smontanaro 

I'm nearly "finished" (is anything really ever finished?) with a Dawes Galaxy town bike, but am struggling with chain clearance issues at the rear dropout. The frame came to me with 126mm spacing, but just a 5-speed freewheel. Since I was going to build it without a front derailleur, I figured I would try to squeeze in a six- or seven-speed cluster. After respacing and redishing, a seven-speed fit just fine, or so I thought. The bullet treatment on the chainstay takes up a lot of space (same inside as shown outside):


As you can see above, the derailleur is attached with a claw having a spacer (no derailleur hanger), which moves the axle forward a bit:

I think if I remove the spacer, I will have enough room for the chain. Will I be OK if I remove the spacer, or will the claw tend to rotate?

Ferrouscious 

The bolt holds the wheel in place. If it is loose or removed, the rear wheel will slide into the left chainstay. Not good. Luckily, it seems that you have oodles & noodles of space. Just pop a chain on there and check the spacing to the dropout socket. Space to the back end of the hanger is fine.

smontanaro 

Thanks for the reply. Note that I have a quick release holding the wheel in place, which also clamps the claw. I wonder if that would be sufficient to keep it all from flying apart (or spinning). The current forward spacing doesn't allow an eight-speed chain to squeeze between the small cog and the chainstay "bullet". As is, is have to revert to a five-speed or narrow spaced six-speed freewheel.

bikemig 

I'm not entirely clear as to what the problem is. Is the chain hanging up on the frame? If it is, it isn't clear to me why the bolt used to anchor the claw is the source of the problem.

In any case if trying to free up some room on the drive side for the chain, I'd try a 6 speed freewheel rather than a 7. In my experience, 6s tend to be a little narrower than 7s. Alternatively just throw a 1 mm spacer on the non freewheel side. The dish won't be quite right but as a practical matter you won't notice.

madpogue 

I think the goal is to be able to move the wheel back further in the dropouts, to allow the smallest cog not to hit the stay. But I think you'll find that the "spacer" you speak of is actually the female-threaded part that the claw bolt threads into. So I think you're out of luck. I'm unable to imagine how "the bolt holds the wheel in place", but it does hold the claw in place. You can't depend on the axle skewer / quick-release holding the claw in place, not to mention that it would be an absolute PITA any time you had to remove the wheel.

Spacer option as mentioned above is your best bet. Increase spacer thickness on the DS by about 1mm, and decrease NDS by same, and re-center the rim.

noobinsf 

I’m also a little unclear as to why the bullet treatment would obstruct the chain. If the stay does not obstruct the *cog*, then why would there be an issue? The chain will run above the bullet part of that stay.

Have you confirmed with a chain that there is not enough vertical clearance between the chain and the "bullet"? A straight-on profile pic would be helpful.

smontanaro 

There's a guy over on The Paceline whose e-sig reads something like, "Don't believe anything I say. I'm an idiot."

I'm that guy today. I wasn't actually threading the chain properly, letting it dangle off the front of the cog. Jeez, I feel dumb.

Chain attached and derailleur adjusted. Now I just need to slap on some pedals to take it out for a test ride.

randyjawa 

Running a seven cog freewheel on a Dawes Galexy frame is the problem. Simply put, you need a longer axle that will accommodate a spacer or two (one for each side). Or, do what I do in a situation like this...

Adjust the rear derailleur to prevent the chain from shifting to the smallest cog or get a six cog freewheel, might be easier yet.

masi61

As a test, you could remove the bolt and nut that are holding the claw in the dropout and then just tighten the quick release skewer good and tight after pulling the wheel as far back as possible in the dropout. Then test the clearance on the repair stand. If you have clearance now, then take the bike for a test ride. You might be all right but you might also have a situation where the claw rotates out of position due to the cable tension during shifting or even just from the housing or the derailleur return spring.

These kinds of issues is partly why frames that don't have a derailleur hanger aren't as versatile as ones with a proper d' hanger.

I suppose you could anchor that claw to the dropout in a different manner such as by drilling a chamfered through hole through part of the claw that overlaps the dropout, then use an index center punch to locate where you could then drill and tap for a small machine screw (or 2) that would hold the claw in place externally without the protruding nut that is mucking up your 7 speed hub idea.

I've even heard of people brazing on an improvised derailleur hanger but this is way outside my skillset. The drilling and tapping could be done by anybody, so long as they are careful about it, locating the screw holes precisely and use sharp drill bits and taps.

3speedslow

You mean... nobody has asked to see a pic of the Dawes!

please!

3speedslow

1 X 5
Here’s mine.

dddd

Sometimes a smaller smallest cog is the answer to keeping the chain from jamming against the end of the seatstay, but here it was apparently only the chainstay end that was contacting the chain when the chain followed the cog teeth away from it's normal path.

I have many times massaged the claw nut with a Dremel to allow the chain a bit of needed free space. Sometimes it is the snout of the freewheel body that actually cuts a notch in the nut, and which may fully correct itself after a few miles of riding IF the interference isn't initially too severe to prevent the freewheel body from turning under pedaling forces.

Even different brands of any particular # of speeds freewheel will have slightly but significantly different mounted length.

Narrower and more-modern chain can help greatly with any sort of chain clearance problem.

SurferRosa

Well, yeah. On a "Dawes Galaxy town bike," do you need the 13t rear cog? What town we talkin' about?

dabac

While the wheel is in place, either q/r or axle nut will do an entirely sufficient job of holding the claw in position. That little screw and spacer/washer is only there to keep the derailer in place with the wheel removed.
Getting the wheel and derailer mounted is a little bit more difficult w/o the holder, but truly no big deal.

smontanaro 

In its original guise (as I found it on CL):



As it sits now (not even off the work stand yet):



I believe the only original parts at this point are the headset, seatpost and wheels. Assuming I keep it long-term, the wheels will probably get replaced. The rear, in particular, has a flat spot.

Miele Man

You can remove that spacer and bolt but be aware that doing so will cause the derailleur to come off anytime you remove the wheel.

Cheers