Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 03-25-11, 08:36 PM   #1
I_like_cereal
Fail Boat crewman
Thread Starter
 
Join Date: Feb 2011
Location: PDX
Bikes: Reynolds 853 Jamis Quest 1990s
Posts: 675
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
This is a warning!!

Whenever your LBS tells you that you have a dip and dice in your braking surface. DO NOT, I repeat DO NOT inflate your tires to 120 psi.

I did and it BENT the sidewall and peeled the brake surface off like tin can.

The best part was I had a slime tube in there and the rim shredded the tube.

It sounded like a gun shot went off and my ears are still ringing. I had slime everywhere. It was gross.
I_like_cereal is offline   Reply With Quote
Old 03-25-11, 09:01 PM   #2
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Bikes: Several, mostly not name brands.
Posts: 16,514
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 120 Post(s)
Eww... nasty!
JohnDThompson is offline   Reply With Quote
Old 03-25-11, 09:05 PM   #3
gitarzan
Lost Again
 
gitarzan's Avatar
 
Join Date: Jul 2009
Location: Columbus, Oh!
Bikes: Soma Saga, 1991 Sirrus, Specialized Secteur Elite, Miele Umbria Elite.
Posts: 1,041
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by I_like_cereal View Post
It sounded like a gun shot went off and my ears are still ringing. I had slime everywhere. It was gross.
Sounds like a scene from a movie.
gitarzan is offline   Reply With Quote
Old 03-25-11, 10:38 PM   #4
hardyt
Junior Member
 
Join Date: Mar 2011
Location: DC area
Bikes:
Posts: 24
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
OP, the dip goes under your lip and the dice hang off the review mirror, not on your braking surface!
hardyt is offline   Reply With Quote
Old 03-25-11, 11:03 PM   #5
Jeff Wills
Insane Bicycle Mechanic
 
Jeff Wills's Avatar
 
Join Date: Mar 2008
Location: other Vancouver
Bikes:
Posts: 7,973
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Quote:
Originally Posted by I_like_cereal View Post
Whenever your LBS tells you that you have a dip and dice in your braking surface. DO NOT, I repeat DO NOT inflate your tires to 120 psi.

I did and it BENT the sidewall and peeled the brake surface off like tin can.

The best part was I had a slime tube in there and the rim shredded the tube.

It sounded like a gun shot went off and my ears are still ringing. I had slime everywhere. It was gross.
I hate to say "I told you so", but... I told you so! At least you didn't have it go bang on a ride, in the rain, 20 miles from home:
__________________
Jeff Wills

Comcast nuked my web page. It will return soon..
Jeff Wills is offline   Reply With Quote
Old 03-25-11, 11:09 PM   #6
Camilo
Senior Member
 
Join Date: Apr 2007
Bikes:
Posts: 4,140
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 60 Post(s)
Why would you inflate your tires to 120?
Camilo is offline   Reply With Quote
Old 03-26-11, 05:05 AM   #7
blamp28
Bikaholic
 
blamp28's Avatar
 
Join Date: Dec 2006
Location: Western, Michigan
Bikes: Trek Fuel 90, Giant OCR, Rans Screamer Tandem
Posts: 1,465
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Camilo View Post
Why would you inflate your tires to 120?
Some tires are inflated to 120 or more. My road tires (700x23) max out at 120. I've always thought of slime for larger mtb type tires though and those usually max out around 60 or 65 psi
blamp28 is offline   Reply With Quote
Old 03-26-11, 05:27 AM   #8
clydeosaur
Senior Member
 
clydeosaur's Avatar
 
Join Date: Aug 2009
Location: Central PA
Bikes: Cannondale Six5, Specialized Stumpjumper FSR & old Hard Rock
Posts: 612
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I run my 23's @ 110 - 120 all the time & have never had a problem.
clydeosaur is offline   Reply With Quote
Old 03-26-11, 05:37 AM   #9
jimc101
Senior Member
 
Join Date: Oct 2007
Location: West Yorkshire, United Kingdom
Bikes:
Posts: 4,809
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
Simplest thing to do if any bike part looks worn is to replace, unless you understand that it could fail on you.

