Totally Confused on Bike sizing

[IT_Dummy]

Been looking at the Carrerra Subway Limited 2012.
My inside leg is 31ins and I am 6ft tall. According to the Halford Guide I should have a 17 in frame.
But looking at other guides. On a hybrid, stood aside it, there should be 2in clearance and on another guide its 3in clearance from crutch to top bar.
Others give a formula inside leg - 2in -10in ( bottem bracket to floor = 10ins so they say)
Here's my problem - I have a 21in Raleigh MTB which I am comfortable on, the distance
from centre bottem bracket to the floor is 13ins
If I went to Halfords and stood astride the bike what should I be looking for ?
Any Member bought a bike from Halfords Altrincham ?

Any help would be welcome Ta

 

[gavintc]

IMO, the relationship of the distance from you to the ground is of only secondary interest. The most important length and set up is the saddle height to pedals and then from that your position to the bars. When seated on the saddle, with the pedal at the lowest point, your toes on the pedal, your leg should be bent slightly. Then lean forward, to identify if the bars are comfortable.

The inside length measurement is not a trouser length, but the distance from crutch to the ground. 31 inch seems a tad short to me for someone of 6ft.

Most bikes are quoted in cm not inches and from your height, I would suggest looking at 56-57 cm frame as a starting point. However, having just looked at the bike on the Halfords site, I see it is quoted in inches and suggest you have a look at both the 18 and 20 inch bikes - take them for a ride to see which one is more comfy.

 

[IT_Dummy]

The inside length measurement is not a trouser length, but the distance from crutch to the ground. 31 inch seems a tad short to me for someone of 6ft.
.

Just measeured it again with the assistance of my other half. (Women always get these things right)
To ground 31in, at a pinch 31.25
Trouser length 30in

We tend to be a bit stocky round 'ere What's Metric?

 

[theloafer]

best way is to sit on the bike have 5 bikes at the mo ..my tourer which is custom made to me is 19 1/2 in all other are slightly bigger cube mt is 18in cannondal synapse road is 51 cm my trek sl1000 is 52 cm and the boardman cx team is 53cm

 

[Cheradenine]

It's not a Hybrid, it's just a MTB with slicks on so stand over will be waaaaaay over 2 or 3 inches, the 2 or 3 inch thing refers to a different, older style of frame.

You need the 18" or 20" model, which ever you find the reach to the bars the most comfortable upon.

 

[IT_Dummy]

It's not a Hybrid, it's just a MTB with slicks on so stand over will be waaaaaay over 2 or 3 inches, the 2 or 3 inch thing refers to a different, older style of frame.

You need the 18" or 20" model, which ever you find the reach to the bars the most comfortable upon.

That makes sense
The Raleigh I have is marked as a 21in but from the bottem bracket to the seat post is 20in
The measurement of the top bar is 21in and I do have "long arms" (no comments about a Gorilla riding a bike please )
So the 20in looks favourite
Many Thanks

 

[Cubist]

That sounds about right. You do indeed have a long trunk given your leg length. You should fit a 20 well enough, as standover isn't all that critical on a hybrid like the Subway. What will make the difference for you is the "cockpit reach" that the 20 will give you. I think an 18 would have been cramped.

 

[IT_Dummy]

That sounds about right. You do indeed have a long trunk given your leg length. You should fit a 20 well enough, as standover isn't all that critical on a hybrid like the Subway. What will make the difference for you is the "cockpit reach" that the 20 will give you. I think an 18 would have been cramped.

It probably explains why I look 15stone and in actual fact I am 17stone. If I had longer legs
I would probably have more weight on my belly (just a theory )
Thats why I have in the past kept to Raleigh's. Their weight limit I believe is 19stone.
One more question for Halfords ! re Subway

 

[Cubist]

It probably explains why I look 15stone and in actual fact I am 17stone. If I had longer legs
I would probably have more weight on my belly (just a theory )
Thats why I have in the past kept to Raleigh's. Their weight limit I believe is 19stone.
One more question for Halfords ! re Subway

Nice theory, but I'm the opposite, long legs, stocky torso and shortish arms at just about half a stone less than you, so where that put us is probably down to mince pie input!

A subway will handle well over 17 stone.... they look practically bombproof.

 

[cyberknight]

IMO, the relationship of the distance from you to the ground is of only secondary interest. The most important length and set up is the saddle height to pedals and then from that your position to the bars. When seated on the saddle, with the pedal at the lowest point, your toes on the pedal, your leg should be bent slightly. Then lean forward, to identify if the bars are comfortable.

The inside length measurement is not a trouser length, but the distance from crutch to the ground. 31 inch seems a tad short to me for someone of 6ft.

Most bikes are quoted in cm not inches and from your height, I would suggest looking at 56-57 cm frame as a starting point. However, having just looked at the bike on the Halfords site, I see it is quoted in inches and suggest you have a look at both the 18 and 20 inch bikes - take them for a ride to see which one is more comfy.

Halfords sizing is confusing as they quote to the top tube from the bottom bracket on a bike in general rather than where it would meet if the top tube was level which tends to be the industry standard.I have rode a subway for a few years with an 18 " frame and i am 5 foot 7 " with a 30.5 inside leg and now i have a giant iguana MTB whit the same size.I am guessing that the 18 " would feel to cramped and the 20 " would be closer to the mark .As long as you have enough seatpost so your legs are right without going over the max height the most important sizing is the reach/ length of top tube.

Try them both and see how they feel .

 

[IT_Dummy]

Nice theory, but I'm the opposite, long legs, stocky torso and shortish arms at just about half a stone less than you, so where that put us is probably down to mince pie input!

A subway will handle well over 17 stone.... they look practically bombproof.

Thanks for the info .. I can have a few more mince pies now !

 

[Peteaud]

Halfords sizing is confusing as they quote to the top tube from the bottom bracket on a bike in general rather than where it would meet if the top tube was level which tends to be the industry standard.I have rode a subway for a few years with an 18 " frame and i am 5 foot 7 " with a 30.5 inside leg and now i have a giant iguana MTB whit the same size.I am guessing that the 18 " would feel to cramped and the 20 " would be closer to the mark .As long as you have enough seatpost so your legs are right without going over the max height the most important sizing is the reach/ length of top tube.

Try them both and see how they feel .

I agree, my MTB is 21" and im 6 foot with a 33 leg.

 

[GetAGrip]

I ride a Subway 18" frame and I am 5'5" and a tetty with a 29" leg and a longish trunk and it's a good fit for me.

 

[Muddyfox]

Bike sizing is a minefield .. i've just been trying to suss out the Thorn Nomad sizing

 

[DiddlyDodds]

Its easy , go Evans Cycles pick a bike to test ride , they will advise the size of frame , have a go and from that you will have a better idea.