Why bolted frame, Dawes

General cycling advice ( NOT technical ! )
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Patrickpioneer
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Why bolted frame, Dawes

Postby Patrickpioneer » 19 Jan 2018, 8:46am

Looking at the bikes on ebay, which I always do just for fun? I came across a Dawes where the rear triangle appears to be bolted, why do that and not braze it?

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barrym
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Re: Why bolted frame, Dawes

Postby barrym » 19 Jan 2018, 8:57am

Good question. Some of the current Pashley range are like this too. In a quiet moment it crossed my mind that it might make them belt compatible .
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Bmblbzzz
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Re: Why bolted frame, Dawes

Postby Bmblbzzz » 19 Jan 2018, 9:21am

It was common on old "roadsters" so presumably that's why Pashley do it -- because they always have done. But I don't know why Dawes are doing it (unless this frame is a rebadged Chinese roadster? or just to increase their retro appeal?), nor do I know the more interesting point of why it was done originally, though I'd guess that was simply to do with practical manufacturing techniques.

pete75
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Re: Why bolted frame, Dawes

Postby pete75 » 19 Jan 2018, 9:51am

One of the main reasons for bolted rear triangles is to enable a full chain guard to be fitted as on this Raleigh Superbe. Chain guards like that were once common on bikes meant for daily transport in all weathers.


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Brucey
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Re: Why bolted frame, Dawes

Postby Brucey » 19 Jan 2018, 10:38am

In the instance of raleighs, IIRC the chaincases came off without having to have bolt-in stays, indeed not all raleighs with chaincases had bolt-in stays. Nor did all bikes with bolt-in stays have chaincases, either.

If that isn't the reason for bolt-in stays, maybe they were just cheaper to make? Or maybe there was at one time a rash of brazed seatstay breakages (not that unlikely) and it was a favoured method of construction for utility bikes because it rendered the frame repairable?

I have often wondered why it was popular to do it this way, but I have yet to hear a compelling argument for it.

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pete75
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Re: Why bolted frame, Dawes

Postby pete75 » 19 Jan 2018, 11:04am

Brucey wrote:In the instance of raleighs, IIRC the chaincases came off without having to have bolt-in stays, indeed not all raleighs with chaincases had bolt-in stays. Nor did all bikes with bolt-in stays have chaincases, either.

If that isn't the reason for bolt-in stays, maybe they were just cheaper to make? Or maybe there was at one time a rash of brazed seatstay breakages (not that unlikely) and it was a favoured method of construction for utility bikes because it rendered the frame repairable?

I have often wondered why it was popular to do it this way, but I have yet to hear a compelling argument for it.

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Some could be fitted without unbolting chain stays, some couldn't. I've encountered both sorts.
Not all versions of bikes with similar frames were fitted them but it must have made production easier to make all the frames in the same way.

It's also probably to do with the way chainstays were made - my 1937 Raleigh frame has the "track " style drop outs formed by pressing the chain stays almost flat and cutting the slot for the axle so bolting the seat stay meant no need for any brazing at the drop out and the top end of the seat stays are fixed using the seat clamp bolt so no brazing their either. Must have been an economical way to do things.

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Re: Why bolted frame, Dawes

Postby Zanda » 19 Jan 2018, 11:50am

I've wondered why too. For a short while I owned a Dutch made Union roadster with stays bolted. It was lugged and brazed at the bottom bracket but bolted at the seat cluster. I've seen a few traditional Dutch bikes made this way.

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Patrickpioneer
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Re: Why bolted frame, Dawes

Postby Patrickpioneer » 19 Jan 2018, 12:38pm

this is the bike, look at the handlebars too,
https://www.ebay.co.uk/itm/Dawes-gents- ... 1438.l2649

mercalia
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Re: Why bolted frame, Dawes

Postby mercalia » 19 Jan 2018, 12:42pm

hmm I wonder how far this could be taken to make a fully collapsable bike? that would fit into a small case?

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[XAP]Bob
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Re: Why bolted frame, Dawes

Postby [XAP]Bob » 19 Jan 2018, 3:23pm

mercalia wrote:hmm I wonder how far this could be taken to make a fully collapsable bike? that would fit into a small case?

All the way if you want - but the bike will be heavier and stiffer than it would otherwise be.

Particularly the main triangle would suffer.
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9494arnold
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Re: Why bolted frame, Dawes

Postby 9494arnold » 19 Jan 2018, 3:40pm

Having looked at the e bay phot, Is that not just a bolt on gear hanger which is quite normal on ATB /Mountain Bikes these days : saves trashing the frame by breaking the fork end if you stick the mech in the back wheel. :oops:

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Re: Why bolted frame, Dawes

Postby 9494arnold » 19 Jan 2018, 3:41pm

And have a look at Brompton/Bickerton/Dahon Folder etc etc :shock:

colin54
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Re: Why bolted frame, Dawes

Postby colin54 » 19 Jan 2018, 5:20pm

I wonder if it might be a bonded frame of some sort with (say) titanium main tubes and steel stays like Raleigh Dyna Tech.

It's unusual for the seat post lug to be level with the top tube like that isn't it, I noticed that the rear brake cable dives into the frame at

the lug as well which is unusual. A rack fitting on the front fork but only a mudguard eye at the rear.

It looks like the Green Dawes used on the Galaxy in the early 90's , I like a mystery!

brynpoeth
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Re: Why bolted frame, Dawes

Postby brynpoeth » 19 Jan 2018, 6:36pm

There is a lot to be said for bolting on the stays, one can repair/change them easily or convert the frame for other wheels + tyres

It must be possible to bolt the top, down and seat tubes too, I bet someone has done it already
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colin54
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Re: Why bolted frame, Dawes

Postby colin54 » 19 Jan 2018, 7:00pm

It looks like this may be a Dawes Vision with bonded aluminium frame, a picture of what looks like this very bike on page 2 of this thread

(note the bars).

http://www.retrobike.co.uk/forum/viewto ... ilit=dawes