If you had replaced the rim, you would have saved the tube and tire; spend a little now, to prevent unnecessary costs later
jimc101 is offline   Reply With Quote
Old 03-26-11, 05:42 AM   #10
mconlonx 
Nobody
 
mconlonx's Avatar
 
Join Date: Jun 2007
Bikes:
Posts: 7,148
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 612 Post(s)
Your new rim will come with a wear indicator. Pay attention to it...
__________________
I know next to nothing. I am frequently wrong.
mconlonx is offline   Reply With Quote
Old 03-26-11, 07:21 AM   #11
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 28,917
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Just looking at what remains of your rim, it's apparent it was badly worn at the brake track. Overinflating that tire just made the inevitable happen sooner.

I inflate 700x23 tires to 120 psi routinely but I also try to replace badly worn rims before they fail.
HillRider is offline   Reply With Quote
Old 03-26-11, 07:29 AM   #12
MichaelW
Senior Member
 
Join Date: Feb 2001
Location: England
Bikes:
Posts: 12,926
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
That is called proof testing, best done whilst wearing eye protection and tough gloves. Its quite a useful procedure if you think your braking surfaces are a bit thin.
MichaelW is offline   Reply With Quote
Old 03-26-11, 10:03 AM   #13
JPMacG
Senior Member
 
Join Date: Dec 2006
Location: Bucks County, PA
Bikes:
Posts: 400
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Please explain what a "did and dice" is. I have never heard that term before.
JPMacG is offline   Reply With Quote
Old 03-26-11, 10:19 AM   #14
davidad
Senior Member
 
Join Date: Feb 2009
Bikes:
Posts: 4,895
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 24 Post(s)
Why inflate a 32mm tire to 120PSI? https://www.adventurecycling.org/res...SIRX_Heine.pdf
davidad is offline   Reply With Quote
Old 03-26-11, 10:26 AM   #15
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,927
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 349 Post(s)
Unlike tubulars where the tire is a self-contained closed pressure vessel, wired-on tires are open on the bottom and require the rim to hold the sides in against the pressure. The stress on the side is proportional to the inflation pressure and the width of the tire.

Here's an easy to understand explanation of how to calculate the stress as related to pressure and cross-section.

Rims are built sufficiently strong to restrain the outward force of the tires they're designed for, but with brake wear progressively lose strength at the critical base of the flange. The point at which they blow apart depends on the tire pressure, and the tire width, and the amount of remaining strength, which eventually becomes inadequate to the task.

If you ever see any hint of cracks running lengthwise along the brake track it's time to scrap the wheel. For those who pick up stones in the brake shoes, a single deep score can be enough to kill the rim.

If your rims are deep enough you can push out the point of failure by mounting the brake shoes so that the brake track in within the box section of the rim and they don't remove material from the critical base of the tire flange.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.

Last edited by FBinNY; 03-26-11 at 10:30 AM.
FBinNY is offline   Reply With Quote
Old 03-26-11, 10:57 AM   #16
HillRider 
Senior Member
 
Join Date: Aug 2005
Location: Pittsburgh, PA
Bikes: '''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
Posts: 28,917
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 94 Post(s)
Quote:
Originally Posted by FBinNY View Post
If your rims are deep enough you can push out the point of failure by mounting the brake shoes so that the brake track in within the box section of the rim and they don't remove material from the critical base of the tire flange.
That's got some limitations too. The last rim failure I had cracked circumferentially right below the bead hook. Fortunately the only symptom was a noticable "tick" when I applied the brakes and the rim and tube held together long enough for me to get home.

Lesson learned: No rim last forever.
HillRider is offline   Reply With Quote
Old 03-26-11, 11:10 AM   #17
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,927
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 349 Post(s)
Quote:
Originally Posted by HillRider View Post


Lesson learned: No rim last forever.
That's the key, you can only buy time, but eventually rims die and need rebuilding.

