Rear Brake In Place

So I have had this rear brake caliper on and off the bike, probably 15 times. My best guess is I will do that another 8-10 times. What you have to do if you want to get it right rather than 'close' or 'that's pretty good'. Caliper pictured in it's final resting spot. The bracket that gets welded to the frame will mount on the bolt closest to the frame tube in the bottom pic. Kind of a shame to hide all the work behind the frame, but it still looks sweet and unlike any other set up I have seen to date.

Rear Wheel Spacer Install

I test fit the wheels spacers, well at least the rear ones and they fit great. I still have to turn up my new front axle on the lathe before I can fit the front spacers. You can see in the last picture the mating line of the rear brake bracket to the wheel spacer. This is what I wanted it too look like, a smooth transition from the brake bracket to the wheel spacer to the wheel. Small .050" or so air gap left between the spacer and the brake rotor which is necessary. The bolts are hardware store mock up ones, they will be replaced later with stainless hex heads drilled for safety wire.

Rear Brake Assembly Models

Here are the models I created to ensure everything fit together as a unit. I felt it was necessary as I am using parts and pieces from multiple different companies that have never been put together how I intended to do it. It's funny how it all works though. My models like all scientific but when I opened the file it was all misaligned. So either my models were off or I measured the parts at home wrong. Oh well, that is part of the deal. I will check it out when I get home to verify everything.

Front Axle Assembly

Here is my front axle set up. Pretty straightforward except for the fact that I making every part. Most bikes built out there use a stock style front axle that slides in from the right side of the bike. and has an ugly flange nut on the left. I laid out the tire the tire and widths of the lower legs to give the right amount of crush on the front wheel spacers. Spacers are aluminum, axle 4140 steel. (think hard steel that won't bend) and the nuts will be stainless. Every nut, spacer or bracket really matters too me. It is easy to look at a bike and see that they used a certain part becuase it was on hand or easy to use, becuase doing it right was too hard, expensive or beyond their available resuorces.

Wheel Spacers

Here are the wheel spacers. At the most basic level wheels spacers can be tubing, cut to length. Well, I have always thought that looked unfinished. I don't want to see the seal and bearing in the wheel. I always noticed it right away, so I would think that other people do too. Small end of the spacers to the outside, big end of the 'bell' towards the wheel. There is a small diameter boss to the inside that lands on the inner race of the wheel bearings. The major diameter covers the seal and flows into the wheel. The really short one stacks up with the rear brake bracket to set the wheel spacing. These parts are my first venture into CNC lathe work. I wrote the program, set up the machine and ran them. Kris (BAKER Machinist) helped me throughout the entire deal.

Front Brake Bracket, Better Pics

Better pics to show what it going on with the front brake bracket. I drew it up on Solidworks, machined it on the Bridgeport. 2-D machining, nothing fancy. Built the necessary offsets to center the caliper over the rotor into the bolt bosses. The H-D lower shock legs that I am running have pressed in stainless washers for the brake boss' to help maintain shape over time from the stress the caliper put on the legs. The bolt boss' on my bracket fit down into the counterbores's where the stainless steel washers reside. Probably doesn't make sense in text form, simple simon if you were here putting it on.

Rear Brake Bracket

Mulitple views of the rear brake bracket I made. Looks like a complicated piece. I spent a lot of time laying it out such that it would wrap the frame as much as possible and be somewhat hidden underneath the right rear frame point. The radius angle matches the same angle as the right rear frame tube that comes off the axle block. The offest required to get the caliper centered over the brake rotor is built into the brake bracket.

Slight adjustments that need to made will be accomplished with stainless steel brake calipers shims. Completely common when dealing with one off parts and paint stackups.

I will machine a brake tab out of stainless that will use the front most brake caliper bolt for a sanitary design. I will later weld it to the frame. I am using stainless so that I can grind the powdercoat off it and then be able to slide the caliper fore and aft with the rear wheel for chain adjustment. It just looks like shit when you see rings in the paint or powdercoat from the brake bracket being slid around.

I machined this on a 2-D CNC Bridgeport. I designed it such that I could use common ball mills, end mill and bull nose end mills, but making it function as a 3-D sculpted part when it fits in the bike. Spending 8 hours to design this bracket and 4 hours to machine it are worth it too me. NO ONE ELSE in the entire world has this same bracket to mount a sport bike caliper on their chopper. That's good enough for me.