Disc vs Rim brakes

Hey all,
Hope this hasn't been done to death already... but:

Picked up my first MTB with disc brakes recently and am not especially
happy with the braking power from the front. They are just basic cable
actuated discs.

They're reasonably smooth and progressive, just not powerful; i.e. I
have to squeeze the lever with substantially more force than for an
equivalent braking force on decent rim brakes.

To my mind, this actually makes perfect sense - as the brake caliper is
much closer to the hub and hence has less "leverage" on the wheel to
stop it. Hence in motorcycles/cars brake discs grow in diameter as more
braking power is required for the application (e.g racing).

A rim brake is logically equivalent to a really massive disc hence has
huge relative braking power.

So - anyone care to convince me otherwise and tell me that my disc
brakes should offer superior braking power? Coz I'd really like them to
;-) I long for single finger endo's that I used to do on my R6.

Jules

"Jules" wrote in message
...
Hey all,
Hope this hasn't been done to death already... but:

Picked up my first MTB with disc brakes recently and am not especially
happy with the braking power from the front. They are just basic cable
actuated discs.

They're reasonably smooth and progressive, just not powerful; i.e. I
have to squeeze the lever with substantially more force than for an
equivalent braking force on decent rim brakes.

I'm only hand waving, as I haven't done any scientific tests, but, my
mechanical discs feel far more powerful and offer far more feel than any Vs
or canti's I've used before.

An unfortunate intimate relationship between my derailleur and wheel means
I've been able to test this more thoroughly recently - my disc bike wasn't
going anywhere for a while, so it was time to drag out the old bikes to keep
riding. My cantis (admittedly not high end - probably early STX) with
Koolstops are hopeless. I can't believe I ever braked as late as I did. My
Vs (LX) are much more powerful and better modulated, but still require more
hand pressure than my disc brakes, and take a moment to "kick in". Worst
thing about discs is mine use pads much more than I think they should.

I can't wait to get back to discs. I'm running 2001 Avid mechanicals with
EBC gold pads.

Maybe your pads are glazed or still need to bed in?

Tony F

Jules wrote in :

snip

Picked up my first MTB with disc brakes recently and am not especially
happy with the braking power from the front. They are just basic cable
actuated discs.

I went from rim to hydraulic disc, I wouldn't go back.

My "guess", your "basic cable discs" aren't that good, the test ride I had
on one set of cable discs and I thought them appaling, that doesn't mean
they all are like that though and I am no expert

--
Trevor S


"Unthinking respect for authority is the greatest enemy of truth."
-Albert Einstein

Jules Wrote:
Hey all,
Hope this hasn't been done to death already... but:

Picked up my first MTB with disc brakes recently and am not especially
happy with the braking power from the front. They are just basi
cable
actuated discs.

They're reasonably smooth and progressive, just not powerful; i.e. I
have to squeeze the lever with substantially more force than for an
equivalent braking force on decent rim brakes.

To my mind, this actually makes perfect sense - as the brake calipe
is
much closer to the hub and hence has less "leverage" on the wheel to
stop it. Hence in motorcycles/cars brake discs grow in diameter a
more
braking power is required for the application (e.g racing).

A rim brake is logically equivalent to a really massive disc hence has
huge relative braking power.

So - anyone care to convince me otherwise and tell me that my disc
brakes should offer superior braking power? Coz I'd really like the
to
;-) I long for single finger endo's that I used to do on my R6.

Jules


Be aware that most disc brakes won't offer full power for a littl
while after purchase (or after installing new pads)... It takes a whil
to bed them in.

Having said that, many cable discs aren't that much better then a goo
set of v's in terms of pure power. They may have better actuation, b
smoother, and better protected from the elements, but that doesn't mea
they'll be a more powerful brake.

Give them some time, play around with the adjustments (my basi
dia-tech cable discs performed much better after a little cabl
tweaking), and when it comes to it replace the pads - You'll probabl
be happy enough with them.

Of course, there's always the solution of rubbing the discs with cok
once a week. Increases power (But creates an awful squeal in th
process!)

Eddie(hydraulic next time)

--
eddiec

Previously had Magura Julie hydraulic disks on the Avanti Barracud
which had absconded in my absence. My current Specialised Stumpjumpe
runs way-cool Schm LX rim brakes.
I single-digit brake & appreciate the feel my V’s give, never lef
wanting for more.
At the weekly Dirt Crits I can always tell a disk-braked bike is comin
up behind me because I can usually hear their squealing at each stop
turn.
Disks are clear of most of the crap the wheels turn through, but the
get mega hot in tight going & them disk pads aren’t cheap.

With such a massive range in both types – disk & V-brake – it’s hard t
say that one type is definitely better than the other.

I think the rule here is that disks aren’t -better - than V-brakes
just *-different-*

--
Marx SS

Jules wrote:
Hey all,
Hope this hasn't been done to death already... but:

Picked up my first MTB with disc brakes recently and am not especially
happy with the braking power from the front. They are just basic cable
actuated discs.

They're reasonably smooth and progressive, just not powerful; i.e. I
have to squeeze the lever with substantially more force than for an
equivalent braking force on decent rim brakes.

To my mind, this actually makes perfect sense - as the brake caliper is
much closer to the hub and hence has less "leverage" on the wheel to
stop it. Hence in motorcycles/cars brake discs grow in diameter as more
braking power is required for the application (e.g racing).

