LR Bite vs Cross vs Drive

[7uptruckracer]

I don't know of anyone on LR stacks my way but a lot of RF AND LR Duals. To each their own.

[Bubstr]

There is no way to mimicking what the car would be doing. Simply doing travel of spring would let you know how much weight is placed onto each spring but all the ballast weight is moving as well. That's my thinking on that at least.

There is such a thing that was used by Drag racers to even out the traction in the rear. It's called a traction dyno. This is not an expencive thing. Something to tug on Chassis at center of gravity and hold backs at tires and scales.

In gear and held back by hold backs as close to tire contact spots as possible, you pull center of gravity to achieve race attitude and the scale weights will reflect weight transfer threw asymmetrical adjustments of anti squat or roll centers for a side pull. the scales reflect percentages of static and transferred weight. Changing bar locations or roll centers will change those percentages. You only scale the tires on the pulling force direction. If pulling from therear , only the rear tires are scaled. Pull from right only right sides are scaled.

The trouble is the pulling force on a LM will rotate fron front to right to rear and it's hard to get all the angles. but it could give you a understanding of where neutral is at any given point.

It's purelya measurement of weight transfer by inertia force. Not sure how i would work for a stock car, but it will make a drag car goo straight and use both rear slicks. It also levels out engine torque forces. Something to play with and make up your own mind.

don't guess center of gravity, measure it.

[MasterSbilt_Racer]

Just wonder what kind of late model chassis has an unloaded LR spring , with anything over 125 lb. of bite? I've never worked with one .

Our Smackdown will with a lot more bite than that.

[drtrkr244]

So you do a stacked set up so its like a take up spring? What rates do you usually use for this set up? Ball park?

400/150 12inch, adj. locking collar until it touches adjuster(at ride height)

Need to have a good spanner wrench. Its a mother to get the bite/ride height set!

[Bcollins82]

400/150 12inch, adj. locking collar until it touches adjuster(at ride height)

Need to have a good spanner wrench. Its a mother to get the bite/ride height set!

What is the locking collar for if it only touches at ride height? The LR never gets back down to static ride height while racing. I can see the advantages of running a dual stage setup on the LR, just curious as to why you suggest setting the locking collar to that height?

[AmickRacing]

When the LR compresses (letting off the gas going into the corner, slowing down for traffic, avoiding wrecks etc) it will act like a normal spring (single rate of say 200 # for example) with the stop collar adjusted to just touching the primary spring.

Without it, it would act like a very soft spring, depending on what rates you have stacked, and that can cause some bad juju when the LR falls.

[Bcollins82]

When the LR compresses (letting off the gas going into the corner, slowing down for traffic, avoiding wrecks etc) it will act like a normal spring (single rate of say 200 # for example) with the stop collar adjusted to just touching the primary spring.

Without it, it would act like a very soft spring, depending on what rates you have stacked, and that can cause some bad juju when the LR falls.

Well, it won't touch getting in the corner or just going around traffic, because the car doesn't settle to static height or lower at those times. I can see where it would be helpful during an erratic move though... Seems like it would be more useful as a tuning tool than just a safeguard though.

[setup479point2]

Our Smackdown will with a lot more bite than that.

Here is a lesson for all you young racers . I've been setting up race cars since 1982 , and I'm still learning every day . My set ups today are not what I did even 5 years ago . You have to be ready to change , and learn WHY you are changing the things you are on the car. I appreciate someone proving me wrong or showing me another way of doing things. Thanks Mastersbilt and Dirtkr244 for proving me wrong , and letting me learn.

[PushinTheLimit]

Just something I noticed on my car last night... I've been running my setup close to 0lbs of bite to get mine to rotate on a tight 1/3 mile high banked track. I've been using a 14" spring on the left rear with a chain limiter but, when the car goes to full hike the the chain is tight... it's off the spring. Should I consider going to a 16" spring instead and try to keep it on the spring?

