deux jambes

I would have tried shaving the spacer much like I used true the backs of plane blades. Used to get those as flat as flat can be. But as it turns out, I made it out of work on time to stop by the bike shop. Picked up the spacers I needed. I’ll keep an eye on the axel length, though I suspect it’s originally meant for 120 mm as the ends sit rather shy in dropouts the way it’s set up now at 127 mm. And I’ll watch the cog/chain/dropout clearance. I’m expecting ~5mm.

mpetry912 

the pic from over the rear dropout looks pretty close to me.

You're looking for a "gun site alignment" of the center rear cog to the plane of the front chainrings.

again, I'd give this a "go". You do have a couple MM to improve the dishing a little bit by moving the hub spacers around but you'd have to re dish the rear wheel. We also don't know if the crank arms are fully seated on the spindle.


Mark Petry
Bainbridge Island, WA USA

cudak888 

While the ~3mm difference may not matter so much for the chainline, the one thing that hasn't been discussed is whether the front derailer you've set aside for the build can reach the upper ring without bottoming out. This recently happened in the Mechanics forum under a similar scenario, and though the BB could have been a tad narrower in that case, the FD simply didn't have enough travel to be compatible with the crank that was installed.

Before shaving the spacer, I'd definitely try a slightly narrower BB to tuck that crankset in by at least 2mm or so. Your Eisentraut's chainstay doesn't look like it was dimpled with a triple in mind, but figuring for frame flex, bringing the crank in another 2mm should still leave you with enough safe clearance against the chainstay. I'd be a bit wary about pulling it inboard over 3mm though.

-Kurt

dddd

No way would I take quite 6mm off of the driveside spacer, I might try for 4mm though.

Remembering that Ultra-6 freewheels didn't usually work on Campag 5s hubs without adding a 1mm spacer, and that was with narrow chain.

Also, when the freewheel starts with a 14t cog, the chain is more likely to reach up to where it might jam against the end of the seatstay when shifting "up" from the 14t cog, although this doesn't appear to be possible on the OP's particular frame here.

As far as the front derailer, indeed you can run out of needed travel in either direction, so perhaps best to back off the limit screws checking for how much extra potential travel is there before tinkering with the bb length. I myself usually do make an effort to shorten the bb on many of my vintage bike builds, but this is usually more the case with lower-end bikes having their typically too-long bb spindle to begin with.

One thing I measure with the rear wheel in place is the space between the outer face of the small cog and the inner face of the driveside dropout. I use about 4mm with modern chain in most cases, but have gone below that a bit IF there is no danger of the chain hitting the end of the seatstay when shifting up from the last cog. Not applicable here, but vintage ~8mm chain needs an extra full 1mm of space in my estimation.

mpetry912 

Exactly right. Here's what Chas is talking about. My Raleigh Pro Mark 1 has the end of the seat stays "domed" and not flushed, so if the clearance is tight the chain will dig into the seatstays shifting out of the small cog. Test it and see.

Mark Petry
Bainbridge Island, WA USA

Salamandrine 

It is a concern for sure. That's why I suggested measuring two or three times before cutting anything. Don't cut first and ask questions later!

The OP says that the current OLD is 127, which kind of makes me suspect a 1mm spacer has already been added, as was common practice when 7 speed was taking over. So reducing 6 mm would bring it to 121 OLD. I think that will be enough just by eyeballing it, but really it's not a problem if 122 or whatever is needed. The main point of this is to get a stronger axle and wheel, and to use the frame with its original geometry intact.

For reference, a campy lock nut is about 7.5mm thick, so if that is removed and the freewheel still clears with a chain, all is good. Can't tell from that photo how much the current clearance is from the small cog to the dropout, but guestimation would be 10-11mm. That's just eyeballing from a photo with a lot of perspective distortion. Measuring is a must.

FWIW that dropout looks like it has very good clearance compared to many.

deux jambes

OK! Believe I got it squared up! Situation vastly improved

Too many posts to respond to individually without getting overwhelmed... So allow me to just say thank you to each of you who have taken the time to engage me here. Because of you, I managed to restore the frame’s original spacing, set up an effective chainline, and align the dropouts as well as derailleur hanger.

Here’s an overview of what took place:

Record hub had been spaced to 127.3 mm OLD by a previous owner. It could be squeezed into the 120 mm frame, but the Ultra 6 freewheel which came with the wheel left a gap of over 9 mm between the small cog and the dropout. Further measurements showed a chainline off by over 3 mm.

I double checked the crank spindle interface, torqued the fixing bolt a bit heavier, and was able to bring the chainset inward by nearly 1 mm.

