Question on bump stops.

[HuckleberryB4]

How much BUMP STOP compression/travel do you usually want when using a bump on the RF?

[7uptruckracer]

Depends on your bump you don't want to compress the bump more then half its static height. Go to RE suspension look up the different style and they have their wheel loading charts with them so you can see how much travel relates to how much load. Most Dirt cars run the Christmas tree style

[HuckleberryB4]

I've been on RE looking on their charts and that's what led to my question. I'd like to soften up the RF some because the track has went very dry slick, but have no idea how much bump stop I'm currently using and honestly don't know how much is acceptable. I'm on a stacked RF (240 spring combo) and want to eliminate the stack. So I'm looking at using the bump more and using a conventional single spring setup. Thanks.

[hpmaster]

It's more a load at a specific travel question. Really doubt you are going to get a whole lot more than that on here. I now shut my mouth and sit in the corner.

[fastford]

when I was on a bump stop, I used the re suspension Christmas tree style with a 250 spring , It wasn't compressing enough to start with so I cut the top ring off, then it went a little to much so I used the shims to fine tune. I don't know if you meant two stage or stacked when you were talking about the set up you were running, the bump stop was fast on a very very smooth slick track, but any roughness and its terrible on equipment, im on a two stage set up now and I like it the best all the way around, it gives you the soft rate to get you in then when it hits the second spanner or second stage your on a stiff spring to get you off the corner, its a lot better all the way around but you need a good shock specialist because it takes a lot of low speed control on your shock to make this work properly, this is also true for the bump set up as well.

[Matt49]

when I was on a bump stop, I used the re suspension Christmas tree style with a 250 spring , It wasn't compressing enough to start with so I cut the top ring off, then it went a little to much so I used the shims to fine tune. I don't know if you meant two stage or stacked when you were talking about the set up you were running, the bump stop was fast on a very very smooth slick track, but any roughness and its terrible on equipment, im on a two stage set up now and I like it the best all the way around, it gives you the soft rate to get you in then when it hits the second spanner or second stage your on a stiff spring to get you off the corner, its a lot better all the way around but you need a good shock specialist because it takes a lot of low speed control on your shock to make this work properly, this is also true for the bump set up as well.

100% agree. The dual stage spring setup is much more forgiving on setup and equipment than even the softest bump stop. You've got to have the right shock setup to make it work right though. The reason many try it and it "doesn't work" is because they didn't have the right shock package.

[HuckleberryB4]

Sorry for the confusion. I am on the 2 stage. 600/400. On a fast tacky track I love it. The car gets a ton of forward bite and the side bite is naturally there. On a slick track the car just wants to skate on entry. I put a camera on my RF and from the instant I get on the gas it's on the lock rings and the single 400lb spring for the whole race. This is obviously why it's skating. So I figured if it was on the main spring the whole time, I might as well eliminate the 2 stage and go to a softer spring and a bump to get into the corners.

[HuckleberryB4]

How much gap between the slider and lock rings is too much? Is there a point where it's better to change springs than to keep increasing the gap?

[fastford]

im on two 500 springs and at ride height there is a little over 1 inch to lock ring, the two 500s gave me the same feel getting into corner as the 250 with bump but if your shock isn't right it will unload in middle and you loose drive off, like matt said, a lot of people try this without the complete package and think its junk, if your not willing to stick with it a while and learn how to use it , its probably better to stay with more conventional set up

[grt74]

Sorry for the confusion. I am on the 2 stage. 600/400. On a fast tacky track I love it. The car gets a ton of forward bite and the side bite is naturally there. On a slick track the car just wants to skate on entry. I put a camera on my RF and from the instant I get on the gas it's on the lock rings and the single 400lb spring for the whole race. This is obviously why it's skating. So I figured if it was on the main spring the whole time, I might as well eliminate the 2 stage and go to a softer spring and a bump to get into the corners.

weve done alot of this (stacked springs and bumps),looking at your set up,i would swap the springs around and run the 600 on the bottom and reset your lock nut with a little more gap,but all of this takes tons of time and you really need a shock/spring rater to help,so you know where you are and where your going,also shock packages are a huge factor in these setups(its not for everyone)as matt has said,also i know i will get tons of questions on this,guys it takes tons of time and testing, there is not a perfect setting on this stuff,different cars,diff drivers,tracks,and so on

[HuckleberryB4]

My shocks shouldn't be an issue. If someone would like to take a look at the vid of my RF setup during a heat race I'd appreciate it. Just give me your email address. Thanks.

[hucktyson]

Most of the blazing fast touring guys are running them and none of the blazing fast touring guys crew chiefs are on this board trying to tell anyone else what those blazing fast guys are doing ...

