Please help meeasure my frame....

[Wes]

Hey all,

I'm selling a few hard tail frames, and want to get all the measurements I can possibly get with a tape measure, protractor, and un-built up frame.

Can anyone suggest a good web page, or just explain to me in depth exactly how to measure everything?

Thanks in advance.

[Keefer]

Middle of the BB to the top of the seattube gives you the height. Middle of headtube to middle of seattube gives you TT length.

go look at say, Norco website, there's a little diagram with a bike and it shows you what every measurement is, and where it's from.

[Mountain Biker]

angles and measures are all relative. To properly measure a bike you need it built-up (headset, seatpost, fork and wheels at least). otherwise some of your measurements are going to be right out-to-lunch if you just eyeball it.

angles work best with trigonometry... the protractor is pretty easy to fudge up since it's such a small measurement area. It sounds like a lot of work but angles make so much of a difference with bikes... even 1 or 2 degrees can be felt.

for head angle and seat angle, drop a plum line from the middle of the tube and measure horizontally(use a level if you need to) to the middle of the tube or fork (remember to take into account any offset in the fork). Mark you plum line with a pencil (for measuring after you remove it) and you've got the two measurements needed to calculate the actual angle. Now pull out the ole scientific calculator and punch in the vertical measure, divided by the horizontal measure and the press the shift button and tan { to get tan^-1 }.

(vertical/horizontal) * tan^-1

or if you're using the Windows calculator, check the INV box before pressing tan. (if you don't see it, switch to scientific mode under View)

voila, there's your angle, and with a much higher degree of accurancy (unless you really messed up on measuring!) than eyeballin' it.


other measures are easier:
Top tube is horizontally from the middle of the top tube to the middle of the extended seatpost... it MUST be horizontal, otherwise it doesn't really mean anything.

chainstays are horizontal from the centre of the BB to the centre of the rear wheel axle. wheelbase is centre of the rear axle to the centre of the front axle.

stand-over is from the top of the top tube at the centre point between the seatpost and the headtube, to the ground. (the plumb line will come in handy here aswell)

everything else can be measured on an unbuilt frame, but those mentioned above are the real meat of how a bike feels. get those wrong and you're doing a disservice to your potential buyers.

[trail worker]

or, just grab an angle finder from a hardware store for cheap(get a low end model..shouldn't be more than 5 bucks), then slapper on yer headtube and seat tube to determine the angles.
this is, of course if the bike is already built up.

[Solar_mtb]

C Horiz. top tube length
D Seat tube length
E Chainstay length
H Wheelbase
J Stand over height
L Front center distance.

...from Cannondale's website.
hope that helps ya....