Cable Droop Limiter

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Martinracing98
Posts: 170
Joined: June 24th, 2006, 7:27 pm

Cable Droop Limiter

Post by Martinracing98 »

I am considering using a cable as a droop limiter. The cable will go wheel to wheel over a center pulley or pivot point. Any opinions on why to do this or not to do this? I am considering it for packaging reason.
problemchild
Posts: 901
Joined: June 25th, 2006, 9:34 am

Re: Cable Droop Limiter

Post by problemchild »

A droop limiter is a droop limiter is a droop limiter. You would need to make sure that your design had suitable fine adjustment.

Some people feel that having a snubber or soft stop on the limiter is important. Others do not. The car will feel slightly different with hard or soft stops although one is not better than the other, IMO. I presume that the cable would be a commitment to a hard stop.

I see no reason not to use a cable, but would question whether the "packaging" of cable, clamps, pulleys, adjusters, etc would be advantagous to the designer. It is nice to see designs that are different from the couple of designs that are common.
Greg Rice
"Happy 50th Birthday"
ajax
Posts: 131
Joined: July 4th, 2006, 9:22 pm

Re: Cable Droop Limiter

Post by ajax »

Are you working with a vintage vee or a newer vee? Cables were one of the first designs used to prevent positive camber in the early vees, and I hear they still are thought to be excellent in the rain! But at some point the Z bar design took over and almost all vees that were seriously raced and originally had a cable were converted to the Z bar. I won't pretend to say I understand all the issues that lead to this, but the cable design always intrigued me as it played no part in the correct spring selections used, as a Z bar does? Maybe others can give the reasons for this?
Martinracing98
Posts: 170
Joined: June 24th, 2006, 7:27 pm

Re: Cable Droop Limiter

Post by Martinracing98 »

problemchild wrote:I presume that the cable would be a commitment to a hard stop.
I can get the cable made with threaded ends on both ends. I think I will be able to use rubber washers to provide a soft stop

problemchild wrote:but would question whether the "packaging" of cable, clamps, pulleys, adjusters, etc would be advantagous to the designer.
I am not certain that it will. The first "standard implementation" that I looked at has its packaging issues on my car. So I am evaluating options.
Martinracing98
Posts: 170
Joined: June 24th, 2006, 7:27 pm

Re: Cable Droop Limiter

Post by Martinracing98 »

ajax wrote:Are you working with a vintage vee or a newer vee? Cables were one of the first designs used to prevent positive camber in the early vees, and I hear they still are thought to be excellent in the rain! But at some point the Z bar design took over and almost all vees that were seriously raced and originally had a cable were converted to the Z bar. I won't pretend to say I understand all the issues that lead to this, but the cable design always intrigued me as it played no part in the correct spring selections used, as a Z bar does? Maybe others can give the reasons for this?
The cable would not change the car from the basic zero roll suspension.
sabre1
Posts: 66
Joined: June 28th, 2006, 12:29 pm

Re: Cable Droop Limiter

Post by sabre1 »

It hasn't been mentioned yet, so I'll point it out. One of your challenges is going to be keeping the cable nestled in the pulley grooves as the chassis moves up and down. Many possibilities. It would be worth your time to research how this was done so you can learn from the trial and error process of others before you. Let us know what you come up with, and good luck.

Happy New Year too! 8)

-Jim
brian
Posts: 1348
Joined: June 26th, 2006, 12:31 pm

Re: Cable Droop Limiter

Post by brian »

I have used a "captive" bracket that wraps over the top of the pulley to prevent the cable from falling out. If you have a significant amount of spring compression,the cable will develop a lot of slack and jump off the pulley.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
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Larry Bradley
Posts: 248
Joined: June 25th, 2006, 12:26 pm

Re: Cable Droop Limiter

Post by Larry Bradley »

Only problem I know of is; cables break, so just be prepared to change it every 3 weeks or so.

LB
Now a promise made is a debt unpaid, and the trail has its own stern code.
brian
Posts: 1348
Joined: June 26th, 2006, 12:31 pm

Re: Cable Droop Limiter

Post by brian »

Wow Larry, that's a real short life! We haven't had any issues like that, maybe you need to go up a step in the gauge.
The above post is for reference only and your results may vary. This post is not intended to reflect the views or opinions of SCCA and should not be considered an analysis or opinion of the rules written in the GCR.
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