A rim brake is logically equivalent to a really massive disc hence has
huge relative braking power.

So - anyone care to convince me otherwise and tell me that my disc
brakes should offer superior braking power? Coz I'd really like them to
;-) I long for single finger endo's that I used to do on my R6.

Jules

Like others have said, I'd be checking out the quality of the brakes.
What make/model are they?

I actually 'upgraded' from Hayes Mag hydros to Avid cable discs. It
turned out that the problems I had with the Hayes were actually a flaw
in the frame, but I'm more than happy with the Avids, which seem to have
a reputation as the best cable discs, and possibly better than some low
end hydros. I wouldn't swap back from the Avid cables to Hayes hydros.

--
Nick

Interesting..

The bike is well run in actually (bought off a mate who rode a few
hundred km on it), so maybe some softer compound pads if they exist.

Or - and I've tried to resist the temptation - time to start tweaking
and searching ebay ;-)))

A pic for anyone interested
http://public-files.farked.com:351/p...new%20toy2.jpg

Jules


eddiec wrote:
Jules Wrote:

Hey all,
Hope this hasn't been done to death already... but:

Picked up my first MTB with disc brakes recently and am not especially
happy with the braking power from the front. They are just basic
cable
actuated discs.

They're reasonably smooth and progressive, just not powerful; i.e. I
have to squeeze the lever with substantially more force than for an
equivalent braking force on decent rim brakes.

To my mind, this actually makes perfect sense - as the brake caliper
is
much closer to the hub and hence has less "leverage" on the wheel to
stop it. Hence in motorcycles/cars brake discs grow in diameter as
more
braking power is required for the application (e.g racing).

A rim brake is logically equivalent to a really massive disc hence has
huge relative braking power.

So - anyone care to convince me otherwise and tell me that my disc
brakes should offer superior braking power? Coz I'd really like them
to
;-) I long for single finger endo's that I used to do on my R6.

Jules



Be aware that most disc brakes won't offer full power for a little
while after purchase (or after installing new pads)... It takes a while
to bed them in.

Having said that, many cable discs aren't that much better then a good
set of v's in terms of pure power. They may have better actuation, be
smoother, and better protected from the elements, but that doesn't mean
they'll be a more powerful brake.

Give them some time, play around with the adjustments (my basic
dia-tech cable discs performed much better after a little cable
tweaking), and when it comes to it replace the pads - You'll probably
be happy enough with them.

Of course, there's always the solution of rubbing the discs with coke
once a week. Increases power (But creates an awful squeal in the
process!)

Eddie(hydraulic next time)c

"Marx SS" wrote:

I think the rule here is that disks aren't -better - than V-brakes,
just *-different-*.

After running the old cantis for 5 years of mixed touring and off-road and
wearing through the rims, my opinion is different. Wear and tear on brake
pads, cables and housings was also quite significant, requiring an annual
refit of all.

With the new hydro-disc equipped bike for the last 5 years (admittedly not
ridden as heavily, but plenty of muddy, technical off-road) my brake
maintenance has totalled.... zip! The disc pads are about half worn,
hydraulic fluid is still original and power & modulation is excellent. I'd
say discs are definitely better. In fact, if it wasn't for the setup costs
and difficulty of fitting pannier racks, I'd change to discs for my touring
bike - it's a rigid MTB and gets ridden on some pretty 'orrible dirt tracks
at times. Some people say that hydro discs could leave you in difficulties
in remote parts if they break down. Well mine have never broken down, but
even if they do, it's easy to carry a bottle, disc bleed kit, and a few
spares. Hell, even if you're in the wilds of Bolivia or Tibet, the local
truck mechanic should know all about hyraulic brakes and have some dot 3
brake fluid. He's more likely to be able to supply this than a new Mavic 36
hole rim.

Cheers
Peter

Hello Jules you wrote:

....., so maybe some softer compound pads if they exist.

I have mechanical RST's on my Avanti Barracuda and they look smaller
in diameter than yours (16cm) but perform really well. Avanti made a
blue early on by putting really hard compound pads on these. I forget
the colour coding but mine are fairly soft in comparison. Might be worth
investigating.

--
Regards, Bob

"Jules" wrote in message
...
Interesting..

The bike is well run in actually (bought off a mate who rode a few hundred
km on it), so maybe some softer compound pads if they exist.

Or - and I've tried to resist the temptation - time to start tweaking and
searching ebay ;-)))

A pic for anyone interested
http://public-files.farked.com:351/p...new%20toy2.jpg

This looks to be the 2004 Yukon going by the colour scheme. It has Hayes
mechanical discs, which have a standard Hayes sintered metal pad I believe.
The latest Australian Mountain Bike mag has a tech talk section (p88) on a
range of Hayes compatible disc pads.

Phantom Cycles www.phantomcycles.com.au have the Hayes standard pads for
$55. EBC also make hayes compatible pads that are pretty readily available
and a bit cheaper - three types: green are general use, red are soft (but
will wear pretty rapidly, race use) and gold are long lasting but lesser
grip. Koolstop also make Hayes-compatible pads. I have some of these and
some EBC greens as spares, but the Hayes pads have just lasted and lasted,
so I have no coparison to make.

Eventually you'll need to change those brakes - they must get scratched and
bashed surely. Then go the upgrade to hydraulic ;-)

Cheers
Peter