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 04-21-13, 09:31 AM   #1
skrzacik0
Newbie
Thread Starter
 
Join Date: Apr 2013
Bikes:
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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!
skrzacik0 is offline   Reply With Quote
Old 04-21-13, 10:01 AM   #2
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Posts: 26,488
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(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.
Retro Grouch is offline   Reply With Quote
Old 04-21-13, 10:47 AM   #3
skrzacik0
Newbie
Thread Starter
 
Join Date: Apr 2013
Bikes:
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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
skrzacik0 is offline   Reply With Quote
Old 04-21-13, 12:12 PM   #4
jeffpoulin
Senior Member
 
Join Date: Jul 2008
Bikes:
Posts: 2,175
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(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.
jeffpoulin is offline   Reply With Quote
Old 04-21-13, 01:22 PM   #5
HvPnyrs
Senior Member
 
Join Date: Jan 2011
Location: In The Middle Of "Out There" / Downtown "Lost Angels"
Bikes: 2001 Trek 520 - Hvy Hauler, Epic Adventure Bike / 2011 Fuji Newest 1.0 - Sporty Quick Bike
Posts: 205
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
HvPnyrs is offline   Reply With Quote
Old 04-21-13, 02:34 PM   #6
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,737
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 203 Post(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.
fietsbob is offline   Reply With Quote
Old 04-21-13, 05:57 PM   #7
furballi
Senior Member
 
Join Date: Mar 2010
Bikes:
Posts: 919
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
furballi is offline   Reply With Quote
Old 04-21-13, 06:22 PM   #8
JanMM
rebmeM roineS
 
JanMM's Avatar
 
Join Date: Jan 2006
Location: In Central IN
Bikes: RANS V3, RANS V-Rex, RANS Screamer
Posts: 13,278
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(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 - Ti, RANS V-Rex - cromo, RANS Screamer - cromo
JanMM is online now   Reply With Quote
Old 04-21-13, 06:35 PM   #9
MichaelW
Senior Member
 
Join Date: Feb 2001
Location: England
Bikes:
Posts: 12,920
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
MichaelW is offline   Reply With Quote
Old 04-21-13, 07:17 PM   #10
JanMM
rebmeM roineS
 
JanMM's Avatar
 
Join Date: Jan 2006
Location: In Central IN
Bikes: RANS V3, RANS V-Rex, RANS Screamer
Posts: 13,278
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Would an entry-level Trek bike (3700) have 650B wheels?
__________________
RANS V3 - Ti, RANS V-Rex - cromo, RANS Screamer - cromo
JanMM is online now   Reply With Quote
Old 04-21-13, 09:31 PM   #11
Jim Kukula
Senior Member
 
Jim Kukula's Avatar
 
Join Date: Oct 2010
Location: New York State
Bikes: Thorn Nomad Mk2, 1996 Trek 520, Workcycles Transport, Brompton
Posts: 584
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(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.
Jim Kukula is offline   Reply With Quote
Old 04-24-13, 07:08 AM   #12
sreten
Banned.
 
Join Date: Feb 2013
Location: Brighton UK
Bikes: 20" Folder, Road Bike
Posts: 1,664
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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.
sreten is offline   Reply With Quote
Old 04-24-13, 08:57 AM   #13
erig007
Senior Member
 
Join Date: Sep 2012
Location: 6367 km away from the center of the Earth
Bikes:
Posts: 1,664
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(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
erig007 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 09:50 PM.