[MasterSbilt_Racer]

Just something I noticed on my car last night... I've been running my setup close to 0lbs of bite to get mine to rotate on a tight 1/3 mile high banked track. I've been using a 14" spring on the left rear with a chain limiter but, when the car goes to full hike the the chain is tight... it's off the spring. Should I consider going to a 16" spring instead and try to keep it on the spring?

If you keep bite the same and spring rate the same, the 16" spring will be unloaded the same amount.

[MasterSbilt_Racer]

Here is a lesson for all you young racers . I've been setting up race cars since 1982 , and I'm still learning every day . My set ups today are not what I did even 5 years ago . You have to be ready to change , and learn WHY you are changing the things you are on the car. I appreciate someone proving me wrong or showing me another way of doing things. Thanks Mastersbilt and Dirtkr244 for proving me wrong , and letting me learn.

You are welcome. I have been at it for a long time, but not quite that long. I also am nowhere near where I was 5 years ago. And I hope I learn some new things continuously. If you don't, you get slower. I feel like I have a good grasp of the dynamics, have some different ideas, but I don't get a lot of opportunity to test. If something works well enough to run good, I have trouble moving too far from it.

[Matt49]

If you keep bite the same and spring rate the same, the 16" spring will be unloaded the same amount.

That is correct. The only way you're going to get the spring to stay loaded longer with the same bite number is to use a softer spring.

[PushinTheLimit]

Thanks guys... I plan to go with a 200lb LR rather than the 225lb that I've been using and see how that feels this weekend.

[drtrkr244]

What is the locking collar for if it only touches at ride height? The LR never gets back down to static ride height while racing. I can see the advantages of running a dual stage setup on the LR, just curious as to why you suggest setting the locking collar to that height?

That was a starting point given to me from Rocket. Plus I was concerned the car would get too tight on entry with that soft of a spring rate. It made a drastic difference in drive, as I found out, I had to continually free the car, unlike before where I was tightening the car up during the night.

[Bcollins82]

That was a starting point given to me from Rocket. Plus I was concerned the car would get too tight on entry with that soft of a spring rate. It made a drastic difference in drive, as I found out, I had to continually free the car, unlike before where I was tightening the car up during the night.

Yeah, the old Mastersbilt car that we tried it on had a ton more drive too.. But as far as the locking collar location, having it set to touch at ride height shouldn't affect your entry because it wouldn't be setting down far enough to touch the locking collar at that point? Did your car come all the way back down to static ride height on the LR on entry? Did you ever try to run the collar down so it used the bottom spring more as the car sat down, and so it didn't have as much preload at full hike?

[setup479point2]

Actually this is for a mod. I find late model guys know more and have more experience than most mod guys. So that's my main reasoning. Not familiar with late model chassis at all on dirt but know they usually use lift bar and pull bar rear end set ups and front end is rack and pretty much allCustom. So on late models you guys run more or less hike in lr and how do you keep it loaded still? Are bar lengths longer or shorter for you compared to lost mods I've seen 16-17 uppers and 14-15 lowers. Thanks.

Just so you know , I think most mod rules state one spring per corner . So all the stacked , duel spring stuff isn't gonna help you.

[Bcollins82]

Just so you know , I think most mod rules state one spring per corner . So all the stacked , duel spring stuff isn't gonna help you.

Unless he races UMP... Then he could throw a cover on, and make sure his body measures correctly and nobody would ever look. I've seen several UMP cars run dual springs on the RR without anyone blinking.

[SuperEight]

If you simply turn say 3 turns into the lr and at full hike you're off the spring say 1/2" and the 3 turns reduced that gap to 1/8" nothing has changed on throttle... This is what I'm trying to clarify.

Why does it have to be off the spring? The fast guys are NOT off the spring... Are you familiar with the fact a race car works in an, "X"?

[DirtRacer9x]

I know plenty of fast guys off of the spring...

[MachineMasters]

Once you hit the chain or limit strap, it does not matter if you have 300lbs of preload in the LR spring or zero preload - the car will not be any different, until the LR starts to go back into compression.