How do I find out the correct frame size?

[Cyclopathic]

As I get more into my cycling the more I want to move from using my hybrid to a road bike/ tourer or somewhere inbetween, I haven't decided yet. Cash is short and comfort is a must so I really need to get it right first time so I am looking for advice about what frame size I should be looking for and how to determine this from my measurments. The ony two I know are that I am 5'10" with an inside trouser measurement of 32".
Apart from frame size what other factors should I be aware of when looking for my ideal mount?

 

[pepecat]

If you go to a decent bike shop, they'll be able to help you with frame size. The other thing to do is just sit on a few bikes and try them. I'm 5'7" and have a 30 inch inside leg, but only ride a 50cm frame. If you're a fella, i think you want some clearance between the top of the frame and the saddle, so that if you're standing astride the bike, your crown jewels aren't touching the top tube. Otherwise the potential for painful accidents is increased.......

I don't know what the reasoning is for having a frame that sometimes looks a bit small, and the seat raised quite high - like this - maybe it's something to do with handling of the bike and the reach to the handlebars, but probably also to do with the sitting position and the power in the legs it gives you. Basically, when you're sitting on the bike and holding the handlebars, when your foot is at the bottom of the pedal stroke, your leg should be nearly straight, but not totally straight.
There are whole websites which will give you info on bike size / fitting, but equally, any good bike shop will help you out too.

 

[Sittingduck]

Just go into a bike shop and try a few? Doesn't matter which shop, as you are only after sizes. Evans is fine for trying out sizing, although a lot of folk wouldn't buy a bike from there (due to after sales service etc).

All bikes are different, just because you may be a 54 in a Specialized Allez, doesn't mean you aren't a 57 in a Bianchi Via Nirone, etc. What shop staff tell you 'fits' may not actually be true. Go for a test ride and you will soon know what feels right (for the particular feel of ride, you are after eg. larger frame for a more relaxed touring setup or a shorter headtube for a more racy approach).


Good luck,
SD

 

[Cyclopathic]

Thanks folks. As I suspected, no definitive answer but some good advice non the less.

 

[Angelfishsolo]

Also remember not all road bikes are equal. Some are designed as racing bikes, some as tourers, some as tri / TT bikes. The geometry will vary on each machine.

 

[gaz]

Get a bike fitting service. Their might not be many in and around Leicester though.

 

[Cyclopathic]

Also remember not all road bikes are equal. Some are designed as racing bikes, some as tourers, some as tri / TT bikes. The geometry will vary on each machine.

This is something I am becoming more aware of and it doesn't help that I am not entirely sure what exactly I want. There seems to be an awful lot of choices to make between an out and out touring type bike and a speedy total racing machine. Budget plays a big part also so this may take care of a lot of these choices. From everything I've read here and heard the thing to do is just to keep looking and trying things out. I have the luxury of not being in a rush, my Python Quantum (called Monty for obvious reasons) is fine for now and capable of taking me out for decent length rides and there is much enjoyment to be had from searching around and taking time over it.
Despite riding since I was a kid I am only just now learning about a lot of bike related things. I have only just heard about audax which I am told is a range of bikes that fall somewhere in the middle of the specification and geometry of the racing and touring road bikes and as if that weren't enough I see that there is a clasification called cyclo-cross which as far as I can tell seem to be like rading type bikes but a bit more strudy, as if for skirting the od field. I get the impression of a sort of off road racer/roadbike despite the contradiction in terms.
I have no idea if these audax and c-sross types of machine have been around long enough or in great enough numbers for them to have trickled down into the less expensive secondhand market. Of course whatever I get I am likely to adapt in some ways anyway.
The more I find out the more there seems there is to find out and I think that in the end my search will come down to trying a bike out one day that I think "bingo" to btu at least I know the general area I'm looking in.

 

[Cyclopathic]

Get a bike fitting service. Their might not be many in and around Leicester though.

There is a posh bike shop in the middle class bit of leicester (it's not a very big area) who shall for the moment remain nameless who do, I am told, offer this service to its customers. I am also told that it is free if you are buying your bike from them but for the measuring alone they charge although I don't know how much. I haven't been in there in a good while though as most of their derailiers retail for more than I paid for my whole bike and going in there makes me feel all unworthy and frightened in case I call the top tube a cross-bar or commit some other hienous faux pas.

 

[Scilly Suffolk]

Audax and cyclo-cross are both types of cycling sports. Bikes bearing either label will have certain features that make them more suited to one activity or the other: as an audax is a long-distance event the bike will likely have fittings for racks & mudguards and have an emphasis on comfort rather than outright speed; a cyclo-cross bike will have clearance for wider tyres than a road bike and V-brakes instead of calipers to allow for muddy terrain.

However, these classifications are not absolute and specifications will vary between manufacturers; equally, just because a bike isn't labeled as such, doesn't mean that it won't be suitable for a particular activity.

"...it doesn't help that I am not entirely sure what exactly I want.": until you decide what you want to do on your bike, you'll struggle to find the best bike for you. Will you be commuting, touring, racing or simply riding for pleasure?

As you said, you need to ride some different bikes and see what suits you: joining a club is a good way of getting some great, non-judgemental advice for free!

 

[Cyclopathic]

Audax and cyclo-cross are both types of cycling sports. Bikes bearing either label will have certain features that make them more suited to one activity or the other: as an audax is a long-distance event the bike will likely have fittings for racks & mudguards and have an emphasis on comfort rather than outright speed; a cyclo-cross bike will have clearance for wider tyres than a road bike and V-brakes instead of calipers to allow for muddy terrain.

Thanks for clearing that up. As I said the more I learn the more there seems to be. At the moment I think I like the sound of a bike set up to suit the audax type event (although I doubt I'd be riding in anything like that). Thanks for the links.

 

[wakou]

Hi, just one thing from your post: DO NOT USE TROUSER SIZE
Decathlon have a wee calcuator, is it a bit rubbish and not up to date and only in french, but will give you a frame size figure to work from.
To get you inside leg measurement for bike sizing, put on your cycling shorts, take a book, stand back to a wall with heels touching the wall. Put the book between the legs and move it up so that it is pressing (doesn't hurt!), and so that the vertical of the book is vertical against the wall. Hold it there and mark the top of the book, measure height to floor.

 

[Cyclopathic]

Hi, just one thing from your post: DO NOT USE TROUSER SIZE
Decathlon have a wee calcuator, is it a bit rubbish and not up to date and only in french, but will give you a frame size figure to work from.
To get you inside leg measurement for bike sizing, put on your cycling shorts, take a book, stand back to a wall with heels touching the wall. Put the book between the legs and move it up so that it is pressing (doesn't hurt!), and so that the vertical of the book is vertical against the wall. Hold it there and mark the top of the book, measure height to floor.

So in effect it's from the floor to the underside of your sack whilst contained in lycra? Have I understood you correctly.

Does it matter what book I use? Any particular author?