Mechanical Disc Brakes

Hi,

I've just had a nasty blowout at high speed which has left my front rim in
shreds. My front V-brakes, M950 XTR, are shot (seem to have fallen apart
inside). Oh, and my old Pace RC-30 forks are succumbing to rust.

So, I'm considering replacing them with a pair of RC-31s. Carbon doesn't
rust...

The question that remains, and which I'm unsure of, is what to do with the
brakes and wheel. I have basically two options, I think:

1) Buy RC-31s with V-brake adapters (£30 more expensive), replace the
V-brakes with new ones and rebuild the wheel with a new rim.

2) Buy RC-31s without the V-brake adapters, replace the wheel with a disk
brake hub and put a mechanical disk brake on. The Avid Ball Bearing one
looks nice.

I'm wondering though whether or not this is likely to be substantially
better than the V-brakes. I'm not really minded to put a hydraulic disk
brake on, because I'm running XTR M951 brake/shifter combos which I'm rather
partial to. As far as I know, you need the dedicated brake levers on a
hydraulic shifter.

The cost is going to be approximately the same (£30-50 more for the disk
brake), the weight is approximately the same (V-brake adapters for the RC-30
weigh about the same as the weight penalty of the disk), so I think the only
question is whether or not the mechanical disk is going to be substantially
better than the V-brake? Oh, and potentially whether the Avid brake will
work with the M951 lever?

As an aside, 160mm vs 185mm - is the 185mm necessary? Or just designed for
people who are constantly on the brakes for DH purposes. I mean, I like
going down hills, but I also like going up them...

Thanks in advamce,

John

"John Appleby" wrote in message
...
Hi,

I've just had a nasty blowout at high speed which has left my front rim in
shreds. My front V-brakes, M950 XTR, are shot (seem to have fallen apart
inside). Oh, and my old Pace RC-30 forks are succumbing to rust.

John - If you're binning the XTR V's could I trouble you for a spare part?
Been looking for the thingie that meshes with the wotsit for a good few
years without success, no-one seems able to order it and its a shame to see
the brakes sat doing nothing for want of thingie. Its a round bit that sits
next to the brake stud and has 6 or so 'teeth'. No problem if you're keeping
the brakes as spares - just thought I'd ask.

So, I'm considering replacing them with a pair of RC-31s. Carbon doesn't
rust...

I owned a pair of these for about 3 months, very nice looking (and nice to
ride for the limited riding I did on them) but the carbon made me nervous.

Snip

I'm wondering though whether or not this is likely to be substantially
better than the V-brakes.

Probably not much difference in overall stopping power but the advantages
are with the discs reliability as well as increased mud and tyre clearance.
I'd vote disc.

I'm not really minded to put a hydraulic disk
brake on, because I'm running XTR M951 brake/shifter combos which I'm
rather
partial to. As far as I know, you need the dedicated brake levers on a
hydraulic shifter.

Yep. Fair enough.

As an aside, 160mm vs 185mm - is the 185mm necessary? Or just designed for
people who are constantly on the brakes for DH purposes. I mean, I like
going down hills, but I also like going up them...

I am perfectly happy running a 165mm rotor on both my bikes, but I am not
the heaviest bloke in the world and I don't drag the brake all the time. As
for the Disc/Q.R. issue - I'm not going there...

Thanks in advamce,
John

Steve

John Appleby wrote:
Hi,

The cost is going to be approximately the same (£30-50 more for the disk
brake), the weight is approximately the same (V-brake adapters for the RC-30
weigh about the same as the weight penalty of the disk), so I think the only
question is whether or not the mechanical disk is going to be substantially
better than the V-brake? Oh, and potentially whether the Avid brake will
work with the M951 lever?

As an aside, 160mm vs 185mm - is the 185mm necessary? Or just designed for
people who are constantly on the brakes for DH purposes. I mean, I like
going down hills, but I also like going up them...

