Am after a new (second hand) road bike, racing or audax. My old 20 yr old bike is a 23″ seat tube and 57 cm tt. It feels pretty right size wise, but am aware that modern bikes have come on! As a rule of thumb, and I’m 6′ just, standard arms/legs!, riding 2-3 hr comfy road blasts, what size frame would be good to look at – 56cm vs 58cm frame? And I know I should try the bike, but not always possible secondhand.

A few pointers with st & tt sizing would be great.

Thanks

Just base your search on TT length and don’t worry about seat tube. If your current bike is comfy and works for you start with that.

Only you will know the right size.

I would agree with the TT length being the most important factor but do double check standover height as todays frames have all sorts of different sloping TT’s. When you find one you like just google a geometry chart for it for piece of mind.

just a word of caution, do not physically measure the top tube and assume it it the top tube length. It is on a traditional frame but not on a lot of newer designs.

The use of compact and semi-compact geometry means the effective top tube length which is what you need isn’t the same as the actual top tube length, hope that makes sense and isn’t confusing?

Personally, I’m just shy of 6′ and 58 would be way too big for me, I’m 32″ legs.

I ride 19 or 20″ full sus bikes, and 18″ hardtails for reference.

I have a very average, and general size on all bikes.

Listen to the above, work out what ETT you need by sitting on and riding bikes, and that’s what you stick with 🙂

Thanks all. My old bike’s effective tt is prob pretty much the same as the actual. Compact geo is the variable/new thing for me I reckon.

Rickon – we sound similar size wise and MTb sizing – what road size do you go for?

Thanks

My bike would probably fit you 😉

http://singletrackworld.com/forum/topic/fs-2011-trek-15-58cm-roadbike-with-upgrades

It’s very difficult to be too prescriptive I’ve had a 56 and 57 that were both a bit small whereas just got a 58 cannondale and it feels spot on- I’m 6ft and a fag end with a 33 inside leg

I ride 56cm road bikes, I can actually ride 54’s with a longer stem. 58cm just feel like a gate on me, but…. with a shorter stem they may well feel good for you.

Pop to a shop and try a few out, make a note of what they are, and find out the ETT online 🙂

(then go a buy a bike from said shop – or buy them brownies, for wasting their time) 🙂

I’m 6′ and ride a 56 langster.. feels like part of me for 30 minute blasts to work and week long jaunts through france. I’m gangly too! 🙂

hope this helps.

‘normally’ you’d be a traditional 56cm but sizing is so weird these days as you mention, best try if you can. best to edge on the small side as you can always use a longer stem and/or layback post for instance….