[hpmaster]

If you run stacked spring set up or shocks with opposing lock rings make sure you use 2" o-rings between your locks. Yup you should have a shock/spring rater or you can miss what you need by a very small amount, as for making work it takes time to learn.

[hpmaster]

Most of the blazing fast touring guys are running them and none of the blazing fast touring guys crew chiefs are on this board trying to tell anyone else what those blazing fast guys are doing ...

And that my friends is the blazing fast truth

[7uptruckracer]

Sorry for the confusion. I am on the 2 stage. 600/400. On a fast tacky track I love it. The car gets a ton of forward bite and the side bite is naturally there. On a slick track the car just wants to skate on entry. I put a camera on my RF and from the instant I get on the gas it's on the lock rings and the single 400lb spring for the whole race. This is obviously why it's skating. So I figured if it was on the main spring the whole time, I might as well eliminate the 2 stage and go to a softer spring and a bump to get into the corners.

If you never come off the lockdown like someone said assess your shock package that would be a concern for your bleed setting. A regular tie down shock doesn't work for this for that reason you never come back off the lockout and it defeats the purpose of what you are trying to do. Most baseline adjustments are 1.5-.75" of a gap but don't be afraid to think outside the box once you get it working. I like the 700/400 myself. As far as bumpstops softer spring will make it engage quicker so you actually hit the bump sooner and travel more so it will actually RAISE your wheel loading. So work with different bumps and you can rig up an external travel indicator to know how far your engaging a bumpstop package to calculate added wheel loadings. A stiffer spring will get you a combined lower wheel loading then a softer one because bumps tend to be really progressive. A lot of guys are working with bumpsprings now as well because like regulars springs they have linear and not progressive curves. On either package consult a reputable shock guy who runs the setups to get you on the right rebound numbers and bleed they don't work right if you stay pinned!

[let-r-eat]

Yeah,All the fast guys crew chiefs are surfing porn sites.

[HuckleberryB4]

If you never come off the lockdown like someone said assess your shock package that would be a concern for your bleed setting. A regular tie down shock doesn't work for this for that reason you never come back off the lockout and it defeats the purpose of what you are trying to do. Most baseline adjustments are 1.5-.75" of a gap but don't be afraid to think outside the box once you get it working. I like the 700/400 myself. As far as bumpstops softer spring will make it engage quicker so you actually hit the bump sooner and travel more so it will actually RAISE your wheel loading. So work with different bumps and you can rig up an external travel indicator to know how far your engaging a bumpstop package to calculate added wheel loadings. A stiffer spring will get you a combined lower wheel loading then a softer one because bumps tend to be really progressive. A lot of guys are working with bumpsprings now as well because like regulars springs they have linear and not progressive curves. On either package consult a reputable shock guy who runs the setups to get you on the right rebound numbers and bleed they don't work right if you stay pinned!


And that seems to be the problem, it's staying pinned, it never rebounds to reset for corner entry. Part of that is my fault because I never lessened the rebound settings. This thread has helped a lot and I'm glad I have video to refer too. I've already contacted Kenny at B&O to see what the shock needs as I believe it's currently setup to be a tie down shock. I'll play with bump stop spacing too.

One last question for you fellas. Does the 600/400 combo seem too light for a full cast motor car?

[7uptruckracer]

And that seems to be the problem, it's staying pinned, it never rebounds to reset for corner entry. Part of that is my fault because I never lessened the rebound settings. This thread has helped a lot and I'm glad I have video to refer too. I've already contacted Kenny at B&O to see what the shock needs as I believe it's currently setup to be a tie down shock. I'll play with bump stop spacing too.

One last question for you fellas. Does the 600/400 combo seem too light for a full cast motor car?
Kenny will definitely get you right! I know he's running rf bumps! I don't see as many on 600/400 period regardless of motor make sure you have the right height springs to that 4" spring crap coilbinds

[grt74]

most of the blazing fast touring guys are running them and none of the blazing fast touring guys crew chiefs are on this board trying to tell anyone else what those blazing fast guys are doing ...

there are alot of guys still running standard springs with a ton of success,its all really a package deal as ive said before but i will say this we currently have 3 different double adjustable shocks for the rf on all of our cars because they all have different levels of control,i think most people get caught up on shock names themselves and not whats in them,valving,bleed,different pistons,ect, all of that and then some goes into building a shock,the easest way to know what you need is to know where you are and then where you what to go and keep very and i mean very good notes,so that even if you have a shock built and it doesnt work youll have notes on what it did to the car,and then you may use it later,
i hope i helped explain it some,but shocks can be very overwhelming,before you go nuts get someone to explain a shock graph and have them explain it in a way that you understand,if you dont understand the graph its going to be hard to move forward
but all setups above will work,standard springs,stacked(with a lock nut),and bumps,of coarse the shock will have to have different levels of control for each setup,top level guys are winning with the standard stuff still too,but they drive different than the other guys
good luck guys,and test test test,it will save a ton of money in the end,not to mention the work of fixing a wrecked car every week
hope i helped some

