Go Back  Bike Forums > Bike Forums > Commuting
Reload this Page >

Cause of flats

Notices
Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

Cause of flats

Old 05-02-15, 07:35 AM
  #1  
mcours2006
Senior Member
Thread Starter
 
mcours2006's Avatar
 
Join Date: Jul 2014
Location: Toronto, CANADA
Posts: 6,061

Bikes: Giant Rapid, Bianchi Advantage, Specialized Roubaix, 1985 Gardin Quatro, Norco Threshold, Raleigh Serengheti MTB

Mentioned: 47 Post(s)
Tagged: 0 Thread(s)
Quoted: 1938 Post(s)
Liked 286 Times in 168 Posts
Cause of flats

I had a flat this morning and had to sit on the side of the road to replace the tube. Took a good 20 minutes b/c the valve stem wouldn't seat properly. This is the third or fourth flat on this particular tire/tube/rim combo. It got me thinking, what's the most likely cause of the flat? Tire manufacturers claim 'flat-resistance', but how does tire prevent a puncture from inside? The road I was on when I got the flat had lots of debris like sand, gravel, and salt on it from winter road maintenance.
mcours2006 is offline  
Old 05-02-15, 07:39 AM
  #2  
trailerpark
Junior Member
 
Join Date: Apr 2015
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
What kinda stems are you using? On Schrader valves I've found it best not to pull them out.

Bad luck is the cause of all flats.
trailerpark is offline  
Old 05-02-15, 07:57 AM
  #3  
mcours2006
Senior Member
Thread Starter
 
mcours2006's Avatar
 
Join Date: Jul 2014
Location: Toronto, CANADA
Posts: 6,061

Bikes: Giant Rapid, Bianchi Advantage, Specialized Roubaix, 1985 Gardin Quatro, Norco Threshold, Raleigh Serengheti MTB

Mentioned: 47 Post(s)
Tagged: 0 Thread(s)
Quoted: 1938 Post(s)
Liked 286 Times in 168 Posts
I've got the presta value stem. The puncture is not near the stem, though.

Yeah, I agree about the bad luck.

I think it's the narrow tires. I've never gotten a flat on my hybrid with the 32mm city tires nor the 35mm studded tires.
mcours2006 is offline  
Old 05-02-15, 08:14 AM
  #4  
wolfchild
Senior Member
 
wolfchild's Avatar
 
Join Date: Feb 2008
Location: Mississauga/Toronto, Ontario canada
Posts: 6,855

Bikes: I have 3 singlespeed/fixed gear bikes

Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 2297 Post(s)
Liked 1,102 Times in 557 Posts
When changing your tubes on the side of the road, you need to be very careful that no road debris, sand particles or little stones get inside your tire.. It's very easy to get new tubes and the insides of your tires contaminated with road crap when doing roadside repairs.. You need to make sure that your tube and the inside of the tire is clean and free from any road debris, because if it's not, then your tube will get punctured from the inside after you pump your tires up.
wolfchild is offline  
Old 05-02-15, 08:18 AM
  #5  
mcours2006
Senior Member
Thread Starter
 
mcours2006's Avatar
 
Join Date: Jul 2014
Location: Toronto, CANADA
Posts: 6,061

Bikes: Giant Rapid, Bianchi Advantage, Specialized Roubaix, 1985 Gardin Quatro, Norco Threshold, Raleigh Serengheti MTB

Mentioned: 47 Post(s)
Tagged: 0 Thread(s)
Quoted: 1938 Post(s)
Liked 286 Times in 168 Posts
Originally Posted by wolfchild View Post
When changing your tubes on the side of the road, you need to be very careful that no road debris, sand particles or little stones get inside your tire.. It's very easy to get new tubes and the insides of your tires contaminated with road crap when doing roadside repairs.. You need to make sure that your tube and the inside of the tire is clean and free from any road debris, because if it's not, then your tube will get punctured from the inside after you pump your tires up.
Thanks, that's good advice. I was off on the grass area of the road, fortunately, and well out of the way of traffic, so I think the contamination was minimal, if any at all. And 50km later it seemed fine.
mcours2006 is offline  
Old 05-02-15, 02:48 PM
  #6  
dynaryder
PatronSaintOfDiscBrakes
 
dynaryder's Avatar
 
Join Date: Apr 2005
Location: BicycleSPACE warehouse in SW Washington DC
Posts: 6,980
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Where are the punctures? If they're on the outer part of the tube(facing tire),then it's from something that got through the tire. Always turn your tire inside-out by section to ensure nothing's still embedded in the casing. If the puncture is on the inner part(facing the wheel),then it could be a bad spot of rim tape,or a sharp edge in the rim. Check your rim tape,and either use a cottonball or carefully run your finger around the rim to ensure everything's smooth.
__________________

