BurittoGrande

I would like to use an older Dura Ace 7900 crankset. Can you buy a compact gearing 50/34 in silver that
would fit? I’ve looked... no luck.

ryansu

What model of bike? Are you asking if you can find a vintage compact crankset or a modern one that will work with your bike? I do not believe that Shimano made a 50/34 crankset BITD and the BCD for their vintage cranks is such that most doubles would only take a 38t ring at best, Some French cranks had a BCD that would allow for smaller rings like certain TA and Stronglight variants, and you can get a vintage inspired Velo Orange crank in 46.30 that will tame most hills.

sdn40

Deore ?

TXsailor

I think any 110 BDC crankset will work someone correct me if I am wrong. My favorite is a triple with 30 39 52. I can climb anything around here and fly down the other side.

Lascauxcaveman 

I don't see how DA 7900 is "older." From a quick google, that is 10-speed stuff with a 130BCD, so you're not going to get a 34T ring on that.

rccardr 

If I recall correctly, 7900 was all 130 BCD, so no compact size rings will fit. Slightly later 7950, however, was available as a compact 50/34.

JohnDThompson 

To mount a 34T ring, you'll want a crank with a 110mm or smaller bolt circle. There are several vintage cranks that would meet that requirement, but not Dura-Ace. Besides the TA and Stronglight options mentioned above, there's the Sugino "Mighty Tour" (110mm BCD), and Sakae Ringyo made a couple 86mm BCD models.

You'd probably find it easier to source 110mm BCD rings than 86mm BCD rings, though.

zukahn1 

For this I would likely go with the Shimano 6206 crankset which could be run as double or triple and was often paired with the DA groupo for compact or triple gearing. Nice looking crank set that just says Shimano that basically matches 80's and 90's DA stuff that allows for nearly unlimited gearing options with readily available chain rings.

jackbombay

That is the cats pajamas right there, you can keep tight spacing in the back but still have HUGE range.




I need to get a tripel on my road bike!

TXsailor

That's what I am putting on my 89 Ironman. The Exage triple on my 88 will get replaced with a DuraAce 7800 for flatter rides and the low mileage chain rings off the Exage will go on the 6206. I'll post some pictures when they are all back together.

BurittoGrande

I am looking to put it on an old Holdsworth Steel frame (1979-1980) that I am restoring. I have some Shimano 600 components to use (or not).

John E

Yes, just search for a crankset with a 110mm BCD spider. Assuming the spider clears the frame, you could even go with a triple spider with a 110mm outer BCD -- just don't populate the granny bolt circle with a third ring.

I put a Sugino 48-45-34 triple on the PKN-10 when I owned it. (Perfect half step plus granny with a 13-15-17-19-21-24 freewheel.) Although I used a small-BCD inner ring, I could have used spacers and long stack bolts and mounted a 110mm 34T inner ring, instead.

due ruote 

SR made 118 bcd cranksets that will at least go to 36. It’s an obsolete size but they are still around, and sometimes for bargain prices.

Here’s a useful chart:

https://www.sheldonbrown.com/cribsheet-bcd.html

Ex Pres 

I like that just 10 short years ago, people would call an old bike a 10 speed, which meant a 2*5 drivetrain.
Now fast forward those 10 years to today, and you refer to an "old" bike as a 10 speed = a 10 speed rear cog [and horrors, not di2, either]

I am glad to find out the subject bike is c'79-80.

CliffordK

For the Dura Ace and Ultegra of that era, you can look at "Triplizers".

Shimano actually sold their form of triplizer on the 7703, 6603, 6703, cranksets, etc. Essentially they ground off the shelf where the inner ring sits, and added their triplizer rings.

While the 7703/6603 rings are hard to come by, the 6703 rings are still generally available.

Of course, it all depends on what your shifters and derailleurs will support.

Other brands make the triplizers not requiring modification of the cranks.

CliffordK

Oh, another point. On the used market, one can often find full cranksets with rings and bolts for about the same price as new replacement rings.

So, search for what you actually want.

natterberry 

I run that on my TX304. Feels nice running around the city.

SpeedofLite 

This. The 7950 crankset (50/34; 110 BCD) is a perfect match for DA 7900 derailer if that's what you are using.
But I don't recall this group having a silver finish option, only silver and black.
Good luck with your build.

FlMTNdude

I swapped my 110 BCD 42 tooth ring for a new 34 a few years ago to make a 48/34 combination. Bought it off the old Niagara or Bike Parts, not sure which. I haven’t looked, but VeloOrange may have some as well.

nomadmax 

I guess it comes down to perspective. Dura-Ace 7900 was introduced in June of 2008, that makes it 11 years old. In the world of Shimano, I'd call that "older" too. That said, I understand what you're saying.