Visit The Dirt Forum for More Information

Author Topic:   Jacobs Ladder
vintage39c
Dirt Full Roller

Total posts: 27
posted September 26, 2004 07:12 PM  
If you have a Jacobs attached to the frame on the left side of the chassis and you move the upper strap up and the lower strap down the roll center will be moved to the left as I understand it. On entry will you increase or decrease side bite by doing this in a nonwing car? Also the affects mid turn and exit?

------------------
Ron Coon
Ron Coon's Vintage Racing
http://vintage39c.tripod.com

rocket36
Dirt Freak

Total posts: 209
posted September 28, 2004 03:38 PM  
though i'm not all that familiar with adjusting a jacobs ladder, i can help with some experience on roll center adjustments.
if you lower the roll centre (which ever links you need to change to accomplish this) you will increase side bite. side bite is usually not much of an issue until mid turn, when the car is trying to change direction. from what i have seen with those non winged sprints, is that they seem to respond to being "backed in". but still, once the car has started to rotate, a lower roll centre will increase side bite.
from the minimal knowledge i have of jacobs ladders, i understand that the roll centre moves in an arc (quite considerable compared to other lateral locating devices) and also increases/decreases its movement speed the more the car rolls.
i'm not sure if that helps or just confuses???
oh, for the record, i run an open engined dirt late model (with a j-bar).

vintage39c
Dirt Full Roller

Total posts: 27
posted September 28, 2004 04:58 PM  
I understand that by lowering a roll center you tighten a car and by raising it you loosen the car. In your situation lets say you use a 36" panhard bar and decide to use a 24" bar, both with a roll center height of 14". If the bar is mounted in the car in such a way that the shorter bar moves the roll center to the left but keeps it at the same height what are the affects?

rocket36
Dirt Freak

Total posts: 209
posted September 29, 2004 04:38 AM  
in that situation, you will just get an increase in side bite. by moving the rollcentre to the left, maintaining the same height, will increase the side bite and the speed that the car rolls.
by running a shorter bar, we would also get an increase in the "pole vault" effect, also increasing side bite

[This message has been edited by rocket36 (edited September 29, 2004).]

Back to the Archives