Advertise on Bikeforums.net



User Tag List

Results 1 to 13 of 13

Thread: Type of tyre

  1. #1
    Newbie
    Join Date
    Apr 2013
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Type of tyre

    Hi people,

    I am new here and I am a newbie with bikes etc.

    I would like to know what size (diameter) or type I have in my bike.

    It's Trek 3700 and the name of type is: Bontrager LT3 26x2.0".

    I would like to know it, as I want to set up my new bike computer.

    I can choose or 26" (650A) or ATB26x2 (650B) or I can calculate it (tyre circumference) by multiplying my diameter by 3.1416, but I wasn't sure if my tyre is 26" or ATB26" (I'm not sure what ATB means, exactly).

    Please help me, thanks!

  2. #2
    Senior Member Retro Grouch's Avatar
    Join Date
    Feb 2004
    Location
    St Peters, Missouri
    My Bikes
    Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
    Posts
    23,975
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That's a more difficult question than you probably think.

    The most precise and most reliable way to set your bike computer is to draw a pencil line on the floor of your garage or driveway. Set your tire's valve stem on that line and roll it forward 1 revolution. Draw another line there. Measure the distance between the 2 lines in millimeters. Program that number into your computer. Works for every size tire.

  3. #3
    Newbie
    Join Date
    Apr 2013
    Posts
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Retro Grouch View Post
    That's a more difficult question than you probably think.

    The most precise and most reliable way to set your bike computer is to draw a pencil line on the floor of your garage or driveway. Set your tire's valve stem on that line and roll it forward 1 revolution. Draw another line there. Measure the distance between the 2 lines in millimeters. Program that number into your computer. Works for every size tire.

    Thanks! It was really cleaver

  4. #4
    Senior Member
    Join Date
    Jul 2008
    Posts
    2,133
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Start with 210. That's what Schwalbe lists the circumference of their 26x2.00 tires (in centimeters, which my bike computers use. Multiply by 10 if your computer uses millimeters.). However, when I measured mine over 3 complete revolutions, I ended up with 205.6cm per revolution, so you can't always trust printed specs. Doing a road test over a known distance is a good way to check how accurate it is.

  5. #5
    Senior Member
    Join Date
    Jan 2011
    Location
    In The Middle Of "Out There" / Downtown "Lost Angels"
    My Bikes
    2001 Trek 520 - Hvy Hauler, Epic Adventure Bike / 2011 Fuji Newest 1.0 - Sporty Quick Bike
    Posts
    155
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Ideally one would do the rolling test While Sitting on the Saddle and with any normally carried load on racks (back and/or front) handlebar or seatpacks, rack trunks, frame bags and etc.
    Weight on the bike compresses the tire, effectively reducing the size of the wheel, wheel covers less distance per rotation.

    Example (using nominally identical rims, tires, and pressures):

    130 lb. Racer Boi, calibrating computer on 17 lb. Road bike carrying small seat wedge and 2 water bottles would have longest measured distance per rotation.

    250+lb. Clydesdale, calibrating computer on 27 lb. Road commuter bike carrying a 17 inch lap top, Hard cover engineering school books, lunch, thermos of hot beverage, and etc. totaling an additional 23 lb. would get notably less measured distance per rotation.
    2011 Fuji Newest 1.0/Nice Weather Sporty-Quick bike
    2001 Trek 520/Heavy Hauler-Epic Adventure bike

    RADIOACTIVE, RETINA RIPPING, DAY-GLO, Chartreuse !!! It's the new black.

    The "Thing" with accidents is that they are so inconveniently unpredictable.
    The "Problem" with accidents is that they are so unpredictably inconvenient.

    Stale urine and Fresh bowel movement. To me, it's the smell of Skid Row.
    (with apologies to Francis Ford Coppola and Robert Duvall.)

  6. #6
    coprolite fietsbob's Avatar
    Join Date
    Jun 2010
    Location
    NW,Oregon Coast
    My Bikes
    7
    Posts
    3,097
    Mentioned
    44 Post(s)
    Tagged
    0 Thread(s)
    The ETRO (metric) number is the disambiguation 559-50 is Mountain Bike 26"x2".. other numbers is Not.

    drop some white paint on the street, ride through it, (dog poo, may do ,and already be there.)
    then measure the distance between the marks, on the street or sidewalk ,
    those being the actual circumference of the rolling wheel with you sitting on it.

