Frame sizing

[iainj837]

My partner is after a bike but she is unsure what size to get. Her inside leg is 31 in what would be the best size frame should she get ?

[drossall]

That's difficult to answer in a simple way.

Evans have some sizing charts which might be a starting point. There's more detail from Sheldon Brown, including the reasons why you can't rely on two manufacturers measuring frames in the same way. His point that the top tube length is more important than the seat tube is central.

It's really best to go to a good bike shop and get advice, or take along a knowledgeable friend. How do you know a good bike shop? Difficult, but if club types tend to go in there, they are probably OK, and if they offer a real range of bikes from something you can afford to something that would take your entire life savings, they may not be too bad. Or tell us where you are and someone may have local knowledge.

[Butterfly]

It's difficult because it depends on several measurements. I have a 30.5 inseam, but although I can ride a 21inch frame, it's not comfortable because my back is so short so I have to stretch to reach the bars. Don't buy a bike without riding it, if possible. And what Drossall says about good bike shops. If you have a friend who knows what they are talking about, definitely draught them in.

[drossall]

It's struck me that certain large chains that sell car parts as well might meet the "bikes you can and can't afford" criterion. However, they are famously patchy, employing really good enthusiasts in some branches, and elsewhere, er, not doing.