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Setting Up Rim Brakes.


Mark W

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Right.

You have a brake. It either doesn't work properly, or doesn't work as well as you'd like. Basically, your brake system can be split into several different areas so you can find the problem and solve it. These are:

Lever

Hoses (or Cables for you phillistines)

Pads

Rim

Setup

First things first:

Rims

"What is a rim for?"

To brake, the fundamental action is getting a block to rub on the wheel rim to slow it down. If said wheel rim is covered in shit/mud/crap/spuff, then it's not really going to work, is it? We're aiming here for maximum friction. This means a non-contaminated rim.

"How do I get a nice, clean rim?"

Basically, use a cleaner. Water works, but it won't work all that well, especially if you've been using tar.

If you want to get a nice clean rim, use Muck-Off to get the main part of the crap off. What we're talking here is moistening a piece of kitchen towel with Muck-Off, then wiping the rim, leave for a minute, then rinse. If you've been using tar, you'll basically need to use metholated spirits to get that off. White spirit will generally do the job.

If, however, you don't want to have a clean, silver rim, you can grind your rim to get it clean. This involves taking off the top layer of rim and getting into the surface beneath. This obviously cleans the rim perfectly. However, when grinding over an old grind, you might notice a deterioration in performance. The best thing to do is get the rim as smooth as possible, THEN re-grind it. This means you start from a fresh surface, which will always be better.

After doing this, your rim should be ready to lovingly accept your Magura/V-brake with open arms. You can tar or grind the rim, or leave it clean, and I'm not going to go into this. Well, I will - a bit. With tar, simple angled stripes across the rim work best. Do about 8 stripes or so at even spacings, then ride down a hill and brush the brakes. It'll spread it out and hey - we're groovy. Grinding's a personal thing, and personally, it's my favourite method to get good working brakes. Do a search for grinding to understand how to do it.

Pads

There are several factors to consider here. If your pads have a lot of life left in them, then simply sanding down/rubbing the pads against a brick wall will rub off any of the surface glaze that brakes accumulate do to the rubber getting messed up with dust, water, etc. This will almost always improve braking, and getting them clean is just a good idea anyway and is good practise. I'm not going to go into detail here because there are a shitload of decent pads out there. Koxx Bloxx, Monty X-Hydras, Plazmatic CRMs, Koolstop Reds - you've just got to experiment. I metaphorically and literally swear by Monty X-Hydras. I love them. My last set lasted through a whole year of roadtrips, street, natural, comps, tar and grinds. They're dandy. Others seem to like Koxx Bloxx. What do I know.

A simple method to improve braking can also be to pour water over the braking surface and then ride with the brake on down a long hill 'til it squeals like a new-born. This also aids bedding in pads.

Hoses (and what to put in them)

The hose itself isn't really that crucial. You can basically use standard Magura hosing and it'll be fine, or you can go tech and get something like braided hosing. It won't make much difference, apart from aesthetically, in the same way as wearing lycra won't make much difference - trials brakes don't operate at the same temperatures as DH brakes (Which braided cables are meant for). I mean, by all means try them, but standard Magura hosing is cheap and works effectively. If you've got a crimp in whatever cable you use, you'll be wanting to get rid of it by cutting your cable shorter or actually getting a new hose.

Now we move onto the contentious issue of brake fluids. People seem quite happy to waste their time moving onto whichever fad is going on at the time. Before it was water, then it was WD-40, and it just seems to change regularly as brakes people used to swear by which had almost mythical instant-returning feel and a nice snappy feeling when you used it lost it's novelty value and basically went shit. Magura Blood is good. It is, after all, the fluid Magura recommend, and quite frankly, they know their braking systems pretty damn well. It might not be as experimental and you won't get people going "ooh" and "aah" when you tell them what liquid you managed to pump into your hoses, but quick frankly - it works! That's the main thing! Mine's stayed in their happily for the last two years without a bleed, and it's not happily corroding my seals or whatever. Screw worrying about whether your brake is snappy enough - you can change that simply by using the TPA properly anyway. It is a good, simple fluid that works. If you can remember the name of the cheap, bulk version of Magura Blood (unlike me), then go for it. Lots of cheap fluid is always a good thing.

Levers

RB or standard - it doesn't make much difference. Some people prefer the feel of the RB levers, but you have to remember the seals die and make the brake piss with the shocking frequency of an old man with poor bladder control. After-market seals are theoretically available, but the words "Blood" and "Stone" spring to mind. If using a standard Magura lever, make sure the lever pivot bolt is neither too tight nor too loose. Just get it so the lever can move freely, really.

If your TPA is sheared (spins with no effect), or you just want a bomb-proof alternaitve, read my other FAQ about changing TPA bolts. It's worth it.

Lastly, and most crucially:

Setup

You could have all the after-market parts in the world, but if you simply bolt your Magura onto your bike and expect it to work you're going to be bitterly disappointed.

"Setup" itself is pretty varied, so here's the deal:

Pad alignment

You want the pads to be fairly close to the rim for maximum power, hitting square and true. Getting it so they hit at the same time, parallel to the rim is the ultimate aim. Just keep fettling and get it sorted. Then, tighten up the clamp bolts and that's that part sorted. Equally, check out the pads section above to make sure they're clean, etc.

Rim treatments

This part of the setup is just involving putting tar on the rims or grinding them - or even leaving them clean. It's really up to you. Tar application and removal is spelled out above.

Bleed

If you have air in the hydraulic system, "Bad shit will go down". Not sure if you've got air in your system? Well, if you can pull the lever and it feels spongy - and it's NOT the seat-stays flexing - then it'd tend to suggest you did. If you CAN pull the lever and it DOESN'T feel spongy, then the bleed isn't at fault, so don't just re-bleed for the hell of it.

Check out other FAQs for bleeding tips, 'cos it's 1:49am and I'm tired.

Levers

Make sure the lever is at a comfortable angle for best braking. It'll also mean you don't get RSI or something stupid like that. For comps, I generally find that having the lever pull back parallel with the bar reduces the strain of braking and staves off arm pump for long enough, generally. However, this is your call. It is usually best to have the TPA so it is set "softer", i.e. set so that it is set nearest the stopping point where the brake should feel spongiest. Shit, that sounded crappy. Basically, if you turn the TPA one way, it'll make the brake feel stiffer. You want the TPA away from this, so you can dip into those "Stiff feeling brake" reserves later. That described it better, and you should by now get the picture.

This is basically it. Setting up a 4-bolt Magura is beautifully easy. You mainly only have to worry about pad alignment, and loosening two bolts, pushing the brake into the right place, then doing them up isn't a challenge, is it? If you do it right, you can basically forget about the brakes. Other things to remember are boosters, but there are gashazamillions of topics of them. You will need one, so buy one. A good one.

Like I said, it's now 1:53am, and I AM tired, so I'm going to leave it at this. It's a simple mechanical (well, hydraulic, but y'know) system. Break it down into it's seperate parts and you'll always be able to work out what the problem is, simply because it'll be staring you in the face. There should be no reason for any more "My Magura's shit" posts or anything like that from now on.

Consider yourselves warned (Y)

Mark.

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Oh, and one more thing about cleaning rims, "Cif" (of Jif to the rest of us) works amazingly well for cleaning rims, get a bit on a toothbrush and total scrub awal...oodles of shite will fall off, thn clean it away with clean water and give it a wip down with a clean cloth then leave it to dry for a bit.

If you give your pads a scrub with Cif as well that really clears them up...

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