Speedthane Bump Stops

[FlatTire]

Anybody know where I might find a force vs. travel graph for the Speedthane conical bump stops?

[DirtRacer9x]

They should have that all graphed out for you. If they don't I'd consider finding a company that does. If not throw them into a rater.

[Nobody]

Anybody know where I might find a force vs. travel graph for the Speedthane conical bump stops?

Which ones you want? the short or tall and what color?

[Nobody]

here is the short red and blue, if you need others let me know

Look at name by hovering cursor over graph to see which color the graph is for, it's named red and blue.

[Nobody]

Keep in mind those brand of bumpstops will die very quickly and not maintain those rates long. They are pieces of junk in my opinion

[FlatTire]

I actually have the 3" bumpstops. I found a "COT-75" on them and was able to find a graph on on RE Susp. website. Thank you Nobody.

I've always wondered about how well the material holds its rate. Do they gain rate or lose rate over time?

What about these CRD coil springs being used for bump stops? Wouldn't you want a progressive spring for a bump stop application?

What if we got away from bump stops and went to a progressive coil spring for the main spring instead of linear?

[HuckleberryB4]

FlatTire I've played with the Landrum bump springs and their linear rate makes them hard to use in our application. The slightest bump sheers the contact patch. I still want to do some testing in the slick though when the track smooths out and slows down.

[RRR_Products]

Both will lose rate whether spring or urethane. Urethanes last longer as long as you have a taller stack. Note any urethane or spring you use should not be compressed more than 33%. After that we've seen the rates of springs fall off and urethane prone to crack. Taller stacks are more consistent and more tunable as well.

[FlatTire]

RRR- not discounting your info at all, but at 1" of compression, the 3" hard stop is only at the 200lb mark(still on the flat part of the curve). I always thought it would compress more.

[HuckleberryB4]

I engage mine approx. 1.25-1.375. I do run an indicator.

[RRR_Products]

RRR- not discounting your info at all, but at 1" of compression, the 3" hard stop is only at the 200lb mark(still on the flat part of the curve). I always thought it would compress more.My info comes from the manufactures of urethane products. Whether it be dye springs or different urethanes the life diminished very quickly when loaded more than 33%. Now we have had loads past that but the life of the part goes down quickly. There are some new dye/bump springs that are being made specifically for 2 stage set ups. I personally am a fan of urethane because it is more cost effective and in my experience forgiving and a lot more tunable. There are circuits where cars are coil binding because urethane springs are not allowed. You have a $50-$100 spring on some cars while there is a spring manufacture out there making springs at $1500 ea that are made to be coil bound and keep the rate longer. As for a progressive bump spring I don't know of any currently nor anyone making them for shock applications. I do not think it can be manufactured cost effectively or the wire cannot take those loads were placing on them while maintaining rate.

[Nobody]

Engine builders purposely run valve springs to within .050 of coil bind or less, reason being is spring surge and doing this so actually makes valve springs last longer and have much better control over the valve train. So if you killing/damaging/wearing out a spring cause it's going more then 50% of compression, you have a POS for a valve spring. Same could be said with bushings.

Whether you want more of a progressive or linear rate to a stop, is really more about how you are using it more then anything. There isn't really a right or wrong way to use one as there are many ways to skin a cat per say. However with those types of stops you are most likely going to be in the 1.250 to 1.5 range on how much you are compressing it. Again depends on many things like: if you using a cup with the bump-stop, thus will increase the life of the bump-stop but also has some negative effects also.

Problem with the spring in the past was they offered little compression before coil binding due to spring design, so if you over traveled one time going in harder or something and it coil bound it became solid. Even compressing a bump-stop pretty dam close to solid it still had some compliance to it. Granted it may not been a ton but still somewhat not solid.

Another thing was rate availability and over all hieght, depending on exposed shaft sometimes the hieght of the spring vs the travel just don't work out right. The springs needed to be tall just to have some travel available to them, so you where stuck with a 3" or taller spring for the most part.

No matter what bump-stop your using, you are going to need to replace it often to keep consistency to the car and it's travel. Just some are better then others.

To make a progressive spring, they would most likely need to make a variable size wire spring like PAC does for coil over springs. Typically making a progressive spring they use the same wire size but change the gap on the coil distance, so you see a tight coil gap and then slowly get bigger. This limits travel on the spring before coil bind, so you get a spring that is 3" tall and can only compress to 2" or more and coil bind. To do this, I think they need to make the spring in the variable wire diameter so you don't lose travel. I haven't seem one, but maybe PSI or PAC makes one.

I know PAC makes them in coil over springs cause I own some of the first ones they did.

[hsdiefusion16]

I have the dyno graphs for the tree and skate style bumps if anyone is still in need. We have a full line of bump springs that we just released here at PAC Racing Springs. I am working on some new designs for progressive springs to help out with some issues that guys are having getting bumps to work just right on the front end of their dirt cars. I also want to add that you guys need to stay away from die springs. They are not made to be used as bumps. They worked at first when people were first developing them but now that our new product line is out the bumps we make blow the cycle tests of die springs out of the water. They are solid safe as well so if you end up going light and bottoming it out then there wont be a load loss or set taken with the spring. Feel free to email me or shoot me a pm on here if any of you have questions or need help getting bumps figured out.
Kody Weisner
PAC Racing Springs
Technical Sales
Circle Track Specialist
kody.weisner@racingsprings.com