Coil Bind v. Bump Stop

[Revman]

Could somebody help me out? I understand the differences between coil bind and bump stops. Just don't understand the advantage of one over the other. Is it that coil bind provides a more progressive damping than the harsh bump stops? Will the Gen 6's go coil bind with the 0 ride height rule?

 

[Magnethead]

Coil binding allows the lowest ride height with the highest spring rate. As a spring is compressed, it's force increases. By coil binding, the maximum force can be achieved, whereas bump stops leave some on the table. It lets the crew chiefs run the softest spring possible.

 

[Revman]

Coil binding allows the lowest ride height with the highest spring rate. As a spring is compressed, it's force increases. By coil binding, the maximum force can be achieved, whereas bump stops leave some on the table. It lets the crew chiefs run the softest spring possible.

Why would teams have used bump stops? Will coil binding return?

 

[Kyle18fan]

My understanding is that the cup cars will be using bump stops on the front more than they did in the past.

 

[StandOnIt]

losing the front height rule will remove the trick shocks that are supposed to raise up the front of the car to pass minimum height requirements. Haven't heard a thing about any different front suspension setup.

 

[Revman]

Andy Graves, VP Chassis for TRD, talked about putting the suspension back into the suspension if you will by going to 0 ride height. He meant that tuning for handling would come back into play instead of dropping the thing on the stops for aero purposes. Thoughts....

 

[Kyle18fan]

Bump stops vary in their intensity and do have some give depending on the material that they are made of, the ones I use on the rear of my moto-cross bike actually compress almost an inch. Some are so hard they dont compress at all

 

[hidesert cowboy]

the reason coil binding was used is because they were not allowed to use bump stops, during the coil binding era. the entire purpose of both systems is to attempt to seal the front splitter or with the old car the valance to the race track. but at the same time keep the front end up off the race track enough to where it doesn't wear the splitter off. the way they pull the front end down is by using a really heavy stiff sway bar, this sway bar actually picks up the left tire because of the load placed on the right, pretty interesting things going on with the front end.

 

[FenderBumper]

I thought coil binding was all about keeping cost down. I think teams used to pay big bucks for springs that would settle just right during the race and still stay within the height rules. Now shocks have become the main cause of ride height issues.

Bump stops vary in their intensity and do have some give depending on the material that they are made of, the ones I use on the rear of my moto-cross bike actually compress almost an inch. Some are so hard they dont compress at all

That's interesting. I didn't think these cars used more than 1/4 inch of bump stop. Anyone know for sure?

 

[Kyle18fan]

I thought coil binding was all about keeping cost down. I think teams used to pay big bucks for springs that would settle just right during the race and still stay within the height rules. Now shocks have become the main cause of ride height issues.



That's interesting. I didn't think these cars used more than 1/4 inch of bump stop. Anyone know for sure?

I think you are right Fender, I think they call those "packers" that go on the shock shaft. It seems to be rather hard to find any good information on this stuff.

 

[Zerkfitting]

Andy Graves, VP Chassis for TRD, talked about putting the suspension back into the suspension if you will by going to 0 ride height. He meant that tuning for handling would come back into play instead of dropping the thing on the stops for aero purposes. Thoughts....

They want to keep the splitter as close to the ground as possible because the cars are so areo dependent. Keeping the splitter down essentially removes the suspension at speed. I think the teams were putting in soft springs in the rear to lay the tail down at speed for areo reasons, I think NASCAR started specing a rear spring. The teams are using the suspension to just meet the min height requirement for tech inspection and removing it at speed. That is the setup for the newly paved, smooth tracks. But suspension will come back as the track surface ages and bumps come back.

I wonder how much a minimal suspension affects a driver's body over time.

 

[Revman]

I think you are right Fender, I think they call those "packers" that go on the shock shaft. It seems to be rather hard to find any good information on this stuff.

I hear ya man. That's why I posted. Thanks to the responders. It's starting to make sense. Thinking that the 0 ride height changes the shock tuning obviously. It is my understanding that you will continue to see bump stops unless NASCAR outlaws it---you would have seen that with the new package post Charlotte test. No more post race ride height violations. Interesting that all in all it seems that things will be as they were, but I have heard many crew chiefs talk about wanting to explore the impact of this change. I have to believe that the shock tuners will have some room to work in the front end.

 

[Kyle18fan]

I hear ya man. That's why I posted. Thanks to the responders. It's starting to make sense. Thinking that the 0 ride height changes the shock tuning obviously. It is my understanding that you will continue to see bump stops unless NASCAR outlaws it---you would have seen that with the new package post Charlotte test. No more post race ride height violations. Interesting that all in all it seems that things will be as they were, but I have heard many crew chiefs talk about wanting to explore the impact of this change. I have to believe that the shock tuners will have some room to work in the front end.