[HuckleberryB4]

7uptruckracer, what springs are most guys on? I'm on the 4" 600 (top) and a 10" 400 (bottom). I mentioned above that I ran a camera on the RF one night and it's not coil binding. It's definitely compressing the 400 and the bump.

[mab475]

First off not running a 247 combo. A 600/400 is a 300 and you have them backwards.

[grt74]

[QUOTE=mab475;1815906]First off not running a 247 combo. A 600/400 is a 300 and you have them backwards.[/QU



REALLY ITS 600X400=240000 THEN DIVIDED BY 600+400=1000,240000 DIVIDED BY 1000=240, THATS WHAT HE HAS AND YES THE 400 SHOULD BE ON TOP OF THE 600 WITH THE LOCK NUT HITTING THE 600,WE HAVE TRIED ALL KINDS OF STACKS AND YOU WOULD BE SURPRIZED AT WHAT SPRING RATES SOME GUYS USE
JUST DONT OVER THINK IT GUYS,ITS ALL IN THE MATH AND TESTING

[grt74]

it's more a load at a specific travel question. Really doubt you are going to get a whole lot more than that on here. I now shut my mouth and sit in the corner.

this guy understands,im done now,ill go to my corner,but if the cars skating that bad it makes me wonder if your looking in the right place to fix it

[Matt49]

I want to add that you don't have to have a spring tester to figure this stuff out. Some pretty simple math will tell you exactly how far the slider travels for a given amount of shock travel. So if you know your gap, you should be able to easily calculate how much travel it takes to close it as long as you know your spring rates.

[HuckleberryB4]

This may be a dumb question but, If I were to swap the springs so I had a 4" 400 on the top and a 10" 600 on bottom, wouldn't the 400 want to coil bind? I'm guessing I'd probably have to run those rates at a 6" 400 and 8" 600.

[HuckleberryB4]

This is beginning to make sense now, but I'm curious as to what happens when you reduce the split between the two springs? Let's say I wanted to raise the combined stacked rate so the big spring engages later. So rather that running a 400/600 stack, I chose to run a 500/600 stack. Is there anything else affected by reducing split other than raising the overall spring weight and getting on the big spring later? Again, I apologize for my ignorance. Just trying to learn and understand. Thanks for your time guys.

[swartzman]

GRT 74 I will tell you now u r correct.. they r not even looking at the right place.. get the dang car off left rear weight and get some right side on it.. and just who are the blazing fast guys? FORGET THE TRICK OF THE DAY CRAP.. keep it simple.. guys come on..

[7uptruckracer]

7uptruckracer, what springs are most guys on? I'm on the 4" 600 (top) and a 10" 400 (bottom). I mentioned above that I ran a camera on the RF one night and it's not coil binding. It's definitely compressing the 400 and the bump.

Just curious why you mentioned a dual stage and a bump in the same thing? Are you on a stack (two springs stacked with a nylon separator) or a dual stage (two springs with lockout nuts) because you can't run a bump with all that stuff, well I mean you can but you'd have to get your wheel loadings right with a gale force or something and its two tools to do the same thing?

[HuckleberryB4]

I'm not looking for a trick setup. I'm trying to understand the 2 staged RF setup. The guy who put me on it obviously didn't know either. So what I thought I "might" have understood, I didn't.

I've still been a top 5 car with it, so my setup must not be too far off. But in the slick on the 2 stage, I can feel the car is LOOSER getting in and I have to wait longer than normal to get back to the gas. It's not skating around the track like some of you may be thinking.


So back to the question on reducing the split of the stacked springs..........would someone please provide me with some insight on this. Thanks again.

[HuckleberryB4]

I'm on a dual stage WITH the lock rings AND a bump stop. This is the way the guy set me up and it was on his Gale Force.

[HuckleberryB4]

After understanding this a little better now, I was able to watch the video and make sense of what was happening with this combination.
When the RF compresses, the springs act as the soft stack and engage the bump stop. When this happens the stack stays acting as the stacked soft rate and I never got on the lock rings. Since I had the 600 on top of the 400 I was fighting myself anyway. But when it hits the bump I was dead in the water and just beat the crap out of the 400.

