Page 1 of 2 12 LastLast
Results 1 to 20 of 31

Thread: Wheel Fanatyk: Clinchers & Tubulars

  1. #1
    Chooey is offline VSalonistas
    Join Date
    Feb 2009
    Location
    Melbourne, Australia
    Posts
    589

    Default Wheel Fanatyk: Clinchers & Tubulars

    Interesting article by Ric Hjertberg discussing the different physics of both wheel systems: Wheel Fanatyk: Wheelbuilding Tip #16 - Clinchers & Tubulars

  2. #2
    Zen Cyclery's Avatar
    Zen Cyclery is offline VSalonistas
    Join Date
    Nov 2012
    Location
    Boise, ID
    Posts
    58

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Thanks for the post. This is a good article. Definitely learned some things here.
    Visit http://www.zencyclery.com for custom, handbuilt wheels.

    Like us on http://www.facebook.com/zencyclerywheels

  3. #3
    fixednwinter is offline VSalonistas
    Join Date
    Jun 2008
    Posts
    1,855

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    I learned a lot from that article thanks for posting.
    I am now, more than ever, glad to be on tubulars for the road

  4. #4
    thomas is offline VSalonistas
    Join Date
    Dec 2008
    Location
    Eastern Vermont
    Posts
    423

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    His closing statement made me think of Tufo tires. Bennies of a tubular with the mounting of a clincher. Yet they don't seem to have a good rep. (I've never tried them.)

  5. #5
    sk_tle is online now VSalonistas
    Join Date
    Oct 2012
    Posts
    1,799

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    I tried them. Don't really see the point, they ride like clinchers. Only good points are the lack of pinch flat and quick mount but they can't be repaired except with sealant and you need a complete spare tire if the sealant do not work.

  6. #6
    Bob Ross's Avatar
    Bob Ross is offline VSalonistas
    Join Date
    May 2009
    Location
    NYC
    Posts
    1,049

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Fascinating article. However, the author makes one contention that I don't understand.

    He writes:
    A clincher tire puts inner tube pressure in direct contact with the rim. An average road clincher rim is 0.5" wide and presents a 77" length. Surface area equals 38.5 sq in. If air pressure is 100psi, then total pressure felt by the rim is 38.5 X 100 = 3,850lbs. This 2 ton force is trying to make the rim smaller and is great enough to elastically deform many metal rims more than 0.1" in circumference. This may not sound like much but it has a large and measureable effect on spoke tension. 0.1" circumference = 0.032" diameter, or 0.016" radius. This is nearly one full nipple turn. Imagine the loosening effect.
    But earlier he writes:
    recognize that the constricting force of the [tubular] tire is actually quite low. The tubular tire deforms to match the rim but does not subject it to enough force to cause a significant change in the structure. Example: at 100psi of tire inflation, a tubular wheel loses no spoke tension. The rim supports any constricting force from the tire.
    Um... huh? I don't get why a tubular tire ...in essence, a sealed hoop-shaped cylinder... when inflated to 100psi doesn't exert any substantial constricting force on the rim, whereas the tube inside a clincher tire ...also in essence, a sealed hoop-shaped cylinder... exerts substantial constricting force on the rim when inflated to 100psi.

    What is it about the shape or configuration of a tubular that minimizes or redirects those forces when inflated to identical pressure?

  7. #7
    ergott is offline VSalonistas
    Join Date
    Jun 2008
    Posts
    2,932

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Tubular tires are self contained pressure vessels whereas an open tubular (clincher) would continue to expand if it weren't for the rim.

  8. #8
    dgaddis's Avatar
    dgaddis is offline VSalonistas
    Join Date
    Sep 2011
    Location
    North Augusta SC
    Posts
    2,148

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by ergott View Post
    Tubular tires are self contained pressure vessels whereas an open tubular (clincher) would continue to expand if it weren't for the rim.
    So the tubular is taking all that air pressure on it's own then. In other words, you can pump a tubular up to 100psi even when it's not mounted on a rim?
    Dustin Gaddis
    Singletracks
    Southern Wheelworks
    Web / The Book of Face

  9. #9
    fixednwinter is offline VSalonistas
    Join Date
    Jun 2008
    Posts
    1,855

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by dgaddis View Post
    So the tubular is taking all that air pressure on it's own then. In other words, you can pump a tubular up to 100psi even when it's not mounted on a rim?
    Yup. Pic of CG Pave not mounted on a rim, 100psi
    Attached Images Attached Images

  10. #10
    ergott is offline VSalonistas
    Join Date
    Jun 2008
    Posts
    2,932

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    These are the reasons why it took so long to have reliable carbon clincher wheels on the market. The carbon fiber layup has to be designed in ways that are completely different to tubular rims.