Shock technology is improving all the time, they are certainly more complex these days than they were ten years ago. Just the improvements in shock oil alone are amazing. I wont miss the stupid "ride height violations" this year

 

[FenderBumper]

I hear ya man. That's why I posted. Thanks to the responders. It's starting to make sense. Thinking that the 0 ride height changes the shock tuning obviously. It is my understanding that you will continue to see bump stops unless NASCAR outlaws it---you would have seen that with the new package post Charlotte test. No more post race ride height violations. Interesting that all in all it seems that things will be as they were, but I have heard many crew chiefs talk about wanting to explore the impact of this change. I have to believe that the shock tuners will have some room to work in the front end.

You will still see ride height violations, as we saw last year. It just won't be because the spring settled too much. These days it's because particles clog the shock valves and keep the oil from equaling out the shock after the race. Typically they end up too low, but they can get stuck after acceleration and be too high and affect handling.

 

[Revman]

Thanks everybody. What an awesome board! Learned more in this thread than all of my searches on the subject in the last 3 months. Great to be here!

 

[StandOnIt]

You will still see ride height violations, as we saw last year. It just won't be because the spring settled too much. These days it's because particles clog the shock valves and keep the oil from equaling out the shock after the race. Typically they end up too low, but they can get stuck after acceleration and be too high and affect handling.

They got rid of the min front height requirement Fender for this year. I don't know about the rear, haven't heard anything, they are shooting sparks, so I guess that is as low as they can go.

 

[FenderBumper]

They got rid of the min front height requirement Fender for this year. I don't know about the rear, haven't heard anything, they are shooting sparks, so I guess that is as low as they can go.

OK, I guess I missed that key detail. That was one of the more annoying infractions because most cars were sealed to the ground during the race.

That rule change may actually be a big one to help even out the competition at the back half of the field.

 

[Revman]

They want to keep the splitter as close to the ground as possible because the cars are so areo dependent. Keeping the splitter down essentially removes the suspension at speed. I think the teams were putting in soft springs in the rear to lay the tail down at speed for areo reasons, I think NASCAR started specing a rear spring. The teams are using the suspension to just meet the min height requirement for tech inspection and removing it at speed. That is the setup for the newly paved, smooth tracks. But suspension will come back as the track surface ages and bumps come back.

I wonder how much a minimal suspension affects a driver's body over time.

Jeff Gordon's back might have some input on this.

 

[Revman]

Listening to NASCAR Radio tonight, and a caller asked the same question I was asking. Brad Gille and Buddy Baker really weren't sure if we would go coil bind or bump stop. Seems to me that unless NASCAR rules against the bump stops, it will be business as usual with some slight differences in shock tuning. Whatcha think?

 

[Revman]

Alright, Buddy Baker interviewed Travis Geisler on NASCAR Radio, and Geisler said that bump stops will be legal but that they won't be as significant of a deal...and that springs will become more important as a suspension tool instead of a mechanism to lift the car back up to pass inspection post race. He said that they wouldn't run coils overs, but that the thinking is the same. Is the reason that they don't run coils overs because it would be too difficult to swap shock, spring, and bump stop combinations? Geisler thinks that this is definitely something that the teams are scrambling to come to grips with.

 

[Kyle18fan]

Alright, Buddy Baker interviewed Travis Geisler on NASCAR Radio, and Geisler said that bump stops will be legal but that they won't be as significant of a deal...and that springs will become more important as a suspension tool instead of a mechanism to lift the car back up to pass inspection post race. He said that they wouldn't run coils overs, but that the thinking is the same. Is the reason that they don't run coils overs because it would be too difficult to swap shock, spring, and bump stop combinations? Geisler thinks that this is definitely something that the teams are scrambling to come to grips with.

Can they even use coil-overs without a complete redesign of the front suspension ???

 

[StandOnIt]

I can't see any reason to get away from bump stops, but getting rid of the spring back up after the race shock will make the difference. The shock can be tuned for up and down motion instead of being used for a spring back. They should be able to keep the car from bouncing up as far when they hit bumps at high speed. The cars should be more controllable.

 

[Revman]

I can't see any reason to get away from bump stops, but getting rid of the spring back up after the race shock will make the difference. The shock can be tuned for up and down motion instead of being used for a spring back. They should be able to keep the car from bouncing up as far when they hit bumps at high speed. The cars should be more controllable.

That is what I am understanding. The CC's seem to think that this change will be big. All I know is that the entry to Turn 3 in Fontana looked painful.

 

[Revman]

Take it for what it's worth, but DW said that Mikey told him the new 0 ride height set ups are some of the biggest changes in NASCAR in years. The set ups are being totally re-thought. Interesting.