Retrobike size v modern compact road size

danwlx

Retro Newbie
Hi All!

I'm new to the site having started to think about buying an old frame and restoring / rebuilding. I searched the forum but didn't find an obvious answer to my query.

I've recently started riding my 2009 Specialized Allez Elite compact again which has a tt of 56.5cm and a st of 53cm. This gives a pretty comfy ride although my neck can ache after a couple of hours, also my bars and saddle are at the same height which seems to differ from most peoples saddle position!

Can anyone give me an idea of how this frame size will translate into a retro frame? For info i'm 5ft 8".

Sorry for the newbie question and thanks for any help!

Dan
 
if your asking what frame size you should go for in a traditional double diamond frame i would say 52 or 54 cm centre to top, i am a little taller then you at 5'9" and i ride a 54 centre to top on the road but i can get away with a 55cm but 56 is too much.
 
I'm 5'10 and I am a bit stretched out on a 22.5" frame. I find my 21.5" more comfortable to ride but I have to have the saddle up quite high. I would agree that you'd want a 21"-21.5" frame, though if your arms and legs are on the shorter side you might find a 20.5" more comfortable.

20.5" = 51cm
21" = 52.5cm
21.5" = 54cm
22.5" = 56cm
 
Consider the top tube length as well. My 1983 Raleigh was spot on when I bought it new. 56cm Tt and 54 ST. I can't ride it now as its too stretched out. I also have a 56 ST Raleigh with a 56TT. Seat tube size doesn't always get the same sized top tube.
 
Dan,

Have you had a bike fit?
Your neck pain may indicate some tweaks to your position could help. In which case, best to get your current ride dialled in perfectly, then translate the dimensions/ contact points to a retro bike.

Alternatively, how often do you shift position during your longer rides? Sometimes neck discomfort can be caused by remaining in a fixed position for too long. It may be that by regularly changing hand position (hoods to drops) and a few short standing intervals will give your neck enough movement to reduce the neck discomfort.

Good luck,

David
 
Buy on the basis of the toptube length also consider the headtube length and the angles of the heatube and seatube.

In the real world, they are far more important than the seatube's actual length (you can easily extend it!!).

So long as the size of the toptube is within your known limits with a reasonable stem length (say 100mm) then you will be able to compensate in almost all other areas (e.g. choice between inline or layback post will give you up to 3cm of effective adjustment of the seatube angle to help get you in the best position relative to the cranks and the stem length can be adjusted at the other for reach).

As you will probably be buying a frame with a threaded headset, you should have no issues adjusting the stem (up/down) for height.

Hope this advice helps.
 
If you want the bars at the same height as the saddle, you might want to go for a slightly bigger frame size, compared with the typical racing bike set-up.. A quill stem only has limited vertical adjustment; you want the top tube height to be high enough so that you can set the stem at the height you want, ie the head tube has to be long enough.

I think you should have no more than about 10cm of exposed seatpin, or maybe less. If the saddle is any more than that out of the frame, then it's probable that with the stem at it's max height, it will be below saddle height.
 
Back
Top