Bump springs

[DEKconsulting]

Thoughts on them and do u think they are better for ur shocks than standard bump stops? Go.

[DEKconsulting]

Come on no one uses these or knows about them. I think tbey will be better for our shocks than slammin them against hard ass stops all the time

[MasterSbilt_Racer]

Once those coil bind, they gotta be mean. And before that, they are a spring. I don't get them, honestly.

[Punisher88]

Pretty sure he was just bumping the post back to the top.. since no one had replied..

[DEKconsulting]

Really arguing with myself if u didnt understand that maybe u shouldnt be lookin

[Krooser]

Post number two could have used a question mark after the first sentence... that would have changed everything.

[collateralDamage]

I like the linear properties of a bump spring. I like the durability of an elastomer. You can make an elastomer linear within an adequate range of travel with some creativity.

[MBR Performance]

A bump spring will out last a bump stop any day

[MasterSbilt_Racer]

A bump spring will out last a bump stop any day

Is durability really an issue? How do bump springs survive coil bind?

[LOSTRACER2]

Thoughts on the RE suspension "bump washer"?

[fastford]

Thoughts on the RE suspension "bump washer"?

i use it on top of there cone bump stop, helps to keep from distorting the top. ive had good luck with anything ive got from these guy,s and there tech help is good also....

[7uptruckracer]

Are you talking seperator washer or Bellvelle stack?

[ALF401]

I posted on here a year or so ago about springs instead of rubber bumpstops and the response I got from these pro's on here was that I was crazy. I was in a shop and saw the spring on the shock shaft and inside the spring cup. It was about the size of a valve spring. This spring may not have had anything to do with it but the guy killing the competition every weekend so he was doing something right.

[MasterSbilt_Racer]

If you want to have a second stage with a 1500#, you can do that with coilovers. Then if you want a stop, rubber is better. What color underoos did that fast guy have?

[King1]

I looked at a Lucas oil car last spring and it had bump springs on it. Went back today and it had pucks stacked and no bump springs. I also saw some screwed up stuff all over that thing. Interesting to say the least.

[Mr.Kennedy777]

I ran bump springs before I ran bump stops and my experience was this: Running bump springs you get an instant jump to a higher cross setup when it contacts the bump spring in the first corner. They are also a little harder to control with the shock rebound than a bump stop in my experience. I ended up rebuilding my shock on the RF about half a dozen times before I was happy with corner exit. It would tighten up in the middle, but I would lose drive on exit super early as it would lift off the bump to soon. At least I think I didn't have strong enough rebound control and it kept lifting off the bump spring too early. I ended up needed a really really heavy valve stack inside the shock to keep the corner down on the bump spring long enough to gain drive on exit. Once I had it figured out it was great. The nice thing is they come in so many different rates and usually leave you decent amount of room for going over ruts and bumps on the track before you bind. Biggest things are having a ball park idea of how much loading your cornering forces create so that you can select the right combination of ride spring and bump spring rate, how much clearance you have when you get on the bump spring (they're usually 2"-2.5" so usually have decent clearance), and rebound speed to keep the corner on the bump spring when you exit the corner lol. Running bump stops I really really liked when the track was smooth, I never ran them on a rough track but if the track is smooth they are waaaaay better than bump springs IMO. The reason I like them is that they tend to give you a more progressive feel, the harder the car gets on the bump the tighter it gets which is something I really liked in the middle, it felt like I could drive the car a harder in without it busting loose or sliding. It was really nice when changing my line to the inside when the cushion got used up, I was able to move down and run the low line and not worry about the back end sliding out at the apex. At this point I had already found a shock valve stack that worked for the bump spring and used it on the bump stop. So here's my two cents on bump springs and bump stops. Bump springs I feel are better on hooked up fast tracks and I think work better running the car down on the bump for the entire race. Once it engages running a shock that is strong enough to keep it down on the bump helps load the RF tire contact patch sooner coming in. Usually need to run a much stiffer RR spring to keep the car neutral in the middle. Biggest benefit in my eyes is the aero platform, lower front, limited camber change, and increased LR loading when utilized properly. Bump stops are better on a dry smooth surface, when it helps to have the car become tighter as you get deeper into the corner or drive the car harder in. They don't need quite as much rebound control because they are progressive, usually helps to have a slightly stiffer ride spring in my experience. I guess it does depend on the type of bump you run. Some load like crazy and some are relatively soft. I think for dirt it's best to run softer bumps with somewhat stiffer ride springs to avoid spiking the load on the tires unless the track is like really really fast and really smooth, then I'd run super soft ride spring with a small stiff bump and lots of gap. That's just me though and I'm sure there are varying opinions on this.

