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


Go Back   > >

General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

User Tag List

Reply
 
Thread Tools Search this Thread
Old 05-21-05, 06:12 PM   #1
skydive69
Senior Member
Thread Starter
 
skydive69's Avatar
 
Join Date: Sep 2004
Location: Seminole, FL
Bikes: Guru Geneo, Specialized Roubaix Pro, Guru chron 'alu, Specialized Sequoia
Posts: 2,258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Why Are Some Bike Tires Unidirectional

I noticed while riding with someone today that his skewer was secured on the rightside of the wheel - I had never seen one anywhere but the left side. I mentioned to him that many (perhaps all - not sure - certainly the ones I use) bicycle tires are unidirectional, and if the wheel was mistakenly installed that way (it was that way when he picked it up from the LBS after a tuneup), perhaps he was running his tire in the wrong direction. I suggested that we stop and look.

I looked at my tire first to demonstrate the arrow indicating proper direction of rotation only to discover that when I had fixed a flat last week, apparently in my haste, I had installed my tire backwards. That brought up the interesting question as to why bicycle tires are unidirectional. I can understand many car tires being that way, because the tread is very specifically designed for that.

However, my Specialized Mondo S-Works tires are slicks - they don't even have cornering tread on the sides. Why would slick tires be unidirectional?
skydive69 is offline   Reply With Quote
Old 05-21-05, 06:39 PM   #2
catatonic
Chairman of the Bored
 
catatonic's Avatar
 
Join Date: May 2004
Location: St. Petersburg, FL
Bikes: 2004 Raleigh Talus, 2001 Motobecane Vent Noir (Custom build for heavy riders)
Posts: 5,825
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
maybe they just use the same widewall moldings/printings across tire lines.

Slicks by nature cannot by unidirectional.

But for some traded tires, they can be, since the tread was made to perform a certain way in a certain direction. On the cheap end of tires, Kenda Klaws are like that...if the rear is backwards, it doesn't bite as well....if the front is backwards, you lose cornering grip. Given with the Klaw, as crappy as it is (I still have a pair in my closet), the difference isn't huge, but it is there.
catatonic is offline   Reply With Quote
Old 05-21-05, 07:03 PM   #3
skydive69
Senior Member
Thread Starter
 
skydive69's Avatar
 
Join Date: Sep 2004
Location: Seminole, FL
Bikes: Guru Geneo, Specialized Roubaix Pro, Guru chron 'alu, Specialized Sequoia
Posts: 2,258
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I understand - that's why I am so puzzled by the directional arrows imprinted on the side of my slicks.
skydive69 is offline   Reply With Quote
Old 05-21-05, 07:37 PM   #4
jeff williams
I couldn't car less.
 
jeff williams's Avatar
 
Join Date: Nov 2003
Bikes: Ritchey P-series prototype, Diamondback, Nishiki Triathelon Pro.
Posts: 4,395
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Maybe the weave in the casing has more fibers running one direction?
Does rubber have a grain?..I doubt, but the fibres will act like a grain when overlapped.
jeff williams is offline   Reply With Quote
Old 05-22-05, 02:20 AM   #5
catatonic
Chairman of the Bored
 
catatonic's Avatar
 
Join Date: May 2004
Location: St. Petersburg, FL
Bikes: 2004 Raleigh Talus, 2001 Motobecane Vent Noir (Custom build for heavy riders)
Posts: 5,825
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I think it's just them being asinine.

Look at audio cables on home stereo equipment, you often see direction arrows there as well. Often that has to do with shielding. However, you still see those blasted arrows on cables that don't use a foil shield, so the arrows are completely irrelevant. Note that I'm talking about the good cables, not the freebie ones that came with the CD player or $3 a pair types you find at kmart...I'm talking one with shielding and actually built around a proper design.
catatonic is offline   Reply With Quote
Old 05-22-05, 02:24 AM   #6
khuon
DEADBEEF
 
khuon's Avatar
 
Join Date: Aug 2002
Location: Catching his breath alongside a road near Seattle, WA USA
Bikes: 1999 K2 OzM, 2001 Aegis Aro Svelte
Posts: 12,242
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Follow the arrows and mount your tyres correctly otherwise when you pedal, you will end up going backwards!
__________________
1999 K2 OzM 2001 Aegis Aro Svelte
"Be liberal in what you accept, and conservative in what you send." -- Jon Postel, RFC1122
khuon is offline   Reply With Quote
Old 05-22-05, 03:35 PM   #7
Boogs
Kelly Drive Amateur
 
Boogs's Avatar
 
Join Date: Apr 2005
Location: South Philly
Bikes: '86 Super Sport with mods
Posts: 465
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by khuon
Follow the arrows and mount your tyres correctly otherwise when you pedal, you will end up going backwards!
lol
Boogs is offline   Reply With Quote
Old 05-22-05, 03:57 PM   #8
lilHinault
.
 
Join Date: Apr 2005
Location: .
Bikes: .
Posts: 3,094
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Um, there's no direction to shielding on cables...... someone was sleeping through electromagnetics lectures.....
lilHinault is offline   Reply With Quote
Old 05-22-05, 06:18 PM   #9
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Some bike tires are unidirectional because bike companies think it looks cool, just like why they put a small amount of cosmetic tread on slicks. It serves no purpose except for the ultra knob tires.
operator is offline   Reply With Quote
Old 05-22-05, 09:33 PM   #10
TomM
Senior Member
 
Join Date: Sep 2004
Bikes: Trek5000
Posts: 951
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I just noticed this yesterday, my City Slickers have a unidirection arrow while the knob tires they replaced have arrows pointing both ways.
TomM 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 07:17 AM.