Which type of brake blocks?

BTW when I bought the new blocks, they were from the same
shop I bought the bike itself from, and I told them which
bike they were for... I get more wary of that shop every
time I go there!

Iain Jones <[email hidden]> said:

*snip*

Quoted message said:

[Scratching]

The bike's got Rigida Vela rims (Google search doesn't
give much info and not listed on Rigida's website), and
Tektro dual-pivot brakes (again, Giant's website doesn't
give much info). And very VERY stupidly, I chucked the
packets the new blocks came in :-(.

I've had problems with Shimano blocks scratching the rim
when wet. This also featured a horrid scraping noise caused
by little bits of aluminium peeling off the rim and
embedding in the block. The scratching occurred with both
Mavic and Rigida rims, though the problem seemed to be
slightly worse with the latter rim.

Brake performance was rubbish too, wet or dry.

I replaced the blocks with Avid Rim Wrangler V brake inserts
(cantilevers with V-Brake shoes) which are much better.
Aztec/Madison blocks seem to be widely available and though
the braking performance isn't brilliant, they don't scratch
the rim. I use these pads with the 105 dual pivots on my
fixed, so far no scratching.

Regards,

-david

More info - just had a look at the brakes, the blocks are
Shimano M50/T

Thanks Iain

Iain Jones said:

More info - just had a look at the brakes, the blocks are
Shimano M50/T

There's your problem 🙂

Regards,

-david likes Shimano blocks not at all

Iain Jones said:

Not long ago I replaced both front and back brake blocks
on my OCR4. Since then they make a terrible noise when
braking, but I left it because I thought it might be
because they're new and they'll bed in and quieten down.
But no, weeks on, they make a terrible scraping noise
especially when wet (as in this evening). It's the kind of
noise you get off completely worn-down blocks, when some
of the metal's rubbed through. But it's clearly not that,
there's loads of wear left on them yet.

A certain amount of noise doesn't matter but I recommend
doing the following anyway:

Replace pads/shoes with something better, eg. Kool Stop
Salmon or Dual. See www.wiggle.co.uk . "Dura holder" will
fit your brakes if you don't already have cartridge types
(but I have a pair of KS refills for sale if you do).

Regularly inspect blocks and dig out any embedded specks of
metal. Keep rims and blocks clean by washing with water
then degreasing with meths. Occasionally give blocks a
light sanding.

Only use rear brake in the wet when really necessary. Rear
braking tends to cause most wear and mess. Keep wheels true,
allow a bit of extra clearance for brake blocks at rear to
cope with wheel flex.

~PB

"David Nutter" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Iain Jones said:

More info - just had a look at the brakes, the blocks
are Shimano M50/T

There's your problem 🙂

Regards,

-david likes Shimano blocks not at all

Seconded - chuck the shimano blocks ASAP.

cheers, clive

Jon Senior said:

"]news:[email hidden]...

Quoted message said:

Seconded - chuck the shimano blocks ASAP.

Interesting, I too am running a pair of Shimano M50/T
blocks on both fixer (front) and Giant OCR (rear). The
latter is relatively unused at present. I get the same
scraping noise, and now I think about
it... the front rim of the fixer is showing some unusual
marks. They are preferable to the [censored] blocks which
came with the Alongha long reach dual pivots I just
fitted, which made no discernable difference to bike
speed in the wet.

I was trying to get inserts for the 105 blocks that came
with the Giant, but the LBS didn't have any originally.
General consensus seems to be Kool-Stop, but I've tried
some of their stand alone (cheap - I think!) brake blocks
and was singularly unimpressed.

My Campag Mirage dual pivots with a salmon coloured version
(made with iron oxide) of "Dura" Kool Stops are the best
brakes I've ever used on any bicycle with rim brakes.
Stopping power and modulation is incredible. They amaze me
every time I use them. However, the same blocks haven't
worked half as well for me on other bikes, even with exactly
the same type of calipers and levers. Just goes to prove
that brake pad type and compound is only one small factor of
braking performance.

Anyway, if you or anyone would like to try some Kool Stop
Dual refills (half salmon, half black), let me know your
address and I'll post you a pair (of half used ones). Please
then either return them if don't like or bung me £1.50 if
you do. They should fit 105's.

~PB p[at]biggs[dot]tc

Thanks for the advice everyone, I never knew Shimano could
be despised so much! Has anyone told them their brake
blocks are rubbish? The blocks that were on when I bought
the bike were Tektro's own, and they were pretty much
silent and much more "comfortable" in terms of controlling
my speed, just the odd screech if I pulled them too
suddenly. But the new Shimanos - there's constantly that
feeling they'll lock up and throw me over the handlebars if
I pull too tight. Another observation last night was little
silver flecks on the edges of the blocks, I assume these
were shaved off the rim...

So - thanks everyone, I'll change them ASAP. Pete - email
on the way.

Iain