What size frame to choose

Peter Salt

Well-Known Member
Location
Yorkshire, UK
Hi Everyone,

I'm looking to buy my first road bike in the near future. Got an opportunity to sit on one today. First time for me! But it got me thinking about frame sizes...

The one I tried was an 'L'. Theoretically way outside my 5'7'' frame. But... It felt OK. Yes, when the saddle got adjusted to my leg length it didn't look very high and the maximum handlebar drop I could get without a dropped stem would be around 5 cm but without any experience it's difficult for me to say if I would ever want a more aggressive position.

On the other hand, there's the argument of weight, correct? But just how much heavier an 'L' size carbon frame is compared to an 'M' or an 'S'?

I also heard that some 'roadies' get one size smaller frame than they theoretically should. Is this true? If yes, why?

Did it just feel right because I'm used to leisure cycling on a 'normal' bike?
 

vickster

Legendary Member
Depends on the bike, but I'd assume a 52/53/54 TT assuming you are a male longer torso'd shorter legged rider (that might be labelled S or M, or 53/54 or something else if they use a different measurement for labelling eg seat tube).
There's no standardised sizing across manufacturers so you need to check the measurements carefully.
FWIW do not buy a frameset that is too big as it may well never fit well, if between sizes, usual advice is to go smaller.
Weight is the least important consideration, you're talking grams...buy lighter more expensive tyres to save those grams and hope you don't get punctures.
Pros might ride smaller to get a super aggressive position, but they aren't normal :laugh:
Did you actually ride the L or just sit on it...you really can't tell that way if it'll be comfortable for longer rides. What bike was it?
 
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Dolorous Edd

Senior Member
The one I tried was an 'L'. Theoretically way outside my 5'7'' frame. But... It felt OK. Yes, when the saddle got adjusted to my leg length it didn't look very high and the maximum handlebar drop I could get without a dropped stem would be around 5 cm but without any experience it's difficult for me to say if I would ever want a more aggressive position.
As you note, in order to feel OK, you are near one limit of what can be achieved on a size L frame - and it may be that OK changes, and you will go beyond that limit and not be able to achieve it.

Try a size M - if you can still feel OK, and are further away from any limit, that gives you greater flexibility to tweak things in the future.
 
If you're 5'7" with a large frame, how much clearance do you have when you stand over it - between the crossbar and you prize possessions? Chances are you'll do yourself a mischief at some point. I'm 5'7" and ride 52cm and 54cm - depends on the bike.
 
OP
Peter Salt

Peter Salt

Well-Known Member
Location
Yorkshire, UK
Thanks for all the views. It was a Giant TCR Advanced 3 from 2016 (https://www.giant-bicycles.com/gb/tcr-advanced-3-2016).

I say I'm 5'7'' but it's more like 5'675''. My inseam is just shy of 32''. Looking at the manufacturer size guide I'm a freak ;-D I actually never thought I have relatively long legs until I started looking into bikes. You can't really tell as they're also quite thick - not form cycling, just naturally.

I did ride the 'L' and it felt OK, but:
- family jewels were less than half an inch away from the top tube when standing up (in trainers)
- the stem on it was super short 35-40 mm
- top tube length was 58 cm

The head tube lengths for this one are as follows:
L: 18.8 cm
M: 14.8 cm
S: 13.3 cm

Am I right in thinking that if the handlebar drop was ~5 cm on the 'L' then with the same saddle height it will be ~9 cm on the M?

I am flexible - can easily touch my toes with the knuckles.
 

vickster

Legendary Member
There's a size guide in your link - S recommended for your height/leg length. You might get away with an M with a shorter stem (but not that short, how twitchy was it to ride??!!!) and less seatpost showing.
58cm TT is massive for your height - I'm just under 5'10, 34" inseam and all my roadbikes are 54s with 100cm stem (albeit more on the endurance end of the scale geo wise).
Sounds it's owned by someone short who also bought a bike far too big!
 
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T4tomo

Guru
There's a size guide in your link - S recommended for your height/leg length. You might get away with an M with a shorter stem (but not that short, how twitchy was it to ride??!!!) and less seatpost showing.
58cm TT is massive for your height - I'm just under 5'10, 34" inseam and all my roadbikes are 54s with 100cm stem (albeit more on the endurance end of the scale geo wise).
Sounds it's owned by someone short who also bought a bike far too big!
echo this, the bike is far too big and wont be comfy to ride. You (Peter) are long legs / short body so you need arguably a shorter reach than your average 5'7" bloke, who wold normally be on a 52cm/54cm top tube.

for reference I am 5'11" with 32" inside leg, so have a approx 4" body / reach advantage on you, and my road bikes have 56cm virtual top tube (i.e measured horizontal.
 

Cycleops

Legendary Member
Location
Accra, Ghana
As @bobzmyunkle says you need to pass the Victor Silvester test. I'm just over six foot but I prefer a bigger frame, usually around 61cm but I also have a 56 that is also comfortable.
Try and ride a few and see what suits you best.
 

AndyRM

XOXO
Location
North Shields
I'm a mutant: 6"1', tiny torso, legs for years and the wingspan of an albatross, I ride a 56 or 58 cm top tube road bike.

I think an 'L' in any size would be way too big for you. As above, 52 or 54 cm would probably be a better fit.
 
OP
Peter Salt

Peter Salt

Well-Known Member
Location
Yorkshire, UK
Thank you for all your opinions. Looking at Giant's website, I should go with an S; the majority of you also say either S or M so will try and find a nice small frame.
 

cyberknight

As long as I breathe, I attack.
Its not just about saddle height and clearance but a lot about reach .
I am the same height and similar inside leg and my bikes are all 54 Top tube and i use a 90 - 110 mm stem dependant on bar reach .
personally i dont run a lot of drop to the bars from saddle as i could probably benefit from an even smaller frame if i wanted to go for a slammed look .
 

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