M
Mark South
Guest
Today I exeperienced something new to me.
About 20 km into my Sunday morning ride, I was coming up a
gentle hill into a tiny village and thinking "Hell, I must
be getting weaker every day, why is this incline so hard?"
So, I stopped for a breather and hopped of the bike. When I
was about to get on I noticed that the bike didn't roll
easily. Lifting the front wheel and spinning it showed the
front brake was binding hard, which explained the difficulty
up the gentle hill.
Now the question: how did this happen? Before you answer,
some facts:
A. The rim was and is true to within better than 1mm.
B. The wheel spun freely at the start of the ride (I
always check).
C. The brake adjuster had not moved - it was locked onto
the locknut.
D. I adjusted these brakes 6 weeks ago and they have been
perfect since then, until today.
E. Ambient conditions were blue sky, sun, steady cool
breeze, temps about 25 Celsius with wind cooling, hotter
out of the wind.
F. I hadn't done any heavy braking on the ride so far.
G. These are dual pivots on a road bike, with plain black
stock Shimano pads.
H. The pads were running just clear of the rim all round.
So, could the pads have absorbed enough sun to heat and
expand and bind on the rim?
Has anyone else ever seen this happen?
Or is there another explanation?
--
Mark South: World Citizen, Net Denizen
About 20 km into my Sunday morning ride, I was coming up a
gentle hill into a tiny village and thinking "Hell, I must
be getting weaker every day, why is this incline so hard?"
So, I stopped for a breather and hopped of the bike. When I
was about to get on I noticed that the bike didn't roll
easily. Lifting the front wheel and spinning it showed the
front brake was binding hard, which explained the difficulty
up the gentle hill.
Now the question: how did this happen? Before you answer,
some facts:
A. The rim was and is true to within better than 1mm.
B. The wheel spun freely at the start of the ride (I
always check).
C. The brake adjuster had not moved - it was locked onto
the locknut.
D. I adjusted these brakes 6 weeks ago and they have been
perfect since then, until today.
E. Ambient conditions were blue sky, sun, steady cool
breeze, temps about 25 Celsius with wind cooling, hotter
out of the wind.
F. I hadn't done any heavy braking on the ride so far.
G. These are dual pivots on a road bike, with plain black
stock Shimano pads.
H. The pads were running just clear of the rim all round.
So, could the pads have absorbed enough sun to heat and
expand and bind on the rim?
Has anyone else ever seen this happen?
Or is there another explanation?
--
Mark South: World Citizen, Net Denizen