Frame sizes? Significant difference?

*Dusty*

I'm looking at buying a road bike, being 5 feet 11 inches tall should I be Looking at 54 or 56 frames? Is there a massive difference in feel?

Cheers all!

lioneld

There can be yes. I've never really paid attention to what size frames i should be riding - for ref, im 5ft 10, 32 inside leg and I have had two Large (55cm) Wiliers, a 54cm Cinelli and a 56cm Pinarello. Yes, you must have the fundamentals in place - not too overstretched, cramped up etc but it needs to feel right, so get your short list of bikes you like in the right price range and go put your backside on a few, best way is to ride them and see how you go

neeb

*Dusty* wrote:

I'm looking at buying a road bike, being 5 feet 11 inches tall should I be Looking at 54 or 56 frames? Is there a massive difference in feel?

Cheers all!

The numbers manufacturers these days use for frame sizes are becoming almost meaningless, e.g. I'm 5' 9" and the official size of my Trigon frame is "520" (52?) but if I was riding, say, a Cube I would be a 56 and would need quite a long stem on it too. You will certainly notice significant differences between one size and the next one up, the gaps are quite large unless you are looking at a brand like Colnago that do many different sizes.

The important things to bear in mind when comparing two manufacturers' frames are 1) reach, which is fairly closely approximated by the effective (horizontal) top tube length, corrected for seat tube angle (as a rough guide, add 1cm to quoted effective top tube length for every extra degree of seat tube angle, so a bike with a 73 degree seat tube angle and 55cm effective top tube will be roughly the same as one with a 74 degree seat tube angle and 54cm effective top tube) and 2) the head tube length, which if too long will prevent you getting low enough and if too short will mean you need an ugly big stack of spacers or a flipped stem... Both these things (especially head tube length) depend a lot on your flexibility and riding style as well as on your proportions.

Unfortunately it's a minefield and it's very common for people to buy the wrong frame size, so do lots of research and get lots of opinions! (or a proper bike fit if you are really keen).

MichaelW

If you know your exact fit position you can shop around for different brands to get the exact size and shape you want.
If you are a newbie and dont know your riding position, then you have to go with the best fit you can find and fine tune over time. You can get some advice from good shops but your position will change as you adapt.
Most modern frames have excess standover clearance so the critical dimension is horizontal reach. As noted, reach is not simply the length, it includes the length in front of the bottom bracket position and that behind the BB. This can vary with the frame angles. When I compare frames, I take a plumbline and a tape measure.