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Improving braking performance

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Improving braking performance

Old 01-27-17, 05:49 PM
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Alcanbrad
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Improving braking performance

I know this is discussed often and I have attempted to find the threads so I am seekinng the forums wisdome and experience.

Bike is a 2014 CoMo carerra equipped with TRP Spyres with Swissstop sinterized metal pads. My experience is the rear braking is marginal and by that I mean the brake lever bottoms out against the handlebar with reduced braking and once I adjust the pad spacing, I have to readjust again less than 100 miles later. In addition to having to re-adjust the pads, I observe that there is a lot of "squeeze" visible in the un-cased cable run. So when I squeeze the brakes, a lot of the brake handle travel goes into tightening the cable with little additional braking force. My attempts to tighten the cable just result in pulling the actuation lever on the brake body.

So between cogitating on the issue and researching the forums and googling it seems that the options are:

-Figure a way to install a stronger return spring in the brake
-use better brake housing.
-upgrade to hydraulic

I have not been able to find anything about modifying the spyre to increase the return spring plus doing so would likely increase braking fatigue.

Investigating better brake housing, I have seen recommendations for Nokon and Jagwire Elite. Both of these appear to be similar approaches, however, I am not sure this would help as the length of housing compared to the length of free air cable run where I see the cable tighteng is very small.

Upgrading to hydraulic is intuitively the best option, however, there is not much in the marketplace (that I can find) in the way of a 10 speed hydraulic Brifters. I would either have to upgrade the whole drive train to 11 speed or downgrade the shifter to 105 class. Neither of which I want to do.

(A possible solution that might be a reasonnable compromise would be a cable to hydraulic converter that attaches close to the brifter end of the run and providing the majority of the brake run to be hydraulic).

My preferred change would be to upgrade to hydraulic without having the modify the drivetrain.

So what have others done to solve this issue? Will an upgrade to a high end compressionless housing over the realatively short distance of housing make a difference? Is there a 10 speed brifter upgrade that is equal or better than the Ultegra I have now? Are there any scenarios I haven't thought about?
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Old 01-27-17, 06:47 PM
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To take up cable slack, you could do what we used to with the Avid BB7... install an inline helper spring to assist in pushing back the Spyre actuator arm. That is the cheap approach.

More expensive is the hydraulic version... Shimano ST-RS685 Hydraulic STI Levers which are mechanical shifting + hydraulic brake. Hose guides and routing solutions sold separately.
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Old 01-27-17, 06:55 PM
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Has the rear braking always been questionable? Front braking good? Assuming the brake lever is appropriate for the brake and that the adjustment is as good as can be, I would consider replacing the cable and housing. With Jagwire compressionless housing. (My experience is only with Avid BB7.)
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Old 01-27-17, 07:02 PM
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Originally Posted by twocicle View Post
To take up cable slack, you could do what we used to with the Avid BB7... install an inline helper spring to assist in pushing back the Spyre actuator arm. That is the cheap approach.

More expensive is the hydraulic version... Shimano ST-RS685 Hydraulic STI Levers which are mechanical shifting + hydraulic brake. Hose guides and routing solutions sold separately.
Thanks twocycle.

Did you find a helper spring specifically for this or did you adapt one to your set up?

Unfortunately the st-RS685 is an 11speed shifter, I am looking for 10 speed so I don't have to upgrade the entire drivetrain.
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Old 01-27-17, 07:08 PM
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Originally Posted by JanMM View Post
Has the rear braking always been questionable? Front braking good? Assuming the brake lever is appropriate for the brake and that the adjustment is as good as can be, I would consider replacing the cable and housing. With Jagwire compressionless housing. (My experience is only with Avid BB7.)
I do have to adjust the front, but not as often.

We live and ride in a very hilly area and require a lot of hard braking.

Brifters are Ultegra 10 speed.

I am wondering with the brake housing only being present for about 25% of the brake line run, would upgrading the housing make a difference?
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Old 01-27-17, 08:13 PM
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Originally Posted by Alcanbrad View Post
I do have to adjust the front, but not as often.

We live and ride in a very hilly area and require a lot of hard braking.

Brifters are Ultegra 10 speed.

