Frame Sizing - Ribble Formula

[jimbut]

Looking at the Ribble cycles site there is a formula for correct frame size. It is, inside leg ( barefooted ) in cm x 0.65. This is formula for horiz. top tube bike. Subtract 4 cm for sloping top tube bike. Is this a fairly accurate prescription for a good fit in most cases ?

 

[punkypossum]

That is odd - well, suppose not very odd as it's only based on leg length, but I actually got measured at ribble and came out as a 54 (sloping), when according to the formula I am between a 50 and a 52!

 

[jimbut]

What height are you ? Using their formula I ( at just under 5 foot 10 ) with inside leg approx 80 cm would require a 48 ( sloping ) ie 52cm horizontal top tube. I have been riding a ( off the peg ) 54cm for some time. Always felt tho` that this slightly on the large side for me ( stretched out a bit over the top tube ). Frame size is a real bag of worms. Wonder if possible to send Ribble certain critical measures ( other than just inside leg ) to get their advice ?

 

[Bigtallfatbloke]

hmmm...that puts me on a 56cm frame!!!

erm....so why then are all the dealers saying 61cm when I tell them I am 6' 2" tall??

My guess is that they ahvent got a clue.

 

[Smeggers]

I'm 6'2" and Ribble put me on a 56cm frame.

It feels ok to me tbh and theres no more than 4" of seat tube showing.

 

[punkypossum]

hmmm...that puts me on a 56cm frame!!!

erm....so why then are all the dealers saying 61cm when I tell them I am 6' 2" tall??

My guess is that they ahvent got a clue.

Ribble apparently have got quite long top tubes - that might have something to do with it...

 

[punkypossum]

What height are you ? Using their formula I ( at just under 5 foot 10 ) with inside leg approx 80 cm would require a 48 ( sloping ) ie 52cm horizontal top tube. I have been riding a ( off the peg ) 54cm for some time. Always felt tho` that this slightly on the large side for me ( stretched out a bit over the top tube ). Frame size is a real bag of worms. Wonder if possible to send Ribble certain critical measures ( other than just inside leg ) to get their advice ?

Just under 6 foot - but female, so my inside leg is something like 86....and I did say I wanted a comfy rather than outright racing position...

 

[zimzum42]

My Ribble suffers from the worst Toe-Clip overlap there is....

 

[punkypossum]

I've got tiny feet, so shouldn't be a problem if I ever get enough money to buy one!

 

[Blonde]

Ribble baikes are sized by seat tube length, not by the top tube length. I made the mistake of thinking it was the top tube length and ended up with a frame about three sizes too big.... I eventually got the right size but I cannot recommend a ribble for comfort if you are female or have long legs - unless you want a very low position. They have a very short head tube in relation to the bike size, so if you have a lot of seatpost showing (which you will do if female or long legged) you will also need a lot of steerer tube showing - which isn't reccommended if you go for the carbon fibre steerer option.

 

[yenrod]

hmmm...that puts me on a 56cm frame!!!

erm....so why then are all the dealers saying 61cm when I tell them I am 6' 2" tall??

My guess is that they ahvent got a clue.

See, I told you a 56/58 cm would do you fine

 

[GrahamG]

Ribble baikes are sized by seat tube length, not by the top tube length. I made the mistake of thinking it was the top tube length and ended up with a frame about three sizes too big.... I eventually got the right size but I cannot recommend a ribble for comfort if you are female or have long legs - unless you want a very low position. They have a very short head tube in relation to the bike size, so if you have a lot of seatpost showing (which you will do if female or long legged) you will also need a lot of steerer tube showing - which isn't reccommended if you go for the carbon fibre steerer option.

I found much the same thing - I'm long in the leg compared to torso and this is then exacerbated by short arms! The Ribble audax frame I had was a nightmare comfort wise.
I decided after several different size/geometry bikes just to have a custom done and took delivery of a Hewitt frame yesterday which looks very different to anything I've seen. I'm a freak

 

[jimbut]

Ta for ALL replies. I was looking at Ribble`s geometry chart on the site. Their 52cm seat tube centre to centre ( horiz top tube ) has a 54cm horiz top tube length. My current bike with a 54cm seat tube ALSO has a 54cm top tube. A 52cm Ribble frame ( 48 on a sloping top.. according to their advice ) is therefore pretty comparable to my current set-up ( I think .. and hope ). My current set-up is not perfect ( feel a tad bit stretched ) but I think perfection is unachievable outside of a made to fit frame. Ta again for all comments.

 

[punkypossum]

Ribble baikes are sized by seat tube length, not by the top tube length. I made the mistake of thinking it was the top tube length and ended up with a frame about three sizes too big.... I eventually got the right size but I cannot recommend a ribble for comfort if you are female or have long legs - unless you want a very low position. They have a very short head tube in relation to the bike size, so if you have a lot of seatpost showing (which you will do if female or long legged) you will also need a lot of steerer tube showing - which isn't reccommended if you go for the carbon fibre steerer option.

Argh...you are putting me off ribble now..., it felt really comfy on the fitting rig, but that is clearly not the same as actually riding the bike...but ribble is so conveniently down the road and at least they do put you on a rig...

 

[yenrod]

Using the Ribble formula i should be riding a 51cm slop.model - yet that'd be FAR to short for me !