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PostPosted: Tue Aug 21, 2018 5:44 pm 
Retro Guru

Joined: Tue Feb 21, 2012 9:53 am
Posts: 867
Location: the shed
Anyone?


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 Post subject: Re:
PostPosted: Tue Aug 21, 2018 10:32 pm 
Devout Dirtbag

Joined: Mon Jul 24, 2017 5:42 am
Posts: 114
I have a 99 Marin which came with original (mech) Diatech disc front and v brake rear. The front brake was beyond pants and a bit of googling confirmed that was the verdict even back in the day. I restoried it mostly to period but put a modern mechanical Avid BB7 disc on the front. Try as I might I still can’t get it to work as well as the V on the rear. It’s better than the Diatech crap though. Different ball park to hydraulic discs.


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 Post subject: Re:
PostPosted: Tue Aug 21, 2018 10:49 pm 
Gold Trader
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Joined: Mon Jan 15, 2007 11:40 am
Posts: 3494
I had a bb7 on the front and xt v on the rear of my parkpre, with xt m739 v levers. Worked very well, but I've swapped to a basic Shimano disc on the front and magura hs33 on the rear, no other reason than "just because". Still haven't tried them much but I do think they're better than cables - less hand effort required for the same braking, no need to adjust for pad wear, etc


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 Post subject: Re:
PostPosted: Tue Aug 21, 2018 11:39 pm 
Gold Trader
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Joined: Fri Jan 23, 2009 2:30 pm
Posts: 14841
Location: Surrey
I had bb7s on my airnimal Joey. Initially it had disc front and v rear but I swapped the rear out. I thought they worked really well, no complaints but I ended up pimpumg the bike and swapped to hydraulics, just because I could. I'd have been happy to stick with the cable discs but they didn't fit with the no expense spared approach to upgrading.


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 Post subject: Re:
PostPosted: Wed Aug 22, 2018 12:40 am 
Old School Hero

Joined: Sat Apr 15, 2017 12:26 pm
Posts: 230
In answer to the original question: no, but I'm tempted to. Reasons: ease of adjustment to suit how I want them to feel; and my daughter has some, no doubt, cheap Tektro mechanical discs on her Carrera and they still seem to provide excellent stopping power - I was amazed at how powerful they are when set up well.


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PostPosted: Wed Aug 22, 2018 6:47 am 
Retro Guru
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Joined: Thu May 17, 2012 11:04 am
Posts: 543
Location: manchester
+1 for the avid bb7's. I fitted them to both my grandkids bikes as they are used much less often than mine ( static hydraulics isn't a good idea for reliability). Take your time to set them up and they are nearly as good as the Hope set up on mine.


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 Post subject: Re: Re:
PostPosted: Wed Aug 22, 2018 7:43 am 
Old School Grand Master

Joined: Mon Feb 11, 2008 9:42 am
Posts: 3117
I've not done it myself, but have converted a few bikes either from hydro to mech, or just built them with mech.

Reasons are usually around field servicability and/or cost/availability. i.e. before drop bar hydros were widely available.
Done a couple of CX bikes and a three or four long distance tourers (flat bar and drop) one of the tourers was planning to ride from Sweden to Turkey then possibly across into Egypt, North Africa and the fact that he could pick up a brake cable inner/outer in pretty much any town or village between here and there was the deciding factor, plus the fact that the fitted pads would last him the entire tour! Getting shimano hydros fixed is another matter altogether. So that's a plus.

He only got to Italy in the end. :D

CassidyAce wrote:
Reasons: ease of adjustment to suit how I want them to feel
Yup, you have to spend a lot of money on hydros to get that level of adjustability and "fettleability"

Rotorhead wrote:
Try as I might I still can’t get it to work as well as the V on the rear. It’s better than the Diatech crap though. Different ball park to hydraulic discs.
TBH, the set up on mech discs is absolutely critical, there is so little motion in the pads and no sort of self adjustment feature as per hydros that if you don't get it spot on you'll never get it right. TBH, you *can* get them almost as good as hydros, but the amount you need to spend, it's probably cheaper to just buy hydros. I've resorted to all sorts of tricks to get them right. Biggest one is getting the best outers you can and being incredibly precise with every stage of cutting, cleaning up, routing and fitting. (cutting with a dremel slicing disc to get the ends at 90 degrees, reaming out and flaring the liner, doing a complete set up and bed in, then readjusting everything to take out any slop. And so on.)


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 Post subject: Re:
PostPosted: Wed Aug 22, 2018 5:09 pm 
Retro Guru

Joined: Tue Feb 21, 2012 9:53 am
Posts: 867
Location: the shed
I have another bike with bb7s and they are pin sharp. I like the feel and obviously maintenance is easier with just a cable.


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 Post subject: Re:
PostPosted: Wed Aug 22, 2018 5:19 pm 
Gold Trader / MacRetro rider
Gold Trader / MacRetro rider

Joined: Thu May 06, 2010 10:05 pm
Posts: 7540
Location: Aberdeen
No.
Tried both, but Hydro wins every time for me.
The TRP hy-rd cable actuated hydros were about the best I’ve tried that involved cables in some way.


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PostPosted: Wed Aug 22, 2018 5:37 pm 
Dirt Disciple

Joined: Fri Mar 17, 2017 2:01 pm
Posts: 78
Yes, for a few reasons I'd now find it hard to go with anything other than a BB7.

Reliability - a BB7 will never leak fluid onto your rotor. This is maybe self inflicted cynicism as I've had a few problems with reliability on 2nd hand hydro stuff but recently I also had a Shimano Deore brake that I bought brand new spring a leak at the caliper. When you read all about the problems people have with Shimano drop bar hydro stuff having horrible lever feel and leaking calipers and cracking pistons etc I really think they've taken a step (or a giant leap) backwards in terms of quality and reliability.

Ease of setup - There's a few tricks to learn for setting up BB7s for sure but once you know what you're doing I don't think setting them up is that much harder or time consuming than setting up a hydro in a pure straight forward bolt on and go situation.

If you factor in shortening hoses, switching lever sides or disconnecting hoses to route them around your frame, then set up time/effort must be about comparable and if you need to bleed anything...I'll be out riding my BB7s while you're rinsing dot fluid out your eyes.

Power - again, it does need to be well set up and that maybe requires you to be a bit more skilled or practised than with hydros but a BB7 can be as powerful as any hydro I've ridden.

Cost - its no mistake that I've put cost at the bottom of this list. Buying stuff new, at UK rrp yeah you can probably get a half decent hydro setup for less than a pair of BB7 calipers but if you're buying used stuff off here or ebay, BB7s can be had for very cheap and you don't need to worry that cheap = gonna piss dot fluid all over you and your rotors the first time you pull the lever.

I always see people recommending stupid expensive compressionless cables for using with mech discs too, but bmx linear cables can be picked up for a couple quid and are just as good.

Plus, you set BB7s up with an allen key set you probably already own, not a bleed kit and fluid that you had to go out and buy just for the job.


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