Dreaming and thinking

[Andre Jute]

Yo, No:

More on the Magura rim brakes that will be of particular interest to you. The HS33 and HS11 differ only in the material of the handles, in that the 33 comes with a booster plate which is an extra-cost option on the 11 (1), and in the ease of adjustment; the rest is cosmetic, the 11 having optional pretty-coloured covers. The 33 have stiffer alloy handles, the 11 have composite handles.

But the adjustment is interesting.

The HS11 is adjusted at the handlebar by a hex wrench/spanner; as I said, in 6500km I adjusted mine only when I changed rim widths.

The HS33 is clearly a competition model, the clearance adjusted as you ride without taking your hand from the handlebar grip by turning a thumbwheel. You can thus on the HS 33 conveniently set up ultra-close instant-response tolerances for riding on tarmac or dry off road, and when you get to the mud or snow give the pads and the rim some breathing space without even slowing. And, of course, you can do this differently for the front and the rear wheel to give you slightly differential braking.

For instance, I have my Magura's set up wide (a fraction over 2mm) because I'm not keen on an overly sharp response, but with just under half a millimetre of difference back to front to give me just that slight delay that gives me a better chance not to lose it when I have to brake suddenly on the loose gravel on many of the small country lanes I ride (or on slurry, or on wet grass in the centre of the very smallest lanes), say when around a corner I suddenly come upon a huge tractor filling the lane from hedgerow to hedgerow.

(1) For ultra-civilized braking, very progressive, take the booster off. In an emergency you will also find the manual grip to replace its power, and in everyday use in traffic only the most aggressive riders will need it. I don't use the booster. Note though, that those who go really wide on their tyres, all the way up to the 60mm I use, will need a custom-cut booster because the Magura item won't fit on a fork wide enough to handle 60mm tyres. It's these small details that can trip you up and be extraordinarily expensive when you start dreaming of out-of-the-ordinary bikes.

[No]

I'm guessing thorn would take care of that if I bought the bike with them? How do you get the custom cut booster? and is the booster that super-structural looking thing?


So, up to a vote now.

For all weather from -20 F (maybe even lower! But probably not often below 10 F)  to 120 F and ultimate reliability which would you choose ?

Paul components moto BMX (I don't like the springs on Shimano brakes. They always are a pain and never stay adjusted)

Or

Magura HS33?

And as for the Magura, if you never have to bleed them or anything, how do you attach the hose to the bike?

[Andre Jute]

I'm guessing thorn would take care of that if I bought the bike with them? How do you get the custom cut booster? and is the booster that super-structural looking thing?


So, up to a vote now.

For all weather from -20 F (maybe even lower! But probably not often below 10 F)  to 120 F and ultimate reliability which would you choose ?

Paul components moto BMX (I don't like the springs on Shimano brakes. They always are a pain and never stay adjusted)

Or

Magura HS33?

And as for the Magura, if you never have to bleed them or anything, how do you attach the hose to the bike?

I have experience of Alaskan conditions (I wrote a book about it) and I wouldn't cycle in them.

The booster is the upside-down U with cutouts. Go to http://www.sjscycles.co.uk/magura-hs33-hydraulic-rim-brakes-black-4-finger-blade-prod28636/ and scroll down a bit and the illustrations will show you the difference between the mounting plate and the booster.

The Magura rim brakes come fully assembled from the pads to the grip, including the tube and the hydraulic oil; it is a sealed system from the factory.  You have to order the right length of brake assembly, one for the front brake, one for the back. I imagine that on other bikes they fit where the normal rim brake cable would run; on my Utopia all cables, tubes etc run in custom-turned clips clips that bolt onto socketed threads on the downtube.

I should think the standard booster will fit Thorn bikes at the biggest tyre size permitted, so the question of a custom booster doesn't arise.

I have no information or opinion about Paul's brakes. But, in general, I don't see how any boutique product (not just Paul's -- any at all) could be superior to the Magura rim hydraulics.

