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Jacobs ladder


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5 replies to this topic

#1
RIOS22

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What is the right jacobs ladder to start with? Not sure of the chassis mfg. but the spread on the chassis is 12". Should be able to run a 12" - 13 1/4" length. Thanks

#2
larryo

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I have no idea. One would think a 13" jacobs ladder would be a good starting point. What is the "spread" of a chassis? I have never heard this term before. If you say you can run between a 12-13 inch jacobs ladder, why not run have way in between. If you want a tighter chassis run shorter and if you want to run it looser run the longer jacobs ladder. I'm surprized nobody came to help you. You can also go to www.hoseheads.com or www.inidanaopenwheel.com and just post your question on the message board and I bet somebody who knows what they are talking about will answer your question.

Sincerely,

Larry Otani


And once you figure it out come back and tell us which one you are goin' to run. :D

I'm kind of curious which one you run. I once went to Sunset, Oregon and this Champion from Arizona was running a very short jacobs ladder on the left side of the car. When I asked him how it ran, he said "I won a championship with it". I thought that was a funny answer. I also have a friend that stole an idea from "Nance" and runs a backwards jacobs ladder on the right side. When I asked him how that thing worked, he said "Come on Larry, you can figure it out". I already forgot what answer I came up with...lol! Good Luck.

#3
Kdull56

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The length of the Jake ladder determines the roll center of the car and the arc of the rear axle travel, which tightens or loosens the car. Basically, the shorter the Jake, the tighter the car. Some guys even experiment with different length straps for specific applications. Whatever length you use, just be sure your driveshaft is running straight form the motor to the rear end and isn't being pulled or pushed to one side. There has been some lengthy discussion/analysis on this topic recently.

Check out these two links.

http://www.spitzraci...les/Page724.htm

http://www.indianaop...ead.php?t=14475


Ken Dull

#4
larryo

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Wow,

Some really wonderful information presented by Ken. I couldn't of done any better myself...lol! Good job!

Not really on the subject but it really amazes me how flimsey the jacobs ladder is. What a piece of junk, tolerance wise. You can shake those things, wiggle them, etc. How can their be any kind of accuracy with the tolerances so loose on all the nuts, bolts and fasteners holding the jacobs ladder together? I guess the reason why they are so loose is for the very reason Ken said not to bind up the torque tube. If the jacobs ladder is so loose, there should be less of a chance of binding up the rear end?

Good information.

Sincerely,

Larry Otani

#5
Kdull56

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That looseness is one of the reasons a lot of guys prefer not to use them on pavement cars. Adjustments have to be a lot more precise on "tar cars". A little bit goes a long way.

#6
larryo

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Well,

I don't know if we answered Rios22's question, but my gut says go with the longest jacobs ladder, which I think was 13.25" for a starting point.

I think most people would agree set up your car loose and slowly tighten it up.

I always wondered why people ran long axels, like a 44-3 and long radius rods that connect to the motor plate, long panhard rods in the front and wide axels in the front. Basically as a starting point make your chassis long, make it wide and make the radius rods as long as possible as a general theme for designing a race car.

A long car, that is wide with long radius rods slows up the reaction of a car and makes it very easy to drive. It slows up all the bumps and ruts in the road and makes the car stable and safe and easy to drive.

Related to the subject is my 1923 T bucket. It has widest axel I have seen or sold on a 23T bucket. The front axle is 50" wide. The rear 54 inches. The radius rods are longest I have ever seen. They are 39" inches long. The car is very stable at over 100 mph. Many people that have owned roadsters approach me an ask about the handling of the car, insinuating that 23T buckets are inheriantly unsafe. I tell them this car is very stable by being long, with the widest axels and the radius rods the longest I have seen adverised or sold for a 23T bucket. And this car has no roll bar and no seat belts. It only weighs 1600 lbs.

Sincerely,

Larry Otani

P.S. I have learned a lot from this post. Thankyou!




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