too big, or too small?

this may be an odd question, but is it better to have a bike that is too bike, or too small?

Obviously just right is the obvious answer, but if you are kind of "between sizes" is it better to go up, or down?

ILIKEFOOD

not much you can do to extend your body if the bike is too big - too small you can do lots to do your best to make it fit, saddle height, stem length, crank length, saddle position. Obviously if it is far too big or far too small you won't have a lot of success in trying to adapt it to make it work.

magicbastarder

the usual advice is to go small and make it bigger.
i've also heard advice that if you're between sizes, measure your arm span. if it's greater than your height, go for the bigger bike, and the converse applies.

nordicb

In MTB scene it is common to go to larger size than fit suggests, for stability and control.
Road bikes, it seems that either proper fit or smaller than should be.
I don't know why anyone would go smaller, perhaps weight saving? Longer stem for directional stability? Perhaps someone knows better.

Lumen

nordicb wrote: »

I don't know why anyone would go smaller, perhaps weight saving? Longer stem for directional stability? Perhaps someone knows better.

ILIKEFOOD knows better.

magicbastarder

magicbastarder wrote: »

the usual advice is to go small and make it bigger.
i've also heard advice that if you're between sizes, measure your arm span. if it's greater than your height, go for the bigger bike, and the converse applies.

Which kind of makes sense, as the distance between the saddle and the pedal is easily adjustable, so you either have 12cm on seat post showing, or 10, but I guess that as the reach is a bit harder to change (other than getting a longer or shorter stem) that is the key dimension.

ILIKEFOOD

ILIKEFOOD wrote: »

not much you can do to extend your body if the bike is too big - too small you can do lots to do your best to make it fit, saddle height, stem length, crank length, saddle position. Obviously if it is far too big or far too small you won't have a lot of success in trying to adapt it to make it work.

I was looking at crank length and trying to find advice, but it seems to be one of those things that is personal choice rather than any hard and fast rule, a bit like which colour cleats to use, or whether or not to wrap bar tape outside in, or inside out

nordicb

Once fitted, the saddle over crank is usually left untouched. This is where frame size is important because the only thing person can adjust then is the stem or handlebars (width, etc). On MTB longer stems is rather a no no, this is why larger frame is needed. On the road frames, short stems are rather a no no, so smaller or good fit frame may be better. Too small frame with long stem may shift weight to the front wheel a good bit, which may feel unstable and is probably a right direction for getting a death wobble. Also longer wheel base aids climbing.

Wishbone Ash

nordicb wrote: »

....I don't know why anyone would go smaller...

Easier to get into an aero position on a smaller bike - hence the reason some pro riders go down a size.

(...and, as you said, the bike will be lighter).

68 lost souls

I was between sizes and went larger, should have gone smaller. Went and got it fit 2 years later and basically told I’d be better to sell it and buy a size smaller. Ended up keeping it and changing cranks plus stem.

Could still do with moving to a narrower set of bars...

Macy0161

Another Brand maybe? I assume the fits are subtley different? fwiw Giant have M/L between their Medium and Large.