Thanks in advamce,

John



Mr. Appleby,
I don't think that anyone can tell you that the Avids are substantianlly
better than V's, that is probably a matter of opinion. I can tell you
this, I recently made the switch from V's to Avid mechanicals and for my
application I like the Avids better. It was not an issues of braking
power for me, but loss of power and feel on long downhills. It is not
uncommon here to have a 3-5 mile downhill with constant braking. I felt
the V pads became soft and hot and had some loss of control. I do not
get that feeling with the Avids (160 mm rotors). They may get hot, but
the feel of the brake is the same at mile one as it is at mile 5.
Plus, I will move the old V's to my fully rigid bike and replace the
cantis (I like the cantis, but are more difficult to set up), so it is
no real loss.
BTW, you can always replace the Avids on the front wheel and see how you
like that before you fully commit. Good luck.
--
Craig Brossman, Durango Colorado
(remove ".nospam" to reply)

2) Buy RC-31s without the V-brake adapters, replace the wheel with a disk
brake hub and put a mechanical disk brake on. The Avid Ball Bearing one
looks nice.
Avid Mech disks are by far the best mech disk (Not juts my opinion user and
mag reviews seem to think the same) , they have very good stopping power
once bedded in. For me they perform far better than the V's they replaced.
Set up is easy due to the fact that they have a system for compensating for
badly faced mounts, fit and forget as long as you use a good set of cables.
As for price I bought both of mine from
http://www.chainreactioncycles.com/v...c&ModelID=2617
The don't come in a box as they appear to be ex OEM, but since the real
retail is supposed to be 40 quid more each, who cares. always get nice
next day delivery from Chainreaction too no bother.


As an aside, 160mm vs 185mm - is the 185mm necessary? Or just designed for
people who are constantly on the brakes for DH purposes. I mean, I like
going down hills, but I also like going up them...

I stuck with the 160 as I vary between 11.5 and 12 stone depending on how
much cake and Chocolate I can eat ;-) No bother stopping at all.

Phil

John Appleby wrote:

Hi,

I've just had a nasty blowout at high speed which has left my front rim in
shreds. My front V-brakes, M950 XTR, are shot (seem to have fallen apart
inside). Oh, and my old Pace RC-30 forks are succumbing to rust.

So, I'm considering replacing them with a pair of RC-31s. Carbon doesn't
rust...

The question that remains, and which I'm unsure of, is what to do with the
brakes and wheel. I have basically two options, I think:
....
2) Buy RC-31s without the V-brake adapters, replace the wheel with a disk
brake hub and put a mechanical disk brake on. The Avid Ball Bearing one
looks nice.

I have Hayes mechanicals with XTR integrated shifter/V-levers -- for a
similar reason. These work great. Not considerably better at normal
braking than Vs; but mud, wet, and long downhills are dramtically
improved. I've heard and read enough good stuff about Avid's that I'd
expect the same.

The down side is that you'll have disc in the front and V in the rear.
Many claim that this is not problem. I did it for a while and found
that it wasn't a problem, but it was annoying -- I couldn't get the
balance between front and back braking as well as when the brakes were
the same. Within 3 or 4 months, I had a new rear hub and another Hayes
mechanical as father's day and birthday presents .

As an aside, 160mm vs 185mm - is the 185mm necessary? Or just designed for
people who are constantly on the brakes for DH purposes. I mean, I like
going down hills, but I also like going up them...

I'm pretty sure that the 185 is for downhill. The only times that I'm
even remotely worried is when I'm hauling down a steep mountain road (on
the way home ) and I come around a bend and find a car driven by a
little wizzened old lady/man, hugging the steering wheel for dear life,
going 10 MPH...

David

John - If you're binning the XTR V's could I trouble you for a spare part?
Been looking for the thingie that meshes with the wotsit for a good few
years without success, no-one seems able to order it and its a shame to
see
the brakes sat doing nothing for want of thingie. Its a round bit that
sits
next to the brake stud and has 6 or so 'teeth'. No problem if you're
keeping
the brakes as spares - just thought I'd ask.

