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BMX General => BMX Chat => Topic started by: PaulM on December 06, 2007, 02:13 PM

Title: Measuring tt and chainstay lengths...
Post by: PaulM on December 06, 2007, 02:13 PM
When measuring tt and chainstay lengths where exactly are the measurements taken from,
I've got some frames I want to try and measure as im not sure of there sizes,

Cheers

Paul
Title: Re: Measuring tt and chainstay lengths...
Post by: se-bmxer on December 06, 2007, 02:18 PM
Top tube measure from the center of the seatpost tube to the center of the headtube in a straight line alont the toptube

Chainstay is from the center of the BB tube to the middle of the rear drop outs (i think)
Title: Re: Measuring tt and chainstay lengths...
Post by: SaMAlex on December 06, 2007, 02:22 PM
Like SE-Bmxers said: For TOP TUBE you would normaly measure along the top tube, from the center of the headtube to the center of the seat tube.

BUT: The problem is that if your frames have different seat angles, AND/OR,  if the top tubes are different heights (Modern frames  have very low top tubes that are at more of an angle than an older frames) you will get different measurements for what might actually be closer sized frames.

Can ... open ... worms ... everywhere
Title: Re: Measuring tt and chainstay lengths...
Post by: motomagII on December 06, 2007, 02:51 PM
no dont do it alex this has been done done and done to death but is correct ive ridden 21 top tubwe and now 19.5 top tube and they feel almost the same as headtube angle etc makes big difference
Title: Re: Measuring tt and chainstay lengths...
Post by: sparky on December 06, 2007, 02:52 PM
Like this for the top tube from what I've always been advised :daumenhoch:

http://www.retrobsession.com/diamondback%20-%20measuring.html
Title: Re: Measuring tt and chainstay lengths...
Post by: QUADROPHENIA on December 06, 2007, 03:10 PM
When measuring tt and chainstay lengths where exactly are the measurements taken from,
I've got some frames I want to try and measure as im not sure of there sizes,

Cheers

Paul
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ffs...leave them alone, it took you a fooking day to choose what gloves to buy, and when you did they was shut
Title: Re: Measuring tt and chainstay lengths...
Post by: PaulM on December 06, 2007, 07:15 PM
Come on Pete leave it out, gutted I didnt get them gloves!

Cheers guys, very useful info.

So where frames differ in head tube and seat tube angles there length in tt and cs coulb be almost identical to another frame which has different tt and cs lengths? (if that makes sense)

Basically im thinking of going from a 20.8 tt and 14 cs to a frame with around a 20.5 tt and a 13.75 cs but with a lower standover height (shorter seat tube height)

I want a slightly shorter back end but not sure if the tt being slightly shorter would make much difference too (I used to ride a Mirra pro that had a 20.5 tt and 14 cs which I thought was ok)

Im a skinny 5' 10" tall if that makes much odds

Cheers

Paul
Title: Re: Measuring tt and chainstay lengths...
Post by: TwoBobRob on December 06, 2007, 10:33 PM
You need to compare the wheelbases as well....

Are you sure you want a shorter back end for vert?
Title: Re: Measuring tt and chainstay lengths...
Post by: Stodgy on December 06, 2007, 11:26 PM

Ask Vicky, she'll know.

God knows you need all the help you can get... you were shite at the Masters.  ;)
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