superunknown said:
Hey all,
I have found a good second hand road bike for sale which I would want to check out but I am not sure if its an appropriate size.
The owner has said it is a 52cm frame, and I have an 84cm inseam.. so according to some guides this means I should get a 54cm frame, but is 2cm really that much of a difference? If its on the borderline I will check it out anyway and it may be fine.
I don't want to waste money getting something that won't be suitable, even though this bike is exactly what I want
First of all, make sure you're talking about your "bicycle" inseam, not your pants inseam.
Second, to find some basic measurements as a starting point (but not gospel!) go to the
www.wrenchscience.com or
www.competativecyclist.com websites and plug your measurements into their fit calculator.
All that said, if your inseam is 84cm (I translate to 33 inches), my guess is that you'll be looking at a 54 or 56 cm frame, depending on your other measurements and personal preferences.
As for how much difference it makes - to a great extent, you can adjust the seat position (up/down and fore/aft) to accomodate your physique. You can also adjust the lenght of the reach (seat to handle bars, aka, toptube+stem length) by a longer stem. There are limits to both of those which may or may not be a factor if you go with the 52. You can only see for yourself.
The thing that is harder to do with a frame that is too short is to get the handlebars up in relationship to the seat. With a shorter frame, the seat post is extended quite a bit to get the right height, therefore the handlebars are lower in relation to the seat. Some people like a low riding position. A smallish frame will be OK for them. Some people are more comfortable with the handlebars within an inch or two to the level of the seat. They would find the smallish frame hard to get comfortable without an unusually steep angled upwards stem. A larger frame, with less seat post extended, might work better.
All that is personal preference. I'm 5-8 inches (172 cm) with a 32.5 inch (82-83 cm) bike inseam (29-30 inch - 75 cm - pants inseam). I definitely feel better on most 54 cm frames than 52's. I recently changed to a 54 from a 52 which I rode for over 10 years but NEVER felt super comfortable on. I had ridden a 54 long ago (in the 80s) which my dim memory always told me was my most comfortable and favorite bike. This new 54 rings true in that regard. I purchased the 52 at a bike swap for the same reason you're talking about - it was what I was looking for, in good shape and at a good price. A mistake in retrospect.
The main difference is the vertical height of the handlebars and it's only an inch or so. My overall reach and seat height is the same, but just getting the handlebars up an inch or so has a tremendous impact on weight distribution, and just the feeling of stability and comfort to me. Depending on how I flip the (conventional, 7 degree) stem, my drop from seat to handlebars is between about 3/4 - 2.5 inches (2-6 cm) with this bike. Plenty of range for me in that regard. All other adjustments (standover, seat post, stem) are well within "normal" range for either a 52 or 54.
GO look at the bike, but wait for the right one! Of course if the price is right, you can always buy it, try to get it to work, but resell it later if it doesn't work out. That's one of the beauties of used bikes, less depreciation.
