Sizing

[Radius]

I know there's no 'real' answer etc. but there's a bike I'm looking at, and there's (obviously) a choice of sizes.
There's a 59cm, which is £100 cheaper (sale) than the 61cm, but I'm 6'2" so I'm not sure (because I can afford it) whether I should just go for the biggest size available?


What would you advise? Thanks


(PS: I can't try the bike out unfortunately)

 

[Dave5N]

So go to the local halfords and try out two similar models?

 

[zacklaws]

I'm 6 foot 1 and a 1/2 and just bought a 58 road bike and fits me perfectly. Took me ages to work out what size I needed but a 58 put me in the mid range size for my height so I read, which meant I could raise or lower my saddle to fit.

Only way to know though as mentioned is try them

 

[Steve Austin]

you need to buy the one that fits....

Would you buy shoes that were the wrong size?

 

[jimboalee]

Do you think Halfords are going to have a 61cm frame ??

 

[jimboalee]

Go for the 59cm.

There are longer seatposts and stems out there, but try reducing the frame size !

 

[jimboalee]

There are sums to work it out, but the best thing to do is visit the LBS and do a 'stand over' test.

 

[JonoB]

I had a similar problem recently and I found this helpful. (cm or small medium large etc)
http://www.evanscycles.com/information/sizing
You can order bikes in at Evans just to try (a small refundable down payment is required). There is no substitute for trying them out, but if this is not possible, the above web page is a good guide

 

[jimboalee]

You should know what I'm like by now.

I knew a chap at Venom Cycles, and a few others in the industry. I have a full size drawing of my 'custom' frame somewhere in the cupboard, just in case it takes my fancy.
But alas, a Spesh SWorks fell into my lap, just the right size.

Anyway, I have all the calcs to size a frame from physical dimensions, as applied by a master framebuilder.
But all one really needs is to know one's 'inside leg', assuming one follows the 'normal' bodily dimension ratios.

BTW, when I was measured up, it was discovered my left leg is half an inch longer than my right. All those teenage years falling off a skateboard, forced my left hip to develop larger.

 

[yello]

Do you walk around in circles? It'd explain a lot.

 

[02GF74]

ok, we are talking about road bike frames?

2 rule of thumb.
1. frame size is 1/3 of your height
2. frame size is 10 inches less you inside trouser measurement.

for the above, frame is measured from centre of bottom bracket along seat tube to centre of top tube. Note that most frames nowadays seem to be measured to top of seat tube; that would add about 1 to 2 inches to the frame size.

So you need to find out how the 2 frames you are interested in are measured.

Also almost more importanly is horizontal top tube length, this is about the same size or a bit less than seat tube.

I am 6 ft and ride a 60 cm (to top of seat tube; which I thnk measure 58 cm old stylee) frame with 58 cm top tube.

You can go probably 1 or even 2 inches off the ideal frame and adjust for it by taller/longer stem, longer seat post and moving saddle offset. Unless you are TDF ride, I personally don't believe it is that critical.

 

[yello]

You can go probably 1 or even 2 inches off the ideal frame and adjust for it by taller/longer stem, longer seat post and moving saddle offset

I'd agree with that. I do think people are just a little too concerned, nay obsessed, with frame size.... bearing in mind that the ideal frame size is a matter of some opinion and, dare I say, fashion.

 

[jimboalee]

Not arguing, just telling another method.

Frame size is hypotenuse of the triangle whose adjacent is :- (Standing height minus seated height) minus (B/B height plus 1 inch).

 

[02GF74]

^^^ yep, and there is also personal preference.

My mountain bike frames range from 17 inch - a bit on the small side but I like it - to 19 inch. The 19 inchers feel different due to different stem/bars/posts and some feel a bit too stretched but after a few minutes, my body seems to adjust and all is well.

The worst thing to do is to go for too big a frame. My first MTB, a TREK 850, was 22 inch but was cheap which is why I bought it and the frame was replaced soon by a 20 inch Saracen and I kept on going smaller.

For road bikes I was on 23.5 inch or 58 cm. (60 cm)

 

[jimboalee]

When I bought my Pug 531 in '75, the dear old LBS owner told me to whip my shoes off. He then put a tape measure up my back and whispered "sixty eight inches".
He then went to the catalogue and his order book and wrote down 58cm,(22 1/2"), which is what I bought.

3 x 22 1/2 = 67 1/2 inches. Close enough, he told me I had another inch or so to grow ( I am now 5' 9" ! )

Now I go on the Evans Cycles website to 'sizing charts' and they tell me a 5' 9" bloke needs a 55cm frame on a road bike.

So, I have a Pug 531 58cm which is the correct size, and a Spesh SWorks 54cm frame which is the correct size.

I was measured up by Venom Cycles in '96. I have dug out my notes from the visit, tucked away in Eugene Sloane's book.
It involved standing height, seated height, arm length, height of the V at the top of the thoracic cage, leg length, body length and combined body and arm length.
From this, they calced height of top tube, length of top tube and the reach of the handle bar clamp from the seat pin.
Venom's size for me with a 74 deg seat angle and an 11" B/B height was 21 1/4" (54cm).

Using a three legged stool deductive approach, the 1/3 height loses.

Sorry and all that