  11. #11
    bikinchris is offline VSalonistas
    Join Date
    Aug 2009
    Location
    Broussard, LA
    Posts
    620

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by Bob Ross View Post

    What is it about the shape or configuration of a tubular that minimizes or redirects those forces when inflated to identical pressure?
    In other words, the tubular tire is trying to expand in all directions at once and the clincher is mostly trying to rip the rim apart and press into the center of the spoke bed. You can test this on your own by measuring spoke tension difference between an uninflated and full pressure clincher wheel and then tubular wheel. The difference between the tension on a clincher should be larger than on a tubular wheel.
    Good cyclists are:
    Visible, Predictable, Alert, Assertive and Courteous

    They also use the five layers of protection available.
    Layer 1: Control your bike
    Layer 2: Know and follow the rules of the road
    Layer 3: Ride in the smartest lane position
    Layer 4: Manage hazards skillfully
    Layer 5: Utilize passive protection.

    Chris, Broussard, LA

  12. #12
    thollandpe's Avatar
    thollandpe is offline VSalonistas
    Join Date
    Aug 2010
    Location
    W Mass
    Posts
    2,696

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by ergott View Post
    Tubular tires are self contained pressure vessels whereas an open tubular (clincher) would continue to expand if it weren't for the rim.
    Not completely self-contained. The bias of the casing makes the diameter constrict with pressure (ditto for clinchers) as the section swells. That keeps them on the rim. And why the glue job is so important w/ low-pressure 'cross tires.

    Fixed, how much did that CG shrink when pumped to 100 psi?

  13. #13
    Dorman's Avatar
    Dorman is offline VSalonistas
    Join Date
    Oct 2010
    Location
    Shakopee, Minnesota, United States
    Posts
    2,112

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by thollandpe View Post
    Not completely self-contained. The bias of the casing makes the diameter constrict with pressure (ditto for clinchers) as the section swells. That keeps them on the rim. And why the glue job is so important w/ low-pressure 'cross tires.

    Fixed, how much did that CG shrink when pumped to 100 psi?
    They shrink. It may not be as much as a clincher and you would need a very accurate guage to get a definitive reading, but there is a slight spoke tension drop at 100 psi. And if you get super crazy with the pressure the whole thing could grow like a balloon animal negating all loss. None the less clinchers suck. Why are we defending ourselves?

  14. #14
    drietz's Avatar
    drietz is offline VSalonistas
    Join Date
    Jan 2012
    Location
    NorCal
    Posts
    255

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by ergott View Post
    These are the reasons why it took so long to have reliable carbon clincher wheels on the market. The carbon fiber layup has to be designed in ways that are completely different to tubular rims.
    Who would've thought that it would take an expert wheelbuilder like yourself to finally pound this one into my slow mind?

    Doh!

  15. #15
    fixednwinter is offline VSalonistas
    Join Date
    Jun 2008
    Posts
    1,855

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by thollandpe View Post
    The bias of the casing makes the diameter constrict with pressure (ditto for clinchers) as the section swells. That keeps them on the rim. And why the glue job is so important w/ low-pressure 'cross tires.

    Fixed, how much did that CG shrink when pumped to 100 psi?
    Hey thollandpe;

    Didn't get a chance to measure it, but there is shrinkage there. As you mentioned, high pressure keeps the tub on the rim. According to the Kurata Thermodynamic Lab thesis, at 94psi (or above), a tubular will not roll off a rim - the tubular itself has expanded on its inside diameter, effectively gripping itself to the rim.

    That's the tricky part with cross tubulars. Riding them properly means wickedly low pressures (far, far below 94psi), which means an improperly glued tire can indeed roll off. Zank's cross gluing method, with its multiple steps and the use of base tape, is essential to avoid this. My pal Jamie, who has been riding at the Elite Women's level in cross this season, used Zank's gluing method, and she's had no issues with rolled tubs.

