Bryan Blanton - 17 November 2008 10:21 PM

Hi i have a question. I didn't want to start a new thread or subject cause i wanted to post my question in an already existing topic or subject.

My question is how long has coil binding and or bump stops been around in nascar?

I think i first heard about it in 2002 or 03 or 04 somewhere around there. But i was just curious if that type of technology existed before than.

Didn't nascar ban coil binding before the start of this year?

I believe the first known car that had coil binding was the 'T-Rex', Jeff Gordon's 1997 All-Star car. NASCAR told them never to bring that car back again.

No, NASCAR didn't ban coil binding, they un-banned bump stops.

The shocks are to control weight transfer, nothing else. The shocks do not control how much weight is on any corner. It effects how long it takes to get to and from each corner.

COT cars run a "tied down" lf with alot of rebound and a soft bumpstop. Just how soft is such a small change in amounts that we will never see or understand how complicated it is.

Weather a car wins a race or not is decided at the teams shop and what they find on the 7 post rather then what they find at the track. R&D;has taken over NASCAR.

The springs are not typical and are made to coil bind. They have so many inches they travel before they attain max spring rate. Mostly 1.5-2.5 inches.

The bump stops are all different for each corner, especially different is the LF and RF bump stops. One will be say a yellow, for the lf and, a black for the RF. The weight curve changes once the bump stop enacts depending on which bump stop is used.

If you want an example of this goto RE suspension inc and look at the tech and part specs. Look at the bump stop graph and look at how the weight changes for every little bit of movement.

It's a balance that takes very hard work and alot of money to get right. NASCAR made a huge mistake allowing this and implementing the splitter. The splitter it's self has been a huge upgrade in price. Very stupid.

It also makes it to where only teams with a WHOLE lot of money can compete. Old school ways of setting a car up don't work any more. Now it's down to hundredths of inches of weight transfer. Exactly why people are against the 7 post systems that are needed to tune these bump stop and coil bind setups correctly. This is why the cup backed teams that run in the NWS and CTS series run so good. Their un-beatable.

That together with NASCAR down sizing the different teams ability to test is all geared towards controlling winners and losers to those that back the sport with the most money.


IE- the death of avg joe million dollar man being able to even come close to getting into NASCAR. Now, they control who wins and loses. You don't think they knew who had the ability to keep up with the needed R&D;to win races before they did this?

I may as well burn all my books. Everything in them is wrong.

red376 - 12 March 2008 06:49 PM

speedsense - 10 March 2008 11:49 PM

RobsanX - 10 March 2008 08:20 PM

What is gained when they use bump stops instead of coil binding?

Actually using assorted bump rubbers of different rates (they are actually springs) for the last 1/2 inch of travel of the suspension before coil bind.
Once coil bind is achieved there is no more movement in the suspension, at least the bump rubber can slow or prevent coil bind by a "sudden" increase in the spring rate (say the main spring is 400 lbs and the bump rubber is 1000 lbs for the last .5 inch of travel before coil bind.
This allows the spoiler to get closer to the ground and still have some dampening of the movement with spring rate before reaching infinity (turning the car into a go kart with no suspension).
Without the bump rubber the car would literally "crash" into coil bind.

You don't think the teams don't have the shocks tuned for every millimeter of travel until the car bottoms out against the bump rubbers? What you are describing is exactly what the shock takes care of or at least what the teams are striving it to take care of.

No, not quite. While the shocks are adjusted according to spring rate, they are velocity dependent and only slow the rate of compression, they don't limit the travel.

Most bump rubbers are 1.5" to 2" (though can be cut to shorten) in height in assorted spring rates. Unlike a coil spring, a bump rubber is progressive in spring rate, in other words the spring rate increases as it's compressed, depending on it's shape.
A bump rubber selection of a high enough rate will, unlike the shock, limit travel.
The only limited factor the shock will have is when it bottoms out.
A shock tuned to a specific race track, will as you say slow the rate and the "crash" though setting up the rate of "high speed valving" (ie-bumps..) would make the car less drivable, less grip and over damped to the spring rate.
Having the shock "support" the car is never a good thing.

The bump rubber, and knowing how to use them can put the shock back into a "proper" operating range.

Having good data acquisition readings, on the assorted bump rubber in use, is a invaluable commodity. Taking the data to a seven poster, gets the shock package completely inline with the chosen bump rubbers, and shock valving for the coil springs AND the bump rubbers is possible.

Which is where most likely where the top teams are in technology- IMHO