Was 531ST heavier than 725?

[horizon]

This is for normal, not over-size 725. I have a feeling any answer will come back with caveats ... Assumes same frame dimensions and fork in same material in each case, 531ST or 725. And I suppose the question is, would 531ST have produced a different bike? Apologies if your response is ...

[Graham]

I get a feeling that the state of the butting will complicate the answer to this one.

Anyhow, it will be interesting to hear whether any difference will be marginal or significant.

[Mick F]

I think - note the word 'think' - that 531ST was just the same as 531c except that the seat tube and the forks were chunkier and beefed up. The metal itself, was the same.

As for 725, I have no idea!

[cycleruk]

The density of both is 7.78 gms/cc.
http://www.reynoldstechnology.biz/wp-co ... S-2014.pdf

To me then they both weigh the same. So it's down to tube diameter and wall thickness.

[PH]

No, all steel weighs the same, it's what you do with it.
There was possibly more choice of gauges in 531 which would have made a slight difference to weight and a larger difference to feel, but I think 631 offers the traditional tubes that are missing from the 725 range.
What has changed is the idea that stiff is good, if you're like me 6'3" and heavy you will probably appreciate the extra stiffness, when someone lighter may not. As the average person has become heavier, frames have changed to match. I’m sure taste and fashion play a part as well, someone brought up on large diameter aluminium frames didn’t like the feel of my lightest steel bike which I really do.

[whoof]

The answer is probably that you wouldn't build the same frame with 725 and 531. 725 was developed to allow oversizing and TIG welding.

[horizon]

This link has some more info. I'm still not clear though whether there was a 531c, a 531ST and an "ordinary" 531.

viewtopic.php?f=5&t=81203&start=15

This link seems to say that there wasn't:

https://en.wikipedia.org/wiki/Reynolds_Cycle_Technology

[steady eddy]

Would you notice the difference after a good lunch!!!

[horizon]

Would you notice the difference after a good lunch!!!

No. but I didn't half notice a difference after accounting for lighter wheels, fewer accessories, less luggage, better components and a smaller frame size. My 531ST Dawes Horizon is built like a tank and weighs the same (great for what I use it for) but my Thorn Club Tour feels like a completely different bike - it even felt a bit squiffy at the back when loaded.

While there won't be much difference after the above factors are taken into account I'd still be interested to know if any of the dramatic difference can be attributed to the frame. My 631 Sardar feels much like my Horizon - solid as a rock and heavy. I'm just wondering if 725 produces a different bike from say 631 or indeed 531ST.

[hamster]

Most of the difference is in the geometry and this gives a different feel to typical 531ST frames compared to 725. ST frames are also older and ideas of what is desirable have changed, along with fashions on fork bends etc. Furthermore 725 has different structural properties, being inherently stronger and therefore permitting thinner-walled tubing.

The different butting profiles will give a small difference in weight.

I bet if you built an identical frame copy of a 531ST in 725 you would be unable to tell the difference riding it in the dark.

[PH]

While there won't be much difference after the above factors are taken into account I'd still be interested to know if any of the dramatic difference can be attributed to the frame. My 631 Sardar feels much like my Horizon - solid as a rock and heavy. I'm just wondering if 725 produces a different bike from say 631 or indeed 531ST.

I'd say nearly all the differences could be attributed to the frame, but not to the flavour of steel it's made from. As hamster says you could build two identical frames in different materials and not be able to tell the difference, you could also build two completely different frames from the same steel.
Good article here from Breton
http://www.bretonbikes.com/homepage/cyc ... e-tourists

[531colin]

Would you notice the difference after a good lunch!!!

No. but I didn't half notice a difference after accounting for lighter wheels, fewer accessories, less luggage, better components and a smaller frame size. My 531ST Dawes Horizon is built like a tank and weighs the same (great for what I use it for) but my Thorn Club Tour feels like a completely different bike - it even felt a bit squiffy at the back when loaded.

While there won't be much difference after the above factors are taken into account I'd still be interested to know if any of the dramatic difference can be attributed to the frame. My 631 Sardar feels much like my Horizon - solid as a rock and heavy. I'm just wondering if 725 produces a different bike from say 631 or indeed 531ST.

If you want to know about the frame weight, strip them and weigh them.
BUT only the 3 main tubes may be the tubing thats on the label. Forks, stays, head tube can all be something else.....thick-walled, heavy cromo is not uncommon on "touring" bikes. (and not a bad thing for hanging pannier racks on)
If you want to know about the ride feel, there are many more variables than the tubing......why do people always assume its the tubing that makes the ride? (Actually, don't bother to answer, I know why.....because its there on an easy-to-read label, and you don't have to think about it, and the bigger the number, the "better" it is......obviously.)

[Bowedw]

I have a frame in 853 frame tubes and stays,also a Thorn Raven Sport in 853 conical tubes, these tubes taper internally towards the bottom bracket so I am informed, the stays are 725.
The two bikes are built for a different purpose, one for lightweight riding(racing but not with my legs and lungs) and the other for tour type riding. A similar comparison would be 531c and 531ST.
631 is the updated 531 and 725 is a stronger steel again. a bespoke frame builder would as part of the design process offer advice on the most suitable tube for you needs but if you decided on 725 over say 631 he would be likely to order a thinner wall tube in 725.
I would suggest that as 725 is stronger than 531, to arrive at a frame to do the same job, 725 could be thinner wall gauge and so would be a lighter frame.
A good 531ST frame is still in my opinion a good choice for load carrying and robust duties and their geometry would be for that purpose so it's never going to be a racer.

[Paul Smith SRCC]

I think - note the word 'think' - that 531ST was just the same as 531c except that the seat tube and the forks were chunkier and beefed up. The metal itself, was the same.

As for 725, I have no idea!

The difference if I recall was the 531C blades were visibly rounder compared to the flatter profile of the 531ST blades. 725 is a popular tube set, often tig welded as opposed to lugged, the latter the norm' with 531, so when comparing the two as built frames you need to take into consideration that lugs will effect the overall weight.

When colleagues pick up my trusty thirty year old 531ST work bike (ignore the Triggers Broom equipment ) with 531ST Fork blades they are amazed that I get the thing rolling at all! I pat the wobbly relaxed one pack around my tummy and say I'm more concerned about saving weight here than on my bike, the heavier the latter the lighter the former will hopefully become

(531ST work fixie, ignore the Reynolds transfers I fitted as 'bling' after a repaint, it's 531ST)

Elaborating more on my carefree attitude to 'winter-work' bike weight it was common practice in my club to put a brick in your saddle bag in the winter for 'weight training', the theory being when you got back on your light summer bike it would feel so much faster! Never did me any harm; or should that be good??? Another thing I did was always had fresh air in my tyres for a race; but all that got me was a few cross toasts at the club dinner and dance

[mig]

lovely bike.

not so sure about the crank arm though