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-   -   TA Pro 5 Vis: a saga (https://www.bikeforums.net/classic-vintage/1218647-ta-pro-5-vis-saga.html)

wasianamerican 12-01-20 01:49 PM

TA Pro 5 Vis: a saga
 
Hi all, newbie here but lurker for the past 2 years. I'd like to share my long, arduous tale involving my TA "cyclotouriste" crankset over the past 4 months.
I came into possession of this coveted artifact in July, when I bought a 1970 Schwinn Sports Tourer, so I got the crank and the BB set. I sold off everything else to a gentleman in Oregon, but I couldn't part with the crankset. Now for the Schwinn enthusiasts here, that means this crank was set up as a double, with two chainguards and a ridiculous ratio of 54t big ring, 36t small. I commute on a 52-40 (yay young knees) so this wasn't going to work. I want to put the cranks on my Raleigh Gran Sport so I set out to make some changes. Here is where everything went wrong.
I bought a 50t outer ring, but somehow completely missed the fact that it was only drilled to be run as a single! It did have the holes for the chainguard though, curious. I had my technician friend drill holes to make it a double (I apologize to the community if I defaced a unique item) but he based the hole spacing off the holes for the chainguard ring and they weren't aligned properly! So if anyone is interested in a 50t outer 50.4 bcd ring with "minimalist drillium" let me know.
So that was a bust. Fast forwards to last month when I found a 48t outer ring on the 'bay for a reasonable price and acquired it.
Last night I finally had time to put it together and !!! The 48t chainring had the newer bolt holes that are countersunk(?) and are meant to be used with the newer allen key bolts, not the very old school nut and washer of the earlier TA rings.
I bought the chainring bolt set from VO that claims to work with TA cranks and once it arrives I may FINALLY have a working Pro 5 Vis.
I'm going to have an aneurism if they don't fit.

Now I have an extra big and small chainguard, a 54t outer ring, a 50t outer ring single, and a bunch of very old school chainring bolts. Oh and a double crankset. That may have French pedal threading.

Any fun stories like this?

John E 12-01-20 03:33 PM

I guess my nearest experiences were:

1) I tried to run a 53-50-39 half-step-plus-grannie on a 1990s Campag. Veloce crank, only to find that the spider was too thick for the half-step gearing, so I switched to something different: a 50-42-39 overdrive-plus-half-step setup. It worked fine, but I would obviously prefer the big gap on the bottom instead of the top. In years past I have built various single bolt circle triples (49-46-43 third-step, anyone?) using long bolts and spacers, and these always worked well with older-vintage cranks.
2) I wanted an 8-tooth 1.5-step drop on my Nervar Star crankset, and, unable to find a 44T/128mm BCD ring, I "stretched" the holes of a standard 130mm Shimano ring. Worked like a champ.

noobinsf 12-01-20 04:39 PM

I thought I might be able to mix Velo Orange and TA rings, using what I had and just adding to get the exact gearing I wanted. Nope, spacing was off, bolt holes, etc. Lesson learned -- now I'm careful about mix and match with the Pro 5 Vis.

Ex Pres 12-01-20 04:52 PM

Not with the TA, but with (what were sold to me as) 122bcd rings. I pulled these out about a week ago, owned 'em for a while now, to see about using one on a Stronglight crank. 39T, just a little lower than the 40s I had, and black ano, too.
What?, bolt holes don't quite line up, but they're really close. Could I just be having a brain fart? Nope, turns out they are BMX rings made for the old SR 118bcd cranks. Don't own one of those at the moment - but I have 2 nice new black 39t rings :)

tiger1964 12-01-20 05:51 PM


Originally Posted by wasianamerican (Post 21813925)
Here is where everything went wrong.
I bought a 50t outer ring, but somehow completely missed the fact that it was only drilled to be run as a single!

...and I had bought a 50T to run as a single, it is drilled for a double, and I have extra holes I don't need. We could have traded. :bang:

wasianamerican 12-01-20 06:04 PM


Originally Posted by tiger1964 (Post 21814284)
...and I had bought a 50T to run as a single, it is drilled for a double, and I have extra holes I don't need. We could have traded. :bang:

What gearing do you run in the back with a 50t up front?

tiger1964 12-02-20 06:50 AM


Originally Posted by wasianamerican (Post 21814304)
What gearing do you run in the back with a 50t up front?

This is for one of several bikes I am building up over the winter (other topics at BF), have not ridden on this setup yet. 13-24 freewheel. It's relatively flat around here, no mountains to climb (I am starting to think I should have one bike with wide gearing, just in case).

Dylansbob 12-02-20 09:11 AM

So Electra made 50.4 cranks/rings for a while on their Ticino line...
 
I had a cheap single ring with double guards I had bought from their pre-Trek webpage. Had a nice little fixie built up to put it on, BUT I got high and forgot to tighten all the 'ring bolts before I test rode it. I now have a ring with little ovals spaced out every 50.4mm.


Keep track of all those antique TA chainring bolts. They are hard to find and somewhat pricey when you do.

Sluggo 12-03-20 10:30 AM


Originally Posted by John E (Post 21814103)
... overdrive-plus-half-step setup...

I have never heard of that. Clever idea.

BTW, I am also blessed with a 54 from a Sports Tourer. Maybe I will make a clock out of it.

JohnDThompson 12-03-20 12:42 PM

1 Attachment(s)

Originally Posted by Dylansbob (Post 21814898)
Keep track of all those antique TA chainring bolts. They are hard to find and somewhat pricey when you do.

FWIW, Velo-Orange sells a modern version of those bolts:

https://velo-orange.com/collections/...0-4-bcd-cranks

clubman 12-03-20 01:48 PM


Originally Posted by Dylansbob (Post 21814898)
... BUT I got high and forgot to tighten...

Snort. No one ever does that....honesty is so refreshing these days.


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