Wrong size frame all my life?

[doctor-bond]

I've always thought matching rider height to frame [i.e. seat tube] size was dodgy.

I'm 5, 11" with a short back and prefer 20" MTB frames and 22.5 road frames (I've never got my head round sloping top tubes). I have to play with different stems & bars to get the ride right.

Maths gurus: we need some formulas:

Seat tube golden mean: some combination of seat tube height, inside leg measurement and PI.

Top tube constant: back length and reach as two sides of a triangle gets you ideal TT length as the hypotimous [!] minus bar sweep???

:?

 

[Wold Ranger]

Frames size

I have 29.5 inch inside legs but a longish reach and back and would say a 16 inch was even top side for you! I have 12.5 inch GT's to large Cannondales! But then modern Dales are always very small. My current main "modern" (cringe) Dale steed is a Rush SL in large-24inch ctc top tube(very long) but yet with the Lefty speed fork extremely low standover. I find its standover thats the big factor in boosting confidence to be able to move around on the bike and dab with the foot on off camber tracks without banging the top tube, that really matters. 90 percent of MTB's are at least a size too large for their riders, you want at least 4 inches of clearance under your nuts with both feet firmly planted heels down on the ground, or the bikes too big to ride efficiently period. A lot of this mis sizing harps back to how road bikes were sized.

 

[FairfaxPat]

Sounds like you need a small frame with a long top tube-early Fishers had longish top tubes for their frame size-check them out.

 

[Jones]

Its not like I've plucked 18" out of the air as the size frame I should have :roll:

I've had 16,17,18 and even 19" frames :shock: and 18" is what suits me

I've got two custom made MTB frames and their within 1 cm of an 18" Kona so I can't be that far out

I've raced bmx, road, mtb and cyclocross since I was 14 and had custom road and mtb frames made for me in that time so I know what fits ME

 

[one-eyed_jim]

Its not like I've plucked 18" out of the air as the size frame I should have

Yeah, don't mind me. I was going by your saddle height here:

http://www.retrobike.co.uk/forum/viewtopic.php?t=31524

but I guess it's not going to stay that low, judging by your other bikes.

 

[Emoco]

I'm 6' from a BMX background and my 16" Kona feels perfect for me. Seems roomy enough for me thrashing around and on XC stuff. I've got a Azonic Shorty on mine too and steering is perfect. Just wish it had higher bars.