dahut

I was asked if I wanted to buy a nice Giant OCR 3, medium frame size bike. In common parlance, Giant gives that as a 50 cm frame. I am 6'1" tall and generally require a 58-60 cm frame - a big difference. Some comment s Ive seen suggest a medium could work for me, but I have my doubts.

My only real interest in it would be if I could turn it into a commuter bike of some sort. So, aside frim the fact that it is a road bike with all the challenges they present to rack and fender mounting, would the Giant just be too small? (pun intended ).

Im thinking I could get an extended seat post and a longer handlebar stem, which would get me up and away from the frame. That might alleviate being cramped over the cranks, but might also put my C/G high enough so the whole thing would feel squirrely, like a circus bike.
I dont know, I havent done this kind of thing on purpose. Oh, Ive bastardized bikes in the past, and made Fankenbikes out of random bits and bobs, but not with any real goal in mind.

I already mentioned rigging up fender and rack mounts and knowing me, the crappy 2300 shift set will beg to be replaced and... by the time I do all that I couldve gotten something that was set up right to start with.

Now, the woman says she'll make me a really, really good price. If it's low enough, Im going to be tempted - I just know I am.

1. Has anyone done this sort of thing, ie, turn a too-small bike into a decent commuter? If so have you some pointers? Maybe some pics?

zzyzx_xyzzy

the seat tube measurement on a bike with a sloping tube means nothing. that giant is more like most manufacturer's 55cm if you're looking at reach-from-the-saddle and height-of-the-headset, but i'd still avoid it:

first, you'd need a stem about this size --

https://www.ebayitem.com/270610825500

-- and second, you'd find that with the tiller of a stem and your weight too much over the front wheel, it will handle like crap.

Don't do it.

MrCjolsen

I'm the same size as you, and normally ride a 58-60 as well. I have one bike that is a 56 and it's take years of tweaking with various bar and stem combos in order for it to be comfortable to ride for any length of time.

Yes, the Giant is too small.

dabac

Peoples tolerance for mismatch is different. I used to ride a small framed MTB with a really long stem, and although the steering felt kinda funky, more like swinging a tiller than turning a bar, the ride characteristics never bothered me. For technical out-of-the-saddle trail riding you keep shunting your center of gravity all over the place anyhow.
Don't really remember how it handled on the road.
But if you aren't looking for speed you might want to set it up for a more upright riding position instead, turning it into a surprisingly snappy utility bike/grocery getter.

zzyzx_xyzzy

Sizing for MTBs and roadbikes seems to be really different these days. Roadbikes vary more in height, MTBs more in length. MTBs have longer frontcenters so the weight distribution isn't as much an issue. a small MTB for technical mountainbiking does make some sense.

Nimitz87

hey andy schleck rides a 55-56cm top tube...he's 6'1 so it must be right!

Chad

Sixty Fiver

I am five foot ten and ride a 55cm road bike... fitting suggests that I can ride 52-56 and my fg road bike is a 52 with a little longer stem and is very comfy.

If you normally ride a 58-60 a 50 cm would be too small.

dahut

I understand the tolerance thing - Im of the mind that, at some point, YOU adapt to the bike. But Im guessing there would be a bunch of trial and error to get any where near a "fit." The consensus so far seems to agree

And in this case, I am bound by speed. My personal expression of "commuting" is getting my @ss to work on time. This means that speed is indeed a deciding factor. Grocery getting and casual toodling are much less of a concern.

Thanks for your insight.

dahut

This is along the lines I was thinking, too. No matter what I do, something is going to be way off.

dahut

I keep having this image of me on a circus bike, perched up in the air with a juggling monkey or something. Not good!


Alright, so lets take different tack. If she makes me a good enough offer, maybe I could sell it on ebay and make a few bills. Then I could apply those to something else. They average about $350-400 on ebay, it seems.

bradtx

dahut, I've found that top tube length is a much more important guide than seat tube length as there are different methods for measuring seat tube length. My old Cannondale is a good example...56 cm frame yet when the seat tube is measured C-C it's 53.5 cm. The top tube is 56 cm C-C. I'm 6' 0" and doubt I could get a smaller frame to fit and ride properly.

Brad

dahut

If Im reading you correctly, it still looks like the Giant is far too small to really be practical for me.

equusbynature

I'm only 5'6" and I ride a 53cm...I feel like a 50 could be too small even for me!

HillRider

+1. Even if really would be equivalent to a 56 measured from a projected level toptube it would be too small. Either buy and flip for the profit it and then buy something the proper size or go for the correct size directly.

bradtx

dahut, I'm suggesting very strongly that you and that frame aren't likely compatible, but there is always the exception. My other (newer) Cannondales are 58 cm with a 55 cm C-C seat tube and a 56 cm top tube.

HTH,
Brad

dahut

And now for the rest of the story -

The bike is actually an OCR1, which is good. But her idea of a really great price is $650.
This is exactly what they sell for on ebay, meaning Im stuck trying to play the 'Greater Fool' game on someone else.

With the frames dicey fit and the fact that there is nothing left in it for a flip, Im taking a pass on this one.

JiveTurkey

Folks, remember that the Giant mediuim-sized frame may have a 50cm seatpost (the traditional way to size), but this doesn't mean anything, especially on a modern frame with sloping top tube.

As stated earlier, the medium has similar geometry of a traditional 54 or 55cm frame. The main difference is that the top tube slopes down so it joins with the seat tube closer to the bottom bracket. But it would still feel like a 54 or 55cm frame for all intents and purposes.