Odd old Dawes? 1-Down? What is this?

[Braindrain]

Hi is of interest to anyone building one of these up from a frame and might help them avoid a costly mistake. I've bought a 46-26 chainset now and it all works with the Claris triple front derailleur. There's enough clearance above the large chainring teeth and I can also fix on an aluminium bottle cage. Now to get the shifting indexed.....

[vipvop]

Q factor is fine, nothing unusual at all.

[gregoryoftours]

Only problem is that the rear derailleur won't change up as the lever on the Shimano combined brake/shifters arrangement isn't operating- can these things be dismantled? I'll have a go

I'm not sure if they can be dismantled, but before you do, try giving the shifter internals a thorough dowsing with wd40 or thin spray lube. Often the grease in old shifters congeals and gums up the small ratchet pawls.Soaking them, waiting a bit and then working them repeatedly can often free them up. If you can get to them easily working the ratchet pivots directly with a pin or small screwdriver can be even more effective.

[gregoryoftours]

Oh, slightly out of date!

[mercalia]

If anyone is building up a frame from those on sale on ebay such as Big Yellow Bike Shop, it's worth thinking about the Q factor or stance width (as with any bike with wide tire clearance). The issue with this bike is that the combination of bottom bracket size ( slightly too big), flared cranks and i think even the pedals accentuate the sense of legs being too far apart. I need to replace the bb anyway and will try find some straighter cranks as there's tons of room between the crank arms and frame. Obvious stuff... but worth a mention.

strange having an original copy I cant say that I get a sense of the legs too far part. BB length is 118mm with the original RSX 46/36/26. The front changer works very well with that BB size. Dawes I think shipped it with 115 I think but the front changer never worked well hard to get to the small ring, and the 118m BB is the one speced for the RSX triple I seem to remember. What BB size are you using at the moment?

http://www.ebay.com/itm/NEW-Shimano-RSX-46-36-26-triple-touring-crankset-170mm-NOS-Square-Taper-110-74-/252877614449?hash=item3ae0ae2d71:g:iaIAAOSwSlBYsqs7



"re Braindrain » 16 Mar 2017, 5:23pm
Mercola: any chance you could post some pictures of the front mech, so I can't see where the clamp ends up?
Cheers"

missed your post and I assume too late now to be of any use to post the pics since you seem to have got it working

[mercalia]

cranks RSX 46-26

has there been a change to to add pic code as I get images added even without placing inline

[Braindrain]

Thanks for going to the bother of taking and posting the pictures. It's useful. Yes, mine is up and running. I really like the bike despite a couple of niggles. Shifting to the middle ring isn't very slick, but it kind of works. My front derailleur is near the limit of its travel for the big ring and my cranks show more clearance to the frame than yours, I guess my chainset and bb combination are wider overall. I might improve thing by fitting a narrower bb to match yours. I've also fitted a n-jump stop as I couldn't get the shifting to work without the chain dropping off the small chain ring occasionally. Also, Judging by the earlier photos the forks I've fitted (from an mtb) don't have enough offset/rake are are more chunky. That might explain why it fells slightly odd when cornering at moderate speed (I have fitted 2" Schwalbe mondials though, it feels a bit over tyred). It feels like it tightens up and falls in on itself (is that understeer?) Can anyone suggest another source of forks, for not too much?

[Tinnishill]

I have been building up another old stock One Down frame and doing some measurement of it. The bike is intended as daily transport for a penniless youth. I thought that I would report the results in order to add to the sum of public knowledge.

The frame was described as 53cm. I measured the tubes with a steel tape measure and an old vernier gauge, between the centres of the joints; I estimated the accuracy of tolerance of my measurement as being about 0.5mm.

The seat tube is 28mm external diameter and measures as 53cm from the centre of the BB to the seat clamp and 49cm from the centre of the BB to the centre of the top tube joint.
The top tube is 29mm dia and 54cm long.
The head tube is 37mm dia and 15cm long.
The down tube is 32mm dia and 62cm long.
The chain stay tapers from 28mm to 16mm dia and 42cm long.
The seat stay tapers from 19mm to 14mm dia and 51cm long
The BB shell is 68mm wide.

I fitted a Surly LHT26 front fork which came with a 400mm steerer, cutting 150mm off it before fitting the star nut. I used a Madison Mpart pro headset bearing.

Other kit used was a Shimano UN55 118mm axle length BB bearing; A set of SJSC touring drop bars; Shimano Tourney A070 "brifters", triple front and road rear derailleurs. We reused a Spa 74/110 triple crank set with new chain wheels at 26/36/46t.

The wheels are stock from a cheap bike shop, reusing old salvaged v- brakes and new "travel agents". Chosen tyre size is 26 x 1.5; Marathon Plus tyres were an ok fit on the cheapo rims.

A rear rack, bell, lights, wired cycle computer and saddle and a lightly used 13t/28t 7 speed freewheel and chain all came off the crash salvage donor bike.

I don't think that it turned out to be an economically viable project, but we did learn a bit about stuff like component compatibility. And it's a good bike.

