Cross Mechanical Disk on full carbon setup. Recomendations for Lightest Brakes?

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kgbianchi
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Joined: Mon Mar 08, 2010 3:12 am

by kgbianchi

So I have the Juin Tech brakes setup with Campagnolo Chorus, Yokozuna housing, So far this seems good. What rotors should I go with to drop the weight of the stock ones? Keep in mind this will be a gravel, CX racer!

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joejack951
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by joejack951

Buddysnack wrote:I have Yokozunas with mine. Weird thing...the Yokozuna housing is so fat, that it doesn't fit into my Ultegra levers. Not sure it's the same issue with Campy.


Yokozuna housing was tight but it did fit into my Chorus 11 levers. I had the levers pre-installed on the bars and was hoping to 'plug' the housing in but that didn't work. I had to completely remove them, insert the housing, and reinstall on the bars. The brake housing was also really difficult to route through the Ritchey Streem II handlebars. Not looking forward to doing that ever again.

jfranci3
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Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Rotors are a simple item. Really consider the trade offs of lightness.
For materials, you practically have the choice of carbon composites, steel, cast iron, and aluminium. Aluminum is the way to go here for a few reasons. Now you have to choose how you're going to use that aluminium. You're going to alloy it and heat treat it yes. Your friction material, caliper size/leverage, and traction dictate that you need about 140-160mm rotors. Now you you to decide how much heat capacity the rotor needs. Brakes convert kinetic energy into heat. Those rotors have three jobs 1) be structurally sound 2) adsorb heat 3) shed that heat. Once the pads get over heat or the brake fluid, it's all over quick.Less mass means less ability to do long descents. Any weight saving you get needs to come from less performance in the rotor or the rotor hub (which I don't think there are savings to be had). You can now punch all the holes you want to in that rotor and thin the rotor out as much as possible, but you're going to lose braking duration capacity (as least with thinning, with holes you lose total performance).

For light load gravel, a 100g 160mm rotor is about as light as you're going to see. If you remove most the surface of that 160mm rotor, you end up with a 78g rotor of stupidity. Hope will do 89g 2 piece rotors, which are more more smarter than the 78g rotors and at least look better- their fine as long as you aren't doing long or repeated descents.

Maybe consider Shimano's 95g RT99 aero-er rotor, which look good, perform, and have heat sink fins.

Buddysnack
Posts: 48
Joined: Thu May 14, 2015 11:22 pm

by Buddysnack

Yeah...the thickness is a bit of a flaw with the Yokozunas

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joejack951
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by joejack951

joejack951 wrote:I can do one better than CAD, assuming you already have or plan to buy HY/RD calipers and use them with Campy levers. I have 4 extra sets of these silver arms that I'm willing to send to anyone who is willing to test them out for me. I plan some small refinements, and to anodize them black for the next round but these arms seem to do the trick for me. I want some more feedback before I go making any more.


For anyone interested I have made progress on this project. See video and comment section here: https://www.youtube.com/watch?v=JoNIqoguOKs&t=2s

Latest arms have slightly shorter cable pull than the original silver prototypes. Family pic (left to right: TRP original, prototype, production):

Image

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Tomstr
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by Tomstr

Very cool! Do you also do arms for the spyre?
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joejack951
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by joejack951

Tomstr wrote:Very cool! Do you also do arms for the spyre?


No, not yet. I have the beginnings of a design but I am uncertain if it truly worth pursuing. It will not be a cheap part, likely twice as expensive as the HY/RD arms to produce given the geometry, which will really shrink the appeal in already small market. Further, the geometry of the Spyre caliper design doesn't make it easy to significantly shorten the cable pull, and Campy levers require fairly little travel. Ideally, I'd make a custom cable adjuster to help the geometry issue but that just adds further cost. I really can't see anyone willing to spend ~$80 extra to make Spyre's work with Campy, can you?

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