How much should I have to preload LR spring

[modsrock]

OK forgive me if some of this elementary, but, I'm new to mods. I have been racing Stock cars for about 20 years.

I have an older mod with a metric clip and metric lowers. Heres what I am running

LF Spring 800 RF spring 1050

LR Spring 250 RR Spring 175

OK before you start on the 1050 RF, anything lighter bottoms out. I read a thread from the guy that builds lightening chassis and he said metrics with metric lowers need to be in that range.. OK on to my question. With that much RF and LR spring in it I shouldn't have to put much preload on the spring to get 30# of bite should I? I also have about 60# mounted high on the Left side. I have a 16" 250# spring and I have to compress it about 3 inches to get 30# of bite. I can't see where the chassis is bent or tweaked, but, I'm thinking it has to be. I have checked the suspension for binds and everything is working free.

[bluemod]

i am having the same problems i am new to mods and i have a lighting and im tring to figure this out also if i put the ride heights were there spose to be i have -bite if i compress it 3 in i have like 40 pounds

[rocketmod19]

i wouls personally soften the rf up to atleast a 900 even though you say it bottoms it out you could have to much chassis role making it bottom out i personally run a metric clipped mod with metric lowers and i run softer then that and dont bottom out. your heavy rf spring could be why you cant get enough so called pre load heavy spring will collect that weight. are you having a problem with the lr spring coming off the spring cups at hike up use a softer lr spring in a tall version and bump up the lr wedge. i see guys ask about preload but never understand why casue when you scale the car goes to where you set it and thats what your springs will have on them

[dirttrackrocker]

????? Say What???

[modsrock]

I'm not sure I follow you??? This is a 4 bar car with the spring behind on an eliminator. If I don't pre load it, I have about 50# of RR bite. The only way I can get 30# 0f LR bite is to pre load it about 3 inches. If I go softer on the RF then that affects the LR, I would have to pre load it even more. If I run anything softer in the RF it bottoms out and pushes real bad. This is a 4/10 mile track that you carry a lot of speed into the corner.

[oldtrackchamp4x]

If i am reading you question right,set your ride heights according to what the builder specifies, put the car on scales to see where you are at bite wise. If you need more left rear bite put one turn in RF and one turn in LR, take out one turn RR and one turn LF. That is if the threads on the bolts and sliders are the same. If you need Less lr bite, just do the opposite. Your ride heights should stay real close to your initial setting. It works for me and this is JMO. Good Luck.

[junebug]

preloading the lr spring isnt a bad thing....i like to keep a little tension on mine at full drop so that it never comes off the buckets....if it does it seems to unload really hard when u lift......just preload it however u need to to get ur ride heights and wedge correct.....and i dont think ur rf spring is terrible if thats what u have to run to keep it from bottoming out, but why are u so soft on lf 250 lbs of split seems like a ton

[johnny v]

your using a 250#spring to hold up , say 750#s of the car ( lets say LR scale reading) ... springs are rated at 1" travel.... so your spring has to be compressed 3 inches to hold the car up..... ( + or - the motion ratio, depending on where the spring is located and how far from the tire contact point).....

I agree with keeping the LR spring loaded at full droop..... esp if the driver is new or can't keep from jumping out of the gas on entry....the only way you can do it on most cars (or most overrail cars that run 15-16 inches of droop) is soft spring rates.... length of the spring doesn't matter if you don't drop the rate.... spring has to be preloaded a bunch and that takes a softer spring, not just a longer spring.......

I would suggest the guys that want to read about the tech aspects of all this is to find, beg, borrow or steal some old Dirt modified mags as Mark Bush has tons of info on these and other very interesting and basic subjects..