[fastford]

very good analysis Mr Kennedy, ive never ran a bump spring, but in the conditions you described using one, i use the 2 stage set up. I was concerned about the little spring coil binding. I was wandering about stacking to real stiff ones together to get the rate i want, but dont think theres room without going with a longer shock, have you tried this?

[Mr.Kennedy777]

I haven't no. What rate are you looking for?

[fastford]

im on 500 when i hit the lock out on 2 stage, thats what i was thinking about two 1000s because i think a single 500 spring might coil bind. I will say the only reason i was thinking about this is to reduce the weight of the 2 stage which i only run on a heavy and or rough track,

[Mr.Kennedy777]

The only issue with that is your bump spring setup doesn't lock out the ride spring. So if you had for example a 300 ride spring and a 850 bump spring, your final rate would be 1150. If you wanted 500 for a final number, you'd have to run a really soft ride spring, like a 225 ride spring and then two 550 bump springs (for a final rate of 275 for bump springs). Which to me is kinda crazy. You would need enough room in the 225 spring to take up enough rate to avoid binding the 2 550 springs that have a combined 2.2" travel taking up 4.5"+ caps and a coupler, so let's just say 5". I'm not sure how much travel your RF has, but to make sense of that application let's just for instance say, you had 2400 lbs of force in a corner, with 7" of shock travel, and pre-load of let's say 500#.. your ride spring would take up 2" of travel before it got on the bump springs, so 550# plus 500# of force, that's 1050#. There is a remaining 1350# of force that needs to be taken up by the combined rate of the bump springs and ride springs, which would require an additional 2.5" of travel, and leave you with nothing before bind. It could be made to work eventually but is it really that much lighter to run a taller shock with a taller spring with different mounting points now to increase available shock travel to accommodate these tall bump springs? It would be a lot of work and then here is the next step... is that 2" before the bump springs going to be enough room for you to achieve the transition of handling at the right part in the turn? I mean you could play with your compression speed I guess.

[Mr.Kennedy777]

I had to edit that.. I'm tired and my math sucked lol!

[fastford]

my 2 stage set up is 2 500# springs, which is a 250# rate until it reaches the lock out, then it goes to the full 500# rate, this is what i would want to achieve with the bump spring , keep in mind this is for a heavy rough condition. in the smooth slick im on a medium cone bump stop and a single spring between 175 and 225 # . I realize the need for more clearance but you could use a 9" shock instead of a 7" and travel should not be affected. I doubt i will ever try this because we stay on the bump most of the time, just thinking out loud and wandering if this could take advantage of both set ups combined into one......

[Mr.Kennedy777]

you mean like a three stage spring?

[fastford]

no, at static height, your just on the primary and at your desired travel you hit the bump, but on a rough track you have more travel than being on a rubber bump or just one short bump spring , like i said i think this could combine the advantages of both type set ups( bump stop and 2 stage) into one. I know there is probably some one on here reading this with more experience than me so maybe we can get some useful input. To me this is the best part about 4M because i have gained a lot of knowledge from here.

[Mr.Kennedy777]

Have you ever ran the dual stage on the RR as a digressive stack? I am wondering how well that works out. You would think it would be a nice way to tune entry and exit just wasn't sure how touchy the adjustments are.

[zeroracing]

Mr. Kennedy, I think this is an interesting thought, digressive type spring set ups on any wheel honestly. I think the issue you may run into on some cars if bottoming the RR tire into the deck or birdcage into the frame rail with a real soft spring once it compresses down. This is an issue we have ran into with some cars, that we get the wheel rate we want, but run out of travel when we hit a bump.

[fastford]

Have you ever ran the dual stage on the RR as a digressive stack? I am wondering how well that works out. You would think it would be a nice way to tune entry and exit just wasn't sure how touchy the adjustments are.

no, but i would think you could control the dynamic load on that tire better, might be touchy on dry slick though.

[Mr.Kennedy777]

I was thinking also on the topic of bump devices. And the bump washers. On the LR corner when it hiked up a lot of the loading is being supported by the bars. Would it be beneficial to use some sort of bump device built into the rod itself, either at the chassis mount or on the birdcage. I was thinking something like a pull bar design, but much smaller, having the heim end cut and welded onto a plate with four bolts, and two other plates in the system... the bolts pass through one plate so that it can slide separating two stacks of the washers and the last plate is secured with the nuts on the other end of the bolts. The bar is connected to the threads and the threads pass through the last plate into the second plate allowing you to pre load the bottom section. One side pre loaded to near full compression and the other side semi pre loaded for a bit of give when it gets up on the bars. We aren't talking a whole lot of travel, maybe 0.25" or so, either way. I was thinking this could help the tire out a little bit at least. Any thoughts??

