My brake blocks appear to be eating my rims

[Kestevan]

I'd like to point out the the "new" Shimano Dura-ace pads appear to be more akin to the koolstop pads and no longer pick up mahoosive amounts of rim destroying metal bits.

 

[Yellow Saddle]

I'd like to point out the the "new" Shimano Dura-ace pads appear to be more akin to the koolstop pads and no longer pick up mahoosive amounts of rim destroying metal bits.

Yes, I believe so. Funny how on the official Shimano professional's forum they deny it had ever been a problem. I still want to know what was changed in the rubber.

 

[swee'pea99]

FWIW (not much, probably) I've been amazed by the performance of these - in my case, second hand, which I took off an old (high end) broken motobecane I bought for spares. They're on the front (only) brake on my fixie, and I live surrounded by hills, so they get a lot of quite hard use. They work really well, dry or wet, I've had them on the bike for what must be three or four years now, and they seem to have plenty of life left in them, and they don't cost silly money.

 

[Ian H]

Quality of brake block material is important, but has no-one suggested learning to use the brakes less?

 

[Kestevan]

Quality of brake block material is important, but has no-one suggested learning to use the brakes less?

Good luck with that in the Pennines... I probably use mine less than most riders ( @I like Skol and @nickyboy excepted) and still go through a rim in 2 - 3 years of winter commuting.

 

[ColinJ]

Good luck with that in the Pennines... I probably use mine less than most riders ( @I like Skol and @nickyboy excepted) and still go through a rim in 2 - 3 years of winter commuting.

Indeed ... This is the profile of Saturday's Settle forum ride:

I tried to avoid braking where I could (ask @Pale Rider, @Sea of vapours and @oldfatfool, who followed me down most of the descents) but my brake blocks were getting very hot nonetheless! Serious injury or death would follow NOT doing significant braking on the descents at 20, 40, 65 and 80 kms!

 

[oldfatfool]

I tried to avoid braking where I could

Indeed my gps measured a max velocity of a smidge under 75 kph

 

[ColinJ]

Indeed my gps measured a max velocity of a smidge under 75 kph

I haven't downloaded my recent tracklogs ... I'll do that now!

PS 71 kph - oldfatfool must have been gaining on me!

 

[confusedcyclist]

For the person that asked, my green swisstops do pick up aluminium. I'll be using koolstop from now on!

 

[KnackeredBike]

For the person that asked, my green swisstops do pick up aluminium. I'll be using koolstop from now on!

I have always been sceptical of Koolstop pads because ultimately the amount of kJ of heat generated when braking is fixed. So the only way you can reduce that is for the pad to be less effective, or better at conducting the heat away. Bearing in mind almost all the heat will be conducted away by the rim rather than the pad, I am tempted to believe they are trading on the fact that when you put any new brake pad on they feel better, not least because they are optimally adjusted again.

But perhaps I am cynical.

 

[Yellow Saddle]

I have always been sceptical of Koolstop pads because ultimately the amount of kJ of heat generated when braking is fixed. So the only way you can reduce that is for the pad to be less effective, or better at conducting the heat away. Bearing in mind almost all the heat will be conducted away by the rim rather than the pad, I am tempted to believe they are trading on the fact that when you put any new brake pad on they feel better, not least because they are optimally adjusted again.

But perhaps I am cynical.

Perhaps not cynical, but confused about cause and effect.

No-one is saying that heat is the problem. Koolstops cope better, not conduct better.

 

[KnackeredBike]

@Yellow Saddle How can Koolstop ones be less wearing then any compound that is comparably hard or soft? Either you sacrifice the rim or pad for any given amount of deceleration force over a particular period of time?

Not doubting you, I just don't understand how it is physically possible without the impossibility of generating less heat whilst stopping?

 

[Yellow Saddle]

@Yellow Saddle How can Koolstop ones be less wearing then any compound that is comparably hard or soft? Either you sacrifice the rim or pad for any given amount of deceleration force over a particular period of time?

Not doubting you, I just don't understand how it is physically possible without the impossibility of generating less heat whilst stopping?

All pads, in fact, all friction generates heat. No-one denies that. The issue is how much one pad wears for the equivalent "quantity of stopping" than another pad.
Have a look a the photos I posted. That should give you an indication.

Pad wear is material loss. This happens when the molecular bonds in the rubber break off. Some rubber compounds (they are all cross-linked polymers but different) break off easier than others. They are stronger, if you wish. That doesn't mean softer or harder, just stronger.

 

[alecstilleyedye]

koolstop is my pad of choice, although campag ones seem just as good...