C'dale BBU('05 and '09)/Super Six/Hooligan8and 3,Kona Dew Deluxe,Novara Buzz/Safari,Surly Big Dummy,Marin Pt Reyes,Giant Defy 1,Schwinn DBX SuperSport,Dahon Speed Pro TT,Brompton S6L/S2E-X
dynaryder is offline  
Old 05-03-15, 08:37 AM
  #7  
willhenry
Member
 
willhenry's Avatar
 
Join Date: Jun 2014
Location: Vancouver
Posts: 25

Bikes: Norco XFR

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Many flats are caused by pinching (between tire bead and rim). It's usually because people install the tube almost flat and a bit of it gets pinched when the tire is levered back on. I always partially inflate the tube before installation to reduce the chances, but it happens.

I'd also inspect the interior of the rim for burrs (carefully, as @dynaryder suggests). Makes sure your rim tape is in good shape.
willhenry is offline  
Old 05-03-15, 09:57 AM
  #8  
TransitBiker
contiuniously variable
 
TransitBiker's Avatar
 
Join Date: Apr 2014
Location: Southeastern Pennsylvania
Posts: 2,280

Bikes: 2012 Breezer Uptown Infinity, Fuji Varsity

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Liked 6 Times in 4 Posts
I have had flats where something innocent got into a tire hole created by a nasty thing i rode over. You could put some masking tape over the hole inside of the tire if it's a concern for more FOD infiltration.

Always check the tire & rim for pokey non-smooth stuff when possible.

As for me, i'm going to be switching to thorn-proof tubes, as the peace of mind is worth the bit of extra cost & few oz of weight

- And.
TransitBiker is offline  
Old 05-03-15, 10:04 AM
  #9  
sirtirithon
Senior Member
 
sirtirithon's Avatar
 
Join Date: Apr 2011
Location: Spokane
Posts: 279
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I have had issues where a small piece of wire was embedded in the tread and could not be felt by running my hand around the inside of the tire yet when under pressure from inflation and riding it managed to puncture the tube again. Talk about frustrating. The best way to deal with that is to use a sharpie and make a reference mark on the tire where the stem of the tube is in relation to the tire, locate the puncture and then closely inspect the tire, folding it and probing around for anything embedded in the tread.
sirtirithon is offline  
Old 05-03-15, 10:21 AM
  #10  
bowlofsalad
Senior Member
 
Join Date: Feb 2013
Location: Midwest USA
Posts: 61
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
I imagine the most common causes of flats on bicycles relates to things puncturing the tire.

There are a pretty incredible range of tires to choose from, and you neglected to mention which you use. The tire you use can make a massive difference in how often you get flats.

Pinch flats are from when the tire is compressed so deeply and hard that the inner tube is cut. Wider tires can help with this.

Schwalbe marathon plus tires are very likely to alleviate any flats, the world of bicycle components looks very different when you look to it for reliability rather than going fast.
bowlofsalad is offline  
Old 05-03-15, 10:22 AM
  #11  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 9,665

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 103 Post(s)
Tagged: 0 Thread(s)
Quoted: 2989 Post(s)
Liked 1,587 Times in 1,051 Posts
Originally Posted by willhenry View Post
Many flats are caused by pinching (between tire bead and rim). It's usually because people install the tube almost flat and a bit of it gets pinched when the tire is levered back on. I always partially inflate the tube before installation to reduce the chances, but it happens.

I'd also inspect the interior of the rim for burrs (carefully, as @dynaryder suggests). Makes sure your rim tape is in good shape.
The trick to very quickly blowing up the tube to the perfect pressure for mounting? Blow it up by mouth. Blow hard. (You can; you're a cyclist!) Much faster than messing with a pump or canister.

