Steel Sizing advice

jimbob33

Hello - I am going to buy a steel framed bike - I am 5'7" what size top tube do I need, no one want to measure you up unliess you pay them loads of money.

I would say I amy pretty proportional, so what size traditional steel frame do I need to go for?

Robert456

I ride a non-sloping italian steek frame, I'm 5'6" and the bike is a 51cm seat tube (170 cranks) with 52.5cm top tube and 11.5cm horiaontal stem (all centre to centre) with a very short 10.5cm head tube (measured end to end where the cups insert). Gives a position for me which is stretched out and low which is what I like

But,

You've asked the million and one answer question, I'd consider myself average proportioned, but what suits me won't suit the next guy of my height.

Traditional frames tend to mean a non-sloping top tube. The advice I'd give is if you have a bike that fits you well, go with the horizontal top tube measurment that this bike would give if it where 'traditional', and remember that fine tuning can then take place with stem length, although extreme's will upset the handling and look out of place. You then need to know what seat tube lenghth suits you. My vintage 531 bike is a hole 2cm longer in the seat tube at 53cm/21inch but is the same length top tube and fits me just the same, and my 1987 (not as vintage) 531c follows this same recipe.

Volume made bikes where made for Mr Average, so maybe that is you!

So, cut a long story short, start with what you've got and work it out.

jimbob33

Thanks for the advice. I have been told to go for a 50.5cm Top Tube which comes with a 49cm down tube. So its a 49 cm frame - it just sounds so small.

father_jack

I'm 5'8", have a 54cm frame, 56.7 top tube. Of course with a horizontal top tube, getting correctly sized from for stand over is pretty important.

carl_p

I'm 5ft 8 and used to have a 52cm steel frame, which had a top tube of 53cm. It certainly wasn't too big and there are other aspects of the geometry that you need to consider such has the length and angle of the head tube. It really depends on your preferred riding position, whether you like to be a bit stretched out, or upright. Try them out first if possible. If it fits it doesn't matter what size it is.

Monty Dog

50.5cm toptube? your knees will probably hit the handlebars when climbing out the saddle unless you fit a disproportionately long stem. I'm slightly shorter and ride 52-53cm toptube which is pretty stretched out. I'd start with something around 54cm - but there are plenty of other variables defined by things like your leg length, saddle setback, flexibility. FWIW standover is fairly irrelevant - more important for MTBs where you need to put your foot down.

Robert456

jimbob33 wrote:

Thanks for the advice. I have been told to go for a 50.5cm Top Tube which comes with a 49cm down tube. So its a 49 cm frame - it just sounds so small.

That's a tiny bicycle, fair enough you can put the seat up, but 50.5cm top tube, that's short. Is someone trying to sell you this frame? I'm an inch shorter than you and wouldn't consider it as it seems very short.

What are you riding at the moment and what would be it's (vertual) horizontal top tube length?

Bike fit's arn't that expensive are they, maybe that would provide you with your measurements?

giant_man

Get yourself measured properly, the only way to get it right.

You're getting nowhere by doing it yourself and hearing off other people ie 50.5cm top tube.

Depending on which steel frame it is, it may be custom sizing only anyway.

huuregeil

http://www.prodigalchild.net/Bicycle6.htm

nickwill

giant mancp wrote:

Get yourself measured properly, the only way to get it right.

You're getting nowhere by doing it yourself and hearing off other people ie 50.5cm top tube.

Depending on which steel frame it is, it may be custom sizing only anyway.

Any self respecting bike dealer will measure you and set you up properly. If not go elsewhere!