MTFCA Forum

I'm thinking about using a nonmetallic cable for my AC brakes. I have the original set up and I am concerned the fragile appearing equalizer is not up to the stiffness of a steel or even an aluminum cable. The original equalizer is pictued with rust next to Dan Mc Eachern's set up.Thoughts appreciated.

Richard

It sounds like you're saying that you're afraid that the equalizer might fail, so you'll substitute good steel cable for something weaker and more rubber-bandy so that something ELSE will fail first?

I know you don't really mean that, but why not contact Dan about your concerns rather than de-engineer a brake system? I personally cannot think of a less appropriate place to mess around experimenting with things. Sleep on it and I'll bet you'll have 2nd thoughts on your own. Be safe.

If you're really not going to use the original set-up, I'll step up and say that I'm interested in it.

I will be fitting my ACs eventually if I ever get the engine back together…

I do not have the cables or link. I am planning to use a marine style pulley for running rigging (steel pulley) of 7x7 stainless cable and then stainless cable 1x19 5mm to connect to the brake pedal. That way all three means of braking will be separate giving me good redundancy… I am half tempted to use Sta-Lok hardware, but that is real expensive now.

I am trying to stay in-period with my speedster, but seem to be edging on modern takes on old tech.

I've been running original cable actuated AC brakes on my '24 since 2013 with no problems. I didn't have the complete linkage to the stock brake pedal, so I used the pulley and cable parts and sold the intermediate pull rod to another member. I chose to actuate my cable via the currently available RM equalizer and its associated special brake pedal. It works just fine.

My concern is the stiffness of steel cable against an original wheel type equalizer. I was hoping there might be a more flexible alternative to a metallic cable but haven't found much on line.I have read that 19 strand steel cable is more flexible than 7 strand. I might go with that.
Any other input?

Richard

6x37 and 8x19 wire rope at 3/16" has the smallest "diameter rating" at 2 1/4". That would be a working diameter where the cable is going over that shiv 100's of thousands of times. In a semi-static use, I think it would be fine for your pulley/equalizer. Remember that when attached at the brakes via a thimble, the radius will be even smaller.

7x19 is more likely what you'll find available and I'd bet that would be fine, too

Remember, the rating for bend radius is for maximum life when constantly flexing past the pulley. I think you ought to look at 3/16" thimble dimensions and you'll see a bend radius of typically 3/4" which I suspect will compare favorably with your equalizer/pulley.

BTW - you may already know it, but you really do need to use thimbles on the ends of the cable...not using them (as I have seen so many times) really IS a safety issue and adds some springiness to the setup which is undesirable. If the brakes you use have a built-in clamping arrangement or otherwise includes some form of strain-relief, a thimble is not necessary.

Hi Richard- I would not hesitate to use steel cable with the original equalizer. After all, the original used a steel cable and there is no reason to think that modern cable is not equal to or better than the old cable. If you need a cable, let me know.

Thanks for the input fellas

Richard, I whatever size or number strand of cable you use make sure it is aircraft rated or arcraft quality and not from the local hardware store or home improvement center. Your life and others are more valuable than saving a few bucks on the cost of cable!

I'm glad to you are using the original set up rather than the incorrect rods. The cable available today is better than anything back than. I got my 3/16" cable from McMaster Carr for my Rocky Mountains. I'm not sure if that is the correct diameter for AC's.