I think that's the part that's broken. It fell off the inner piece some time
back and I can't get it to mesh back correctly (I have to bolt it on very
carefully). As a result one half of the brake is pulling harder than the
other and I have to compensate with the screws. The brakes aren't pulling
together quite as well as they should as a result and so braking power is
reduced, plus pads wear too much on one side.

So, I'm considering replacing them with a pair of RC-31s. Carbon doesn't
rust...

I owned a pair of these for about 3 months, very nice looking (and nice to
ride for the limited riding I did on them) but the carbon made me nervous.

Well I've been riding a Trek 9900 carbon frame for coming on 7 years now.
I'm past the point of nervous there i guess

I am perfectly happy running a 165mm rotor on both my bikes, but I am not
the heaviest bloke in the world and I don't drag the brake all the time.
As
for the Disc/Q.R. issue - I'm not going there...

Yeah hmm I'm left wondering whether the increased power of a correctly setup
V-brake might actually be all I need. I don't have a problem with clearance
and I've never had a problem with fading on the XTR pads.

The only problem is on the rear where I need a booster to stop frame flex,
but since my frame won't take a disc brake on the rear anyhow, I'm not sure
if I'll bother.

Thanks for the reply, it's given me food for thought.

Regards,

John

"John Appleby" wrote in message
...
Hi,

2) Buy RC-31s without the V-brake adapters, replace the wheel with a disk
brake hub and put a mechanical disk brake on. The Avid Ball Bearing one
looks nice.

I just bought 160 mm avid mech's to replace avid v's that I will use with my
existing LX levers. I should be riding them by the weekend after next I
hope. I'll let you know...oh I am keeping my v's on the back.

I think that normally the v-brake stopping power is fine and 160mm is
definately ok for x-coutry. Disks must be nice for the UK weather, no?
especially in the fall, winter and spring....and summer too I guess.

I never felt the need for disks but I'm getting a great deal on the brakes
and wheel and I hope to ride more over the upcoming wet and muddy months.
Maybe get something other than XTR v-brakes? it doesn't surprise me to see
flimsy, overpriced XTR stuff breaking down. I have el cheapo avid v's that
I never had trouble with.

SDC

Carbon doesn't rust...

Steel doesn't delaminate.....

Andy Chequer just a thought

I just bought 160 mm avid mech's to replace avid v's that I will use with
my
existing LX levers. I should be riding them by the weekend after next I
hope. I'll let you know...oh I am keeping my v's on the back.

Your feedback would be interesting. I shan't be buying just yet, because I
have spent too much on my bike already this month

I think that normally the v-brake stopping power is fine and 160mm is
definately ok for x-coutry. Disks must be nice for the UK weather, no?
especially in the fall, winter and spring....and summer too I guess.

Perhaps; I've never found a problem with V-Brakes myself. I find it's mostly
a question of picking the right tyres for the conditions.

I never felt the need for disks but I'm getting a great deal on the brakes
and wheel and I hope to ride more over the upcoming wet and muddy months.
Maybe get something other than XTR v-brakes? it doesn't surprise me to
see
flimsy, overpriced XTR stuff breaking down. I have el cheapo avid v's
that
I never had trouble with.

Well to be fair, they are the original M950s from when they first came out
in 1996 (I think, or was it early 1997). Anyhow, I can't complain.

I've not got a bad word to say against XTR; I've got some M900, some M950
and some M960. Some 1994 M900 hubs that have never been serviced and still
run sweet as anything. The only question in my mind is this new Hollowform
II crankset. I can't really be dealing with £75 for an outer ring when I can
buy a full RaceFace set for £65. Plus the reported poor BB bearing life in
early models. But then I always did think that Shimano were a ripoff on the
chainset. So I bought the RaceFace turbine set and I'm very happy with it so
far. Moreover, ISIS looks like it's a good technology that's here to stay.

Regards,

John