Ben
79pmooney is offline  
Old 05-03-15, 11:47 AM
  #12  
tjspiel
Senior Member
 
tjspiel's Avatar
 
Join Date: Jun 2007
Location: Minneapolis
Posts: 8,097
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 52 Post(s)
Likes: 0
Liked 9 Times in 8 Posts
Originally Posted by sirtirithon View Post
I have had issues where a small piece of wire was embedded in the tread and could not be felt by running my hand around the inside of the tire yet when under pressure from inflation and riding it managed to puncture the tube again. Talk about frustrating. The best way to deal with that is to use a sharpie and make a reference mark on the tire where the stem of the tube is in relation to the tire, locate the puncture and then closely inspect the tire, folding it and probing around for anything embedded in the tread.
A trick I learned here was to find the most prominent logo on the tire and center that over the stem. It's the same concept as your sharpie... without the sharpie.
tjspiel is offline  
Old 05-03-15, 11:48 AM
  #13  
79pmooney
A Roadie Forever
 
79pmooney's Avatar
 
Join Date: Oct 2014
Location: Portland, OR
Posts: 9,665

Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder

Mentioned: 103 Post(s)
Tagged: 0 Thread(s)
Quoted: 2989 Post(s)
Liked 1,587 Times in 1,051 Posts
Originally Posted by sirtirithon View Post
I have had issues where a small piece of wire was embedded in the tread and could not be felt by running my hand around the inside of the tire yet when under pressure from inflation and riding it managed to puncture the tube again. Talk about frustrating. The best way to deal with that is to use a sharpie and make a reference mark on the tire where the stem of the tube is in relation to the tire, locate the puncture and then closely inspect the tire, folding it and probing around for anything embedded in the tread.
Yeah, the 21st century cyclist's curse, automobile tire reinforcing wire. Pieces of very sharp wire can get picked up by your tire that are shorter than the distance from tread to inside of cord. But they will travel through to your tube. That is a good reason for patching tubes. When patches start appearing in the same place, you know exactly where the issue is. You can find hidden wire when you know ahead of time it's location within an inch.

Ben
79pmooney is offline  
Old 05-03-15, 03:30 PM
  #14  
ThermionicScott 
working on my sandal tan
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Posts: 20,749

Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers), All-City Space Horse (hers)

Mentioned: 93 Post(s)
Tagged: 0 Thread(s)
Quoted: 3030 Post(s)
Liked 1,080 Times in 738 Posts
Originally Posted by 79pmooney View Post
The trick to very quickly blowing up the tube to the perfect pressure for mounting? Blow it up by mouth. Blow hard. (You can; you're a cyclist!) Much faster than messing with a pump or canister.

Ben
+1. And if one doesn't want to use their lungs, I prefer pushing in the air by mouth, if that makes sense. I can get a little more pressure that way without straining anything and getting light-headed.
__________________
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
Originally Posted by noglider
People in this forum are not typical.
RUSA #7498
ThermionicScott is offline  
Old 05-03-15, 09:21 PM
  #15  
Big Lebowski
Senior Member
 
Big Lebowski's Avatar
 
Join Date: Apr 2012
Location: Kansas City
Posts: 328

Bikes: Trek 9th District, CAAD 10, Crux

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by mcours2006 View Post
The road I was on when I got the flat had lots of debris like sand, gravel, and salt on it from winter road maintenance.
Until 2 years ago, I had the same issue with road sand causing flats. I was using Gatorskins, but a sharp flinty stones that get dumped on the roads during the winter still got through it. I've since switched to a Kenda tire with a small tread and I have had no issues.
Big Lebowski is offline  
Old 05-03-15, 09:48 PM
  #16  
prathmann
Senior Member
 
Join Date: Nov 2008
Location: Bay Area, Calif.
Posts: 7,239
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 659 Post(s)
Likes: 0
Liked 4 Times in 3 Posts
Originally Posted by mcours2006 View Post
Took a good 20 minutes b/c the valve stem wouldn't seat properly.
...
It got me thinking, what's the most likely cause of the flat?
Did you push the valve stem a little into the rim before inflating the tube to be sure you didn't get the section near the valve pinched under the tire bead? Easy for that to happen and it'll keep the tire from seating properly near the valve stem and can also cause a blowout flat if it dislodges the tire bead.

As to the cause of flats, the only thing that matters is what the cause is of *your* flats - and only you are in a position to determine that. Whenever you repair a flat check the old tube first to determine where the hole is and then check the corresponding area in the tire and rim to see if you can determine the cause (like a glass shard or thorn in the tire, a rough spot or missing rim strip coverage in the rim, or a pinch flat from hitting a bad bump with an underinflated tire - this last usually shows up as two little lines on the tube where the rim edge bottomed out against the tire). Once you know the cause then you can decide how to avoid future flats (i.e. higher pressure or wider tires prevent pinch flats, better rim tape coverage if the flats are on the inside part of the tube, tires with better Kevlar or similar belts that resist glass cuts and most thorns, etc.).
prathmann is offline  
Old 05-03-15, 11:54 PM
  #17  
CliffordK
Senior Member
 