[mercalia]

Thanks for going to the bother of taking and posting the pictures. It's useful. Yes, mine is up and running. I really like the bike despite a couple of niggles. Shifting to the middle ring isn't very slick, but it kind of works. My front derailleur is near the limit of its travel for the big ring and my cranks show more clearance to the frame than yours, I guess my chainset and bb combination are wider overall. I might improve thing by fitting a narrower bb to match yours. I've also fitted a n-jump stop as I couldn't get the shifting to work without the chain dropping off the small chain ring occasionally. Also, Judging by the earlier photos the forks I've fitted (from an mtb) don't have enough offset/rake are are more chunky. That might explain why it fells slightly odd when cornering at moderate speed (I have fitted 2" Schwalbe mondials though, it feels a bit over tyred). It feels like it tightens up and falls in on itself (is that understeer?) Can anyone suggest another source of forks, for not too much?

with the original 3 ( 46,36,26 RSX) x8, 24 speed RSX sti units the front changer has to be set up very carefully, there is no margin for the outside screw- too close and wont get to the large ring and too far, will go to the large ring but not shift back: Its so sensitive I have had to change the setting in cold/v hot weather by a small fraction of a turn of the out side screw; also shifting to the large ring has to be done carefully as it is too easy to jump it off the ring altogether ( as I said a very tight margin for the screw setting, so cant solve the problem that way ). The RSX sti dont have any fine adjustment control to nudge changeing. I dont have any problem with middle/small ring shifting, but has to be done slowly with care

[vipvop]

My One Down frame just snapped at the drive side drop out, but fixable. I had to get a couple of quotes, some bike workshops insist on replacing both but I was told by a well respected frame builder that its almost always the drive side that fails and not necessary to replace both - its more that the drop outs are ordered in pairs. So a lot cheaper...

However, the reason I'm posting is that the frame repairer pointed out that the holes drilled in the top of the seat stays as part of the tig welding process are a bad idea. Water can accumulate at the drop out, so he recommended spraying in some WD40 and filling them in. In the interest of preserving these decent frames..

[mercalia]

My One Down frame just snapped at the drive side drop out, but fixable. I had to get a couple of quotes, some bike workshops insist on replacing both but I was told by a well respected frame builder that its almost always the drive side that fails and not necessary to replace both - its more that the drop outs are ordered in pairs. So a lot cheaper...

However, the reason I'm posting is that the frame repairer pointed out that the holes drilled in the top of the seat stays as part of the tig welding process are a bad idea. Water can accumulate at the drop out, so he recommended spraying in some WD40 and filling them in. In the interest of preserving these decent frames..

sorry to hear of your trouble - hasnt affected me , yet: I have read here that some had problems with the rear carrier brackets breaking. Yes I have wondered about the holes you mention. Not sure which ones you are referring to - there are 2 at the top near the seat pin and four at the bottom near the drop outs ( 2 each at bottom on each stay) so 6 in all. You coulld consider they represent a drain system? At the moment my bike never sees really bad weather so I have never botthered, but I keep this in mind.

re filling them in - maybe a use for the glue gun?

[vipvop]

I meant the top holes which are made for gases to escape during tig welding. Drop outs are brazed but rest of the frame is welded. Maybe spraying some WD40 in there is enough. There shouldn't be any water in the chainstay,

[mercalia]

I meant the top holes which are made for gases to escape during tig welding. Drop outs are brazed but rest of the frame is welded. Maybe spraying some WD40 in there is enough. There shouldn't be any water in the chainstay,

well with all the water spraying up from the road maybe could find a way into the chain and seat stys holes near the drop outs? Any way I have squirted some Car lube into all of them and sealed them with glue-gun glue - easy to remove should have to

[Brucey]

My One Down frame just snapped at the drive side drop out, but fixable. I had to get a couple of quotes, some bike workshops insist on replacing both but I was told by a well respected frame builder that its almost always the drive side that fails and not necessary to replace both - its more that the drop outs are ordered in pairs. So a lot cheaper...

However, the reason I'm posting is that the frame repairer pointed out that the holes drilled in the top of the seat stays as part of the tig welding process are a bad idea. Water can accumulate at the drop out, so he recommended spraying in some WD40 and filling them in. In the interest of preserving these decent frames..

If the breakage is in the dropout itself, it can be repaired by MIG or TIG welding. A skilled welder will make the repair all solid and then will fettle it back into whatever shape you want; original shape or an improved stronger shape. If the breakage is in the tube next to the dropout, and corrosion is implicated, then the final section of tube (at least) needs to be replaced. This can be done by welding or brazing.

Waxoyl (or similar) is best for corrosion proofing the insides of tubes.

BTW the breakage may be a symptom of something else. Typical causes for broken dropouts include

- broken rear axle (usually with screw-on freewheel hubs, rather than cassette hubs)
- bent rear axle
- using the wrong width rear hub in a frame
- frame damage or poor frame alignment

if the rear dropouts flex noticeably when the QR is tightened, the frame alignment (vs the hub width) is poor, and the dropout will be seeing service stresses plus a large preload because of the flex. This sort of thing can easily break frames.

cheers

[vipvop]

BTW the breakage may be a symptom of something else. Typical causes for broken dropouts include

- broken rear axle (usually with screw-on freewheel hubs, rather than cassette hubs)
- bent rear axle
- using the wrong width rear hub in a frame
- frame damage or poor frame alignment

if the rear dropouts flex noticeably when the QR is tightened, the frame alignment (vs the hub width) is poor, and the dropout will be seeing service stresses plus a large preload because of the flex. This sort of thing can easily break frames.

The break is where the drop out enters the chainstay and looks like fatigue, there's no rust, so a new drop out will be brazed. Thanks for your suggestions, definitely worth looking at. I'll check the OLD and make sure there isn't any stress from wrong axle width or frame damage. Think its OK though, the bike has done a lot of heavily loaded touring including Alaska to Patagonia so this might have been a long time developing. As the bike shop said, its a common break and almost always happens on the drive side..