I am wondering with the brake housing only being present for about 25% of the brake line run, would upgrading the housing make a difference?
Would be relatively inexpensive and easy to see if new housing would help. I'm not familiar with helper springs - sounds worth looking also.
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Old 01-27-17, 08:47 PM
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Are your brifters Ultegra 6500 or 6700? I found the 6700 had a much better pull ratio than the 6500 for the disc brake.
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Old 01-28-17, 01:12 AM
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https://www.flickr.com/photos/430814...shares-ME6266/

The link above shows the DIY brake booster I made for a pair of Avid BB7's. No booster was necessary until I installed the inline Travel Agents so the long pull calipers could work with the short pull Tektro levers after the drop-bar conversion. There are now TRP Spyres on this tandem and compressionless housing is recommended by TRP except for a small amount of regular housing near the lever.

Even on a tandem, the rear brake is prone to locking up before the front and a huge amount of power simply isn't necessary back there. IMO going full hydraulic would be a terrible waste of money. What you want to do is make sure that whatever cable you are using for the rear brake has no kinks or frays and ideally it will be waxed or lubricated in some way. Housing should not have tight turns Even if you have most of the run to the rear caliper free of housing it only takes one tight turn in the housing to make the rear caliper stick. I got the springs for the booster from Home Depot and cut them with a borrowed pair of metal snips. They do add back pressure at the lever but I got used to it. Better braking, and an improved handshake: win-win.
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Old 01-28-17, 05:45 AM
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I second the remarks about housing. Compressionless housing is essential. Since your problem is limited to the rear this tells me that the problem is housing. I dont think a "brake booster" like the Travel Agent adapters that Leisesturm has is what you want here. What these do is increase mechanical adavantage so that the pads move more when you pull the lever. These allow the use of long-arm V-brakes that were designed for use with flat bar levers to be used with road levers. It sounds like Leisesturm had similar cable-pull mismatch. This was common before V-brakes became available with shorter arms (like Paul mini-V) that work with road levers. Our Co-motion had long-arm V-brakes with Travel Agent adapters. They worked very will but they are very fiddly when changing cables and sort of Rube-Goldbergish and inelegant, IMO. I note also that there is a tradeoff- you get more brake pad travel, but the force at the pads decreases. This is not a problem with the long-arm Vs since you are essentially correcting a cable pull mismatch- there is plenty of power but not enough cable pull, so trading a little power for more brake pad travel is acceptable. With disk brakes is entirely different. You may not be able to afford less power. It will also make the action on rear very different from the front.
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Old 01-28-17, 05:50 AM
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Originally Posted by Leisesturm View Post
https://www.flickr.com/photos/430814...shares-ME6266/

The link above shows the DIY brake booster I made for a pair of Avid BB7's. No booster was necessary until I installed the inline Travel Agents so the long pull calipers could work with the short pull Tektro levers after the drop-bar conversion. There are now TRP Spyres on this tandem and compressionless housing is recommended by TRP except for a small amount of regular housing near the lever.

Even on a tandem, the rear brake is prone to locking up before the front and a huge amount of power simply isn't necessary back there. IMO going full hydraulic would be a terrible waste of money. What you want to do is make sure that whatever cable you are using for the rear brake has no kinks or frays and ideally it will be waxed or lubricated in some way. Housing should not have tight turns Even if you have most of the run to the rear caliper free of housing it only takes one tight turn in the housing to make the rear caliper stick. I got the springs for the booster from Home Depot and cut them with a borrowed pair of metal snips. They do add back pressure at the lever but I got used to it. Better braking, and an improved handshake: win-win.
So you've replaced with Spyre's? Do you still use the Travel Agents? I note that the rotor on the bike pictured appears to be rather small, like 160mm. Replacing with 200mm rotors would greatly improve the braking, as braking force is proportional to the ratio of rotor radius to wheel radius.
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Old 01-28-17, 02:36 PM
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Originally Posted by marciero View Post
So you've replaced with Spyre's? Do you still use the Travel Agents? I note that the rotor on the bike pictured appears to be rather small, like 160mm. Replacing with 200mm rotors would greatly improve the braking, as braking force is proportional to the ratio of rotor radius to wheel radius.
Good eyes. No, the Travel Agents are no longer necessary, since they have the correct pull to match the Tektro levers. I changed both rotors to 180mm although, believe it or not, the 160's worked pretty darn well. My stoker is blind, and fearless. When we are out with the club, and have crested whatever climb our sadistic ride leader threw into the route... wheeeee... while all the other Captains are cooking their inner tubes or boiling off the brake fluid their master cyclinders, me and mine use terminal velocity, instead of the brake pads, to control speed. As I understand it, the Travel Agents for v-brakes improve brake response as they replace the noodle with a low friction pulley. The inline version though is a horror, and introduces so much additional drag that return springs that were adequate before can no longer retract the pads. I think if the o.p. enlists the aid of another person to tighten the cable clamp, while they yank for all they are worth on the cable end, to get every last bit of slack out of the system, they will find greatly improved rear brake action.
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Old 01-29-17, 06:30 PM
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Originally Posted by Leisesturm View Post

