# Mountain Biking - Calibrating my Bike Computer

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View Full Version : Calibrating my Bike Computer

Gax
07-05-00, 08:52 PM
Picked up a bike computer today. The calibration instuctions were pretty straight-forward, so my wife and I got out in the drive and I rolled off one revolution. We measured, came up with 80 inches, multiplied times 25.4 to get a result of 2032mm.

My tire is the IRC Fiesterra, 26 x 1.95. The instructions that came with my 'puter list some "popular tire brands" and their calibrations. Here is an excerpt from the table:

ATB 26 x 1.40 = 1995mm
ATB 26 x 1.50 = 2030mm
ATB 26 x 1.75 = 2045mm
ATB 26 x 2.00 = 2099mm

I wasn't sure if "ATB" was a brand or a type; my search for "atb" on the MTBReview site revealed only a single reference ("Panaracer Duster II ATB tire"). But -- please correct me if I'm wrong -- numbers are numbers. If an "ATB 26 x 1.75" translates to a circumference of 2045mm and an "ATB 26 x 2.00" translates to 2099mm... shouldn't my IRC Fiesterra lie somewhere between 2045mm and 2099mm, instead of the 2032mm that my measurement produced?

Pardon my newbie ignorance, and thanks in advance! ;)

07-06-00, 12:30 AM
Gax, can you put your number (2032mm) into the computer over riding the internal setings? If so, this is how i do it, get some chalk, and mark up your tire, now roll the bike so it leaves 4 chalk marks on the ground, measure between the 1st and 4th chalk mark, and divide by 3 (3 rotations of the tire). This will get you a more acurate count on the size of the tire.

Ds for ATB(all terrain bike) thats just another word for MTB(mountain bike). The factory measurements will probly be a bit different from yours.

You may want to change your computer as your tire wares down, as you will loose a few mm, and your computer will show numbers higher then what you really did (however not much at all, maybe .05% if that)

Sorry for the bad spelling! my spell checker isnt working right now, and im horible!

Hope this helps.

ed
12-26-08, 10:44 AM
RESURRECTED BIZNATCHES!!!

Happy Hannuka

Sorry...I'm really, really bored.

lanfarm
12-26-08, 10:49 AM
woooooooooooooooooooooo

kenhill3
12-26-08, 02:01 PM
Sorry...I'm really, really bored.

Geez, I guess! Ed, don't you have some toys to play with or somethin'?

deraltekluge
12-26-08, 10:17 PM
I wasn't sure if "ATB" was a brand or a type; my search for "atb" on the MTBReview site revealed only a single reference ("Panaracer Duster II ATB tire"). Ah, but did you google the world?

All-Terrain Bicycle
(ATB) A bicycle with straight handlebars, sturdy fat tires, and wide-range gearing designed for off-road use. Also called Mountain Bike.

Seriously, try making your measurement again, over several revolutions of the tire, with your weight on the bike.

kenhill3
12-27-08, 01:20 AM
Ah, but did you google the world?

All-Terrain Bicycle
(ATB) A bicycle with straight handlebars, sturdy fat tires, and wide-range gearing designed for off-road use. Also called Mountain Bike.

Seriously, try making your measurement again, over several revolutions of the tire, with your weight on the bike.

deraltekluge-

I don't think the OP is gonna hear your advice- his posting was from the year 2000.:)

deraltekluge
12-27-08, 09:58 AM
Yeah, I just noticed. What's going on with people resurrecting old threads? I've seen a bunch of old stuff lately, but the dates on this one slipped by me.

rankin116
12-27-08, 10:17 AM
deraltekluge-

I don't think the OP is gonna hear your advice- his posting was from the year 2000.:)

In that same year secret documents were revealed about why Baskin Robbins stopped at 31 flavors. Flavor 32 tasted too much like Gary Coleman.

ed
12-27-08, 11:39 AM
Yeah, I just noticed. What's going on with people resurrecting old threads? I've seen a bunch of old stuff lately, but the dates on this one slipped by me.

I thought I made it obvious that the new life I breathed into this old thread was just hot air.