[Matt49]

HuckleberryB4, if I'm understanding what your are describing I would say you need to take about ten steps back and rethink what you're trying to do.
The stack spring setup with LOCK out nut and the soft spring setup with bump stop are two DIFFERENT setups that are both tools to accomplish basically the same thing. But they require different shock characteristics in most cases. Running them in combination (which is what you are describing) is unnecessarily complex and is making an already confusing situation for you even more confusing. Just my opinion.

[HuckleberryB4]

I agree Matt and that is what I'm doing. Unfortunately I put my trust into a guy that told me how great this setup was and I allowed him to set me up on exactly what I posted above. I didn't know much about the dynamics of it, but knew I wanted to improve and that's what I thought I was doing. This post has helped me understand what is happening on a dual stage and now that I have a better understanding I should be able to be more successful.

Although, I am still wondering what to expect with a larger or smaller spring split?

[fastford]

let me get this strait, your on a two stage spring with a bump stop added also?

[HuckleberryB4]

Yes. That's what I was setup with.

[Matt49]

I agree Matt and that is what I'm doing. Unfortunately I put my trust into a guy that told me how great this setup was and I allowed him to set me up on exactly what I posted above. I didn't know much about the dynamics of it, but knew I wanted to improve and that's what I thought I was doing. This post has helped me understand what is happening on a dual stage and now that I have a better understanding I should be able to be more successful.

Although, I am still wondering what to expect with a larger or smaller spring split?

I've never really thought much in terms of "split".
Figure out what you want your final rate to be (bottom spring) and then set your top spring based on what you want you initial rate to be. Then the gap can be determined based on how much travel you want before making the rate change. You just have to know how much each spring moves for a given amount of stack compression which is easy to figure out.

It is still very important that you get your shock rebound dialed in to keep you on the bottom spring long enough to get the corner exit benefits of it but not so long that it never lets you get setup for the next corner. Remember, you want to be on the stack on entry and on the bottom spring on exit.

[fastford]

with a tie down shock and that set up you were basically on a solid susp on rt frt, if you were on any roughness at all I bet it was a hand full.

[FlatTire]

Huck-

Larger or smaller spring split isn't what I would be concerned about. Its about having the correct combined(primary + secondary) spring rate for entry and the correct primary rate for exit based on track conditions, shapes, and driving style. Just put your rates into the combined spring equation and see for yourself.

Say you had a 600 primary with a 400 secondary. You end up with 240 combined. So on entry you will have a 240lb spring effectively and for exit you will be on the 600 primary. For your concern, I guess you would call this a 600-400 = 200lb spring split.

So lets increase the spring split like you talked about and use 700 primary and a 300 secondary. This gets you to a 210 combined. So on entry you are on 210lb and you exit on a 700lb. This would be a 300lb spring split if you want to call it that.

You first select the spring rate you want for entry and for exit. It doesn't matter what the split is. What does matter is having the correct spring, you put on what you need to help the driver go as fast as he can.

The only time I could see this spring split come into play is on those odd ball tracks where its extremely d-shaped and slick and the car needs to be turned very quickly without using rear brake, yet you need to carry a ton of speed into the corner for entry. You might want more "split". You'll need something a bit softer than normal to entry for the combined rate and something stiffer than normal for exit.

So perhaps the more symmetrical turn 1 is to turn 2 and turn 3 is to turn 4, the less split. The less symmetrical, the more split. The more I think about this, the more I see where you are coming from.

[HuckleberryB4]

Makes sense. So the difference between the springs don't really matter. All I'm looking for is what stacked rate I want for entry and what primary spring I want for exit.

Thanks a ton for everything guys.

[7uptruckracer]

Makes sense. So the difference between the springs don't really matter. All I'm looking for is what stacked rate I want for entry and what primary spring I want for exit.

Thanks a ton for everything guys.

Correct Call up B&O tell them Kenny your running a Dual Stage and you need your RF to be done up. He mostly runs bump so listen to what he says there they are very very very fast on his stuff right now. Spring setups are linear in their loading and bumps are progressive which is why they don't work in the rough tracks because it spikes wheel loadings. Both have the same goal essentially. Allow the car to travel then Load it up. Now that you aren't on a bump if you run dual you might have to get off the short height and go to two 7" springs or in 8 and a 5 or what have you taller springs travel more before coil bind and your 4" probably will bind. Anyways definitely call kenny hes the man down here in NC and VA

[drtrkr244]

Just a thought here......It sounds like you have plenty of traction in the front tires if your car gets loose off the gas. Try adding traction to the rear of the car or just right rear.I always tried to work on the part of the car that needed more traction instead of taking it away from another part.