Hello Matt Simkins and All,

Nice Effort! And nice machining.

I would prefer a design that eliminated the cable on the side and either used a center pull bare cable or solid rod.

Aero is VERY important and maybe a new approach with a mini hydraulic cylinder or leverage in the fore and aft plane translated to the brakes via a jackscrew.

How about a straight push brake pad onto the tire with a back up for tire flats? (No wear on carbon wheels.) Hmmmm ..... maybe it would push the front wheel out of the drop outs ..... yikes .... not a good way to stop.

Incorporating the fork sructure into the front brakes will be a design that is hard to beat.

Good luck.

Cheers,

Neal

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Cheers, Neal

+1 mph Faster

finally...

I'm pretty amazed that no one has come up with a modern aero brake, so kudos.

I'd definitely buy this brake. I'm not a big fan of Tom's setup (sorry Tom!) mainly because after the cable hanger and the actual brake itself, I don't think you're saving anything over a *properly routed* front brake (there are other tricks to reduce the amount of cable being run, like running it from the right hand lever).

Here's what will stop me from buying the brake: it needs to work with wide rims. The Stinger 6's are 28 mm wide at the rim. So the distance between the pads needs to be about 34mm with reasonable-thickness brake pads.

Also, I agree w/Dave on the pad holders (countersunk bolts, no fins on the shoes)--but it really needs to use a standard DA pad.

Personally, I don't care what they weigh or if the stopping power sucks. For a rear brake, I really don't care about the stopping power

Surely a cantilever brake utilizing foil shaped lever arms which integrate with specific forks, would be the best - They would effectively be the leading edge of upper fork (legally exceeding 3:1) at all times unless braking. They would stop waay better than any standard road brake and be pretty much invisible, to both the wind, and the eye.

Send your money to my nigerian account...


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nec rege, nec populo, sed utroque

Great concept Matt.
I also would like to see a center pull for it.

If only this design had a center pull & transfered to the front.....
(will also need a cam to strengthen the minimum cable pull)

bingo.

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nec rege, nec populo, sed utroque

These are designed to fit the new 23mm wide rims, but the edges on the brake arms line up perfectly on a 20mm rim. 28 mm are ultra wide and they probably wouldnt fit such a monster. Are you sure that is the width at the braking surface? I thought 23mm was as wide as they get, not true?

That is wild, but actually, it looks really nice. The brake housing and wire is definitely going eat into the benifets, but that is really clean hardware. Who made that?

Funny you mention that. I do have a design that pushes a plate into the tire. When I showed the design to people they were highly skeptical. I agree that the idea has merit though.

for the most part, yeah. The Stingers, particularly the 6's, are quite a bit wider though.

That said, I expect that rims will continue to get wider (the newest 303's look pretty wide, and I expect that Zipp will follow suit w/the wide rims), so that may be an issue to consider.

No...there's no stop for the cable housing, but I could see how a stop (a removable one) could easily be added to the "pivot plate".



Yeah, I could see how CFD could be a bit complicated with the wheel rotating against the direction of travel right next to it!

When I was talking about "field testing", I was referring to some of the types of road tests I've done using Robert Chung's "Virtual Elevation" method...in the past I've apparently been able to discern differences as small as .001-.002 m^2 of CdA which corresponds to ~ 10-20 g of drag (@ 30mph tunnel speed).

If you send me a prototype, I'd be glad to test it out :-)

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http://bikeblather.blogspot.com/

Here's the set up on my P3

Front
http://i20.tinypic.com/7295r4.jpg




Rear
http://20.media.tumblr.com/...rlRHyxkx1Co1_400.jpg

Tom,
I have never heard of this method, but am going to look into it more. It looks like you need a power meter. I would be glad to send you the prototype to do this test. However, a key feature was machined wrong so part of one of the springs will not stay in. Remember, this is a prototype. If you test these particular brakes they would likely drag on the rim. The return spring works fine and the brakes stop, so at least I have been able to test them under hard braking. I would love to hear more about this method. Perhaps I can give you a call?
simkinsdesigns@gmail.com

