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-   -   Wheel Scales? (https://www.rctech.net/forum/electric-road/416570-wheel-scales.html)

kjdad 07-14-2010 06:41 AM

Wheel Scales?
 
Anyone here use scales to corner weigh their cars? Kinda like how 1:1 race cars are prepared? I don't know if such a tool is on the RC car market other then the tweaking tools? I am interested to see how my TC5 scales out at each corner especially since I need to add weight for the class I run. I thining if building one with some used pocket scales and some MDF for fun.

pinggoy 07-14-2010 08:35 AM

you can use pocket scales... also i think muchmore sells one.. but your better of buying a 9-13$ pocket scale at walmart.....

RossoTorro 07-14-2010 09:30 AM

I bought 4 of these.

http://cgi.ebay.com/Mini-Electronic-...item1c11559187

Works great!

lochness42 07-14-2010 09:39 AM


Originally Posted by RossoTorro (Post 7669581)

+1 got same make

kjdad 07-14-2010 10:02 AM

Thanks guys...

Here is what I am looking to do.

http://grassrootsmotorsports.com/art...orner-weights/

I am also interested to see what happens when I put a large fan in front of the body. Nothing scientific..just intrested to see if downforce produced.

sdunnmcp 07-14-2010 11:35 AM


Originally Posted by kjdad (Post 7669709)
Thanks guys...

Here is what I am looking to do.

http://grassrootsmotorsports.com/art...orner-weights/

I am also interested to see what happens when I put a large fan in front of the body. Nothing scientific..just intrested to see if downforce produced.

You not going to get good results but it will be fun to see.

The reason the results are not going to be accurate is because the air entering the wind tunnel needs to be flowing directly at the object and no turbulance. The fan is going to have air going in many directions. I have thought about this a lot and I think you would need to make a tunnel about 10ft long and maybe use small long cylinders for the air to go through before going over/under the object.

Also I think our bodies create a lot of drag which isn't always measured by scales.

I am still interested in your test. Please post your results.

Steve Dunn

kjdad 07-14-2010 11:56 AM

Totally understand. I don't even own a air speed guage so my tests would be very subjective. If I do see a result I could build the Mythbusters style of air tunnel using boxes of straws clustered together to refine the air flow...but not sure I want to take it that far:)





Originally Posted by sdunnmcp (Post 7670029)
You not going to get good results but it will be fun to see.

The reason the results are not going to be accurate is because the air entering the wind tunnel needs to be flowing directly at the object and no turbulance. The fan is going to have air going in many directions. I have thought about this a lot and I think you would need to make a tunnel about 10ft long and maybe use small long cylinders for the air to go through before going over/under the object.

Also I think our bodies create a lot of drag which isn't always measured by scales.

I am still interested in your test. Please post your results.

Steve Dunn


sdunnmcp 07-14-2010 01:17 PM


Originally Posted by kjdad (Post 7670103)
Totally understand. I don't even own a air speed guage so my tests would be very subjective. If I do see a result I could build the Mythbusters style of air tunnel using boxes of straws clustered together to refine the air flow...but not sure I want to take it that far:)

That would be fun. I have just little experience with the Wind Tunnel at Purdue University. We put a NHRA Pro Stock Motorcycle in the tunnel and we learned a lot. Even then I was thinking about R/C car bodies.

Maybe someday I will try the Mythbusters method....

Steve Dunn

Brian McGreevy 07-14-2010 02:44 PM

Definitely one of the better ways to get a perfectly balanced car. You need to add the corner weights (i.e. LR and RF, RR and LF) and get those close to get the right balance. Assuming your suspension is not bound, your droop is even and you don't have a lot of slop in your car, if you can get your corner weights within 10-15 grams you'll be good. It takes practice, but I often do it by hand when I have less time. It was easier with foam tires as they hardly deformed at all.

RossoTorro 07-14-2010 06:48 PM


Originally Posted by kjdad (Post 7669709)
Thanks guys...

Here is what I am looking to do.

http://grassrootsmotorsports.com/art...orner-weights/

I am also interested to see what happens when I put a large fan in front of the body. Nothing scientific..just intrested to see if downforce produced.

With the corner weights that is on ebay you can get same result.
Place one under each wheel and you see if you are tweaked or weight ratio front/rear. I use it on all my cars, also i have setup lots of other rc cars at our track.

Kevin Koback 07-14-2010 09:34 PM

This is the 4-scale setup most of the oval guys use.....Includes a straight board that is recessed for the scales, and also a level to use. It is critical to have the scales be on a flat and level surface since it doesn't take much to change corner weights.

http://www.lefthander-rc.com/catalog...oducts_id=1685

They also make a 2-scale setup which is about $50, just takes more effort to use.

JasonC 07-15-2010 10:41 AM

This May help you out also

http://www.rctech.net/forum/electric...-tweaking.html

Crashby 07-15-2010 11:28 AM


Originally Posted by JasonC (Post 7674642)

There is also a very cool iPhone application, CrossWeight, that allows you enter each of your corner and the app will calculate the front weight%, rear weight%, left and right weight % as well as your corner %. There are six screens to allow you the ability to keep track of six cars and can also email the data to an email address.

Very cool!

tudor_47 07-17-2010 12:38 AM


Originally Posted by RossoTorro (Post 7669581)

Very nice find!
I ordered 4 for myself aswell, in hoping they will work OK.
I am thinking it would be possible to make a board with 3 screws in to make it level before taking measurements.

RossoTorro 07-17-2010 03:16 AM


Originally Posted by tudor_47 (Post 7681369)
Very nice find!
I ordered 4 for myself aswell, in hoping they will work OK.
I am thinking it would be possible to make a board with 3 screws in to make it level before taking measurements.

I bought 2 cheap plastic levels and took out the bladder in middle that i fastened to a board, one on top and one on the side. That way i can place the board completely level before i put the car on.

http://i513.photobucket.com/albums/t...irit_Level.jpg


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