Frame size question

[Garz]

Guys I am now eyeing up a winter hack type commute to do up and looking at the famous bay there's one with a frame size stating 18-23. The guy is stating that its for a person of height 5' 2" and am wondering if it would be ok for me as im 5' 6"?

My current bike is an 18" boardman (small) that fits well.

 

[Rob3rt]

Guys I am now eyeing up a winter hack type commute to do up and looking at the famous bay there's one with a frame size stating 18-23. The guy is stating that its for a person of height 5' 2" and am wondering if it would be ok for me as im 5' 6"?

My current bike is an 18" boardman (small) that fits well.

Ask him if its an 18" or a 23" thats a pretty big size bracket Nearly 13cm difference between a 18 and a 23.


I quickly worked out using some equation someone told me that based on your height theoretically you would ride a 21" frame. Of course inner leg is a better measure. Ebay guy needs to clarify! Unless im missing some sizing convention etiquette, here.

 

[tyred]

What I would do is to measure the distance between the centre of the BB and the top of the seat tube on your own bike (should be 18" as it's an 18" frame) and measure the length of the top tube from front to back and ask the seller to do the same and compare measurements to see if it's in any way similar to your current frame.

 

[Garz]

OK well he states (probably not 100% accurate):

Frame 18/23 (as per sticker at bottom of frame) - suit anyone up to 5ft2in tall

- BAR DIMENSIONS:
Top bar 21.5''/55cm (from middle of where seat starts to the middle where the bar meets handlebars)
Bar from seat to pedal 19''/48cm (from middle of where seat starts to middle of where bar meets pedals)
Bar from pedal to handlebars
23''/59cm (from middle of pedals to middle of where the
bar meets handlebar)
- WHEELS: middle to outer rim of wheel 12.5''/32cm; Full tire 26''/67cm

my frame dimensions from boardmans site:

Size Top Tube effective (cm) Seat Tube (cm) Head Tube (cm) Seat Angle (deg) Head Angle (deg)
Chainstay (cm)

Small 54 50 13.5 74 72.5 40.5

 

[Rob3rt]

Ask him to measure from centre of bottom bracket to top of seat tube (I think this is the correct way to measure the size). Im guessing its roughly a 50cm frame by adding about 2cm onto his measure which appears to be from the top of the bottom bracket to the top of the seat tube.


You would need a 56cm frame (using rule of thumb) which is roughtly a 22" frame (my above calculation was wrong, I took your height as 5' 2" instead of 5' 6", my bad)


edit: the way I thought it was measured was wrong, see 02GF74 for the correct way to size the frame)

 

[02GF74]

arrgghhhh - what happened to my post??

anyways, here it is again.

frame sizes is measured from centre of botom btacket, along seat tube, to centre of top tube or end of seat tube - so can vary as much as 10 cm. modern frams have sloping top tube which further adds to the confusion.

the top tube is a constant in all of this.

so ask the seller to measure top tube horizontally (again cntre to centre) and compere with your bike.

if it is within +-1 cm you'll be fine.

 

[02GF74]

just spotted this:
Top bar 21.5''/55cm (from middle of where seat starts to the middle where the bar meets handlebars)

my frame dimensions from boardmans site:

Size Top Tube effective (cm) 54

what exactly does he mean by: [/b]where the bar meets handlebars[/b]

is it the handle bars i.e. includes the stem or just up to the headset tube?

if the former, then too small.

 

[accountantpete]

The 18/23 is the tubing- not the bike measurement.

Is it a sloping top tube?

 

[Garz]

No its an old raleigh banana bike pete. Seems to be 48cm seat tube and a 55cm top tube so around my ballpark size. Probably not best to go by this guys measurements as he clearly could be out.