I must either not stop enough, or have worse roads than most (probably true) because in over 100,000 miles of riding I've yet to ever wear out a rim's sides. My rims tend to die from impact damage, usually caused by rain filled potholes. It's kind of like getting hit by a bus before the coronary artery disease gets you.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 03-26-11, 02:34 PM   #18
coldfeet
Senior Member
 
coldfeet's Avatar
 
Join Date: Dec 2007
Bikes:
Posts: 2,119
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Jeff Wills View Post
I hate to say "I told you so", but... I told you so! At least you didn't have it go bang on a ride, in the rain, 20 miles from home:
Or at speed on a downhill, I cringe just thinking about it!
coldfeet is offline   Reply With Quote
Old 03-26-11, 03:06 PM   #19
bkaapcke
Senior Member
 
Join Date: Jul 2005
Bikes:
Posts: 3,227
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Get Schwalbe marathon racers and forget the slime. bk
bkaapcke is offline   Reply With Quote
Old 03-26-11, 03:08 PM   #20
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,927
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 349 Post(s)
Quote:
Originally Posted by bkaapcke View Post
Get Schwalbe marathon racers and forget the slime. bk
Definitely will reduce the mess, but won't prevent rim failure.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 03-26-11, 03:18 PM   #21
xizangstan
Senior Member
 
xizangstan's Avatar
 
Join Date: Aug 2010
Location: Colorado-California-Florida-(hopefully soon): Panama
Bikes: Vintage GT Xizang (titanium mountain bike)
Posts: 1,061
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I think I know why they invented disc brakes for bikes...
xizangstan is offline   Reply With Quote
Old 03-26-11, 05:43 PM   #22
jeepr
Senior Member
 
jeepr's Avatar
 
Join Date: Mar 2011
Location: Detroit, MI
Bikes:
Posts: 552
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Sounds exciting!
jeepr is offline   Reply With Quote
Old 03-26-11, 07:11 PM   #23
Jeff Wills
Insane Bicycle Mechanic
 
Jeff Wills's Avatar
 
Join Date: Mar 2008
Location: other Vancouver
Bikes:
Posts: 7,973
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Quote:
Originally Posted by davidad View Post
32mm tire on the back of a tandem or (in my case) a rear-wheel-biased recumbent. I chatted with Jan Heine a couple months back here in Portland about this article. Very interesting and very opinionated person. But he backs up his opinions with testing.
__________________
Jeff Wills

Comcast nuked my web page. It will return soon..
Jeff Wills is offline   Reply With Quote
Old 03-26-11, 09:15 PM   #24
BCRider
Senior Member
 
BCRider's Avatar
 
Join Date: Mar 2008
Location: The 'Wack, BC, Canada
Bikes: Norco (2), Miyata, Canondale, Soma, Redline
Posts: 5,456
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by xizangstan View Post
I think I know why they invented disc brakes for bikes...

Mountain bikers that used to ride a lot of downhilly areas in the days before disc brakes and lived in areas with LOTS of rain tended to go through at least one set of rims a season. Some went through two. The grinding action fo the mud in the pads combined with lots of energetic braking pretty much added up to "sanding" through the rim braking tracks in those heady days before discs became the solution for such riders.

I live up close to "The Shore" and talk with a fair number of riders that consider this crazily extreme riding site to be "just another EXTREME day in the park". Those with a few years under their belt if asked "what is the best ever tech introduction for mountain bikes would likely rank suspension forks as number one but then waffle back and forth over disc brakes or full suspension as number two and three from the stories I've heard.
BCRider is offline   Reply With Quote
Old 03-27-11, 11:35 AM   #25
1saxman
Senior Member
 
Join Date: Jan 2011
Location: VA
Bikes: Trek 930 (1992)
Posts: 172
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by mconlonx View Post
Your new rim will come with a wear indicator. Pay attention to it...
I've come back into cycling after a long hiatus, and I've read here before about the 'wear indicator' in a rim. What is it and how can you tell if a rim has it? If I had to guess, I'd say it is a dark-colored layer under the surface of the rim that becomes visible with wear. Am I close?
1saxman is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 03:27 AM.