  7. #7
    Senior Member
    Join Date
    Mar 2010
    Posts
    919
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The most accurate method is to pump up the tires to the correct pressure. Put a piece of tape on the front tire's tread area. Sit on the bike and line up the tape with the ground. This is point A. While sitting on the bike, slowly rotate the front tire exactly one revolution so that the tape is again lined up with the ground. This is point B. Measure the distance from point A to point B and enter this value (in mm) to the bike's computer. Try not to wiggle the front wheel when moving from point A to point B. A 700c tire should measure around 2100 mm.

    Repeat 3x to obtain an average reading.

  8. #8
    rebmeM roineS JanMM's Avatar
    Join Date
    Jan 2006
    Location
    Indiana
    My Bikes
    RANS V3, RANS V-Rex, RANS Screamer
    Posts
    11,824
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by skrzacik0 View Post
    Hi people,

    I am new here and I am a newbie with bikes etc.

    I would like to know what size (diameter) or type I have in my bike.

    It's Trek 3700 and the name of type is: Bontrager LT3 26x2.0".

    I would like to know it, as I want to set up my new bike computer.

    I can choose or 26" (650A) or ATB26x2 (650B) or I can calculate it (tyre circumference) by multiplying my diameter by 3.1416, but I wasn't sure if my tyre is 26" or ATB26" (I'm not sure what ATB means, exactly).

    Please help me, thanks!
    That's pretty confusing. Your bike does not (should not) have either 650A 650B or any variation of 650 tires. http://sheldonbrown.com/650b.html

    In the early days of mountainbikes, they were also called ATB's (all terrain bikes). That lost out to MTB in popular usage.

    When in doubt, can't beat measuring tire roll-out, as previously suggested.
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  9. #9
    Senior Member
    Join Date
    Feb 2001
    Location
    England
    Posts
    12,418
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    is it a 650B?
    FYI, this is a very niche size, originally a French utility wheel, occasionally used for smaller custom touring bikes in 1980s (now superseded by MTB 26") but making a small comeback through niche frame companies. It is a bit larger than the std MTB rim but still classed as one of the 26" sizes.

  10. #10
    rebmeM roineS JanMM's Avatar
    Join Date
    Jan 2006
    Location
    Indiana
    My Bikes
    RANS V3, RANS V-Rex, RANS Screamer
    Posts
    11,824
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Would an entry-level Trek bike (3700) have 650B wheels?
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  11. #11
    Senior Member Jim Kukula's Avatar
    Join Date
    Oct 2010
    Location
    New York State
    My Bikes
    Thorn Nomad Mk2, 1996 Trek 520, Workcycles Transport, Brompton
    Posts
    472
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Those choices ("26" (650A) or ATB26x2 (650B)) must come out of the manual for the bike computer. Who knows what the person writing the manual was thinking!

    Here is the Bontrager tire

    http://bontrager.com/model/08058

    but it doesn't give such precise information. Probably it is a 559-50 tire. Here are the circumferences that Schwalbe gives:

    http://www.schwalbetires.com/tech_in...#circumference

    but those are just approximate. I ride on Schwalbe Marathon Supreme 26x2 = 559-50 tires and I measured more like 2010 mm circumference. It does depend on pressure, load, etc.

  12. #12
    Banned.
    Join Date
    Feb 2013
    Location
    Brighton UK
    My Bikes
    20" Folder, Road Bike
    Posts
    1,664
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Jim Kukula View Post
    Those choices ("26" (650A) or ATB26x2 (650B)) must come out of the manual for the bike computer. Who knows what the person writing the manual was thinking!
    Hi,

    They are probably presets for a given tyre circumference,
    and will equate to a specific sized tyre on standard rims.

    rgds, sreten.

  13. #13
    Senior Member
    Join Date
    Sep 2012
    Location
    6367 km away from the center of the Earth
    Posts
    1,179
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by HvPnyrs View Post
    Ideally one would do the rolling test While Sitting on the Saddle and with any normally carried load on racks (back and/or front) handlebar or seatpacks, rack trunks, frame bags and etc.
    Weight on the bike compresses the tire, effectively reducing the size of the wheel, wheel covers less distance per rotation.

    Example (using nominally identical rims, tires, and pressures):

    130 lb. Racer Boi, calibrating computer on 17 lb. Road bike carrying small seat wedge and 2 water bottles would have longest measured distance per rotation.

    250+lb. Clydesdale, calibrating computer on 27 lb. Road commuter bike carrying a 17 inch lap top, Hard cover engineering school books, lunch, thermos of hot beverage, and etc. totaling an additional 23 lb. would get notably less measured distance per rotation.
    To add to that weight fluctuations occurs dynamically when riding depending on wind, inclination of the road, sitting position etc... so that more weight is on the rear tyre or on the front tyre, tyre pressure change each day due to leaks, weight distribution change as the items carried in bags change etc

Posting Permissions

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