531 ST Frame Sizing

For discussions about bikes and equipment.
NorwichVelo
Posts: 215
Joined: 16 Dec 2013, 10:57pm

531 ST Frame Sizing

Postby NorwichVelo » 30 Aug 2016, 9:35am

Hello

Can anybody with more experience than me on Touring Frames explain why most 531st frames are either 22 inch or 23 inch? Most what I'd call racing frames seemed to go 22 1/2 and 23 1/2 etc. Is it a European influence? From memory all my bikes have been going up on the 1/2 inch as far as I can remember. I currently ride a 22 1/2 inch 531 steel racing bike frame with the stem and saddle level (bad back) I'm 5'10" with a 32" inside leg. The stem and seat post are showing approx a few inches so in theory I could go to a 23 inch. I'd welcome any thoughts on this please.

Regards

User avatar
NATURAL ANKLING
Posts: 11609
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: 531 ST Frame Sizing

Postby NATURAL ANKLING » 30 Aug 2016, 9:57am

Hi,
32" leg so the 22.5 is a tad large based on clearance when astride the bike, a few inches saddle pillar is an indication.
Even so 23 will be limit for sure. 700c?
Based on comfort, I should talk I am on 24" with 33.5" :mrgreen: I have lived with it, restricts saddle setback but cured with a different seat post.
It then becomes a discussion about saddle and reach.............................
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: 531 ST Frame Sizing

Postby Roadster » 31 Aug 2016, 2:23pm

[quote="NorwichVelo"]

"Can anybody with more experience than me on Touring Frames explain why most 531st frames are either 22 inch or 23 inch? Most what I'd call racing frames seemed to go 22 1/2 and 23 1/2 etc."

I don't know about nowadays but, according to my Holdsworth catalogue from 1984, the sizing steps used to be the other way round:
their Mistral tourer with ST tubing was offered in 21.5", 22.5", 23.5", 24.5" and 25.5" sizes, whereas their racier Elan and Special models were offered in 21" to 25" sizes in 1" steps. Their top Competition and Professional framesets offered wider choice from 21", 22", 22.5", 23", 23.5", 24" and 25" sizes. This was probably due to frame geometry, the Mistral having a 72 deg. seat angle and the racier frames having steeper 73 or 74 deg. seat angles.

I'm the same height/inseam as you and find my 23" 531ST frame perfect for me. It has 3.25" of seatpost showing (from bottom of Brooks Flyer rails to top of seat tube) and this also looks right to me on a traditional bike, but then I don't like to see a yard of seatpost sticking up as is fashionable today.
Last edited by Roadster on 31 Aug 2016, 2:35pm, edited 1 time in total.

mercalia
Posts: 13186
Joined: 22 Sep 2013, 10:03pm
Location: london South

Re: 531 ST Frame Sizing

Postby mercalia » 31 Aug 2016, 2:33pm

Dawes Galaxy used to go up to 65cm - 25" or thereabouts

User avatar
Mick F
Spambuster
Posts: 48747
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: 531 ST Frame Sizing

Postby Mick F » 31 Aug 2016, 4:23pm

Yes, half inch sizes.
Mick F. Cornwall

User avatar
NATURAL ANKLING
Posts: 11609
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: 531 ST Frame Sizing

Postby NATURAL ANKLING » 31 Aug 2016, 8:29pm

NATURAL ANKLING wrote:Hi,
32" leg so the 22.5 is a tad large based on clearance when astride the bike, a few inches saddle pillar is an indication, For you :?:
Even so 23 will be limit for sure. 700c?
Based on comfort, I should talk I am on 24" with 33.5" :mrgreen: I have lived with it, restricts saddle setback but cured with a different seat post.
It then becomes a discussion about saddle and reach.............................

Edited_ see above.
My 24" has 4" from the rails to the top of top tube and that's close when astride.
That's about as low as it looks asthetic style old school.
This is the limiting factor for comfort getting on or off bike.
Any lower for saddle and it looks like you nicked the bike or borrowed it from your bigger brother :)
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

Brucey
Posts: 38530
Joined: 4 Jan 2012, 6:25pm

Re: 531 ST Frame Sizing

Postby Brucey » 31 Aug 2016, 8:38pm

personally I wouldn't get hung up on the odd half inch of seat tube; it is all about where your backside and hands end up. Between seat angle and top tube length variations, (plus what length stem you are happy to use) you could be OK on a 22" frame, a 22.5" frame, a 23" frame or even a 23.5" frame depending on the frame design.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

NorwichVelo
Posts: 215
Joined: 16 Dec 2013, 10:57pm

Re: 531 ST Frame Sizing

Postby NorwichVelo » 31 Aug 2016, 10:39pm

Thanks everyone having got on and off what I think is a Raleigh Randonuer or Royal 23 1/2 inch frame I think it's too big for me. I can just about stand astride it but Iim struggling to cock my leg over. It's just old age. Pity as it's going no cheap.

