnets. Just wondering if you use the same or have a tool for better precision (prolly bought mine on ebay)

 

[1reason]

Checked my scale, yeah it wasn't grams, not sure what it was as the scale LCD print is kinda small and even with my reading glasses it's small (it reads in oz, grams and two others)

Probably grains. shows 'gr' on my scales. Grams just shows a 'g'. working from memory there, so I might be off. Grains are usually used for things like reloading ammo or sizing bullets for reloading.

1 gram =15.4323584 grains... according to google

And we have a winner, give this man a cigar. yup, that's it.