soft RF spring helping or hurting?

[3wheelinphotos]

How about are you doing anything in the rear to make more traction or just changing the RF spring?

[Dirtmod13]

Giving lr more drop and less rear steer to tighten mid and exit. Just doesn't seem to be enough. Can't run stacked or bumps

[HuckleberryB4]

More Drop = More rear steer = Loose
Less Drop = Less rear steer = Tighter

[hsdiefusion16]

What is the rule for bumpstops and stacked springs?

[7uptruckracer]

Those are two completely different animals

[hsdiefusion16]

Yes they are, I work for a spring company so that's why I asked.

[Matt49]

More Drop = More rear steer = Loose
Less Drop = Less rear steer = Tighter

But you could also say:
More drop = more thrust angle and cage indexing = tighter exit
Less drop = less thrust angle and cage indexing = looser exit

[HuckleberryB4]

Agreed. I almost went back and edited with those other possible affects. I "personally" feel that the LR bar adjustment or LR drop has more to do with the change in roll steer, than the change in indexing/thrust angle.

[billetbirdcage]

But you could also say:
More drop = more thrust angle and cage indexing = tighter exit
Less drop = less thrust angle and cage indexing = looser exit

This is another pet peeve of mine.

There's too many things to drop amount to throw out really simple guidelines on what it does, like Matt's post and the one he quoted.

Hike on LR does 2 basic things adds wedge and adds rollsteer, both of these are contradicting each other in whether they tighten or loosen a car. Obviously when hike first starts it adds very little steer for the amount of wedge it adds thus a tightening effect because the wedge tightens more then the small amount of rollsteer loosens the car. As the hike gets farther on it's travel it comes to a point where the steer increase becomes large enough compared the the amount of lift/wedge is added thus gets to a break-over point (just a term I use, not talking over-centering the cage) where going farther will only loosen the racecar.

Pretty straight forward so far, but here is part of my pet-peeve. Many will go off that 45 degree's someone started (probably Mark Bush), while it's good basic general guideline to help the uninformed it had huge flaw's in it. Like it doesn't take into consideration of bar lengths, the lower bar angle being used, or the bars location on the birdcage.

My point is you can have the breakover point happen before or way after the top bar is at 45 degree's, depending on the arrangement of the rear suspension.

Not picking on the guys posts, just voicing an opinion on something and Matt's posts eludes to not lumping into a easy generalization of it.

[Matt49]

I'll add two more points and then I'll go back to doing something else.
1) Adding hike also increases the vertical center of gravity which increases front to back weight transfer on corner exit.
2) More rear steer theoretically makes the car looser because it helps "turn" the car. But this isn't necessarily a bad thing slick conditions, contrary to popular belief.

[25drtrkr]

This is another pet peeve of mine.

There's too many things to drop amount to throw out really simple guidelines on what it does, like Matt's post and the one he quoted.

Hike on LR does 2 basic things adds wedge and adds rollsteer, both of these are contradicting each other in whether they tighten or loosen a car. Obviously when hike first starts it adds very little steer for the amount of wedge it adds thus a tightening effect because the wedge tightens more then the small amount of rollsteer loosens the car. As the hike gets farther on it's travel it comes to a point where the steer increase becomes large enough compared the the amount of lift/wedge is added thus gets to a break-over point (just a term I use, not talking over-centering the cage) where going farther will only loosen the racecar.

Pretty straight forward so far, but here is part of my pet-peeve. Many will go off that 45 degree's someone started (probably Mark Bush), while it's good basic general guideline to help the uninformed it had huge flaw's in it. Like it doesn't take into consideration of bar lengths, the lower bar angle being used, or the bars location on the birdcage.

My point is you can have the breakover point happen before or way after the top bar is at 45 degree's, depending on the arrangement of the rear suspension.

Not picking on the guys posts, just voicing an opinion on something and Matt's posts eludes to not lumping into a easy generalization of it.

Billet, in a recent DLM mag tech article, Mr. Bush stated that indexing generally overrides roll-steer. The article was about changing the bar angles laterally to fine tune your set-up. Its been my experience also. Whats your opinion on this?

[7uptruckracer]

This is when you get out the tape measure and angle finder and see what changes and when. I am currently having this situation on a rocket that runs the Shorter LR upper. Trying to figure out if long bar and more angle is better with a constant hike number or it the short bar and adding angle quicker is better, which you sometimes get late exit loosness from. It really depends on the track and the driver in most cases but I find more on the longer bar these days

[billetbirdcage]

Billet, in a recent DLM mag tech article, Mr. Bush stated that indexing generally overrides roll-steer. The article was about changing the bar angles laterally to fine tune your set-up. Its been my experience also. Whats your opinion on this?

Ain't read it so in the dark here, but going of what I understand from your post..... I disagree I guess.

I assume when you say indexing your talking rod position on the birdcage and not the static clocking of the cage or rotation of the cage during hike.

Too vague to really give and answer without knowing what was said.

[25drtrkr]

Ain't read it so in the dark here, but going of what I understand from your post..... I disagree I guess.

I assume when you say indexing your talking rod position on the birdcage and not the static clocking of the cage or rotation of the cage during hike.

Too vague to really give and answer without knowing what was said.

The article was about moving the rod position side-to-side on the frame mount and/or the birdcage. He said the effects of indexing generally overrides the effects of rollsteer.

[billetbirdcage]

The article was about moving the rod position side-to-side on the frame mount and/or the birdcage. He said the effects of indexing generally overrides the effects of rollsteer.

When I refer to indexing, I generally use that to refer to rod position on the cage as in up or down location in the slot from axle tube centerline, but anyway.

Depends on how far you believe the rear end/bars are traveling side to side. I redrew in cad real quick because my memory sucks and couldn't remember the actual numbers.

From straight to X (X = travel in inches left or right)

17" bar from straight to 2" of angle = .117 shorter
3" travel = .266 shorter
4" travel = .475 shorter

Say its traveling 4" total

If bars are straight on LR, then the LR pulls forward .475 at the birdcage

If bars had 1" of toe to the right static and moves the same 4" then:

+.118 back for first inch travel left then forward -.266 for the next 3" for a total of .148 forward

A difference of .327 of steer at the cage between straight bars vs 1" of toe to RF, but I also don't think it's moving that far unless you got a ton of J-bar in the car, long chain length, so that number is likely more then actually seen.

Just to show you 4" of travel right to left is unrealistic, I drew it up in cad also:

19.5" j-bar starting a 8.5 of static rake

X = total rear end travel for inches dropped at pinion (keep in mind this is drop in pinion NOT the LR drop)

1" of drop = .520 to left
2" of drop = 1.118 to left
3" of drop = 1.801
4" of drop = 2.583

More static rake of 10.5" and 4" of drop at pinion is only 3.393 to the left

You can do the math or check for yourself what is likely a more reasonable amount of left movement on the rod ends and see if it makes that much difference for yourself.

Keep in mind the rotation of the rear end (rear view) is going to effect each rod ends movement left or right also, meaning that the RR upper rod will also move more left from the rotation of the rear end cause the LR is dropping and/or the RR compressing. (see below)

This may be small but still there and should be taken into consideration.

Only from rotation of rear end:
LRU = left then maybe back right
LRL = right
RRU = Left
RRL = Right then maybe back left

Billet