Promax Brake Extender

[Tom Norton]

I came across these on a thread on Bike Forum. They are used on Canti brakes and will provide up to 16mm of​ reach.
Anyone here have any experience with them?

[nash...@gmail.com]

No, but I was thinking about it the other day. Seems like some skepticism out there on the forums but no stories of anything bad happening.

I was thinking what if I converted my cross check? Maybe they don't look so elegant, but they apparently work in some circumstances.

[Ian A]

Do you have a product link? I believe rhe extenders you refer to require the camti posts on the frame to be the removable kind. The CC ones are brazed on - non- removable.

http://www.jrbicycles.com/promax-be-1-brake-post-extenders

IanA

[Joe Bunik]

Here's an up-conversion of a Bontrager Race Lite to 650B using those
(or similar BMX) gadgets (and a custom Rick Hunter fork):

https://flic.kr/p/f79gc8
https://flic.kr/p/f7ow3y

=- Joe Bunik
Walnut Creek, CA

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[nash...@gmail.com]

Ah, I didn't think of that. Surly puts removable posts on their mtn frames and I was thinking of those. Oh well. Nothing wrong with the venerable cross check as it is. Sometimes I'm just looking for a project. Haha

[Ian A]

These might work - https://www.aliexpress.com/store/product/Refires-451-eiosix-v-wheel-Advanced-eiosix-v-406-wheel-18-bird-car-20-brake-seat/416335_1730291049.html

[Nhat]

I used the Promax extenders to convert my Litespeed Appalachian to 650b. Both the ti frame and aluminum Kinesis fork have the removable canti posts. The extender/brake combo has been working well with no issues after ~1500 miles of dirt, gravel, pavements, and some easy single tracks. I'm planning to switch to a steel fork to see if it'll soften the front end (maybe just perception). Here are some pictures of the setup.

[Justus Gunther]

I did this to my wife's cyclocross frame. Are those TRP brakes, they look real snazzy with that black brake cable.

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[Nhat Vu]

They are the TRP CX9 models, which works well with Shimano 5700 brifters.

[Ian A]

To follow up on my own post, those are 406 to 451 adapters which is Reach of ~22mm. I bought some out of curiosity, before I worked out the reach! They might be handy for something, if and when they arrive.

[se]

Hi

How is the brake post extender solution prevailing?

[Justus Gunther]

I used them a while back on an aluminum nashbar touring frame to go from 700c down to 650b, they worked fine. Most steel frames with canti's don't have screw removable canti stud so it won't work on those.

On Sat, May 2, 2020 at 11:20 AM se <shane.e...@gmail.com> wrote:

Hi

How is the brake post extender solution prevailing?

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[Eli Torgeson]

I am interested in this as well. Has anyone used these with Rene Herse cantilever brakes?

Ahhh...the issue is that there is no vertical adjustment in the RHs. They say you have to get your canti posts brazed just right, or you should have your soon-to-be replaced canti in the center position.

I hope to be able to run a 700c wheel from a 650b braze on. The delta should be 19mm. (622 - 584)2 = 19.

Eli

In Albuquerque

[bruno ducamp]

I tried to use such brake extenders to revamp a 26 MTB with 650B wheels.

Well, it did not work for me. Too much increase - these 16mm - to use cantilevers ( Modolo or Shimano BR AT 50) with 650B wheels

My solution was Paul BMX V Brake Motolite which allow for a large tuning of the shoes 

much cheaper similar looking calipers were available a couple of years ago but they seem to have "gone" from ebay.

maybe these "foldable calipers" should also do the trick

https://fr.aliexpress.com/item/4000790300041.html?spm=a2g0o.productlist.0.0.5f484d29T4ZwJd&algo_pvid=e0ddc1e0-baa6-4984-ac9d-b94ef0ff3cd0&algo_expid=e0ddc1e0-baa6-4984-ac9d-b94ef0ff3cd0-12&btsid=0b0a01f815929026218613053e559a&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

https://groups.google.com/forum/#!topic/650b/Gdls1Hz34-k

Bruno, Paris, France