Utility Cycling - Big Dummy sizing

Hey,

The good news is that my LBS can get a Big Dummy for me in the next batch, the bad news is that they only have size 20" and 22". I had originally gone for the 18", but would a 20" be a better fit? I am 183cm tall.

This is the annoying thing about buying a bike before you have had a chance to try it.

Neil

Well it all comes down to top tube length. The stand over on all the BD frames is quite low so I'd just ignore it unless you are really short - which you are not.

So looking at the effective TT of the various BD frames:

16" = 573.4mm
18" = 596.0mm
20" = 614.0mm
22" = 631.6mm

I'm 183cm so around your height and ride a 18" BD. The TT is quite long [longer than my 58cm LHT which is a big bike] and I wouldn't want a bigger frame with the Titec H-bars I'm using. If I went with some swept back bars like the ones shown on the complete BD sold by Xtracycle I could go up a frame size to a 20"

So ultimately you need to decide which type of handle bar you are going to use and that will help you sort out which frame will work. My sense is a 20" with flat/riser bars will have a cockpit that is on the long side even with a shortish 80mm stem. Having said that you could go down to a LBS and measure some bikes with effective TTs similar to the BD frame sizes you are interested in and get a feel for what your BD would fit like.

Thanks for the good advice Vik.

So I went into the shop and sat on a few bikes. The guy in the LBS was very helpful and found a bike with a top tube length that matched the BD TT length. Even with a huge 130mm stem on it, it felt about the right size. I have now ordered the 20" and should have it mid-late August.