Andre Jute

[No]

Why is it that these brakes never require bleeding or anything, but regular hydraulic discs do?

[ajbenie]

Have you considered going for a V-brake at the front and a disk at the rear. That is the way my Nomad is set up, primarily due to rim wear issues with other bikes. The rear disk ensures that you will always have one brake that is working, and at least in my experience on ice and snow it is the rear brake I want to need to be working as it is too easy to loose control of the front. When I bought mine I did quite a bit of research into the Hope (dot5.1) and the Shimano (mineral) disk brake, and there where some reports as to the Shimano sticking in the cold. Which is why I went with the Hope. My wife has a Utopia Velo Roadset (step through) with Magura disk brakes (mineral) and that had no problems in the cold (-22C is the coldest we have had since getting the bikes), so if the Shimano problems are real then they are nothing to do with mineral versus dot5.1. As for bleeding the brakes, they shouldn't need it, if everything is tightened up correctly at the factory and your not using some silly ultralight weight spec. I have a suspension fork as well but haven't used it much yet so I can't comment on that (I would guess that NZPete might have some input as to the suspension fork seals as it does get cold in NZ).
I haven't seen any signs of wear on my front rim yet (Andra CSS), but then I use the rear for control and the front only for stopping. If it is wet then there is a minimal delay before I get full power on the front. The delay is very short and helps stop the front from skidding immediately, so I've gotten used to braking harder in the wet if I need to stop fast. In my case the tires (Winter vs Supreme vs Mondail) make a bigger difference as to how fast I stop than water/mud on my rims


If you go with a thorn then I would go for a Nomad with a rear disk and a front V-brake (it what I did). Try it and see, if you don't like the V-brake you can always add a suspension fork and disk later.

/Andy

[Danneaux]

If you go with a thorn then I would go for a Nomad with a rear disk and a front V-brake (it what I did).

...Or go with a disc-compatible Rohloff, at least, so all bases are covered (the disc-mounting tab is all ready and waiting on the Nomad frame, "just in case").

That's the route I went, figuring as much as I prefer v-brakes all-'round with drop handlebars at present and in the foreseeable future, that might not always be the case. Always good to have options that help future-proof the bike or add versatility, especially for minimal additional up-front cost.

Best,

Dan.

[Slammin Sammy]

Why is it that these brakes never require bleeding or anything, but regular hydraulic discs do?

I have just finished installing HS33 on Atilla the Nomad (I know, I owe you guys some photos!). Magura says their brakes never need bleeding (once installed correctly) because the Royal Blood brake fluid used is not hygroscopic (water-attracting). This makes sense.

AFAIK, the HS33s get delivered in one size, with identical hose lengths (1200mm, from memory). Front and rear are identical, as are left and right calipers. You actually cut the stiff nylon hose with the fluid inside (it stays remarkably intact, as long as you don't let the ends whip around), and thread it through the bosses underneath the top tube (rear brake), then simply re-attach it to the master cylinder with an included slip nut and olive. Tighten sufficiently, and there are no leaks!

It's important to get the lengths right (measure twice, cut once), or you'll either have to replace the entire hose (if you cut too short), or cut the olive off to shorten if it's too long. I did the latter with the rear brake, the only hassle being that the olives aren't reusable, and you only get one per brake. I had to buy a Magura service kit in order to get spare olives (~$25.00).

Other than that hiccup, the brakes are superb. I am using the standard black pads that came in the kit on my CSS rims, and will monitor wear closely. I will also test their wet-weather ability this weekend (with a garden hose - once again, we will have glorious weather here in Godzone!). I ordered a set of Magura Green Frogs (for ceramic/CSS) as spares.

One other slight bother - it's hard to align the front brakes so that the pads parallel the chord of the rim. I tilted them back to get close, but you're limited by the booster (not an issue if you're not using one). They seem to work fine.

Pikkies this weekend, I promise!

