Topic: aluminum disc brake stay arm

[MetroRedneck]

Anyone running an aluminum brake stay on a 750F or other disc brake with a top mounted caliper?  How thick is your stock?  Think it has more than 18,000 psi when applied?  Anyone know if I am right in remembering torsional rigidity being equal to yield strength for 6061?

[slikwilli420]

Won't be any different than the big drum on the other 750's, both are too much brake but plenty of people run the aluminum stay. If it makes you uneasy, build one from 7075 instead.

[calj737]

6mm will be fine.

[754]

6mm Wall ? It pushing not pulling.. umm flat would likely fold, tubing or thicker material would be my choice..
Maybe square or rectangular with sides milled to save weight..
 If you start off with say 1.5  inch Aluminum roundyou could make a dog bone shape , to have enough meat for the Clevis ends, then mill the smaller middle part into a  I beam shape... keeping top and bottom round....yummy..

[Don R]

I agree with Frank.  Pushing from the top is an entirely different deal, most bikes have a tubular strut on top for a reason. Maybe an aluminum looking powder coat would do?

[754]

I will look into it, if I can get some machine time, I have a F model to try it on.
Sounds like a nice product to try to make.,
 Also am trying to work with a machinist south of the border, trying to get the frame kits back on line soon.

If anyone has a F rear torque tube to measure, see how wide it is diagonally,  across the clevis end.

[Yamahawk]

When you clock your caliper, make sure the stay is as close to 90deg. as you can, for best torque on the stay arm. I adapted a Kawasaki Mean Streak rear wheel (5"x17" rim) and caliper bracket to my 2006 Kawasaki Concours, and had to clock the caliper to around 8:30 on the clock, to clear the hard bags. I cut the clevis ends off of a spare stay from eBay, and welded a piece of sch40 stainless 1/2" pipe to the ends, and bolted it to the caliper bracket. I did have to cut off the inside ear of the caliper side clevis to clear the rim. But, it works like a champ. The plus was, I got to use the larger rotor and the two pot caliper from the Mean Streak instead of the Concours stuff.
Charlie

[calj737]

If you start off with say 1.5  inch Aluminum roundyou could make a dog bone shape , to have enough meat for the Clevis ends, then mill the smaller middle part into a  I beam shape... keeping top and bottom round....yummy..

1.5” There’s not enough room running past the tire for an arm that big  Tubular aluminum in a wall section from 0.63-0.93 is more than enough. The clevis applies the force across the face of the ends, and then thru the wall section along its length. 3/4” tube is plenty.

[754]

 1. 5 or whatever  it takes solid  round, turned down to say an inch, between the Clevis ends.
 
Now the round central section gets milled to about 5/8 wide , so that is the width by the tire.
 Then,  those flat side's get milled from one or both sides, but not right thru..
 Leaving an I beam or channel shape,  with a Clevis each end to attach it.
 So start off with a dogbone, trim each end into a clevis, then lighten the piss out of the middle.

[MetroRedneck]

Thanks for the input.  I'll need to work something out.  I've got 8mm flat stock which isn't gonna fly.  I also have the stock 750F stay arm, but I'm still unsure of fitment with the CBR1000 caliper bracket and clearance to shocks.  Hopefully i can start mocking up this weekend.

754 if you are thinking of making something shiny I might be interested in it.  I'll take some measurements for you.

[754]

 Dont go to a lot of trouble, got one I can get at on the weekend.

[MetroRedneck]

Checking out factory arm on the hurricane as an off the shelf option and there’s not much meat to it at all. 

[MetroRedneck]

Bracket side