[MasterSbilt_Racer]

I was thinking also on the topic of bump devices. And the bump washers. On the LR corner when it hiked up a lot of the loading is being supported by the bars. Would it be beneficial to use some sort of bump device built into the rod itself, either at the chassis mount or on the birdcage. I was thinking something like a pull bar design, but much smaller, having the heim end cut and welded onto a plate with four bolts, and two other plates in the system... the bolts pass through one plate so that it can slide separating two stacks of the washers and the last plate is secured with the nuts on the other end of the bolts. The bar is connected to the threads and the threads pass through the last plate into the second plate allowing you to pre load the bottom section. One side pre loaded to near full compression and the other side semi pre loaded for a bit of give when it gets up on the bars. We aren't talking a whole lot of travel, maybe 0.25" or so, either way. I was thinking this could help the tire out a little bit at least. Any thoughts??

That ain't legal... Lol

[Mr.Kennedy777]

Why did they make it so that you can't cushion the LR through either the rod or the birdcage assembly? Is it a possibile safety issue or what is it? Scared of trying new things? If we're talking unfair advantage this piece would cost maybe 200 to make at home lol.

[MasterSbilt_Racer]

Why did they make it so that you can't cushion the LR through either the rod or the birdcage assembly? Is it a possibile safety issue or what is it? Scared of trying new things? If we're talking unfair advantage this piece would cost maybe 200 to make at home lol.


Its part of the current idiocy of the sport. I used a shock and bumpstop for my top link in 2015 with a chain parallel to it for preventing extension. The cushion seemed to help a bit.

[Punisher88]

Coleman racing products builds a piece that works great for that. Works really nicely and has a travel indicator made onto it.

[Punisher88]

Part #24640. I replaced their bushings with a hard bumostop. I could tell a difference in forward. It would actually bog the motor a bit. I also slotted the shaft and out a pin in it to keep it from over extending.

[billetbirdcage]

http://shop.penskeshocks.com/images/P/htd.jpg



OUTLAWED!

[MBR Performance]

Depends on where you race lol.

[Matt49]

I've been saying for years that our left rears are too stiff on the bars the way they are and that dampening the top bar could be helpful (see Penske device above). This is why the "heavy" LR components (steel wheels, lead on the axle, etc.) are in trend. They are compensating for the lack of critical dampening when the car is barred up by making unsprung weight. It's a crutch for a crutch. I digress...

[Brian Gray]

We have been hiding these springs inside the shock for quite some time now. Nothing new

[Punisher88]

http://shop.penskeshocks.com/images/P/htd.jpgOUTLAWED!Although this would most definitely work better with being more adjustable and tunable... I didn't have that kind if cash. I made mine for around 200 bucks.

[MasterSbilt_Racer]

We have been hiding these springs inside the shock for quite some time now. Nothing new

But that just works like the bump stop limiter.

[Brian Gray]

But that just works like the bump stop limiter.

Yes and no. Most of the new bodies I am using have an adjuster to raise and lower engagement, there is also a bump rubber on the shaft as well. The important part though is we also added a contact spacer that increases rebound preload on the stack at engagement. Working pretty well too. Been moving on from this though to work more on my dual piston setup .

[racer2e]

This makes it displacement dependant? So the last bit of rebound travel has more dampening?

[sidewinder69]

so if this top rod collapses any, then your birdcage should roll forward then shortening your lr shock center measurment.... so then you have increased your spring load if your spring was already into the coilover nut, and if you go pass the tipping point of too much load on the lr, you pick the weight up off the right rear and cause it to loose traction.

[MasterSbilt_Racer]

so if this top rod collapses any, then your birdcage should roll forward then shortening your lr shock center measurment.... so then you have increased your spring load if your spring was already into the coilover nut, and if you go pass the tipping point of too much load on the lr, you pick the weight up off the right rear and cause it to loose traction.

That is a possible scenario. Not necessarily a likely one. Depending on a bunch of variables.

[sidewinder69]

Ill say I've got a couple penske rods and moved all over the place... It definitely isnt a magic wand like people thinks.

[MasterSbilt_Racer]

Ill say I've got a couple penske rods and moved all over the place... It definitely isnt a magic wand like people thinks.

I agree it is no magic wand.

[MBR Performance]

Ill say I've got a couple penske rods and moved all over the place... It definitely isnt a magic wand like people thinks.Wanna sell one of those Penske rods?

[sidewinder69]

Call penske direct. $475

[Mr.Kennedy777]

How much does that spring bar weigh in total??

[sidewinder69]

About 5lbs