soft lr spring

[riddle28]

ive been experimenting with a softer LR(125), when the track is fast the car is hard to beat, when it blows off it never gets the rr in the track. Hard to explain but what it feels like in my mind is instead of compressing the RR as the LR rebounds its just using the rr as a pole vault of sorts and rebounding the LR and not planting the rr. Shock travel is alot less now too. I havent changed anything else, same bite and ride heights. Are there any supplemental changes you need to make to go along with the soft LR?

[collateralDamage]

It sounds like you have too much preload.

[riddle28]

I’ve got what it takes to get my normal bite up

[collateralDamage]

I have used a bumpstop and packers to hold the left rear up if it droops too much. Just make sure you aren't racing on the bumpstop! There are other ways around it as well.

[garrett87]

Sounds like you are not driving in deep enough and keeping it up on the bars. We had the same problem with the softer left rear. I was told it was entering the corner and it was.

[billetbirdcage]

Like garrett said it can be driving or track style causing the issue.

First thing is you need know: Is the LR setting down more then before. If so then you need to look at driving or it may be due to a more paperclip style track where you off the gas and on the brakes while the car is still going in a straight line.

Figure out if the LR is in fact coming down more by asking crew guys (I know most of them are just watching the race and not really what the car is actually doing, lol.) or get some video unless you have data to look at.

After that you can decide where to look next or what to do to fix it, but since you lost RR travel I'm gonna guess the car is setting down more then it was before, but that might not be the case and that is where you need to start.

[riddle28]

I’m pretty good at trail breaking not setting the lr down, we can’t run bumps so I can’t do that anyways. I softened almost 100 lbs and i can feel the lr digging harder(more bar angle with increased droop) but feel like what I’ve gained on the lr I’ve lost on the rr

[mmarineservice]

Take some of the drop out of lr when it starts to slick off

[Jim11h]

We were just told by a chassis builder to basically run top lr rod in bottom hole and with full drop adjust bars so that birdcage is straight up & down. This same person also says he runs a 100# RR spring (gotta be bump I'm thinking). Says the soft lr & birdcage give drive in slick.

[MasterSbilt_Racer]

We were just told by a chassis builder to basically run top lr rod in bottom hole and with full drop adjust bars so that birdcage is straight up & down. This same person also says he runs a 100# RR spring (gotta be bump I'm thinking). Says the soft lr & birdcage give drive in slick.

100# rr or lr?

The birdcage deal is just a geometry problem. You get rid of anti-squat lock and bring compliance back to the system.

[CCHIEF]

Crate or true super late....what make make/model/year... or updated to? ,what springs are you running everywhere else. What do you change up when the track loosens up... if anything? What did you run in the LR previously...and why did you change up. Did the car handle well in low traction previously. "when it blows off it never gets the rr in the track" ...... so the car is loose on corner entry/decel/braking??? and therefore loose overall in slicker conditions

[riddle28]

steelhead, 09 bwrc, 350 rf 500 lf 250 rr and was on 225 lr before the swap, the only reason i swapped was to get some more hike and roll steer out of it which it does in the traction. We ran well at talladega all year last year, one of the slickest tracks in the south, loose from center off but steers in great. It just skates off the track and doesnt plant. No other changes ive made other than the spring, which is why i was wondering about supplemental changes before i swap back to i know what works and look elsewhere for speed

[CCHIEF]

No experience with BWRC, "loose from center off but steers in great." is this on your old deal or with the 125? So if you actually got more "hike and roll steer", the car will be looser, Steer gets excessive in the last inch of travel)Possibilities>>softer rf spring will load the rr more, don't know what you can get away with on those cars...Ive been as low as 250 rf on blue rockets on smooth momentum tracks with a 125 in the lr, and they recommend a 325 as a baseline, but they have the necessary ground clearance >> limit your drop to keep roll steer in check 1/4" @ a time if your beyond (more) than the recommended baseline, the baseline is usually a good compromise of steer vs dynamic wedge. Too much roll steer will kill a well balanced car. Your car will definitely roll up easier with the soft lr spring, you may need to increase lr compression to control hike down, hike down tightens the car and un loads the rear of the car... It's all about entry..... its all about entry...attitude and yaw, keeping chassis roll in the car as the track loses traction and keeping the rr loaded. Ideally your front wheels should stay as straight as possible thruout the corner, the car should need minimal steering input once initially steered into the corner, part of that is setup and alot of it is driver. If your swinging beyond 11 turn in to 3 o clock exit, your off in the slick...usually tight to loose just as you begin exit(indicates tight entry or excessive roll steer) you can lower your LR lower bar @ frame but that will tighten entry an tighten rolling the corner.but may work well for you. What you need from the car to keep the steering input to a minimum is what and where @ you need to relay to your crew(chief) or make mental notes of if your calling the shots. You make no changes as the track slows down to maintain roll in the car? Now and pre soft LR?

