Traction Measuring Tool

I'm looking for info on the device used to measure the amount of grip or traction on the starting line. All of the pro and some of the alky teams have it. Does anyone know who makes it/where I can purchase one?

Thanks,
Brandon Booher
NHRA TAD #323
217-840-1500
underby6@gmail.com

 

http://www.competitionmotorsports.us/

 

Here's a low buck approach........

Go talk to your local police authority. They will have a traffic investigation unit no doubt, or ask them for the next level of authority who investigates serious traffic accidents. They can probably show you their tricks for coefficient measurements.

You can determine the local coefficient of friction of a road/track surface using a simple concrete filled peice of tire (or slick) attached to a fish scale, dragged in the horizontal plane.

The number you obtain will be a bit unique to your particular setup, but it will be "very" repeatable if done the same way every time.

Police departments do this every day all over the world as part of accident scene reconstruction.

 

I have thought about this ever since I saw one the first time on TV. It seems like you would want to have a piece of the same rubber loaded at the same pressure as your car would, I realize there are a lot more variables than that but it seems that would at least get you close.

Having run a 10.5 car in the past I know lots of times I have been to tracks where it was really sticky and pro-mods were hooking up really well but the surface was way to soft and greasy for my car and it would just smear the surface, later when it would tighten up the pro-mods would run about the same but my car would turn around completly. With this in mind it seems like trying as much as possible to approximate the actual conditions of tire to track with the device would yield the best results.


Maybe a piece of slick with a foot pedal where it would apply an adjustable amount of pressure and measure the maximum force prior to slippage, this would be light and easy to use.

Just my two cents,

Richard Gavle

 

Using the low buck method you need to always pull parallel to the ground to be accurate, or at least always in the same direction.

What weight block and what range scale do people recommend? I assume to be truly accurate the weight/contact area should be tweaked sufficiently to exert the same pressure as the car will.

A gauge with a tell-tale on it would be useful as then you could get both the static and dynamic coefficients of friction.

 

Thanks guys, got one ordered from the website listed.

Brandon Booher
NHRA TAD #323

 

Sorry for the delay, Brandon. I just woke up.

BUt after doing a search on the price since it seems so high I came up with another seller,

http://www.dragwheelz.com/osc/product_info.php?products_id=570&osCsid=a02e0a67c9d912f16cc7bdfde405823a

I don't know a thing about the website so buyer beware, but at least its 160cheaper than an already high price.

Again sorry for the delay, Brandon

 

It's the same price as you have to buy the torque wrench to go with it. They're charging $160 for the wrench so it puts it at $1360, but thank you for the info. I know it's off subject, but the first site makes some cool stuff. Check out their chute mechanisms.

Brandon Booher
NHRA TAD #323

 

Thanks for the reply Brandon. I really had mixed feelings about posting due to the conflict, glad to hear the price point was the same. I will check out the site also.

Richard Gavle

 

Here is something else...

http://www.insidetopalcohol.com/showthread.php?t=24222

 

Hmmmm, if memory serves, we used a chunk of a slick fastened to a brick, and a pull string and a fish scale...40 years ago at Irwindale. It was a good show.

 

Simple traction measuring device.

I HAVE HAD AN IDEA FOR A LONG TIME FOR A DEVICE THAT WOULD BE CHEAP, EASY TO USE AND WOULD BE FAST. IT WOULD ALSO MEASURE SAY A 20 FOOT AREA OF THE STARTING LINE OR ANY OTHER AREA OF THE SURFICE.
IN GOLF TO GIVE THE PRO'S AN IDEA OF THE SPEED OF THE GREENS THEY USE WHAT IS CALLED A STEMPH METER. IT IS A SIMPLE DEVICE THAT YOU SET UP AT A GIVEN DEGREE TO THE FLAT SURFACE THAT HAS A V SHAPE FOR A BALL TO ACCELARATE DOWN. tHE FUTHER THE BALL ROLLS THE FASTER THE PUTTING SURFACE.
THE SAME IDEA COULD BE ADAPTED FOR USE ON A DRAGSTRIP.
BY USING A RUBBER BALL THE TACKIER THE SURFACE THE SHORTER THE ROLL. YOU WOULD SIMPLY LET THE BALL ROLL DOWN THE RAMP AND MEASURE THE DISTANCE THE BALL ROLLS FROM THE END OF THE RAMP.
JUST A FEW DIFFERENT CONDITIONS AND YOU COULD ESTABLISH YOUR OWN BASELINE. THE BALL WOULD NEED TO BE CLEAN EACH TIME IT IS USED.
I HAVE THOUGHT ABOUT BUILDING AND SELLING THEM BUT IT IS SO SIMPLE THAT AS SOON AS A FEW PEOPLE SAW IT THEY WOULD BUILD THEIR OWN FOR UNDER 20 DOLLARS.
IF YOU WANT TO BUILD ONE BE MY GUEST. JUST REMEMBER WHOSE IDEA IT WAS.
BOB HOLLEY

 

Has anyone had any dealing with this company, Competition Motorsports? I've sent several e-mails asking for some sort of assistance, as they provide no phone number and are unlisted in the Yellow Pages or by address search. By far....so far...the worst customer service I've received with a racing related product. You would think for a tool this expensive they'd want to sell them/return an e-mail...and who doesn't list a phone number these days?

Brandon Booher
NHRA TAD #323

 

yeah right

I can just see Rick Stewart and the other NHRA starting line gestapos the first time you run out to the line and roll your rubber ball out on the track, or you're out there with the fish scale and the concrete fillled tire patch. I hope they get that on TV!!! lmao

Before anyone blasts me I am just kidding, I realize we're not just talking about NHRA nationals, but you gotta admit it brings to mind a pretty funny visual!!

 

I guess you could go out to the start line with your 1500 dollar torgue wrench with a rubber pad you stand on and make about ten tests so you could have a true reading of the whole start line traction. I guess it would repeat as long as the same weight guy was standing on it. But wait you would have the comfort of knowing it has to be great because you paid so much for it. After all if it is not expensive it must notwork.

 

I would certainly hope that the device has a spring (or simalar adjustable device) that applied force to the friction material and that the guy standing on it only assures that the spring (or simalar adjustable device) is compressed and the device does not move, of course I could be wrong.

Like I said before, in my humble opinion you would want to have a pad of material similar in coefficient of drag to the tire you run and loaded at close to the same PSI as your car on launch and drag it in the opposite direction of the car measuring both breakaway point as well as sliding drag resistance of course I would assume the guys who designed the device for sale tested its efficacy so maybe the sliding drag is not needed only the breakaway point. If you use a lightly loaded device then the only thing you will quantify is how tacky the track is, however if the surface of the track is gooey then it will smear till it tightens up an extreme example of this would be if you put chassis grease on the track it would stop a rubber ball pretty quickly but would do little to hook a slick.


Richard G