check braking surfaces for wear! yeesh
#1
enginerd
Thread Starter
check braking surfaces for wear! yeesh
Had a tire blow off the rim after fixing a routine flat. Saw this:
Upon closer inspection, there were several small dings around the rim. The braking surface was very, very worn. We built this 48H Deep V wheel about 4 years ago. I guess it's a great sign we're riding enough!
I know the black arts so rebuilding to a fresh rim was no big deal.
All done!
With higher loads and higher speeds of tandems, this was a good wake-up call to pay close attention to details.
Upon closer inspection, there were several small dings around the rim. The braking surface was very, very worn. We built this 48H Deep V wheel about 4 years ago. I guess it's a great sign we're riding enough!
I know the black arts so rebuilding to a fresh rim was no big deal.
All done!
With higher loads and higher speeds of tandems, this was a good wake-up call to pay close attention to details.
#2
Senior Member
Join Date: Dec 2011
Location: NE Ohio
Posts: 2,576
Bikes: 1992 Serotta Colorado II,Co-Motion Speedster, Giant Escape Hybrid, 1977 Schwinn Super Le Tour
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 448 Post(s)
Likes: 0
Liked 112 Times
in
85 Posts
Learning to build a wheel is one of my winter projects! I already asked the LBS guys if they might teach me.
#3
enginerd
Thread Starter
go for it! it's actually pretty straightforward. it's math, not voodoo. take your time, don't be afraid to start over to correct tension errors, and you'll get it. I've had many a wheel that had a hop that could only be fixed by detensioning and starting over. a pain in the butt but in the end the wheel is better for it.
this is all you need:
this is all you need:
#6
Senior Member
Join Date: May 2012
Location: Point Reyes Station, California
Posts: 4,703
Bikes: Indeed!
Mentioned: 92 Post(s)
Tagged: 0 Thread(s)
Quoted: 1499 Post(s)
Liked 3,400 Times
in
1,119 Posts
Many years ago Robert Wright, a wheelbuilder from Santa Cruz, CA, put out a little book called "Building Bicycle Wheels" a very nice, concise how-to book. It still pops up used pretty regularly.
Brent
Brent
#7
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,486
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3866 Post(s)
Liked 1,911 Times
in
1,362 Posts
Usually I feel it in the brakes before the rim actually goes. Usually there'll be one spot that's a little thinner and it'll start pooching out and I'll feel it. I'll stop braking on that wheel and creep home. With the higher pressures on tandem tires, though, that margin of safety is uncomfortably small, so I'll replace my rims earlier than I would on my single.
#8
Senior Member
One advantage to disc brakes is the rim is not worn down from braking.
#9
Senior Member
Join Date: Mar 2008
Location: Santa Cruz, CA
Posts: 88
Bikes: a lot... mostly vintage, one vintage made of plastic, er carbon
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Great recommendations for both books. Building a good wheel isn't real difficult to do if you pay attention to details. It has been years since I built a wheel, but this thread is encouraging me to do so when I am ready to switch our vintage Santana over from 27" to 700c
#10
Senior Member
Join Date: Jan 2010
Location: Eugene, Oregon
Posts: 7,048
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 509 Post(s)
Likes: 0
Liked 9 Times
in
8 Posts
Good point, but I kinda doubt the rim damage in the OP's picture was caused by braking (but perhaps a lack of braking before hitting a giant pothole, or something). I don't have a lot of tandem experience, but I have always been a fairly heavy rider and live in a hilly area. In 40 years of riding I have never worn through rim braking surfaces before other issues (like the picture above) destroyed the wheel.
Great recommendations for both books. Building a good wheel isn't real difficult to do if you pay attention to details. It has been years since I built a wheel, but this thread is encouraging me to do so when I am ready to switch our vintage Santana over from 27" to 700c
Great recommendations for both books. Building a good wheel isn't real difficult to do if you pay attention to details. It has been years since I built a wheel, but this thread is encouraging me to do so when I am ready to switch our vintage Santana over from 27" to 700c
#11
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,486
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3866 Post(s)
Liked 1,911 Times
in
1,362 Posts
Good point, but I kinda doubt the rim damage in the OP's picture was caused by braking (but perhaps a lack of braking before hitting a giant pothole, or something). I don't have a lot of tandem experience, but I have always been a fairly heavy rider and live in a hilly area. In 40 years of riding I have never worn through rim braking surfaces before other issues (like the picture above) destroyed the wheel.
Great recommendations for both books. Building a good wheel isn't real difficult to do if you pay attention to details. It has been years since I built a wheel, but this thread is encouraging me to do so when I am ready to switch our vintage Santana over from 27" to 700c
Great recommendations for both books. Building a good wheel isn't real difficult to do if you pay attention to details. It has been years since I built a wheel, but this thread is encouraging me to do so when I am ready to switch our vintage Santana over from 27" to 700c
Yeah, definitely build your own wheels. You do need a Park TM-1 tension meter. It will pay for itself in two wheels. Besides, it's fun and you get more reliable wheels. When I buy my spokes, I spec the hub and rim and the shop sells me the correct length. I know, I could figure it myself, but it's nice to have the vendor spec it. I always use DT 14-15 double butted spokes, for my singles and tandem. Deep V's build up nicely for our tandem.
#12
Senior Member
Join Date: Mar 2008
Location: Santa Cruz, CA
Posts: 88
Bikes: a lot... mostly vintage, one vintage made of plastic, er carbon
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Wow, never too old to stop learning as they say! Failures like that are what make me really miss riding tubulars (which I wouldn't be using on either my tandem or my commute bike which besides spin class "bikes" account for the vast majority of my riding now). Really good to know. I would have sworn that was from a pothole, but in thinking about it I get it now. Thank you for the clarification! I guess my commute bike is just so overbuilt (super-strong 26" MTB wheels) it hasn't been an issue (this despite a 800 foot daily descent rain or shine).
#14
Senior Member
I don't know about you, but 20 years ago now only did I weigh less but I thought I was immortal which I expect led to far less use of the brakes
#15
Senior Member
Join Date: Mar 2008
Location: Santa Cruz, CA
Posts: 88
Bikes: a lot... mostly vintage, one vintage made of plastic, er carbon
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I think this accelerates the plan to ditch our 27" wheels for new 700c wheels once we wear the current set of Gatorskins out. Thanks again for the heads up!
#16
just another gosling
Join Date: Feb 2007
Location: Everett, WA
Posts: 19,486
Bikes: CoMo Speedster 2003, Trek 5200, CAAD 9, Fred 2004
Mentioned: 115 Post(s)
Tagged: 0 Thread(s)
Quoted: 3866 Post(s)
Liked 1,911 Times
in
1,362 Posts
To keep track of brake track wear, you really need a pin micrometer. I have a physicist friend who owns a machine shop and uses one. IIRC he said 1.5mm is about the failure point on his singles. Tandems should be more conservative.
#17
enginerd
Thread Starter
A guru at a shop once told me this is partly due to much more effective modern brakes. Road dual pivots, linear pull mtn brakes with modern pads have more squeeze than sidepulls ever did.