[fastford]

are you on a stacked LR or a single spring?

[tmo54]

Lengthen your left side rods and add a few rounds to the rr. That's what we do when adding droop to keep drive off

[cjsracing]

I have a similar problem when running a soft LR (125). The car is fast on the cushion and with traction (won a heat around the cushion), but when it slicks off the car goes to junk and 2 things typically happen:

1. Try to run low and the right rear doesn't dig and the car just slides up the track or
2. Try to run middle to high and I just shove the RF up the track.

Not sure how to fix #1 other than get off the 125.

For #2 I think I either have to much extended load (190 lbs) and I'm over powering the RF or I'm coil binding the RF (1600 lbs at 4" on a 300lbs spring) and the RF isn't digging.

The right rear is typically 170+ degrees when I come in from a 20 lap feature.

WRS2 tires, can't run bump stops or stacked springs.

[7uptruckracer]

If you think you are coil binding go to a barrel spring. What other changes are you making for the slick?


I have a similar problem when running a soft LR (125). The car is fast on the cushion and with traction (won a heat around the cushion), but when it slicks off the car goes to junk and 2 things typically happen:

1. Try to run low and the right rear doesn't dig and the car just slides up the track or
2. Try to run middle to high and I just shove the RF up the track.

Not sure how to fix #1 other than get off the 125.

For #2 I think I either have to much extended load (190 lbs) and I'm over powering the RF or I'm coil binding the RF (1600 lbs at 4" on a 300lbs spring) and the RF isn't digging.

The right rear is typically 170+ degrees when I come in from a 20 lap feature.

WRS2 tires, can't run bump stops or stacked springs.

[cjsracing]

If you think you are coil binding go to a barrel spring. What other changes are you making for the slick?

when it slicks off I usually make the following changes:

1. 3 to 4 turns out of the RF in order to help it get over on the RF (this puts the 4" number about 1600 on a 300 lbs. spring, I usually start the night with a 4" number of 1770ish).

2. Lower RRB 1 hole on the frame.

3. Lower Jbar 1/4" on pinion.

4. Slick track shock settings

[billetbirdcage]

I think you have a masters, which I have very little experience with so this may not be correct.

The few I messed with, didn't like high LR extended loads. If your at 190#, then once you drop LRL bar it's even higher. At that range they become inconstant and get tight across the middle but aren't tight enough to drive with some yaw in the car to get thru the throttle tight. It seems you fight a battle there, if you get in just right the car goes around the corner but get in a little straight or slow and it pushes, get in too crooked or hard and it skates. Again very little experience with masters and may just been a weird car.

Since your not allowed a stack or something to reduce or set the extended load number, you can either just try going up on LR rate some or just dial out some static rounds but will mess with other things doing that.

[cjsracing]

I think you have a masters, which I have very little experience with so this may not be correct.

The few I messed with, didn't like high LR extended loads. If your at 190#, then once you drop LRL bar it's even higher. At that range they become inconstant and get tight across the middle but aren't tight enough to drive with some yaw in the car to get thru the throttle tight. It seems you fight a battle there, if you get in just right the car goes around the corner but get in a little straight or slow and it pushes, get in too crooked or hard and it skates. Again very little experience with masters and may just been a weird car.

Since your not allowed a stack or something to reduce or set the extended load number, you can either just try going up on LR rate some or just dial out some static rounds but will mess with other things doing that.

That's pretty much exactly what it's doing and I do have a masters. I talked to someone yesterday and I think I am going to back the extended load off come feature/slick track time and see what happens. If that doesn't work I'll go back to the 175 lb LR spring and maybe get rid of the heavy birdcage.

I've got 3 planned races this weekend so hopefully I'll figure something out.

[Punisher88]

Can't you calculate your extended load by how much the spring is compressed?

[billetbirdcage]

Can't you calculate your extended load by how much the spring is compressed?

Yes, just measure springs compressed length on the car with rear end hanging. Then calc the rough pressure by subtracting that from the free hieght of the spring times the rate

Example: extended measurement of spring is 12.75" and it's a 14" spring so 1.25 x rate = extended load # or least a rough estimate.

[DK1]

Try taking the heavy cage off. I had a similar problem. Car was bad fast when track had any kind of moisture in it and then when it went slick you’d drop ancor. Took the heavy cage off and left everything the same and was instantly better.