Author Topic: Mercury disc brake question  (Read 1952 times)

phopwood

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Mercury disc brake question
« on: February 25, 2021, 11:19:49 am »
I have not posted for a while. 

I am looking to upgrade my RST to a mercury frame, a few years ago I tried a Mercury 520L and it fitted me so much better than my RST.  I have not used my RST much over the last few years, I have been using my Audax.

This will be a flat bar bike and I am planning disc’s front and back.

At the moment TRP Spyke calipers are like hens’ teeth to get hold of.  What are the alternatives to Spyke if I still want to go the cable operated route, I could go Spyre road calipers and change the levers to Tiagra flat lever?

If I go the hydraulic route, most of the levers on Hydraulic brakes are very short and look too short to use with a rohloff shifter.

Anyone using hydraulic discs on a flat bared Mercury and is the lever length a problem.

Peter

Aleman

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Re: Mercury disc brake question
« Reply #1 on: February 25, 2021, 01:17:54 pm »
This may not help you but I am using hydraulic Rim Brakes AND a hydraulic rear disc on my Raven Twin. I did spec the 4 Finger levers on the Magura Rim Brakes. I have no issues with the Rohloff Shifter and the front lever on the right hand side of my FFT bars. I'm also using the Ergon GP5 Grips with the modified Right grip for the Roholoff

The LHS of the bar is a bit cluttered as it has the Magura and Hope (2 Finger) levers on, but I have no issues using either singly (one finger, index and middle, on each lever), or both at the same time, when I need to grab a fistful of brake ... so far only required in testing :D

JohnR

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Re: Mercury disc brake question
« Reply #2 on: February 25, 2021, 04:59:40 pm »
My 2020 Mercury came fitted with TRP Spyke M disc brakes and Shimano Deore XT trekking V brake levers on Thorn MK3 Flat track bars. I've no complaints about the brakes although I did change the handlebars to these https://www.sjscycles.co.uk/handlebars/600-humpert-ahs-basic-comfort-handlebars-cw-comfort-barends-254mm-clamp-black/ which I find much more comfortable than flat bars with the Ergon GP5-L bar ends.

PH

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Re: Mercury disc brake question
« Reply #3 on: February 25, 2021, 10:07:57 pm »
There's quite a few questions there Peter, I'll try and separate them out/
I could go Spyre road calipers and change the levers to Tiagra flat lever?
Peter
First one, yes.  The Spyre and Spyke are the same brakes with different cable actuation.  Shimano changed the cable pull on all their road groups a few years ago and ideally you'd need to find out if the Spyre is optimised for the original or newer and buy the correct levers, though the difference will be in feel rather than braking ability.
Quote
If I go the hydraulic route, most of the levers on Hydraulic brakes are very short and look too short to use with a rohloff shifter.
There's a few longer levers, I have two types. Shimano Deore T6000 (Deore comes in two flavours, M for MTB and T for Trekking) which is identical to the M6000 other than the longer levers. I don't think these have ever been commonly available in the UK, I bought from Germany, though that's no longer as easy.  I wanted a long lever so it better matched the V brake lever on the other side. Shimano's lower groups. primarily aimed at hybrid type bikes, also have longer levers.  I have a pair of these (BL something, the lettering has worn off)  they came on a Kona hybrid and will be going back on another build shortly.  In all respects, I haven't noticed any difference between these and the Deore.
Levers and Rohloff shifter - Not on my Mercury, but on another bike I have the M6000, there's no conflict.  I've been out this evening on that bike,  having read your post, I paid some attention to it - my hand it partly resting on the shifter as I brake, that might have been an issue with the triangular one, it isn't with the current design.
EDIT - This is with the twistshift specific Ergon GP grips.  I've recently notices some people using full length grips with a Rohloff shifter, I'm not sure of the thinking behind that.