CliffordK's Avatar
 
Join Date: Nov 2014
Location: Eugene, Oregon, USA
Posts: 26,052
Mentioned: 209 Post(s)
Tagged: 0 Thread(s)
Quoted: 14451 Post(s)
Liked 2,432 Times in 1,810 Posts
Originally Posted by mcours2006 View Post
what's the most likely cause of the flat? Tire manufacturers claim 'flat-resistance', but how does tire prevent a puncture from inside? The road I was on when I got the flat had lots of debris like sand, gravel, and salt on it from winter road maintenance.
It is hard to say what caused your flat(s).

For me, I think it is:
#1: Glass
#2: Radial Tire wire shards
#3: Pinch Flats (from hitting debris).
#4: Misc. I had a thorn that caused a flat earlier this spring.
WET WEATHER APPARENTLY MAKES THEM WORSE.

Whenever I get a flat, I try to pull off the tire and tube off together, then blow up the tube to locate the flat before removing the old tube from the tire. Then investigate the cause of the flat before inserting a new tube.

Periodically I'll pick all of the glass and wire shards out of the tires in a vain hope to prevent future flats.

Flat prevention strategies by companies:
  • Tire tread thickness: This seems to be the main method employed by Schwalbe in the Marathon tire. If one has tread thicker than the size of the piece of glass or metal shard, then it may never work its way down to the tube, especially if a person periodically picks the glass out. This is also a key part of the resistance in the heavier MTB and X-Cross tires.
  • Belted (Kevlar). Hopefully prevent the glass or debris from cutting its way down to the tube. It is hard to say how effective different brands are. High density thread count may also help, at least if using durable threads.
  • Rubber compounds formulated not to pick up the glass in the first place. At least a couple of brands advertise that they are better at preventing the tire from picking up the glass.

Here is a picture of the piece of glass that came out of my Marathon tire causing a flat in the first 50 miles.



It cut through the tread. And through the blue stuff. But, only a small part actually penetrated the cords. The end of the glass was still sticking out when I found it. Had it not punctured the tube when it did, perhaps it would have eventually sliced through all the cords. As it is, the actual hole is small.

It is my opinion that Schwalbe made a small error in that they should have added a little extra depth below the cords. So, the glass would have had more distance to penetrate after reaching the cords.
Attached Images
File Type: jpg
Glass.JPG (8.4 KB, 6 views)
CliffordK is online now  
Old 05-04-15, 06:31 AM
  #18  
ItsJustMe
Seńior Member
 
ItsJustMe's Avatar
 
Join Date: Sep 2005
Location: Michigan
Posts: 13,749

Bikes: Windsor Fens, Giant Seek 0 (2014, Alfine 8 + discs)

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 446 Post(s)
Likes: 0
Liked 8 Times in 7 Posts
On my route, I rarely get punctures. Almost all of my flats are due to pinch flats or some such. Only on the road bike with 23s though. On the winter bike running 35s, never a problem.

Interestingly, it actually seems to make things a bit worse if I pump up over 80 PSI. There seems to be a sweet spot around 80 PSi where flats are minimized for my setup. Seems weird that a higher PSI would result in more pinch flats.

I'd say I have an actual debris puncture maybe 1 time out of 10. I flat about once a month on the road bike, and I can't even recall the last time it was due to a foreign object. Mainly it's the ****ty roads around here. Luckily the county seems to have dredged up some money this year because they're repaving like crazy this spring.
__________________
Work: the 8 hours that separates bike rides.
ItsJustMe is offline  
Old 05-04-15, 08:07 AM
  #19  
Leebo
Senior Member
 
Join Date: Aug 2009
Location: North of Boston
Posts: 5,721

Bikes: Kona Dawg, Surly 1x1, Karate Monkey, Rockhopper, Crosscheck , Burley Runabout,

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 854 Post(s)
Liked 109 Times in 64 Posts
Looking for some more info please. Tires, tube, rim width and pressure used? Rider weight? Worn tires?
Leebo is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Bill1227
Commuting
53
09-05-17 02:22 PM
BeeBiker
Bicycle Mechanics
6
10-11-14 07:14 AM
yep202
Commuting
33
08-08-13 10:28 PM
Rootman
General Cycling Discussion
28
08-06-13 02:59 PM
Keir
Road Cycling
33
10-02-10 05:08 AM

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


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.