It seems there's possibly 3 different forums I could have made this in, so im hoping this is by best choice.

In college I was given my fathers 1980's something Palo Alto road bike. I cleaned it up really well and did a full tune up on it. A couple years after getting the bike the inner chain-ring snapped in half one day and its been in my basement ever since (about 5-6 years now). I could easily get a new chainring and be good to go but i'd like to try to keep all the parts consistent and not swap out anything with a brand or model that wasn't originally on the bike.

Im just now getting around to trying and replacing the part and i'm having some trouble finding what I need. Searching just "Specialties TA vintage chainring" doesn't really help. So i'm hoping someone here can tell me what model of chainrings I have so I can search more specifically, or even better if you know of where I can find a replacement chainring.

Like in the title its a Specialties TA 45 tooth inner chain-ring. I dont know anything about the year it came out other than sometime in the 1980's, or what model it may be.

THanks

The crankset is a TA Pro vis 5. Here's a thread with lots of background info.

As far as replacing the inner chainring, several online vendors sell them, including Boulder Bike:

TA cyclotourist chainrings & hardware

Well that was quick and easy, thanks!

One more question while im at it. Does the diameter of the chainring matter, or are all 45 tooth chainrings the same diameter? And if I had a 45tooth could I use a 40tooth chainring of this same model?

As noted by Mister Lerner, Boulder is a great source. Good folks to deal with. Should be fine going with a 40t.

BTW: In your search, try spelling TA Specialites or Spécialités TA. Have fun with the project!

Boulder Bicycles in Colorado, or Spa Cycles in Harrogate, England. I've ordered from both. Funny, the shipping cost is about the same, but faster coming from the US, as you might imagine. If they have the right part, "Buy American!" (Franco-American?)

Ouch! Just looking at your pics makes me think "that must have hurt!"

Anyway, I wanted to suggest replacing the mounting nuts and bolts while you are doing this repair. Velo Orange sells an updated version using hex nuts and bolts but they appear to be out of stock at the moment. These really work well. Best of luck on your repair.

Nuts and bolts are still manufactured by Spécialités TA Visserie

Look over the parts from Boulder pretty well before you install. I recently bought a Stronglight 93 crankset from them, and the spider was cracked in several places. They were very apologetic, refunded my money instantly, and asked me to destroy it. If I hadn't looked at it closely, I might have had a fairly spectacular crash. If it had been given more than a once over, they never would have tried to sell it. Good guys though, no hassle at all when I spotted the damage.,,,,BD

I hope this isn't reviving a too long dead thread but I ordered a 40t chain ring from Boulder with no problems, but i have also realized as mentioned above that I need to get some new hardware as well which is proving just as difficult to find. Boulder has a set of hardware for a double but it seems pricey.
I have done some ebay searching and found hardware that says its for a Pro vis 5 but they all seem to come with 5 bolds instead of the 6 I seem to need. And I keep seeing ref. 25, what does that refer to?

Thankfully I didn't fall nor was I going very fast when it happened. I had only just started pedaling and suddenly the chain ring gave out. I guess what had happened is over the course of who knows how many months all the hardware for the chain rings worked itself lose and started falling out one by one and I didn't even know it until the chain ring snapped in half. Then I saw that all the bolts were gone.

Look at the photo on pastorbob's post further up in this thread. You'll see two groups of hardware in that photo. The group of six bolts on the left in that photo include spacers and these are the ones that hold the chainrings together. The group of five on the right that do not have spacers are the ones that hold the large TA chainring to the crankarm. I'm not near my TA stuff right now so cannot tell you if the length of the bolts is different from one group to the next but it looks like they are not different.

If your large (outer) TA ring is securely bolted to the right crankarm but your smaller (inner) ring is not securely bolted to the outer ring, the set of six bolts, nuts and spacers on the left is what you need. That is if you have a double. If you have a triple you'll need a set with six more spacers and probably longer bolts or nuts with longer sleeves that will hold three rings together with enough spacers separating them.

Ref. 25 is just the TA reference number for the bolt set:

Specialites T.A. - ref:25

These Pro vis 5 cranksets were very very desired for their super low tread or Q profile that was easy on the knees, and the incredible versatility with chainwheel sizes. I think you can build any triple you want between 26 and 68 teeth. That's an incredible range of options.

I'm curious how flexy they are and what people think of them. Boulder Bicycle got some Spécialités TA Pro vis 5 cranks in, and Velo Orange is reproducing them I think. They used to be the standard crank, back in the day, for any serious touring or tandem build. The insane thing is they are compatible with everything from 5 speed through at least 10 speed.

The cranks are pretty common, if you can find the Spécialités TA crankset attached to the Spécialités TA pedals you have something very valuable. I keep hearing they are eventually going to remanufacture those pedals. We'll see. They were beautiful.

Velo Orange sells a set of bolts for TA cranks, it was about $20 or $25 for the whole set. They also sell TA-compatible chain rings.

I have T.A. road pedals om my PX10. The grease fittings are nice and the replaceable cages were nice when you could get the replacements. I'm not as impressed with their looks as you are. Velo Orange was selling them for $150 a while back. They require an unobtainable tool to take them apart.

For years I used TA double cranks on my offroad bikes and TA triples on my touring bikes; 46-26T offroad - 50-46-30 on the tourers.



I ovalized several TA 26T chainrings on the offroad bikes running a 34T rear sprocket when I stomped on them from a dead stop on steep sections of trail that I should have walked up!

Since I ran 1/2 step gearing on my triples I found that 28T or 30T chainrings reduced the amount on chain rub on the middle ring and I only gave up 2"-4" of gearing plus they're stronger!

After the last oval 26T chainring I gave up on TA cranks for offroad. I guess that I could have messed around and found a steel ring to fit but I had a NOS Shimano Deore XT triple with 48-38-28T chainrings.

Since I was running the TA cranks on a Shimano cartridge BB, all I had to do was install the Shimano cranks, add a link or two in the chain and adjust the front derailleur... Besides, I like the Biopace chainrings with 175mm crank arms for climbing.



I'm not sure how the OP racked up that inner chain ring but the 26T rings that I ovalized were stretched at the bolt holes... I guess that I'm still an animal!

verktyg


Chas.