OK, that's the factual stuff, would you like some opinion  ;)
I have had three cable disc brakes,  Avid BB7, TRP Spyke, Paul Components Klamper.  They all work fine, they all stop you as you'd expect. 
The Spyre is the only one where both pads are moved by the lever.  The advantages, if any, are too small for me to notice.  The disadvantage is that the mechanism had to be made small enough to fit between the rotor and spokes and as a consequence the components suffer more from wear and corrosion.  After two winters of faultless performance mine started playing up, the adjustment that is fiddley to start with wouldn't stay set.  I tried various remedies, before giving them a complete strip down and rebuild - that wasn't an experience I have any intention of repeating.
BB7's are a bit agricultural, to look at and in use, but they work fine.  They do feel a bit rough after a while, but are easy to strip, clean and grease.  I'm not keen on the pad retention, where they slot in without any retaining screw/pin.  I've never had, or heard of, a problem, but I like the reassurance of a physical retainer.
The Klamper is a thing of beauty, as it should be considering the price, works like a BB7, just better.  Smoother, nicer feel at the lever, easy to adjust, looks easy to strip (I haven't had to do so yet) There's a vid somewhere explaining why they chose to just have one moving pad.
All three recommend adjusting for wear by moving the pads in rather than shortening the cable.  If you do just take up the slack with the cable, the TRP will be less effected than the other two. 
Hydraulics - I've only used the three models already mentioned.  I chose Shimano because I prefer the idea of mineral oil rather than DOT.  I swapped the Spyke on the rear of the Merc for the Deore T.  I find the difference between cable and hydraulic discs to be greater than the difference between cable disc and rim brakes (Of any flavour) It isn't that I've ever had a brake that wouldn't stop me, it's just the ease of doing so and the control that gives you.  Plus, by their nature they're self adjusting, and when they do need maintenance it's simple (Though something else to learn) I know, - can't be fixed at the side of the road, but then neither can a lot of my bike. I wouldn't choose them for an exotic expedition, but otherwise I'd need a convincing reason not to use them (Like on my folder)

Last point - the way I use my Mercury, I chose the 853 V brake fork, I've never doubted that was the right choice.  When I bought a bigger tyred tougher bike, the right choice was a disc fork.
« Last Edit: February 26, 2021, 06:53:41 am by PH »

phopwood

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Re: Mercury disc brake question
« Reply #4 on: February 26, 2021, 08:28:27 am »
Thanks all for your replies, very useful information. 

I must confess I would have preferred v-Brakes all round as I like v-Brakes, they just work, and I have several sets spare in the garage.  I did also think about V's on the front and disc on the back.  But I prefer same on front and back which leads me to discs all round. 

I brought a bike in 2003 with shimano deore hydraulic disc brakes; they still work well today, and have never failed, so I am not worried by Hydraulics.

The Klamper are as you say a thing of beauty but a little out of my price range for this build.

I have ordered the frame and forks, I have a few other things to get including getting my Rohloff converted for disc brakes, while all this is happening I will decide on brakes, cable or hydraulic, long or short levers.  Who would ever have thought brakes could be so complex.








PH

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Re: Mercury disc brake question
« Reply #5 on: February 26, 2021, 10:01:20 am »
I must confess I would have preferred v-Brakes all round as I like v-Brakes, they just work, and I have several sets spare in the garage.
That would also have been my preference, partly to avoid the cost of having the hub converted, but also because I've never had any issue with V brakes.  Though now I've got used to the idea, I'd probably chose it again.   
Well done on finding a frame in stock, good luck with the build, look forward to the comparison with the RST.

pinkbunnyok96

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Re: Mercury disc brake question
« Reply #6 on: February 26, 2021, 04:26:23 pm »
have had a mercury for a few years now with shimano xt disc never found lever length a prob but I am on the short side going hydrolic good move never had to service them new pads once every couple of years regardless of miles

phopwood

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Re: Mercury disc brake question
« Reply #7 on: March 31, 2021, 07:20:24 am »
Hi I went for Shimano deore hydraulic disc brakes with short levers and they fit and work very well.  The brakes are very powerful so the short levers don't mater and the short levers are not affected by the rohloff shifter.

Peter

GamblerGORD649

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Re: Mercury disc brake question
« Reply #8 on: March 31, 2021, 04:05:33 pm »
I love my cable TRP Spyre on my heavy custom Rohloff tour bike and the SA 4 finger levers. They are set to long pull, can lock the disc instantly every time. I leave the gap bigger to eliminate fussing, I have track ends. The resin pads are best, IMO. Never screeched once. I haven't broken a cable in 35 years. I see no benefit to hydro at all. My bikes are not mudders though. My shifter knob is on the TT, where they belong, IMO.

My SA XL-FDD dyno drum brake pads finally are wearing down after 25,000 miles. So I built the same for a new wheel and put the old one on my new all SA roadster.
« Last Edit: March 31, 2021, 04:11:28 pm by GamblerGORD649 »