Next, I removed the locknuts, cones, washers, and spacer from the axel. The axel measured 134.2 mm but did not need shortening since the 7.5 mm Campy dropouts would accommodate it without any protruding ends.

I settle on using the two original keyed washers (one in each side), a 5 mm spacer, and an extra 0.5 mm washer from the parts bin.


The result is an axel spaced at 121.9 mm OLD with 6 mm of axel extending past locknuts on each end. Gap between the small cog and dropout is 4 mm. Ran the chain through and clearance looks good!

Way its set set up now, the chainline measures 44 mm in front, and 43.55 mm in the rear. Close enough for me to call it good, and move on to dishing the wheel towards the left now!

deux jambes

^^^ Ha! That last photo reminds that I DO NEED to shorten the skewer still.

Road Fan

If the OP is going to narrow the front chainline, that's reasonable given he measured I think 45 mm and the usual target value is 42.5 to 43.5. So taking 2.5 to 3.5 mm off the drive side offset is a decent idea. This would need a new Shimano BB with spindle length 5 mm to 7 mm narrower than what you have. The physical limit is whether any part of the inner faces of the chainrings, crank arms, chainring arms, or chainring bolts is in danger of hitting the chainstay as you pedal. I don't know exactly how much margin you need with any given frame since flex depends on materials, chainstay/BB shell design, and your riding style - faster spinning and smoother spinning mean less BB sway. With a high-planing rando frame I found 5 mm to be adequate, but I don't know how much narrower I could go. On my bikes I try hard to match front chainline to standard specifications, with equal crankarm to chainstay clearances. After that I check the rear chainline. If it's off I do the string test to make sure the rear triangle is balanced and has correct OLD. If it's correct I dig into wheel axle offset, rear OLD and dishing to try to get the chainline correct with matched OLD and the rim dished so it is in the plane of the main triangle. This could all be done with high accuracy if I was a framebuilder/machinist with precision alignment tools, but that's not me. I just follow this step-by-step procedure to achieve a good if not perfect alignment. I have one frame with a need for rear-end alignment, but I made an improvement by adjusting wheel dish. I still need to shim the BB to the right maybe 2 mm to cure mild chain drag. But with the rims both in-plane the bike rides better.

When I work on the rear wheel to try to achieve a balanced and aligned installation, I modify the NDS bearing locknut/spacer stack as needed. When I reassemble the axle if the spin cannot be made smooth, I add bearing overhaul to the work plan. I'd recommend that to anyone with the need and the skills. If the result is that the cogset cannot be fit and maintain adequate DS dropout clearance, then so be it, it needs a narrower freewheel. If prior to all this work a 126 frame was expected to handle a wide-7 speed or an 8-speed freewheel, that is a wheel with a poor dishing compromise anyway, and since that has a lot to do with a wheel maintaining its integrity, that has priority over an excessively wide freewheel or cassette. So for my bikes I will follow the path of such project expansion, if it's needed and can't be deferred.

deux jambes

Yes, it was 44.9. And I thought that was reasonable since SB suggests a target of 45 for a road triple. However, if I’m not mistaken, the TA Pro 5 Vis is a bit narrower than an average triple? So maybe your numbers are better suited for this crank. Really, it seemed to me that the configuration in the rear was the real culprit.

Anyhow, gotta keep things simple here, or I’ll never get to ride the bike before the rains come. Gotta try to make the best outta what I have. And if you check the post above yours, it looks as though things might be in good order.

Once again, everyone’s input is appreciated!

dddd

Good post Road Fan!

I don't think more than 3mm is ever needed for chainstay clearance, I've used 2mm with no issues (when the chainring runs true of course).

Salamandrine 

Everything looks good to me. Dish the wheel back to center and ride!

SB is correct. 45 to the center chainring of a triple is the usual ROT. A triple is not the same as a double. However, if in practice you can push it another 1 or 2mm. At 44, IMO your chainline set up is pretty ideal for a triple with an ultra 6 and nominal 120 triangle.

deux jambes

Nice to get get a confirmation on that. With a 48-38-28 chainset, I foresee the majority of my riding on the middle ring. I really wanted that to zero in on the center of the freewheel for that purpose.

Dish accomplished! Made a hell of a mess out of it last night so I started from scratch this morning, and took my time with it. Center of the rim is smack dab in center with the OLD.

Should be a pretty solid wheel. Tight, but not too tight. Tension is uniform within about 15%

Cut 6mm off the skewer too, and filed a bevel on it.

Hoping to start hooking the rest of the mechanicals up this evening, and if all goes well, take her for a spin by the weekend.

Thanks again for all the help!