User avatar
NATURAL ANKLING
Posts: 11609
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: 531 ST Frame Sizing

Postby NATURAL ANKLING » 31 Aug 2016, 11:07pm

Hi,
Mines a raleigh randonneur 24", inside leg 33.5 and 24" is the limit, took it because that's all they had in the shop :)
So you would be 22.5 max.
Rode 23 and 23.5" for years in my youth.
Sloping top tube yes, horizontal and my shorts rub the bands to hold the pump.
Go for a sloping modern frame and no problem, I don't like sloping top tubes that much but it works.
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

User avatar
Gattonero
Posts: 3709
Joined: 31 Jan 2016, 1:35pm
Location: London

Re: 531 ST Frame Sizing

Postby Gattonero » 1 Sep 2016, 11:50am

Brucey wrote:personally I wouldn't get hung up on the odd half inch of seat tube; it is all about where your backside and hands end up. Between seat angle and top tube length variations, (plus what length stem you are happy to use) you could be OK on a 22" frame, a 22.5" frame, a 23" frame or even a 23.5" frame depending on the frame design.

cheers


I agree with this.
There's a lot more to consider before the seat tube. Top Tube and Head Tube length will make substantial difference.
Also the choice of stem and shape of drop bars can make a lot of difference (bars reach and drop can change over 1"!)
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...

NorwichVelo
Posts: 215
Joined: 16 Dec 2013, 10:57pm

Re: 531 ST Frame Sizing

Postby NorwichVelo » 1 Sep 2016, 11:13pm

I think I've shone some light on things I got an old Raleigh catalogue and they were still using the 221/2 inch etc format for their Royal and Randonuer. I've always thought (rightly or wrongly) of imperial frame sizes being centre of bb to top of seat tube and metric being centre of bb to centre of top tube. It's just difficult when people use different methods for their sizes. Anyway the frame is too big but the bloke kept it for me bless him so I felt obligated and I bought it. So I have a 23 1/2 inch 531st frame for sale, swap or trade. I'm working for Charlotte's tandems so I'm after bits and pieces that will help there.

Thanks for all your comments and help.

User avatar
Mick F
Spambuster
Posts: 48747
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: 531 ST Frame Sizing

Postby Mick F » 2 Sep 2016, 9:05am

Yes, Imperial (old fashioned?) measurements are from centre of BB to top of seat tube.
Mine is a 23.5" ............. 531c, thirty years old this October. :D
Mick F. Cornwall

pwa
Posts: 12115
Joined: 2 Oct 2011, 8:55pm

Re: 531 ST Frame Sizing

Postby pwa » 2 Sep 2016, 9:31am

It has always seemed to me to be pointless to measure the seat tube / bb from centre bb to centre top tube, since what you really need to know is the measurement to the top surface of the top tube, or more precisely the top surfaces of the seat clamp and head tube. Those are what dictate where you can put the bars and saddle, and that is what counts. Knowing only the measurement to the centre of the top tube leaves you wondering about the radius of that tube.

User avatar
Mick F
Spambuster
Posts: 48747
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: 531 ST Frame Sizing

Postby Mick F » 2 Sep 2016, 10:11am

+1
Mick F. Cornwall

Binkyboy
Posts: 83
Joined: 29 Oct 2010, 5:05pm

Re: 531 ST Frame Sizing

Postby Binkyboy » 2 Sep 2016, 10:44am

"Can anybody with more experience than me on Touring Frames explain why most 531st frames are either 22 inch or 23 inch? Most what I'd call racing frames seemed to go 22 1/2 and 23 1/2 etc. Is it a European influence? From memory all my bikes have been going up on the 1/2 inch as far as I can remember. I currently ride a 22 1/2 inch 531 steel racing bike frame with the stem and saddle level (bad back) I'm 5'10" with a 32" inside leg. The stem and seat post are showing approx a few inches so in theory I could go to a 23 inch. I'd welcome any thoughts on this please."

The frame size is determined by the builder, based on
a) what the customer specifies (and that could be down to the nearest mm if needs be, because they are cut to suit,
b) the most common heights of typical buyers, if he is building for stock. Hence the preponderance of mid size frames.

In the good old days, the frame size (as measured up the length of the seat tube from centre of BB to top of seat lug) was your inside leg length, without shoes, less 10". This allowed for crank length and seat pin and saddle height.
I'm 6ft and, using the above formula, where my inside leg length is 34", the frame size is 24", and that's what all my traditional steel frames have been.

The modern "compact" frames with sloping top tubes, are anyone's guess!