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If you got the same frame built out of 631 rather than 853 would there be a significant weight difference?
> < this much
> < looks pretty insignificant on my ipad, how would it feel when I picked it up?
you'll struggle to find 2 frames in identical guages etc to give an accurate answer.
When I got a custom frame my builder sent me listings of weights of individual tubes, it was interesting. I don't think I have it now tho.
Depends.... as a 853 weighs exactly the same as 631.
If you used the same diameter/wall thickness tubeset the frames would weigh the same
It it is however stronger (but not stiffer) so you can use less of it.Or have a bike that is much stronger.
853 is stronger by volume. I'm sure I've found a document with tube thicknesses before. In theory, the 853 frame can be made lighter for the same strength. But it depends if the different grade tubes are drawn differently.
IIRC 853 Pro is thinner walled than 853. I've a feeling 853 is same weight but stronger than 631.
http://www.daveyatescycles.co.uk/custom_bike_frames-Racing-25.php
so 631 is 853 without the heat-treatment, so weight will be the same.
I doubt you'd notice particularly by the time you had it built up. I did have a frame built from coloumbus ultrafoco a little while ago which was noticeably light but by the time you've built it up it's lost in the noise. The advantage of the 853 is in it's UTS so you can in theory push thinner wall thickness but to be honest a usable frame has a lot of tube thickness redundency just so you don't ding it with a careless sneeze. It depends on how the bike is designed etc as to how it affects the handling.
That said you're clearly looking at a custom frame in which case you might as well go primarily for the framebuilder you like or if you have the choice, go for 853 for the badge and the perceived "prestige" in case you have to sell it.
a usable frame has a lot of tube thickness redundency just so you don't ding it with a careless sneeze
Really? I thought this only applied to aluminium.
I'm getting a frame built by Bob Jackson and probably dropping in to order it tomorrow.
When I asked them about weight they just said 'its neither here nor there' and more or less said they didn't understand people ordering steel frames and then trying to make them stiff like carbon (which I respect as they could have an extra £200 out of me for 853), however as the time approaches my weight weenie head keeps kicking in.
Half a pound won't bother me, more than that has me thinking.
given how light steel frames can go (1.3kg on the road) I don't see why buyers shouldn't be concerned about weight.
My steel HT is around 4lb with sliding dropouts IIRC. Rides nice
853 is no stiffer than 631, its just got a higher UTS.
Ben, stiffness is what you could consider. A light steel frame is rarely a very stiff one. And I'd agree, why have a very stiff steel road frame unless you're super-strong? Dario Pegoretti knows more than I do though... I like a bit of spring but it depends how hard you want to push it to feel that spring. Going from 28.6 top and 31.8mm down tubes to 31.8 top and 34.9 down makes quite a difference imo, but doesn't add enough weight for me to really care about it.
If you then want a lighter or equal weight bike with those larger tubes, 853 lets you go thinner wall and keep the durability up.
I'd agree, but I'd also expect a builder to give some idea, or be able to work it out and give me guidance on the options on stiffness vs weight compared to a stock (or customer's existing) frame. I got a frame from a builder who was a bit vague once - it wasn't what I was after so for the second one I figured it out and did the numbers myself )'its neither here nor there'
They weren't vague, more a case that my 4 and 6 year old boys were with me tearing up up the showroom so it was a briefer conversation than I'd have liked.
They did suggest swapping out the chainstays for 725 for some stiffness when climbing.
The other dilemma is silver or black and what colour lug lining?
853 is lighter than 631 if you have the balls to remover the Reynolds 853 sticker.. bet you don't! 8)
swapping out the chainstays for 725 for some stiffness when climbing
Unless the 725 stay is bigger than a crmo one, it won't be stiffer. Reynolds chainstays (esp in the round-oval-round shape) are pretty stiff but 525 and 725 versions are both the same dimensions. I'd have to look up the wall thickness but the 725 could be thinner wall, so an almost undetectable amount less stiff.
I'm not trying to discredit a builder here, only to clarify what is meant when tube grade and proerties are discussed (lessons from a not-great custom experience here)
Hi Jameso, both the 631 main tubes and 725 stays will be oversize
Ok. Hope that didn't all come across as egg-sucking 101, just a 'weight between steel alloys' question and a custom frame mentioned made me wonder. A nice custom steel road bike should be a beautiful thing so it's good to be sure )
a top tube for example:
BX5050 or BX2060
one of them is 631 and the other is 853, they are both the same diameter 28.6mm they are both the same length 635mm etc etc they both weigh the same amount but one has been heatreated to a higher UTS.