"Gusset" under downtube

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peetee
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Re: "Gusset" under downtube

Postby peetee » 8 Oct 2019, 5:10pm

I would like to think that these gussets are fitted with prior attention to the guage of the tube at the lower join of the gusset. The butted section of tubes are often of a set length and the tubes are cut to size to suit the bike. This can leave quite short sections of 'thick' tube and it's quite possible that on shorter frames the gusset may Overlay the thin section creating a potential stress raiser.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

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531colin
Posts: 12529
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: "Gusset" under downtube

Postby 531colin » 8 Oct 2019, 5:40pm

peetee wrote:I would like to think that these gussets are fitted with prior attention to the guage of the tube at the lower join of the gusset. The butted section of tubes are often of a set length and the tubes are cut to size to suit the bike. This can leave quite short sections of 'thick' tube and it's quite possible that on shorter frames the gusset may Overlay the thin section creating a potential stress raiser.

This is the third time I've linked this on this thread.....https://www.torchandfile.com/assets/images/PARTS%20LIST%202019.pdf
Refer to the 725 tube list, the "thin" middle section is 350mm, with 2 tapers 30mm long, except the biggest diameter tube which has 330mm middle section and two, 40mm tapers.
I don't think its a problem.

peetee
Posts: 1467
Joined: 4 May 2010, 10:20pm
Location: Cornwall

Re: "Gusset" under downtube

Postby peetee » 8 Oct 2019, 5:48pm

531colin wrote:
peetee wrote:I would like to think that these gussets are fitted with prior attention to the guage of the tube at the lower join of the gusset. The butted section of tubes are often of a set length and the tubes are cut to size to suit the bike. This can leave quite short sections of 'thick' tube and it's quite possible that on shorter frames the gusset may Overlay the thin section creating a potential stress raiser.

This is the third time I've linked this on this thread.....https://www.torchandfile.com/assets/images/PARTS%20LIST%202019.pdf
Refer to the 725 tube list, the "thin" middle section is 350mm, with 2 tapers 30mm long, except the biggest diameter tube which has 330mm middle section and two, 40mm tapers.
I don't think its a problem.


A couple of months ago, IIRC, a poster was enquiring as to the provenance of a far Eastern built 725 frame because of its relatively cheap price. Invariably you get what you pay for and I would expect such a frame to have compromises. It is not beyond expectation that the necessity for a short tube could involve one cut and two mitres leaving very little butted section at one end.
Caveat emptor, never assume.
Current status report:
Latter side of fifty and feeling less than nifty.
Too many bikes on pegs and too few miles in the legs.

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531colin
Posts: 12529
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: "Gusset" under downtube

Postby 531colin » 8 Oct 2019, 6:04pm

peetee wrote:……...A couple of months ago, IIRC, a poster was enquiring as to the provenance of a far Eastern built 725 frame because of its relatively cheap price. Invariably you get what you pay for and I would expect such a frame to have compromises. It is not beyond expectation that the necessity for a short tube could involve one cut and two mitres leaving very little butted section at one end.
Caveat emptor, never assume.

Thin mid-section 350mm.
Two, 30mm tapers 60mm.
Two, 60mm thick section 120mm
Overall tube length 530mm

alexnharvey
Posts: 841
Joined: 10 Jan 2014, 8:39am

Re: "Gusset" under downtube

Postby alexnharvey » 8 Oct 2019, 6:18pm

peetee wrote:
531colin wrote:
peetee wrote:I would like to think that these gussets are fitted with prior attention to the guage of the tube at the lower join of the gusset. The butted section of tubes are often of a set length and the tubes are cut to size to suit the bike. This can leave quite short sections of 'thick' tube and it's quite possible that on shorter frames the gusset may Overlay the thin section creating a potential stress raiser.

This is the third time I've linked this on this thread.....https://www.torchandfile.com/assets/images/PARTS%20LIST%202019.pdf
Refer to the 725 tube list, the "thin" middle section is 350mm, with 2 tapers 30mm long, except the biggest diameter tube which has 330mm middle section and two, 40mm tapers.
I don't think its a problem.


A couple of months ago, IIRC, a poster was enquiring as to the provenance of a far Eastern built 725 frame because of its relatively cheap price. Invariably you get what you pay for and I would expect such a frame to have compromises. It is not beyond expectation that the necessity for a short tube could involve one cut and two mitres leaving very little butted section at one end.
Caveat emptor, never assume.


Seems like you are assuming quite a bit based on very little evidence. It's cheap so it must have short butts? Idle speculation on your part with zero evidence I would wager.
Last edited by alexnharvey on 8 Oct 2019, 6:21pm, edited 1 time in total.

landsurfer
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Re: "Gusset" under downtube

Postby landsurfer » 8 Oct 2019, 6:20pm

531colin wrote:
peetee wrote:……...A couple of months ago, IIRC, a poster was enquiring as to the provenance of a far Eastern built 725 frame because of its relatively cheap price. Invariably you get what you pay for and I would expect such a frame to have compromises.


My experience of 525 / 520 "Eastern" built frames is only positive.
Colin, are the excellent steel SPA frames made in the far east ?
As are iPhones, MacBooks and the latest Volvos ...

I have 2 Jamis Aurora framed bikes which are excellent in every way ..
The days of "Made in China" being a guide to poor quality are long gone ...
One of the biggest bike producers in the world is in Taiwan ..
My motorbike was made in India .. just up the road from the Triumph factory .. next to the Kawasaki factory.
Trek and Harley Davidson both produce their "Proudly made in the USA" products in India, Thailand and Taiwan.
Be a do'er, not a watcher. Be a Sceaphierde, not a Sheep.
Mike Hall, Jenny Graham .. Respect. .... The Road Goes On Forever !

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531colin
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Location: North Yorkshire

Re: "Gusset" under downtube

Postby 531colin » 11 Oct 2019, 7:40pm

landsurfer wrote:….
Colin, are the excellent steel SPA frames made in the far east ? ……..

Steel and titanium, both built in the Far East.
At the moment, its the obvious place to go, you can't argue with the price or the quality.....or the reputation, which is important for the end customer.
For a long time, some Shimano stuff has been proudly labelled made in Malaysia, and probably other places as well. I guess its only a question of time before somebody breaks ranks and gets their frames made somewhere else; that'll start a price war.

djnotts
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Joined: 26 May 2008, 12:51pm
Location: Nottingham

Re: "Gusset" under downtube

Postby djnotts » 11 Oct 2019, 9:26pm

"The lower end is not welded and there is a distinct gap between plate and downtube."

The original On One Inbreds all had the open end. As I recall, Brant used to say squirt a bit of WD40 up occasionally.