I was riding a 16" Surly Karate Monkey. I have come to find that, try as I might, I can't make this bike fit me well for the way I ride it. it's just a little too small to ride with a short stem and wide bars, and I would have to put a stem 50mm or so longer to make it work. I want to keep the cockpit set up the same and increase the reach. I have already sold my Karate Monkey frame, so I am in the market for a new frame.

Maybe I am splitting hairs here, but I know from experience how much small changes in geometry can affect a ride. I am 5' 8 1/2" tall with a 32" inseam. I do NOT have the luxury of test riding any bikes.

I have limited options for a replacement frame (I would have to quit my job and get another job at another shop if I want more options, it's that simple), so I am considering two frames with both have a ETT close to 600mm.

rounding these figures to the nearest whole MM:
16" Karate Monkey- 576mm ETT, 591 stack, 395 reach (my old frame, for reference)
18" Karate Monkey- 599mm ETT, 603 stack, 415 reach
17.5" Soma Juice- 595mm ETT, 577 stack, 429 reach
(note that the Juice head tube is 10mm longer)

18" KM ETT is 23mm longer and the reach is 20mm longer.
Juice's ETT is 19mm longer and the reach is 34mm longer.

(a little trig tells me that the distance between the top of the HA and the BB are:
16KM 710mm
18KM 732mm
17.5J 719mm

I don't know if that tells me anything, but there it is.)

I guess the short question is: do I want to get a frame that is appropriately long for me by getting a frame with an appropriately long "reach," or assume that the effective top tube will suit me either way with enough spacers under my stem?

A longer ETT that doesn't give you the desired frame reach only helps if you can live with more saddle setback. Power and desired weight distribution will determine your saddle setback, so unless it was wrong before, a longer ETT that doesn't give you more reach doesn't help.

The best thing to do is figure out your desired bar height and reach (both relative to the BB). Then for each frame you can calculate what you'll need in terms of spacers and stem length to achieve that. A tool like the free version of www.bikecad.ca | Bicycle Design Software will save you a bunch of trig once you get past the learning curve.

the frame I had was too short in the reach. I was just noticing that the longer ETT does not necessarily correlate to a longer reach.

I downloaded that BikeCAD program earlier today and now I can't get anything donw because it came with a bunch of annoying adware that I can't get rid of!

You measure all those In Person?


I suppose many people have their own definitions ... Heres an old one .

Horizontal line with a vertical line thru the BB axis behind the BB is 'setback' to seat tube center line. 'reach' is the forward portion to the head tube steering Axis.**

Combining them is the effective top tube. between CL of the seat and Head tubes.. horizontal

** you may include stem length , to Reach and measure to the spot on the saddle you sit on , for a Bike to Bike comparison, if you wish

to include your seat post choice and where you tightened the saddle rails on the head of the Post.



CAD for the frame build? ? set back is angle, degrees, of seat post + tube length..

There's nothing to download for the free version. It's a Java app that runs in the web browser. Perhaps you're talking about downloading Java? In that case, the crapware that comes with Java is Oracle's doing and has nothing to do with BikeCAD. You have the option to not install the extra junk when you install Java.

That must have been a different bike CAD program that i got on accident.