Borderline frame sizing - choose the bigger one or the smaller one?

[Gingerbreadman]

Both small and medium size Giant frames seem to fit me just fine. I guess I am at the top end of one and the bottom end of the other. So which one should I choose?

A smaller frame is lighter - so I guess the small one - right?

 

[vickster]

I'd go smaller having suffered chronic tennis elbow from an over large frame. You can always add a longer stem

However, ride both to confirm which feels best

 

[Fab Foodie]

I'd go with the smaller one, there are more options to make a smaller frame fit than a big one. Longer stem, layback seat post etc.
Agree with Vickster, try them both first.

 

[HorTs]

I think the general advice is to go for the smaller if borderline - having said that I went for the larger. I hope this has made your decsion easier.

 

[GrasB]

I'd go for the one that gives you the most adjustment room after it's been adjusted to a reasonably close fit.

 

[Kestevan]

Depends....
I'm an odd shape, I have a very long torso and shorter than average legs for my height. I found that on the road bike I preferred the larger size frame, as this allowed me to stretch out a bit without using a stupidly long stem.

Conversely on the mountain bike I opted for a smaller frame, with lots of seatpost and a slightly longer stem. This gave me a bit more standover height (the previous larger frame was a tad close for comfort in that area).

 

[MrWill]

Smaller frame is likely to end up with you having a lot of seat post showing and a lot of spacers. If you are indeed at the top end of one, I'd say get the bigger one, with shorter stem, possibly a non lay-back seat post

 

[Cyclist33]

I'd go with the smaller one, there are more options to make a smaller frame fit than a big one. Longer stem, layback seat post etc.
Agree with Vickster, try them both first.

Er, shorter stem, zero-setback seatpost etc... I mean to say, by the terms you've used one could equally say the exact obverse in favour of a larger frame. In fact since most bikes come shipped with a seatpost that does have a setback...

 

[GrasB]

Er, shorter stem, zero-setback seatpost etc... I mean to say, by the terms you've used one could equally say the exact obverse in favour of a larger frame. In fact since most bikes come shipped with a seatpost that does have a setback...

The seat post should NOT be used to adjust reach as it changes the saddle/BB arrangement which has a big impact on hip angle. To resolve that one needs to drop the handle bars which on a larger frame is going to be a problem!

 

[Venod]

I had this problem when I bought a Planet X frame they both felt OK, I went for the large and rode it for a couple of years but I was never 100% happy, I think the medium would have had me feeling the same, I think its because they are compact frames they feel different, I now have 2 Kinesis 54cm frames and am very happy with the fit, but they are not a compact design.

I would say go small.

 

[Cyclist33]

The seat post should NOT be used to adjust reach as it changes the saddle/BB arrangement which has a big impact on hip angle. To resolve that one needs to drop the handle bars which on a larger frame is going to be a problem!

Well not insurmountably so... most bikes have space up and down the steerer so you can adjust to suit. Likewise the seat position (in two dimensions + lean angle of saddle) isn't hard-and-fast, it's what works for you. They're just variables to be tweaked and provided your larger or smaller size bike has the potential for such tuning, it shouldn't be a no-go. Course, it's best if you sit on and go, "Perfect" - but I have never found it so and even now am tuning the ride on my Giant and Jamis - the Giant is 1cm lower on the seat and about 0.5cm further back, the front is slammed by around an inch while the Jamis is slammed by 2cm; the Giant has 1cm longer effective top tube but a 90mm stem while the Jamis has a 100mm stem. In theory their reach ought to be the same but I have got the Giant set up so that it's longer and flatter with the Jamis shorter but with a forward feel to the pedalling. Both fit fine. One's body is capable of great adaptability.

 

[Cyclist33]

For what it's worth, I usually go for the smaller if it's a question, having said everything I have!

 

[GrasB]

Sorry but you can't simply adjust the layback of the saddle for reach then tweak things a little. Once you change the position of your saddle you've got to totally re-evaluate your entire bike fit including the length of cranks you're running on. Normally changing your saddle position more than about 5mm means changing your entire fit philosophy.

 

[Fab Foodie]

No you adjust the layback of the seat to get your position relative to the bottom bracket. Cranks don't need changing. Once you've done this you adjust the stem for reach. On too large a frame if you get the seat position relative to the BB correct chances are you will end up with a stem that's too short and will make life twitchy and your body over stretched.

 

[CopperCyclist]

I'd go smaller, if it's really borderline. Easier to assist bigger than smaller in many ways - plus if you want to be a weight weenie, surely it's lighter!