LR Bite vs Cross vs Drive

[setup479point2]

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 .

[Bcollins82]

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 .

No kidding... I was always pulling the limit chain loose at the axle so I can get more rounds in because it's preloaded so hard.

[DirtRacer9x]

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 .

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.

[drtrkr244]

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 .

2009 Rocket blue/gray always had 3/4-1" of threads left. In fact, that was a common adj. to run down adjuster to the spring, when the track slicked off.

[setup479point2]

2009 Rocket blue/gray always had 3/4-1" of threads left. In fact, that was a common adj. to run down adjuster to the spring, when the track slicked off.

Interesting , haven't yet worked with a blue/gray . Currently have a black , blue / gray must have a bit different drop . Learn something every day. So for slick you added about 70 lb. more bite .

[drtrkr244]

Interesting , haven't yet worked with a blue/gray . Currently have a black , blue / gray must have a bit different drop . Learn something every day. So for slick you added about 70 lb. more bite .

We ran that a few races but ended up running the stacked spring on the LR.

[DirtRacer9x]

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?

[7uptruckracer]

Don't confuse stack with a Dual Stage setup.

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?

[Bcollins82]

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?

A stack is not like a take up spring. A stack is normally a shorter, stiffer spring on top, with a free floating collar between it and the lower spring. It just makes a long, soft spring that doesn't bow like a normal long, tall spring would. You can use any combination of rates, then use the formula to calculate the rate. The formula is (spring X spring) / (spring + spring)= stacked rate, so if you have a 400 on top of a 200 it would be 200 X 400 / 200 + 400 = the stacked rate, so 80000 / 600 equals a 133.3 lb spring. That combo 400 over 200 is what Mastersbilt reccomend to us for a stacked combo back in the day.

[Bcollins82]

Well are you guys using a stacked set up or 2 stage?

Dual stage is mostly used on the RF, stack is mostly used on LR.

[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?