Why don't we have hydraulics for drop bars?



stuart doc wrote:

> I know Magura once dabbled with them but why haven't they become
> popular?
> Tourers and Cyclo Cross must be a big enough market to make it
> feasible?


Same reason as there are no decent V-brake levers, I suppose. You need
too much lever travel to get the right amount of travel and force at the
rim, and there ain't the space on a dropped bar.
 
So what levers are hooked up to your HS-33's then Pete?
Or did you see what levers were on the Cannondale?
It's my T2000 i'm planning to massacre!

__
Stuart
 
> Would not the same type of lever work for both disks and hydraulic rim
> brakes, or do the rim brakes need more fluid to be displaced?

The Maggie hydraulic rim brakes use the wierdest hydraulics I've ever
seen: when you get the brakes, the levers are already connected-up to
the calipers, with the pipes filled with brake fluid (Magura "blood").
You can then carefully cut the still-full pipes to shorten them and
stick a new olive on and refit, all without draining or bleeding the
system. I guess its because the fluid is more viscous and not
hydroscopic, like normal brake fluid.
I don't know why this system can't/isn't used with the Magura disks,
though.
The rim brakes do displace more than disk calipers, but surely that
just a matter of master/slave cylinder capacity ratio (mechanical
advantage)?
-rory
 
in message <[email protected]>, James
Thomson ('[email protected]') wrote:

> "Simon Brooke" <[email protected]> wrote:
>
>> Would not the same type of lever work for both disks and
>> hydraulic rim brakes,

>
> I don't know of any collection of data, and I don't use disks, but in
> general I wouldn't assume intercompatibility, either between rim and
> disk brakes or between different brands of disk.
>
>> or do the rim brakes need more fluid to be displaced?

>
> I'd assume that's the case. Magura note that their disk- and rim-brake
> levers are not interchangeable.


It should be possible to make a lever with interchangeable cylinder
sleeves and pistons which would work with different displacements.

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

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stuart doc wrote:
> So what levers are hooked up to your HS-33's then Pete?


Standard HS-33 levers. I ride a Streetmachine GT recumbent tourer
though, so drop bars are a pretty moot exercise for me these days.

> Or did you see what levers were on the Cannondale?
> It's my T2000 i'm planning to massacre!


Didn't see, I'm afraid. I just thought, "oooh, Maggies! I've not seen
them on a drop-bar tourer before!", which looking elsewhere in the
thread is probably part of the reason why they're a bit hard to come by
now... :-(

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/
 
Zog The Undeniable wrote:
>
> Same reason as there are no decent V-brake levers, I suppose. You need
> too much lever travel to get the right amount of travel and force at the
> rim, and there ain't the space on a dropped bar.


Nothing much wrong with the DiaCompe drop bar V-brake levers

--
Tony

"I did make a mistake once - I thought I'd made a mistake but I hadn't"
Anon
 
"Zog The Undeniable" <[email protected]> wrote:

> Same reason as there are no decent V-brake levers, I suppose.
> You need too much lever travel to get the right amount of travel
> and force at the rim, and there ain't the space on a dropped bar.


That's not true of the HS66. There's very little lever motion once the pads
hit the rim, so there's actually less lever travel than in a typical cable
system, especially if you use the Magura brake boosters.

James Thomson
 
"Simon Brooke" <[email protected]> wrote:

> It should be possible to make a lever with interchangeable cylinder
> sleeves and pistons which would work with different displacements.


Of course, and any aftermarket lever will need to be compatible with a
range of calipers if the market is going to be worth having. My original
point to Günther was more about the likely market being more biased towards
disk brake use these days. Hydraulic rim brakes never had the acceptance
that disks have today.

James Thomson
 
"stuart doc" <[email protected]> wrote:

> Or did you see what levers were on the Cannondale?
> It's my T2000 i'm planning to massacre!


They'll have been Magura HS66 levers. One of the fancier Cannondale tourers
came with a full Magura HS66 set about 5 years ago.

You can sometimes find the levers on ebay.de, but prices tend to go quite
high. The HS77 used the same lever, so search for both terms.

James Thomson