Bike frame sizes

[gords]

How are mountain bike frames measured these days? Is it the same across all manufacturers?

[pritch]

There is absolutely no standard way of doing it, unfortunately.  For example, my 19" Orange is pretty much the same as my mate's 16" GT.  The only way to really tell is to sling your leg over the bike.

[gords]

The only way to really tell is to sling your leg over the bike.

Umm, slightly difficult if I'm looking at something on ebay and it's the other end of the country :roll:

I've found a couple of sites that give ways of working it out

You can get a rough idea of the size of frame you require if you measure your inside leg - crotch to floor - then subtract 9" / 23cm or 10" / 25cm for a road bike (or a mountain bike used as a road bike) or 12" / 30cm for an athletically-ridden mountain bike. Hence a rider with a 32" / 81cm inside leg who owns a 23" / 58cm road bike usually requires a 20" / 51cm mountain bike.

So I'd guess at a 20" frame as I'm 5" 8' / 32" inside leg ...

[Manicminer]

Watch out in case you mix up frame size with wheel size.

I am looking for a bike for myself and it looks like I need a 26" frame with 20" wheels

[gords]

it looks like I need a 26" frame with 20" wheels

Shouldn't that be the other way round? :?

[Manicminer]

it looks like I need a 26" frame with 20" wheels

Shouldn't that be the other way round? :?

My mistake. :oops:
I need a 22" frame and 26" wheels (just checked).

[Dave]

A lot of bikes are now sold as small medium large but if its in inches for your size gords i would say 18' 19 inch frame MTB with 26inch wheels i ride a 18 inch GT fits just right.

[Bush Tucker Man]

Frame sizes are still as far as I know (or ought to be) either
Centre to Centre
Centre to Top

That is to say, the centre line of the Bottom Bracket spindle (the axle in the shell at the Seat Tube & Down Tube) to the top  (or centre-line) of the Top-Tube (cross-bar for the non-cyclists amongst you )

If it's a sloping Top-Tube, ie Giant, consult the shop
My Pace had a sloping Top-Tube, but it measured as a 16" C-C measurement & had a ideal length Top-Tube.

On the road I usually ride a 54.5cm C-C, that's what my titanium Dyna-Tech is.

For MTB racing I used the same position as on the road (even down to handle-bar height)

Cyclo-Cross, I lowered the saddle by 1cm, it helped for running dismounts & remounting

Seat height ought to be set by the knee-angle, practically straight at full extension (without rocking the pelvis when pedalling

One thing that is equally important as the Seat-Tube length, is the saddle set-back.
Ideally for the most efficient position, the kneecap (with cranks hoizontal) ought to fall a couple of MM's behind the pedal spindle.

I wish I could justify a Trek Madone to SWMBO, it'd give me an incentive to start riding again :D  

[littlepow]

Best to get a slightly smaller frame if you intend to take it off road, this will allow a greater freedom of movement and reduce the eye-watering experiences from not being compress your legs to absorb landings.

If it helps I'm 6'2" and use 16" Marin full suspension and a 17" Trek front suspension.

Good luck and happy riding, oh and walkers still won't like!