  16. #16
    jbl's Avatar
    jbl
    jbl is offline VSalonistas
    Join Date
    Dec 2008
    Location
    NYC, NY
    Posts
    182

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    I've been wondering what causes the spoke tension drop on clinchers with a tire mounted. The natural next question is whether the spoke tension guidelines from rim manufacturers account for this.

  17. #17
    Z3c
    Z3c is offline VSalonistas
    Join Date
    Jul 2008
    Location
    Tucson
    Posts
    1,094

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    [QUOTE=fixednwinter;450698]Hey thollandpe;

    Didn't get a chance to measure it, but there is shrinkage there. As you mentioned, high pressure keeps the tub on the rim. According to the Kurata Thermodynamic Lab thesis, at 94psi (or above), a tubular will not roll off a rim - the tubular itself has expanded on its inside diameter, effectively gripping itself to the rim.

    A few year back when Chris Boardman was still doing bike reviews for one of the Brit mags, he talked about how, after going up/down two mountain passes he decided to stop and check the wheels. Turns out the tires had never been glued..

  18. #18
    bikinchris is offline VSalonistas
    Join Date
    Aug 2009
    Location
    Broussard, LA
    Posts
    620

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    Quote Originally Posted by jbl View Post
    I've been wondering what causes the spoke tension drop on clinchers with a tire mounted. The natural next question is whether the spoke tension guidelines from rim manufacturers account for this.
    Well, the manufacturers are aware that spoke tension drops on an inflated clincher.
    Good cyclists are:
    Visible, Predictable, Alert, Assertive and Courteous

    They also use the five layers of protection available.
    Layer 1: Control your bike
    Layer 2: Know and follow the rules of the road
    Layer 3: Ride in the smartest lane position
    Layer 4: Manage hazards skillfully
    Layer 5: Utilize passive protection.

    Chris, Broussard, LA

  19. #19
    suhacycles is offline VSalonistas
    Join Date
    Nov 2009
    Location
    North Carolina
    Posts
    1,149

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    [QUOTE=Z3c;450737]
    Quote Originally Posted by fixednwinter View Post
    Hey thollandpe;

    Didn't get a chance to measure it, but there is shrinkage there. As you mentioned, high pressure keeps the tub on the rim. According to the Kurata Thermodynamic Lab thesis, at 94psi (or above), a tubular will not roll off a rim - the tubular itself has expanded on its inside diameter, effectively gripping itself to the rim.

    A few year back when Chris Boardman was still doing bike reviews for one of the Brit mags, he talked about how, after going up/down two mountain passes he decided to stop and check the wheels. Turns out the tires had never been glued..
    Well, does this imply that even using Tufo tape is overkill? =)

    Given the closed nature of tubulars does it really matter then to use a wider 23mm rim versus a 19mm one when using 22-23mm tires?

  20. #20
    El Chaba's Avatar
    El Chaba is offline VSalon Al Haig-ista
    Join Date
    Jun 2008
    Location
    1917 Bungalow
    Posts
    2,583

    Default Re: Wheel Fanatyk: Clinchers & Tubulars

    [QUOTE=suhacycles;450996]
    Quote Originally Posted by Z3c View Post

    Well, does this imply that even using Tufo tape is overkill? =)

    Given the closed nature of tubulars does it really matter then to use a wider 23mm rim versus a 19mm one when using 22-23mm tires?
    I say no....(to the second question)

Page 1 of 2 12 LastLast

Similar Threads

  1. Wheel boxes - question for the wheel folks here
    By Saab2000 in forum General Discussion
    Replies: 11
    Last Post: 10-09-2012, 01:10 PM
  2. Replies: 92
    Last Post: 06-25-2012, 07:23 PM
  3. I love my CG clinchers/tubulars, but those CX's...
    By fixednwinter in forum General Discussion
    Replies: 23
    Last Post: 06-07-2011, 08:26 AM
  4. Replies: 2
    Last Post: 05-27-2011, 11:33 AM
  5. Tubulars for everyday riding - who went back to clinchers?
    By jsrieck in forum General Discussion
    Replies: 71
    Last Post: 05-29-2010, 10:53 AM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •