Road Bike Sizes

[Francois Visser]

I am a MTB rider, but I am looking for a first road bike. I am 1.71m height, what frame size should I search for in centimetres (as in classifieds on this site)?

[Cyclewizz]

Should probably look for a 54cm, maybe even a 56cm

 

You normally have to come down a size from MTB to Road.

[Bub Marley]

Should probably look for a 54cm, maybe even a 56cm

 

You normally have to come down a size from MTB to Road.

I would say 52-54cm. 56cm seems excessive.

 

Again it depends on the manufacturer. Once you have found something that interests you, you can search for the manufacturers specs to get an exact size because the geometry is different for every manufacturer.

[Rick Sanchez]

Google "road bike size calculator" and that should give you a good starting point in terms of the size you should be looking for. Once you find something you like in the classifieds, Google the manufacturer's geometry and size guide and take it from there

[DieselnDust]

I am a MTB rider, but I am looking for a first road bike. I am 1.71m height, what frame size should I search for in centimetres (as in classifieds on this site)?

What's your inseam?

 

You could go maximum a 54cm top tube with reach not longer than 385mm.

But likely 51cm to 53cm bike sizes will accommodate you. Or size small.

 

All depends on your physique, flexibility, arm length, to get the exact size.

[Grease_Monkey]

What's your inseam?

 

You could go maximum a 54cm top tube with reach not longer than 385mm.

But likely 51cm to 53cm bike sizes will accommodate you. Or size small.

 

All depends on your physique, flexibility, arm length, to get the exact size.

Yup that seems spot on. Obviously depending in your build - but OP you are not in any world a 56cm frame - I am 1.78 with long torso (ie: I use a bigger frame than most people my height) and bought a 56cm and promptly sold it because it was just too long!

[s14phoenix]

Well the best is to go and try the bike in the various sizes to be sure.

 

I went for sizing and they said a 56 or size L road frame. I tried it and hated it as the reach was too far. So I bought a medium.

 

At 178cm I wish I had a size small frame (aero frame) as the medium is just too long for me to be completely 100% comfortable and 95% is not 100%.

I ride a medium MTB (also changed from size L down).

 

Some things to consider:

 

1. aero frames have longer reach usually than "non Aero" frames in the same sizing.

2. aero frames may have shorter headtubes to get you down lower in the front also.

3. compact frames may have short seatstay but long top tube so check the geometry (like 52 seatstay and 55 top tube - so flat but long)

4. even some really tall pros ride small frames - with long stems and long seatposts but they are quite flexable and can get down that low so don't buy too small either.

 

In my opinion I would fit you to a small (typically Giant TCR sizing).

and probably a max of 50 to 52 in other sizing maybe even smaller rather.

[David Marshall]

Not straightforward due to the above.  Some manufacturers measure top tube actual, others effective horizontal top tube and for some strange reason some measure the seat tube.  The general rule (which works out for about 90% of a population) is to measure your inseam (feet about 15 cm apart) and multiply by 0.653 to get the right effective top tube length.  This line is measured from the centre of the head tube where the top tube joins the head tube to the centre of the seat tube keeping the line horizontal.  If you are like me and fall into the 10% of odd balls it is more difficult. You will then need to select a frame to best fit and then play around with seat post and stem lengths. Your frame design then becomes a lot more important.  I measure for a 58 and due to my short body ride a 54.  A very compact frame with long seat  post becomes unstable and a short head tube leaves you with an excessive amount of steerer sticking out of the head tube,  Long bodied guys will have the opposite problem.

[Dirkitech]

Should probably look for a 54cm, maybe even a 56cm

 

You normally have to come down a size from MTB to Road.

never heard of coming down a size between mtb and road, but 56 is definitely too much for probably most people below 1.8m tall.

I have however heard of dropping a frame size moving to a TT bike, but that could just be hearsay.

 

OP, as with some of the other posts, start looking at around 51-54cm. Different brands' sizing vary significantly- for instance, on a Giant you may be a large (54) but on Specialized a medium (52)

[Francois Visser]

Thanks to all your super-helpful comments guys!!

[DieselnDust]

Also being a MTBer primarily, do consider what are termed "endurance" bikes. these are typically have a longer headtube and shorter reach to allow for a more upright seating position without having to resort to a whole carton of spacers. Examples of this type of bike would the Giant Defy, Cannondale Synapse, Specialized Roubaix, LOOK 765, Bianchi Infinito CV and Intenso CV etc. Still very racey in handling and response but more comfortable and hence a little more familiar to you coming from an MTB

[Longbarn Killer]

Measure your inseam from foot to crotch and multiply by 0.65. This will give you a good guide on frame size. Just bear in mind that this is for a "standard" frame where the top tube is straight and the sizing is measured on the seat tube (most manufactures use the seat tube when quoting sizes). 

 

This is more or less what the frames are:

50 = XS

52 = S

54 = M

56 = L

58 = XL

60 = farm gate

[Thomo]

I think this size.

 

https://www.bikehub.co.za/classifieds/320276-scott-cr1/