Bike/frame sizing

JSL

Hi,

New here so aologies if this has already been talked about - I had a look but didn't see anything.....

Its been a long time since I last had a road bike and I am now totally confused by the sizing I thought that I could use the inside leg - 10" whcih gives me 20" or ~51cm.

I thought that was straight forward until I started reading about folk - about the same height as me (5'8") having frames up to 54cm and some being advised to have frames less than 50cm. Ever one tells me that 'size matters' so I was hoping that someone could perhaps clarify this a bit for me before I spend my hard-earned cash...

Thanks

STEFANOS4784

Best bet is to get fitted properlt by a bike shop, failing that there are websites. Some interesting bits and bobs here:
http://www.cyclemetrics.com/Pages/FitLi ... _links.htm

Watch out though, i found that the online calculators suggested frame sizes quite a bit larger than what i like and find comfortable.
P.s welcome!

careful

I agree with the advice about the bike fit - but a bit of background info wont hurt. The old inside leg - 10" formula used to be quite common for pretty standard frames with horizontal top tubes, similar frame angles and about 4 to 5 inches of seat tube. Many frames now are 'compact', ie varying angles of slope on the top tube. The first problem is that different makers measure them different ways eg centre of bottom bracket to top of top tube or sometimes to centre of top tube, often to theoretical top of top tube if it were horizontal. Partly for this reason, many riders pay more attention to the horizontal distance from the centre of the seat tube to the centre of the head tube. In my case (just under 6'), I like a 55 or 56 frame with about 55cm long top tube. My advice FWIW, dont even rely just on a fitting - try as many as you can before you buy.

topdude

5' 8" tall / 30" inside leg, you are looking at a 54 / medium frame.
Of course the advice above is sound, go to a few bike shops and try some bikes for size

redddraggon

52cm or 54cm (both compared to Traditional Geometry). I'm about the same height but with a 31" inside leg and I'd go for a 52cm.

neeb

The other really important dimension in modern frames (apart from "effective top tube length", i.e. the the horizontal distance from the centre of the seat tube to the centre of the head tube mentioned by careful) is head tube length - you don't want to have to use loads of spacers to raise the bars or else find that you can't get them low enough. This can vary quite a lot among frames with the same effective top tube; bikes labeled as "sportive" tend to have longer headtubes for a more upright riding position.

bikerZA

I'd say you're looking at a 52.

I'm 5'10, and ride a 54.

neeb

I'm 5'10, and ride a 54.

On the other hand, I'm 5'9" and I'm either a 54 or 56 depending...

Bike fit definitely a good idea. 100 quid plus may seem like a lot of money, but if it's done properly it's a bargain...

giant_man

Get yourself measured properly. It's the only way of knowing for certain. If your present frame is too large or too small, you can do certain things to change, but it won't be as good as a thorough measuring. Look upon it as an investment.

JSL

Thanks everyone for the replies, hints and suggestions. Much appreciated