Sizing...

[roadiewill]

OK, you've probably heard this before, but a little help is needed. How do I calculate the fram size that I need for a road bike?

Thanks.

 

[Maz]

Hi/Welcome:
I asked the same question in the "know How" section. Apparently how frames are measured varies from one manufacturer to another. Is there a particular brand of bike your are interested in?

Link:
http://www.cycle-cafe.net/forums/showthread.php?t=9034

 

[Chris James]

Horribly crude but the old school method was measuring your inside leg (your actual measurement to the ground, not trouser inside leg) and then knocking off 10 inches for the frame size.

This was for a horizonatl top tube bike. Nowadays larger standover heights and compact geometriesd are more fashionable and muddy the waters!

How tall are you and what sort of proportions do you have? (i.e. do you have unusually long arms or legs) I am sure someone will be able to suggest a reasonable size for you.

I assume from the question that you are from a MTB background? In which case the normal advice about trying different bike sizes might not be the most helpful as road cycling position differs from MTB position - a road bike will typically stretch you out more.

If it helps as a guide I am just under 6 foot tall, 33 inch inside leg, fairly long arms (slightly positive 'ape index') and have a 57cm (middle of BB to top of top tube) frame on my audax bike. A 56cm would be fine for me though too.

 

[roadiewill]

Well I was looking at the Giant SCR 1 with size 55 frame. I am also just under 6ft. If it helps at all, (I know different brands change sizes) but my spesh MTB is a large.

 

[HJ]

You could try the late Sheldon Brown's site for advice see here.

As this is beginners should point out the Sheldon's site is an incredible resource for technical cycling information. Sheldon (yes that was his real name) died recently and will be sadly missed.

At the end of the day the best way to decide is to find a good local bike shop and try a few, if you can.

 

[DLB]

At the end of the day the best way to decide is to find a good local bike shop and try a few, if you can.

i agree, and wouldn't buy a bike without trying it for size first (unless it could be returned for a refund if it was unsuitable)

 

[punkypossum]

Definitely try before you buy, but these might give you a rough idea:

http://www.bikefitting.com/English/Frame.aspx
http://www.bikebuster.com/frame-guide.html

 

[Maz]

Well I was looking at the Giant SCR 1 with size 55 frame. I am also just under 6ft. If it helps at all, (I know different brands change sizes) but my spesh MTB is a large.

You're about the same height as me then. I have a 57cm frame bike (Specialized Sirrus), but like PunkyPossom says, try before you buy. Make sure you can straddle the bike without your groin touching the top tube when both feet are firmly planted on the floor. And take it for a test ride as well, of course.

 

[roadiewill]

However much I would like to physically test the bikes, I cant really as the LBS dont stock the SCR series and I ca find much better reductions of last years stock online. I am thinking of getting the SCR 3.0 now as the 1.0 I was looking at was not actually reduced.

Are they good bikes for that price range?

 

[Jacomus-rides-Gen]

You're about the same height as me then. I have a 57cm frame bike (Specialized Sirrus), but like PunkyPossom says, try before you buy. Make sure you can straddle the bike without your groin touching the top tube when both feet are firmly planted on the floor. And take it for a test ride as well, of course.

Be careful though - its not just straddle.

I am 6foot dead on and need a 54cm frame because I am seriously inflexible - it is imperative to try before you buy.

 

[punkypossum]

However much I would like to physically test the bikes, I cant really as the LBS dont stock the SCR series and I ca find much better reductions of last years stock online. I am thinking of getting the SCR 3.0 now as the 1.0 I was looking at was not actually reduced.

Are they good bikes for that price range?

If you are going to buy online, can you not get yourself to a bike shop that stock the range first? They might be willing to price-match or throw in some freebies....

 

[roadiewill]

Good idea, might try that if I have time.

 

[postman]

Any half decent shop will let you sit on the bike.My latest purchase i had to put down a ten quid deposit non returnable if i did not like the bike.But worth it if it saves you lots of dosh on the wrong bike.

 

[roadiewill]

OK, so I managed to get down to my LBS today and suprise suprise, they actually had the SCR 3 in stock. The large is the right size, so feel better buying online now. Just hope that they stay in stock for a few more weeks.

Thanks for the help.