jan nikolajsen 

Thanks ultraman, some good info there!

Okay, finished up the job and rode the bike around the neighborhood a bit. Seems smooth enough. Also lost about 2 pounds in the process mostly in the area of wheels. The current ones are silver Record 10's/Open Pro with DT Comp's instead of Weinmann concaves on some fine old Normandy hubs.

fender1

Nice Bike Jane! Electra makes a 50.4 bcd crank (FSA actually) that has clearance for modern drive trains. I am using it w/ a Velo Orange 46th ring & 30 inner ring, 10 speed 11/36 rear and Campy NR fd. The arms are curved slightly and allow for easy clearance between the crank arm and FD. The bike I am riding is 135mm rear.

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jan nikolajsen 

Alright, just to round things up with an actual experience: Today I did a 65 mile test on this weirdo drivetrain (10 sp Campy with ancient TA cyclotouriste crank), a ride that included more than 5500' of ups and downs - so lots of shifting. And not once were the chain jammed between rings or other crap. In fact it was unusually quiet and smooth. Eerily so.

In other words, for me and my set-up, using a narrow chain and wide rings with the wrong spacing is a-okay.

buldogge

Nice pic Jan...

Was the ride mostly gravel? What tires??

southpawboston

Good to hear those results, Jan.

jan nikolajsen 

Actually just looks like gravel. All paved, but snow covered up the steepest shady parts. Folding Tour Guards, 28mm in 700.

rootboy 

Dang Jan. You're making me homesick. Ah, the skies of Utah.

jan nikolajsen 

How's this: came across a flock of bighorn sheep along the river:

ColonelJLloyd 

Your pics always rule, Jan. Thanks for sharing them and your chainring/chain results.

cosmonhat

Hi Jan. Thanks for sharing your success story. Any updates on the performance after that first longer ride?

I'm thinking about doing the same with a triple Stronglight 49D crankset and 10 speed rear cluster. What bottom bracket did you use, e.g. spindle length, iso or jis, etc?

Thanks

VeloBrox

Dude, that cage is looooong. And would you cross the chain that badly on the road?

-holiday76

Jan bought a carbon bike and left the forum shortly thereafter.

thirdgenbird

Stellar build!!!

i had issues shifting under power when I was running c record cranks on a 10spd drivetrain. Switching to a 10spd outer ring (no other changes) made it the best shifting bike I've ridden. Glad it worked for you, that setup looks perfect.

edit: just noted post age...

Ex Pres 

I was hoping Velobase had an answer on the BB spindle length, but it doesn't. The BB I have for my double 49d (not yet installed) is a 120mm length, old Stronglight, which is reputedly ISO. So the triple will take a longer spindle than that. IIRC it's a 124mm, but it's whatever out there for Stronglight that's longer.

JohnDThompson 

Stronglight 125 spindle is what I would use.

dddd

I've tried different chains on so many different-age cranksets, and can never be certain if a nine-speed, or even an 8-speed chain will not allow the chain to "skate" to the inside of the smaller ring after a downshift.

Older Stronglight 93's have been problematic in many cases even with 8-speed chain, while the Schwinn Varsity and SuperSport steel chainrings always have worked well with 9-speed chain (from the box of C9 chains I was given some years ago).
Many Stronglight-patterned SR-Apex cranks have the same or wider chainring spacing, such that it is even possible for the chain to skate atop a half-step chainring's teeth using a traditional Sedis bushing chain!

The inside width of chains varies very little, but some of the early Japanese narrow chains (intended for 7 or U6 freewheels) can actually pinch/grab thicker chainring teeth enough to require a light tug to remove, and today's 10 and 11-speed chains are also slightly narrower inside than most of the earlier chains.

I looked into getting a custom-sized, piloted counter-bore spot-face cutter made, for taking thickness off of the side of chainring tabs, but instead have successfully narrowed the chainring spacing in many, many cases by simply removing the smaller ring and bending each tooth the paltry half-millimeter using an adjustable wrench.
Lastly, the lateral position of the tips of a chainring's teeth can be altered slightly by simply holding a tilted flat file against the rotating chainring's teeth.
This can be awkward in terms of keeping the crank turning smoothly with the file possibly snagging on chainring features or one's arm getting bumped by the turning cranks. I choose a longer file for this job, which generally addresses both issues if one pays attention to the goings-ons.

Road Fan

I've been experimenting with the best gearing setup for my Terraferma for a few months now. It has a White Speedy rear hub, 130 mm, with a Shimano-splined freewheel. I've tried it with both 9s and 10s rear ends, and they both work fine with a Deore or a long-cage Ultegra 10 rear mech. In the front I first tried a 46-30 front TA double (ancient chainrings with good teeth) with a 10-speed chain. I found it very hard to change the front without over shifting into the chainring/crankarm gap. The biggest instant problem was the chain jamming on the chainring bolts and being a pain to pull out and re-align. Here the root cause was a huge overshift being needed in the front to force the non-pinned CR to grab the chain and lift it into place. The cage was shoved outboard so far it pushed the chain too far. The finesse fix is to manually overshift the front mech then pull the cage back in once it starts to grab the chainring. This is difficult at a high cadence.

Part of this is made worse by the long free-length between the small CR and the large one, and the absence of pins on the old chainrings. Large chainwheel spacings could have as well made the problem worse.

My solution was to go to a triple 46/36/26 with only 10 teeth between rings. This has improved front shifting considerably, though I think I'm going to look into what chainrings might have pinning and 10-speed spacing, and fit the 50.4 format. It might be the Elektras. I could also go to 46/38/30, which should shift even a little better.

I'm also finding that downtube friction shifting of a 10-speed rear end is very fiddly. Every shift needs feathering and it's much more sensitive than a 7-speed. I think some Ultra-Shift Ergopowers are in the future for this bike. But they are lower priority than the GB fenders and the front rack.

fender1

^^ I use the Electra crank w/ VO 50.4, 46/30 rings. They are made to be used w/ narrow chains (9 & 10 speed). They work great. I use an indexed bar end to shift a 10 speed 11-34 rear cassette. It all works great.

looks like this:

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dddd

In The cases where a modern, narrow chain won't readily grab the teeth of the next-larger chainring during upshift, I've found that a slight modification to the bigger ring can fix that up, such that a large amount of over-shift is no longer required.

By bending each 3rd or 5th tooth toward the left of the bike, the bent teeth will reach out enough to grab the chain during upshifts without compromising running smoothness. A half-millimeter is all that it takes!

Further, and this is where the odd number (3 or 5) comes in, the often-sluggish downshift from the middle ring of a triple will also be improved by this modification, enhancing the inner and outer side plate's specific functions (relative to shifting).
I usually concentrate on the (2 out of 4) quadrants of the chainring where the teeth are closest to the two crankarms, as this is where the chain tension will be lower during the pedaling cycle, thus aiding the chances of a successful shift.

I should also note that cyclic flex of the bottom bracket, as well as any out-of-plane warpage of the chainring, will greatly affect what arc portion of the chainring's teeth makes a shift more likely to occur. Often this is the biggest factor, such that shifts will be seen to only occur with the crank in a certain range of rotational position.