Which type of brake blocks?

[Iain Jones]

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.

When I took my bike in for a service last week, I mentioned
this to them and the guy said they probably were the wrong
type of block (didn't say what different types there are),
and he'd look at them. Next day I collected the bike and
they seemed OK but now they're noisy again.

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 don't want to leave this much longer cos I'm sure it's not
doing my rims any good. Any clues, anyone?

Thanks Iain

[Iain Jones]

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!

[David Nutter]

Iain Jones <iain.jones1980@NOSPAMbtinternet.com> 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]

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

Thanks Iain

[David Nutter]

Iain Jones <iain.jones1980@NOSPAMbtinternet.com> said:

*snip*

> [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

[Pete Biggs]

Iain Jones wrote:
> 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

[Anonymous]

"David Nutter" <David.Nutter@durham.ac.uk> wrote in message
news:slrnc8045j.csn.David.Nutter@pc059147.lincoln.ac.uk...
> Iain Jones <iain.jones1980@NOSPAMbtinternet.com> 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

[Pete Biggs]

Jon Senior wrote:

> news:c5p3l3$10a$1@newsg1.svr.pol.co.uk...
>> 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 crap 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

[Iain Jones]

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