Sam

[Andre Jute]

I have just finished installing HS33 on Atilla the Nomad (I know, I owe you guys some photos!). Magura says their brakes never need bleeding (once installed correctly) because the Royal Blood brake fluid used is not hygroscopic (water-attracting). This makes sense.

There you go, No, Slammin' Sam has answered your question.

Can't say I've ever had trouble with the cheaper Shimano disc on my stadsportief Gazelle, except that it ate pads at an alarming rate. I don't think I ever made a thousand klicks on a set of pads.

AFAIK, the HS33s get delivered in one size, with identical hose lengths (1200mm, from memory). Front and rear are identical, as are left and right calipers. You actually cut the stiff nylon hose with the fluid inside (it stays remarkably intact, as long as you don't let the ends whip around), and thread it through the bosses underneath the top tube (rear brake), then simply re-attach it to the master cylinder with an included slip nut and olive. Tighten sufficiently, and there are no leaks!

It may be that the official aftermarket kit has only one size, but the last time I looked, all the discounters were selling different tube lengths, which they bought up as surplus stock from bike manufacturers, who presumably get their kits made to size at Magura.

It's important to get the lengths right (measure twice, cut once), or you'll either have to replace the entire hose (if you cut too short), or cut the olive off to shorten if it's too long. I did the latter with the rear brake, the only hassle being that the olives aren't reusable, and you only get one per brake. I had to buy a Magura service kit in order to get spare olives (~$25.00).

I have the service kit too, because I make a habit of buying one with the bike or component if available; it usually works out cheaper than paying carriage a second time. But if I knew then how reliable the Magura's would prove to be, I wouldn't have spent the money.

BTW, you can buy hose separately, for about ten euro. I bought that one too, and might use it as I'd like to raise my handlebars further still and the limit has now been reached on my hydraulic tubes. Though if I have to pay 25 smackers plus carriage for each olive...

Andre Jute

[ajbenie]

Normally bleeding the brakes is to get rid of air in the system and not water. However, if air is getting in, then water is also getting in and that is a problem. In the case of mineral oil the problem is that you can have more corrosion and some very interesting viscosity effects at low temperatures. With dot 5.1 oil the problem is that the boiling point falls as you add water which means that your repetitive braking performance drops (repeated use, using as a coaster brake). The only reason that we have an issue is the effect of weight weenies on design. The lower weight they desire makes it harder to produce a good seal at all temperatures and means that when things get hot, water and air can get in and it is also harder to get rid of the heat. A thicker rotor helps as does a larger calliper, which is why thorn doesn't use the race version of the components.

The difference between dot 5.1 and mineral oil when you have good components is none existent. Just make sure that the seals are OK and you'll be fine. Repeated bleeding and addition of small amounts of oils (from the same bottle) – will cause problems.

When I did my Rohloff oil change I flushed my brakes and measured the water content of the oil in the lab. There was no significant difference between the oil I was putting in and the oil I took out (all oil contains water, even mineral oil). So I would expect the Hope brakes to not need a change for several years to come. It will be interesting to see what effect seal wear will have over time, but as I alluded to in my last post I use the rear brake a lot. By the way car manufacturers recommend changing brake fluid every 2 to 5 years (due to water build up), and in most cars the brake fluid reservoir is a lot more poorly sealed than on a bike. So you should be able to get at least 2 years before changing the oil (my test suggests a lot longer interval should be possible).

If you have good quality brakes then they shouldn't need bleeding, once installed. You might want to do an oil change once in a while (every couple of years) but that's more a case of peace of mind than anything else. My experience from other systems is that water will get in at some point cause problems and that is irrespective of whether the system uses dot 5.1 or mineral oil. Flushing the system is easy and you can do it at the same time as doing the Rohloff oil change. With the hope bleed kit it takes about 15 minutes.

/Andy
 
P.S. don't buy dot 5.1 in a bike shop, you'll just get ripped off. Car/motorbike places are a LOT cheaper for the same thing.