return of the rim brake

bluechair84

We've taken a lot of influence from technology over on the pussy motorised world of two wheels... has anyone ever worked out a trickle-down time to us superior pedally-type bikers?
Cos I'm wondering when this is going to happen
http://www.youtube.com/watch?v=jipktSz15fo&feature=related
Rim mounted hydraulic disc brakes?!

I could see the caliper mounted to the brace, and a braking surface on the rim... hmm... Over-the-handlebars much?

chedabob

Am I missing something? They look just like normal discs brakes, but rather than the rotor bolting to the hub they're attached to the outside of the wheel.

Kiblams

Just looks like a massive rotor to me... :?

bluechair84

I'm wondering if it's something that will work it's way to mountain bikes though - sticking the rotor way out at the rim will cause all sorts of problems for manufacturers but the power and modulation would be huge.
Plus, might save weight by using the braking surface of the rim with very small pistons rather than a dedicated rotor and larger pistons.

Kiblams

bluechair84 wrote:

I'm wondering if it's something that will work it's way to mountain bikes though - sticking the rotor way out at the rim will cause all sorts of problems for manufacturers but the power and modulation would be huge.
Plus, might save weight by using the braking surface of the rim with very small pistons rather than a dedicated rotor and larger pistons.

Im pretty sire it's just a rim sized rotor...

Edit: just taken a closer look and its a rotor that is mounted on the rim, so it's stilla a rotor much the caliper goes on the inside of it rather than the outside as normal.

supersonic

Modulation will not be any better, as this can be factored into the desoign of any brake. Braking 'power' would be more for a given input though due to increased rotor size.

I can't see it happening as current brakes are plenty powerful enough, and putting more steel away from the axle is not a good idea.

Raymondavalon

That's not quite new or innovative, some 500cc GP bikes embraced that design years ago
I think this design would be overkill on an MTB, the weight penalty and disc''s vulnerability to damage are just two factors that scupper this idea in the MTB world.

Anonymous

arent mgura hs33 essentially disc brakes which use the rim of the wheel as a rotor?

if so, theyve been round since forever.

bluechair84

I was seeing comparisons with hs33. In essense... it's exactly the same thing just not made all CNCed...
I imagine the biggest issue after weight penalty would be rim dings.

supersonic

sheepsteeth wrote:

arent mgura hs33 essentially disc brakes which use the rim of the wheel as a rotor?

if so, theyve been round since forever.

Could say the same about canti brakes too!

peter413

sheepsteeth wrote:

arent mgura hs33 essentially disc brakes which use the rim of the wheel as a rotor?

if so, theyve been round since forever.

Your not wrong

Was riding with someone who had a Chameleon from like 2000 and it had one on the back, was well chunky from what I remember

bluechair84

I figured, with the general demise of cable actuated disc brakes now that hydrualics are so cheap that, cable powered brakes were defunct unless you were saving weight. I hadn't thought of the hs33s when I first posted... but they were bloody powerful. The more I think about it... the more I think they are exactly what I was initially talking about :shock:

Just can't get the metallic / sintered pads like in dis brakes.

Anonymous

supersonic wrote:

sheepsteeth wrote:

arent mgura hs33 essentially disc brakes which use the rim of the wheel as a rotor?

if so, theyve been round since forever.

Could say the same about canti brakes too!

aye, the reason i drew the line at maguras is that they are hydraulic.

Raymondavalon

I have Magura HS33s on my rigid HT, they work exceptionally well, plus there's dozens of pad compounds to choose from too..

mudsucker

Buell motorbikes have been using rim mounted rotors for years so its nothing new : http://www.buell.com/en_uk/

Twilheimer

I was just going to say that, damn it.

Northwind

Yup. Though it doesn't work so well for Buell, fair play their bikes are heavier than mine but most of them are slower, and yet still the big rotor doesn't work as well as my single 330mm rotor and basic R6 caliper and lever. it doesn't have the handling benefits they claim either since the rotor's lighter, but further out from the axle. Basically it's one of their gimmicks. Looks good though.

Andy525

I thought this comment on the Suzuki was very apt.


Fantastic, but Vinnie of the bikermice from mars already had that bike in the early 90s?

Chaz.Harding

You mean like the Buell motorbikes use?



It's been around YONKS, now. And yeah, this is a fairly common bike, totally stock as you can buy them from the dealer.

RupertCommunicator

It's an ancient idea that didn't take off on MTBs for a number of reasons:

1. The rotors would weigh a ton since they would have a circumference of over two metres on a 26 inch wheel! This is almost four times the circumference of eight inch DH rotors therefore would weigh approx four times as much. And it would be rotating weight as well!

2. The power on normal hydro brakes is more than powerful enough. There is no need to triple the max braking power by increasing the leverage. All this would do is compress the modulation curve, leading to really grabby brakes.

3. The rotors would get absolutely ruined very quickly. Remember how often you pick that wheel width gap in the rocks and then imagine how often you would smash the rotors.

4. The caliper would be mounted high up the fork meaning that the rotational force on the fork leg between axle and fork mount would be massive. This would mean a requirement for stiffer fork legs and large forwards bending forces would occur on the fork near the area where the stanchions overlap with the lowers.

5. The rotors would get a lot more wet and muddy being much closer to the ground, one of the main reasons they are better than rim brakes!

On a motorbike these aren't such large problems because:

1. The forks are only short travel on road bikes and can be much heavier and wider.

2. Weight isn't such a massive penalty on a super powerful motorbike.

3. You don't get many rocks and tree stumps on the road.

4. It takes many times more power to stop a massive bike at 160 mph compared to an MTB travelling at 40 mph, so there is no need for such an overkill solution to move over to an area where there is already an excellent solution.

That is all.

Northwind

Buell do use that design on their offroader as well. It's s**t though to be fair.

Chaz.Harding

To be fair though, it's not as if their off-roader is a bona-fide trail machine. It's more at the occaisional dirt track / gravel / fire-road / muddy field at a big biking event direction.

Still, they are brilliant brakes (and very good bikes too!)

joshtp

A few things.... its been around for ages, it is overkill, and produces many problems on an MTB, and Magura rim brakes are already basicly that, but much lighter, and very,very powerfull

I have Magies on my trials bike, and aside from rim dings screwing things up, and rims being liable to get coated in mud very quickly, they are absolutley awsome... infact its only those two problems that, in my opinion stops them being common on normall MTB's, as they are very light, have awsome power and feel, and are super easy to service, and are mega reliable... and you can fix them with almost anything.

the lack of those 2 probs in trials biking (for the most part) means that they are totaly common, and standard for trials.

Northwind

RTW-Chaz wrote:

To be fair though, it's not as if their off-roader is a bona-fide trail machine. It's more at the occaisional dirt track / gravel / fire-road / muddy field at a big biking event direction.)

Or to put it another way, nothing a Lightning can't do anyway

psymon

mudsucker wrote:

Buell motorbikes have been using rim mounted rotors for years so its nothing new : http://www.buell.com/en_uk/

exhibit a) my old buell before it was nicked!