Help with modern road bike sizing

[Woz]

Head over to the geometry geeks website, they have loads of info.

At 5’11” I also ride a 56

That's pretty wicked that site is. If only the database was full of old retro tat, it would be a god send.

Oh yeah, I liked also the fairly no nonsense descriptions which I'm including here:

https://geometrygeeks.bike/understanding-bike-geometry

 

[Woz]

Thanks for all the info gents.
If it wasn’t for the fact that I like a short reach I wouldn’t bother going to look at this “medium” frame, but as the seller is happy for me to try before I buy I might as well go have a look. I’ll take some measurements from my steel road bikes to see if anything lines up (pedal to seat height, seat to bars etc)

Best way. Suck it and see. Your height is only 1 cm off their recommendation for the next size down.

 

[mattr]

So What does the 56 refer to on this chart?

The size between 54 and 58.

Probably the old school effective seat tube length.

 

[d8mok]

The size between 54 and 58.

Probably the old school effective seat tube length.

But it’s not just a size it refers too it’s a measurement. It’s clearly ‘size 56 cm’ on the frame and the only measurement which is 56cm is top tube centre to centre. Not saying I’m correct but it’s illogical to have cm on their if it doesn’t mean anything.

 

[Splatter Paint]

So What does the 56 refer to on this chart?

Equivalent seat tube length on a non-compact frame.

 

[mattr]

But it’s not just a size it refers too it’s a measurement. It’s clearly ‘size 56 cm’ on the frame and the only measurement which is 56cm is top tube centre to centre. Not saying I’m correct but it’s illogical to have cm on their if it doesn’t mean anything.

It's a nominal size, doesn't *have* to refer to any measurable dimension.
Don't try to apply logic to it. It's an outdated system that should have been retired a couple of decades ago.

I can still remember all the confusion when giant started with their compact geo.
Loads of shops sold frames/bikes based on the measured dimension/seat tube length rather than the actual size of the frame, was rather amusing at the time.

 

[Woz]

It was so much simpler back in the day.

If you could grab at least a full fist around the seat-post and put a foot down without catching the two plumbs on the cable run, it was good to go!

 

[mattr]

Yup, that's why I ended up on frames that were way too big for me for years...

 

[novocaine]

I thought the rules now said that you had to pay some crazy fee to some bloke who's had 30 minutes training on a fancy bit of technology, who will then tell you that, due to your inseam measurement and arm to nose ratio that you are indeed on the wrong size bike and should consider a frame that is 2mm smaller? which is great, because he just so happens to have that exact size in stock.

and whilst you are at it, your saddle is the wrong shape, you're using the wrong cleat float and crank length and due to the size of your manhood, you should try really be riding in a short with less padding, perhaps these rather dashing Rapha shorts, digitally designed using the latest materials which are in no way similar to Lycra.

or have misjudged the modern bicycle industry?

 

[Woz]

Back in the day bike fitting was free, much more finely tuned with lots of experience...."No, it's not too big, you will grow into it".