STI + brake release

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mark a.
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STI + brake release

Postby mark a. » 12 May 2017, 2:54pm

I have Tiagra STIs and wide-profile cantis on my bike. My brake blocks don't quite clear the tyre when removing the wheel, so the tyre must be deflated. Before I changed to STIs I had some Tektro levers which each had a button toggle that opened up the lever and hence also the brakes to give ample clearance. That was great.

Is there a solution that would give me the same effect but with the STIs? I've survived for years as it is, but it would be nice and I'm about to do some fettling and might as well do it while I'm changing cables, bar tape etc. Currently I have a hanger from the head tube on the front (no adjuster) and a Surly hanger (with an adjuster, but I don't think I've ever used it) on the back. The STIs themselves have no adjustment.

I don't even know what the term is I'm meant to be looking for. Brake relaxer? Brake release?

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meic
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Re: STI + brake release

Postby meic » 12 May 2017, 3:05pm

It is a pain isnt it?

The original design is that the brake release is a small lever on the dual pull caliper brakes that the STIs are meant to be used with. Campagnolo do it the other way around, I think.
I use a combination of adjusters that can be slacked off to give enough cable slack to disconnect the cable and some filing off of the cradle for the straddle cable's barrel.

There is possibly another problem that even when you have enough cable slack to open up the brakes, there still isnt enough room in the forks for the brakes to open into and you still cant get your wheel out!
Yma o Hyd

mark a.
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Re: STI + brake release

Postby mark a. » 12 May 2017, 3:52pm

Hmm, so I should look at some barrel adjusters? Ones with hopefully enough travel to make difference. The Tektro* solution was just so satisfying to use I wish it was somehow possible with STIs. I see the point about them being designed for shiny road callipers, though.

On the second point, luckily my bike is a Surly Crosscheck which has massive clearances so the brake blocks move well out of the way of my 32mm tyres.

(* I guess this is standard on all non-STI levers, but Tektro is what I had)

markfh
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Re: STI + brake release

Postby markfh » 12 May 2017, 3:58pm

What is available for bikes with threaded headsets is the Dia Compe 1254 Front Brake Cable Hanger 1 Inch with Quick Release (see https://www.sjscycles.co.uk/brakes/dia-compe-1254-front-brake-cable-hanger-1-inch-with-quick-release/). You may be able to find something similar.

Also some cantilever brakes come with a stradle cable one end of which is demountable so that you can unhook it to allow for a wheel change.

Do you know the make and model of you particular brakes?
Last edited by markfh on 12 May 2017, 4:15pm, edited 1 time in total.

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cycleruk
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Re: STI + brake release

Postby cycleruk » 12 May 2017, 4:10pm

If you squeeze the canti' brakes together do you have a wire connection that you can unhook?
You'll never know if you don't try it.

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meic
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Re: STI + brake release

Postby meic » 12 May 2017, 4:33pm

On many set ups there isnt enough slack in the cable to unhook it. I needed to fit both an adjuster and to file some metal off just to be able to release the cable.

I fitted a cross top lever in order to provide the front adjuster, for the rear I could use a Jagwire adjuster in a cable stop.
Yma o Hyd

mark a.
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Re: STI + brake release

Postby mark a. » 12 May 2017, 4:45pm

The brakes are Kore something-or-other, whatever the shop had that looked closest to Tektro 720. As meic says, there isn't enough slack to release anything. There would be if there was some kind of lever or cable release mechanism... which is were I started :D

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meic
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Re: STI + brake release

Postby meic » 12 May 2017, 5:01pm

It is on Tektro 720's that I took the file to the cradle which holds the straddle cable's barrel.
They went a full 180 degrees around the barrel along the axis of the canti-arm, which means that it is considerably more than 90 degrees around from the line of the cable.
I figured having just 90 degrees of cradle, relative to the cable was quite adequate.
Yma o Hyd

mark a.
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Re: STI + brake release

Postby mark a. » 12 May 2017, 10:57pm

I'm not sure I'm up for filing my brakes, but I can see why it wouldn't be a problem. The Kore brakes really are similar to the 720s.

Trying to add more barrel adjusters, filing etc might be more trouble than it's worth. I've lived with the annoying brakes for a few years, so I suppose I can live with them for longer.

gregoryoftours
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Re: STI + brake release

Postby gregoryoftours » 12 May 2017, 11:20pm

A bit ugly, but maybe these would give enough slack to release the brake-

https://www.cyclebasket.com/m9b0s313p28 ... _Adjusters

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Redvee
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Re: STI + brake release

Postby Redvee » 13 May 2017, 2:33am

gregoryoftours wrote:A bit ugly, but maybe these would give enough slack to release the brake-

https://www.cyclebasket.com/m9b0s313p28 ... _Adjusters


First saw those fitted to a £3k TT bike but that had lo pro integrated brakes in the forks/seat stays so was necessary.

meic wrote:for the rear I could use a Jagwire adjuster in a cable stop.


That's the solution I used with v-brakes a Dia Compe adjustable noodle up front.

markfh
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Re: STI + brake release

Postby markfh » 13 May 2017, 7:45am

If you have almost enough slack in the straddle wire then a straddle wire with a shaped end can help with demounting and remounting the end of the straddle wire. The shaped end gives you a bit of leverage to help get the end out and back into the end of the brake.

e.g. https://www.sjscycles.co.uk/cables/cantilever-brake-straddle-wire-with-quick-release-nipple-350-mm-long/