I'm 5'6" and my inseam is 30". Irrespective of this, where do I go to find my ideal stack and reach? Are there online tools? I'm in Los Angeles, and Helen's does bike sizing for free, but I'm not looking for something that's part of the sales process. Bike fitters are, I believe, are something you do AFTER you already have the bike.
How do experienced cyclists get sized correctly?
Originally Posted by
Kontact
Honestly, there is a lot of voodoo to your question. Generally, sizing should work out in such a way that height will be a good predictor of somewhat "standard" frame sizes, while the Stack or headtube length allows options of sitting up or leaning over more. If you are at a height that is well within a the range for a particular size, and you get an appropriately high or low front end (Stack), then the rest of your fit should come from selecting proper bars, stem, etc.
Recommending a top tube length makes some sense, but if it comes on a bike that is too low, you haven't accomplished a good fit choice.
That said, real 51cm top tubes are rare and are very hard to find without "faking it" by the maker leaning the seat tube angle too far forward. Are you 5'3" or shorter? If not, or you don't have really short arms, I'd suspect the measurements you submitted might not be spot on.
I think what is likely to work for the most people is a size based on height, and a choice of low or tall head tube based on rider posture preference. If you're 5'10 and are moderately flexible, most everyone's 56cm frame should be a reasonable choice.
Originally Posted by
Wheever
In addition to what Kontact said above, I would add that your *proportions* need to be taken into account when sizing a bike. I'm 5'9", and I was told over and over that a 54 was the right size for me, but it wasn't. I have very long legs for my height, so actually I needed a top tube 1 size smaller--52. (With a 100mm stem, rather than the 90 that the bike came stock with. On the 54 bike I first bought, I had to go down to a 80mm stem, which made the bike very twitchy.) when I went to buy my second bike, again, the salesman was trying to put me on a 54, but as soon as I got on a 52, I knew it was right!
So I recommend you measure your cycling inseam carefully. If you have short legs, you might need a longer top tube, long legs, a shorter top tube. Go try a bunch of bikes. If you can try a model in the different sizes, so much the better.
How tall are you, and what is your cycling inseam?