since6

While awaiting the arrival of these First Generation Dura Ace triple cranks I wondered if anyone knows/has experience with the spindle length needed for them?

Or, is this a wait until they arrive and then measure what is needed?

If the latter what should I measure in order to get the right sized spindle?

My thanks for your advice.

Take Care.

T-Mar

That would appear to be a nicely executed owner modification. First generation Dura-Ace cranks were produced from 1972 to 1980. I've got all but two of the catalogues and I've never seen a triple listed. The standard double spindle was 112mm but it was asymmetrical with the drive side being 3mm longer. My starting point for a modern, symmetrical, sealed cartidge BB would probably be 122mm. You might be able to get by with 117mm, if the drive side chainstay is heavily crimped. In the end, there will probably be some trial and error.

Kuromori

My rules of thumb for triple to double or double to triple is 10mm if you're working with 43.5/45 chainlines. If you can get a cartridge with the fixed cup on the drive side, you can easily put a BB shim in there to move the spindle over.

since6

Thanks T-Mar and Kuromori.

I had wondered about the triple but thought as there was a lot of imitation of Colnago by Shimano during this time period, and I've seen rare Record triple cranks that in design are very similar to this, that perhaps such existed. But missing from catalogs.

Should I be concerned about risk of failure due to missing crank arm material due to drilling of crank arm?

Though I seem to recall such was the same for the similar Campagmolo Record triples.

Your thoughts are welcome.

I'll post detailed pictures disassembled after it arrives.

since6

Here are pictures of the Campagnolo triple crankset I referenced to in my post above which is of similar design, time period (?) to the Shimano Dura Ace triple crank set I have coming in the mail. By the way this set is on sale at Ebay for any looking for same.

It would seem that given the similarity of design, though Campagnolo only has a drill hole through the outside of the crank arm, while the Shimano Dura Ace arm I have coming has the bolt hole and what appears to have been a machined recess for the bolt to set down into (will only really know after it arrives), that durability should be comparable?

Anyone else with anything similar to the above Shimano Dura Ace triple? What has your experience been?

Again my thanks.

JohnDThompson 

That Campagnolo triple, like your Dura-Ace, is not a factory drilled triple, but an end-user modification (albeit nicely done in each case).

The spider flutes on the factory drilled Campagnolo triples ended short of the mounting holes, while on the end-user modified triples, the mounting holes land in the flutes. Here is a picture of a factory-drilled Campagnolo triple crank:



I'm not aware that the 1st generation Dura-Ace crank was ever offered as a factory-drilled triple.

since6

Learning a lot today, thanks all.

Do any members have end user modified triple cranks similar to either Dura Ace or Record cranks shown in my pictures

How have they held up?

Any issues in use?

top506

I've been happy to use 'tripleizer' middle rings and call it good.

Top

merziac

Never seen or heard of any "homebrew" versions failing, seen many, many Campy's done, some poorly and still no failures, can't imagine the Shimano's would be any different, full speed ahead IMO.

Merz drilled plenty of later Shimano's for triples and probably many others, don't think he gave it a second thought given he did a lot of them.

Bob Freeman still drills many for this, not sure which ones he will or won't use.

I have 2 done by Merz, lots of miles on both. The MTB also has the pedal adapters he made, no flats so not coming out without a fight. He seemed to be fond of the AX/DX crank for this mod as he was in on the ground floor when Shimano had him build a show bike for it when it came out.

since6

Thanks Merziac and Top 506, you echo what my builder friend said that these when done right have proven to be reliable and he had not heard of one failing. He too mentioned Bob Freeman's work.

I want to use this set of cranks and chain rings because I am trying to complete a first generation Dura Ace build on a bike and with this crank set and set of chain rings I will be down to looking for at a set of Dura Ace brakes/brake levers.

Biggest issue with the first generation Dura Ace brakes on my other vintage bikes is the use of a metal brake adjustment wheel, as opposed to the rubber O-ring wheel, my vintage bikes with the metal brake adjustment wheel all have the right side top tube missing paint from being whacked by this metal part. There is one Superbe part, front derailleur, so I could look at the Superbe Pro hidden spring brakes, I have a set on my Erba and they are really nice, but then would break up the component build.

merziac

You're welcome, I'm sure Bob would be happy to weigh in, great guy and resource for anything.

I would try to attach a small band of adhesive heat shrink tubing to the adjuster to help protect the frame or a small clear bumper like for cabinets, maybe a small clear cable rub patch double thick, maybe.

since6

Well the last part fell in place. Picked these up to finish the Dura Ace build, but with a couple twists to original parts left.

Frame is at the paint shop getting one rust spot dealt with and touching up the lug insert colors, then all will be left as is and clear coated. I liked the patina on these brakes/levers as they will fit in with all the existing parts on this 1976-77 bike build.

Will post when all is done.

Thanks all. The spindle hunt begins once the triple crank arrives.