.... I think if the o.p. enlists the aid of another person to tighten the cable clamp, while they yank for all they are worth on the cable end, to get every last bit of slack out of the system, they will find greatly improved rear brake action.
I wish it was that simple. When I apply the brakes, the actuating lever moves immediately until the pads engage, then slack is consumed from the line and the I get more brake force. I have to keep the pads adjusted ridiculously close to the rotors to get acceptable performance. (BTW I have 6700 brifters)

I believe I have 2 phenomena going on here: 1- the spyre return spring is not engineered strong enough to remove cable slack over the long cable run, and, 2- the pad adjust screws are not holding their set point.

That said I have heard some great experience/advice here. I picked up an assortment of compression springs and ordered a set of compressionless brake housings (Jagwire Elite Road) and will give them a try and report back down the road after I get some miles on them.

Thanks everyone for the help.
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Old 02-06-17, 01:08 AM
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Originally Posted by Alcanbrad View Post
I wish it was that simple. When I apply the brakes, the actuating lever moves immediately until the pads engage, then slack is consumed from the line and the I get more brake force. I have to keep the pads adjusted ridiculously close to the rotors to get acceptable performance. (BTW I have 6700 brifters)

That said I have heard some great experience/advice here. I picked up an assortment of compression springs and ordered a set of compressionless brake housings (Jagwire Elite Road) and will give them a try and report back down the road after I get some miles on them.

Thanks everyone for the help.
I have had some good experience recently with Yokozuna compressionless housing and TRP Hy/Rd brakes on my single bike (upgrade from BB7s). Would now consider for our tandem too.
There is a known issue with the Hy/Rd as they are designed for cable pull on current Shimano 11 speed levers. Older Shimano, SRAM and Campy levers need a modification to the brakes to make the work. Am wondering if the Spyres have a similar issue.
Good luck!

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Old 02-26-17, 07:53 PM
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OP here, I tried changing the housings to compressionless (Jagwire Link Elite Road) which did not make any improvement. I didn't expect much since the housing only constitutes about 25% of the total brake cable run. With the new housing and cable, there was still a lot slack in cable that would actuate the brakes when tensioning the slack out of the cable so I tried the return spring as suggested earlier. The spring was curved as the earlier posters picture and the slack in the cable was removed, however, the slack was now in the curved section of cable inside the spring so there was still no improvement.

So I shortened the spring a little bit and widened the end loop so it would capture the cable cam near the cable fixing bolt.

Here is a picture:


There was still enough spring tension to remove the slack and now the rear brake performance is very good. I am quite pleased and braking is crisp and confident.

The root cause is the Spyre return spring is under-strength for application as a tandem rear brake. A stronger return spring isn`t required for most applications. I wish TRP either offered a stronger, or adjustable spring option, or an aftermarket return boost spring.

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Old 02-28-17, 01:23 PM
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That added spring for a stronger return is a great idea. Eliminating slack in the longer rear cable run is like a shot in the arm, it'll give you improved braking. Compressionless housing may not be that noticeable but I figure if I'm replacing my housing why not just go with it to cover all my bases. Glad that you've figured it out!
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