Here's a write-up on it from the man himself:

http://anonymous.coward.free.fr/...cda/indirect-cda.pdf

I have my own spreadsheet that I put together for doing these analyses, plus Alex Simmons has kindly put his own spreadsheet versions up on the files section of the wattage training list on google groups:

http://wattage.googlegroups.com/...ioEG5q2hncZWbpWmJ7IQ


I do my testing on a local road that I affectionately call "the halfpipe". Basically it's a stretch of road that has an incline on each end, which allows me to do "out and back" laps and make the turnarounds at very low speeds and thus avoiding braking (since braking in this approach would appear as a non-existant very steep hill!). I use this method to check out all sorts of equipment and positioning options for myself. Last year I undertook the task of attempting to determine the drag differences, if any, between my friend's P3C and my P2K. I posted the results in the following thread:

http://forum.slowtwitch.com/...%20borrowed;#1802183



I'd love to test it out and compare it to some other brakes (including my own contraption). Would the brake still "drag" if the inner cable wasn't attached? I was thinking for quick changes in the field that I'd just swap the brakes and then just put in place an outer cable housing for the runs and not bother attaching the inner cable. I'll still have my rear brake for any braking that's needed (as I described above, in the actual runs I avoid braking altogether.) Having the brake drag during the test wouldn't work well since the power to overcome the drag would be lumped into the aero and rolling resistance drags.

I'll email you my phone number and we can set up a time to talk :-)

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http://bikeblather.blogspot.com/

Any update on this thread? Matt or Tom?

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Want: 58cm Cervelo Soloist. PM me if you have one to sell

Vintage Cervelo: A Resource

I have a set of shimano ax calipers very aero but hardly confidence inspiring when you try to use them I weigh about 170 pounds and can average about 29 mph in most time trials up to about 50 miles but probably lose time on more technical courses as im worried about their braking performance before turns. these brakes are good for drag strip courses but anything technical they let you down and if its wet as it is alot in scotland forget it. These prototypes from simkins look good to me and i would definately buy them if they work well
(buy the way matt i emailed you some photos of ax calipers hope you got them)

the front brake looks a lot like a campy delta, although that might have been said before. delta brakes looked really nice, but didn't work so well, and were a pain to maintain. sorry, not to cast aspersions, it's just historical.

The back isn't a P3? I'm confused

Hey Matt, it's great to see you're still at it with developing some more useful aero brakes. Your current design seems to show a lot of the aspects that we talked about when I bought your original iteration, and is most likely getting into the range of the other brakes I am using.

I missed the original post a couple of months ago, so is there an update now on how the design is shaking out? I will be first in line for this new brake, though I am only interested in a front for my Zipp 2001 (still have the original rear which works great), and I have created a custom hydration solution for my Softride that integrates with a super old Weinmann center pull design.

Keep up the great work. Innovation is your friend.

Chris

Chris,
The latest brake is going really slow. I have another prototype being made. This one has to be perfect. The first priority of the new design was getting something that worked in the wind. The aero part is pretty much worked out. Now the effort is going into making it easy to install, stop well, mistake proof, fit a wide range of frames and wheels, and all of that sort of thing.
Thanks, Matt

Matt,
The front brake looks nice. I would have to see a lot of data to change from a traditional break. Also, I think there is no real substitute for braking power. If you want to make a greta brake, find something to replace the side pull Quartz. I have them on my Argon and they don't work. The look great. But coming into a corner I want o stop and those are horrible. Additionally, with the emergence of rear side brakes on the front fork I think this is a market worth getting into. There is no need to emphasize drag when you can use the fork and instead maximize stopping power and weight.

hi matt just wondering how you are getting along with the new prototype. any more ifo or pictures

cheers
m@tty

m@tty,
Working on it. The new prototype is being tested for reliability and it is working great. I think the design is ready and am going to make the big plunge to machine a batch. I really think this is going to be a popular brake, but you never know. Given the short life of the Shimano AX, Campy Delta, and Sampsons, an aerodynamic road brake is pretty niche, but lets see.
Thanks,
Matt

Matt-

I think your design rocks! Let me know when you're ready for production and I'll be ready with my credit card. ;)

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"100% of the people who confuse correlation and causation end up dying."

Thanks for the update Matt. I have my cheque book at the ready too. Hope they will be available in black.

m@tty