would babb,erb,s.shepperd still be competitive at all with rayburn swing arm-pullbar. with todays shock tech. esp. on l.r.?????????
I say unequivocally, YES. I also prefer the long pullbar, but I never saw Moyer or Babb with anything but the short one. Rayburn Swing arm was still finishing in the top 10 at the world as late as 2009. I think too much is made of where we are now versus 8-10 years ago. Sure the cars(4 link) drive better now, but track records should be falling every week by the way these cars are touted versus the older stuff, but I would say the rate of progress in overall speed is stagnant for the most part. They've gotten more consistent, but not much quicker in my view. I've yet to see a 4-link dig as hard off the corner as a Rayburn Swing arm can. JMO
Don't hammer down, short tracks work better for a swing arm/pull-bar deal? That seems to be their sweet spot IIRC... there seems to be more competitive Rayburn's on some of those shorter tracks in the south than we see here in Cheeseland....
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It isn't the lap times in time trials and heat races that has changed. It's the lap times in the slick features that has gotten faster with the more recent technology.
I say unequivocally, YES. I also prefer the long pullbar, but I never saw Moyer or Babb with anything but the short one. Rayburn Swing arm was still finishing in the top 10 at the world as late as 2009. I think too much is made of where we are now versus 8-10 years ago. Sure the cars(4 link) drive better now, but track records should be falling every week by the way these cars are touted versus the older stuff, but I would say the rate of progress in overall speed is stagnant for the most part. They've gotten more consistent, but not much quicker in my view. I've yet to see a 4-link dig as hard off the corner as a Rayburn Swing arm can. JMO
i believe that they can still be competitive,the problem was they would just flat dump when you let off the gas,i would think with todays shocks along with stiffening the chassis like they are doing today(cj's cars would flex alot) they would be very competitive, look at what rumbly was doing, trying to control the rear steer, most 4 bars have too much rear steer come feature time, as far as the pull bar, show me something that creates more forward drive than that, now controlling that, theres the key,
CJs new swingarm stuff is pretty good. They are quite a bit different than the older stuff. He just needs a few good drivers on it to show how they work. There have been a few who drove his personal car testing that had nothing but good to say about it. I put it on a mod late in the year with CJs help, and won 3 of 6, and broke leading one of them. Should have been 4 for 6. As far as I know, there are only a handful of them out right now. If I had an older Rayburn, I would be calling him up and getting it changed over to the new stuff.
Pull bars and Lifts are kinda the same thing anyway. One pulls up the chassis with axle rotation and tbe other pushes up the chassis on axle rotation so they are kids doing the same things with the differences in how to adjust them and packaging.
Pull bars and Lifts are kinda the same thing anyway. One pulls up the chassis with axle rotation and tbe other pushes up the chassis on axle rotation so they are kids doing the same things with the differences in how to adjust them and packaging.
There is a big difference in the anti squat application point and the transition from lifting to neutral is also very different.
There is a big difference in the anti squat application point and the transition from lifting to neutral is also very different.
I get that. I was just trying to point out they have the same job to do.
Riddle this for discussion purposes. If you were remove the Sixth Coil on a Lift arm, remove the spring from a pull bar, mount them to the car in the same place, (basically remove the adjustable part of both) would they not act the same? Would the measured amount of anti-squat come out the same?
No. The long pullbar we ran looked like a regular pullbar only it had a extension. Was mounted on left side of bell and ran down between driveshaft and c@ckpit to the forward driveshaft loop and had 2 mounting holes. just looked like a long pullbar as opposed to his standard one. Just a singular long straight device. We also preferred the short 14-3/8 swing arms.
I get that. I was just trying to point out they have the same job to do.
Riddle this for discussion purposes.
Originally Posted by Lizardracing
If you were remove the Sixth Coil on a Lift arm, remove the spring from a pull bar, mount them to the car in the same place, (basically remove the adjustable part of both) would they not act the same?
No, they wouldn't.
Originally Posted by Lizardracing
Would the measured amount of anti-squat come out the same?
No. I'm guessing your exposure to pullbars is all theoretical, is it not?
No it's not. I race a USRA Modified and never even drove a lift bar although I've drawn up designs while contemplating trying it. I haven't yet. Not sure if I will.
I am being theoretical however for discussion purposes. I try not to speak on the internet forums in absolutes because too many variable exist and the limited amount of info I think might steer people in a direction not intended when they seek advice. How would you calculate Anti-squat on a lift arm?
Anti-Squat is a function of the rear linkage arrangement as well as the lift arm or pull bar, or any other torque absorbing device. The most popular anti-squat for 4 bar theory/literature has a flaw in it and is not 100% in my opinion, it is a close approximation but needs to be taken further to be accurate. Anyways back to the purpose, your line that you usually use for the pull bar in your anti-squat drawing is a line from the top to bottom of the 5th coil spring.
All of that said they react differently in the car and a driver could easily tell if you changed one for the other. The pull bar can get you more instant bite, but it wears off quickly and is violent! The 5th arm is much smoother and has more down track traction.
I think we are agreeing that the pull bar comes on faster but falls off faster and the lift arm comes on slower and last longer. I could agree if one were to graph the dynamic Anti-squat, they two types would look different thereby explaining why they would act different. However, and the big butt, is they both are controlling axle wrap by lifting the front end and and if the axle is allowed to rotate within the birdcages than the old theory's of calculating the anti-squat via linkages has to be looked at. Is this the flaw you speak of? If so, the flaw would be that assuming the links were solid in both configuration the axle wrap is independent of the calculation yes?
One of the big differences in the two the is overlooked is the forward thrust on the rear end with a pull bar. It can radically change the thrust seen on the links to promote hike/lift. Torque arm you basically only have the forward drive of the rear end against the mass of the car (resisting acceleration) to apply thrust on the links to promote lift, where the pull bar also has this but adds the thrust of the pullbar trying to shove the rear end forward also.
That is part of the reason a typical older swing arm car doesn't get up with torque arm like it will with a pull bar unless some of the links are changed angle/length/etc wise.
Last edited by billetbirdcage; 12-12-2016 at 06:38 PM.
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rayburn swing arm/pullbar
Originally Posted by matmat99
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