Classic & Vintage - 10-speed shifting on old cranksets

I've got a hankering for brifters on my Vitus 979, but I'd like to keep the Dura-Ace 7402 crankset on there for aesthetic reasons. Will the spacing on the crankset play nice with 105-5600 shifters, or am I looking at a 1x10 build with a nonfunctional front shifter? I know the absence of pins and ramps on the chainrings will make the shifting a bit rough, but I'd like to at least have the option of two chainrings and having one nonfunctional shifter rubs the OCD in me the wrong way. Any help or advice appreciated!

From Sheldon (http://sheldonbrown.com/speeds.html): I've added bold for emphasis. According to him, you should be fine. I've not done it myself, so can't comment from experience.

Old Chainrings, New Chains

There is a lot of confusion about the compatibility of narrow 9- and 10-speed chains with older cranksets. Shimano says you should replace the inner chainring(s) with specially designated 9- or 10-speed ones, but then they're all too eager to sell you stuff, whether you need it or not.These chainrings have the teeth slightly farther to the right than the older chainrings to work a little better with the narrower chains. There is no difference whatever in the crank spiders.The manufacturers also are concerned about clueless users. The worst-case scenario is that you will be riding along with the bike in its highest gear (large front, small rear) and then for some bizarre reason shift down in front before downshifting in the back. (There is no shift pattern in which it is reasonable to shift in this sequence.) [Not with a 9- or 10-speed cassette, to be sure -- John Allen] If you do shift this way, there's a small chance that the chain might "skate" over the edges of the teeth for maybe half a turn.In practice this "problem" almost never materializes. Many, many cyclists are using 9- and 10-speed chains with older cranksets and having no problems whatever.

The new 10sp brifters will pull the correct cable travel for use with any of the post-1996 Shimano front double derailers, but avoid any Dura-Ace front derailer from before the nine-speed era (it will move too far for the modern shifter's cable travel (which would then require unwanted, excess cable slack in the small-ring position).

The chainring spacing isn't unique to your Dura Ace crank, but using the much narrower chain will require that the small chainring be substituted for one that is intended for the narrower chain.
The small ring (as quoted above) is what determines chainring spacing on all modern Shimano cranksets going back 25+ years.
I would think that even a nine-speed inner chainring will be fine on your crank with the narrower 10sp chain, if you can find one laying around.

Brifters? :rolleyes: Take yourself over to the road forum and leave your C&V membership card by the door on the way out. :roflmao2:

I'm running Arabesque cranks on both 7700 (9) & 6600 (10) with no problems. I have 9 speed chainrings on both though. As stated the spider thickness is the same on all Shimano cranks. The difference is in the small chainring offset and thickness of both inner and outer. I find I like 39-53 better than 42-52.

I do get away with using 9sp chain on a surprising number of old cranksets, even on 1960's Varsities!

But, I recall building up a new Cannondale frame with 9-speed gear, using a pair of Shimano 600 chainrings from the mid-80's 6sp era.
After just a few downshifts in front, the narrower chain got stuck between the rings and was pulled past the chainstay, gouging it pretty severely.

Also, some chainrings will allow the sideplates along the left side of the chain to skate atop the tips of the inner ring, eventually milling little notches which increase the frequency of not only the skating, but of actually getting the chain wedged between the rings and bending them.

I have resorted to bending all of the small chainring's teeth toward the big ring using an adjustable wrench, but the half-millimeter adjustment to the tips of the teeth requires an acquired feel to get consistent results. Never broke a tooth this way, and have been able to get Stronglight 93 chainrings to play nice with narrowr 8 and 9-speed chains.

Thanks for the info! I have a full set of 105 that I'll be swapping over sans crankset, so the crankset is the only bit I'm concerned about. I feel pretty confident that I can find 9 or 10-speed chainrings at the co-op if I really need to, but it sounds like it won't hurt to try it out with the original chainrings first.

Oh man, absolutely! Running 105/ultegra group with a 10 speed chain.. and using 6 speed Biopace rings! Works really well, the chain rarely gets stuck between the chainrings, and when it does, I can get it out with the FD. Go for it!

So, this should work w/ Sugino chainrings as well? I want to run my Trek 710 w a wide range 10spd rear cluster and keep the Mighty Tour double I'm currently running.

So, this should work w/ Sugino chainrings as well? I want to run my Trek 710 w a wide range 10spd rear cluster and keep the Mighty Tour double I'm currently running.

You won't know until you try, but getting the chain stuck between the rings often does damage, and the only 10sp inner rings you will find for a 110mm double would be compact 34 and 36t.

Ill swing by the shop and see if there are any 10spd 34t inner rings. This would be great if it works

wait...you're gonna redish a 9/10 speed rear wheel for the 126mm Vitus frame? For whatever it may be worth, I lucked into a first generation STI DA front shifter (mated to a slightly later left Ultegra STI for the front) on my Vitus & I have a nice 14 speed STI setup that's almost C&V period correct enough that I usually don't get asked to leave the room when I speak up!....but if you're running a 130mm hub in the Vitus...well......I dunno...

I use a 10 Speed chain on a first gen Chorus crank (7speed chainrings) with no problems. I would try it out with your current chain rings.

....but if you're running a 130mm hub in the Vitus...well......I dunno...I have the same reservations. This is one frame you do not want to bend, pull or put on tension. There is a way to run a 130 hub: cut the axle for length and redish the wheel. Use the hub with a spacer kit and a BMX sprocket as as to run as a single speed. And you may have to play with the axle spacers.

There are one or two member who have 979's with modern transmisions, but I don't know (or recall) what they did.