Thread: wheelbase v. ladder bar length

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Ok, just thinking again.... 95" wheelbase, light (2400 lb) car.... I want a good hook with slicks, but streetable, also... I know a 4 bar would be better but I want to run an adjustable ladder bar to keep the car consistent on the drag strip, and the ease of "softening" the bite for the street. Anyway, do you think a short wheelbase car would like a 30" or a 32" length???? Going to have some engine setback, too. Front sparkplug will be at the front wheel centerline, running a Windsor with a 5 speed..... Whatcha think????

Dave,

Alston says that the choice of length for a ladder bar setup is basically the amount of room you have. He recommends between 32" and 36" for most applications.

He says that short wheelbase does not require a shorter ladder bar. The important factor is the relationship of the ladder bar extended with the instant center of the car.

Linky

I would think that the longer or shorter front mounting points would have a lot to do with instant center??? I also dont believe that the choice of length varies only for the room available.

Originally Posted by Henry Rifle

Dave,

Alston says that the choice of length for a ladder bar setup is basically the amount of room you have. He recommends between 32" and 36" for most applications.

He says that short wheelbase does not require a shorter ladder bar. The important factor is the relationship of the ladder bar extended with the instant center of the car.

Linky

With the new adjustable style of ladder bars, I should be able to dial in the instant center where I want it...granted not the amount of choices a 4 bar setup gives, but enough to make the chassis work.... I'm wondering if I can "soften" the hook and slow the reaction time down a bit (problems with a short wheelbase) by playing with the bar length....like maybe 38" to 40"....????

S&W and Comp Engineering both use a 30" bar to give the regular 104"+ wheelbase, 3,000 pound car drag car with a 'glide a good hard hit.... Mine will be 95", 2500 pounds, and a 5 speed..... My thinking is that a longer bar, shocks with a soft setting on the down should tend to keep the front end down and still offer a good hook-up and not give a bunch of guardrail to guardrail excitement evertime I shift!!!! The "Doorslammers" book, and the majority of the others I have for reference just don't seem to address the short wheelbase, light car with ladder bar question??????? Not building anything yet, just thinkin' out loud.......

PS--
In reading Alston's tech article, I see they offer a set of bars with poly ends for street,,,,,,hmmmm......36" double adjustable bars with poly ends, and very close attention to the correct rate spring for the double adjustable coilovers???????? Whatcha think????

Originally Posted by BigTruckDriver

I would think that the longer or shorter front mounting points would have a lot to do with instant center??? I also dont believe that the choice of length varies only for the room available.

probably very true with the regular type long wheelbase heavy car with an automatic.....but of course I have to do something entirely different!!!!!

As to the room issue, got to build a chassis, so I can make room for whatever is going to work best.....

Dave, I'd use the urethane front mounts to provide a little "give" to the system when going diagonally over a bump. Ladder bars are pretty harsh on the street with solid Heims. Also, cobble up some retention loops for the front. If the tech inspector at your dragstrip is worth his salt, he'll be lookin' for 'em. Morrison shows 'em at the bottom of page 32 and calls 'em a 360* front brace kit.....
http://www.artmorrison.com/2006cat/32.pdf

Defin itely got to have the hoop on the rod end!!! I had the distinct misfortune to watch a front heim break once!!! Not a pretty sight, lots of collataral damage.....

My chucklhead moment. I didn't mean instant center. I meant center of gravity.

hmmmm. back to the drawing board.... Got the body off the frame and did some rough measuing....even a 32" bar is gonna place the crossmember a ladder bar would attach to right under the middle of the seat!!!! Guess it's gonna have to be a 4 bar with poly's so I can play with the kids uptown, too..... Going to be a challenge with the 95" wheelbase getting all the components put where they belong or it's gonna be a whole bunch of big wheelies!!!!!!!! Oh well, nothing like a little excitiement once in awhile!!!! Might as well put a straight axle under the front and have some real fun???????

Other interesting measurements place the top of the roof at 54" and the ride height at 5". Kinda like a go-kart with a cage.....

Hey Scooter, better get to tuninin', we might have to have that 302 shootout afterall!!!!!!

I went through this a couple years ago with my 92 inch wheelbase anglia. Ladders were too long for me too, and I was advised to go 4 link by a local rod builder. Right or wrong I dont know I have not driver the car yet, but they are there.

Yup, plenty of room for a 4 bar...probably have to go that way... Think I'll probably go with Poly ends and Watts linkage for some better street manners though..... Just that IMO it's a whole lot easier to keep the hook consistent with a ladder bar, guess I can do it with a 4 link too,,,,.....