BYOT: Build Your Own Triple
 

I picked up two bikes today, and both were equipped with what looks like a home-built triple crank set. Anyone seen that before? Experience with it?

http://www.mijnalbum.nl/Grotefoto-AV8IATVE.jpg

http://www.mijnalbum.nl/Grotefoto-MEWJLM6W.jpg

That should work, as long as the inner ring is properly centered on the spindle. The only homebrew triples I have ever done used long stack bolts and spacers, which restricted me to the same BCD for all three rings. I was fond of a third-step variation on half-step, such as: 49-46-43/13-16-19-23-26, which gave me 14 usable ratios with an incredibly smooth ratiometric progression.

That will be self-centering in that configuration.

Nifty idea!

I've been meaning to do this for a year now, but haven't yet acquired the proper bolts to affix the little chainwheel, hoping to do a little slicker installation than the ones pictured. Also I have been way too distracted by all the cheap vintage triples I've been picking up from fellow forumites in the FS section.

I've posted this one before, but it brings a smile to my face everytime I see the old pics.

Forget a triple, build a QUAD!

My favorite as found modification. Notice the homemade pant/leg guard.


http://farm9.staticflickr.com/8036/7...bb27c671_b.jpg

http://farm9.staticflickr.com/8032/7...1ca5761d_b.jpg


http://farm9.staticflickr.com/8034/7...af799f23_b.jpg


Somewhat incredibly, I still have that crankset, minus the fourth ring, on the bike.

http://farm6.staticflickr.com/5450/9...a6403bf5_b.jpg

TB

I am impressed. The only place I had previously seen a quad was on a hand cycle. Finding a long enough crank spindle must have been a challenge.

Mountain tamer quads were available during the late '80s and early '90s for mountain bikes. Tripilizer chainrings can still be found kicking around. Still, it's kind of interesting to see the home-brewed ones and the garage engineering that made it all possible, so thanks for sharing those pics. :D

I like the minimal design of the pant guard. Must have been an engineer who made that.:)

;)http://i291.photobucket.com/albums/l...s/IMG_7874.jpg

Seeing those Suginos makes me sad. I love those cranks. Too bad those bolts are probably eating away at the spider's finish.

I have seen several Sugino's with the long stack bolts and spacer type triples. Sugino actually sold a few touring cranks in the 80's that where made this way stock.

Interesting mod, both from the same seller.

And you know you have to treat the crew to a beer when you hit the magic 100 bikes mark before the end of the year, right :P?

True -- this is why Sugino came out with the reduced BCD touring cranks. I was doing mine with the old 144mm BCD, which set a lower limit of 41T (very hard to find) on my inner ring. I later tried to do a 53-50-39 triple with some newer Campagnolo cranks, but the spider was too thick for half-step gearing. I did run 50-42-39/13-15-17-19-21-24 (half step plus overdrive?? :) ) for awhile, but I didn't like the big gaps on top.

Arguably the best way to play to triple-stack game is with a 110mm BCD, something like a 48-45-34/13-15-17-19-21-24. (Been there ... done that on the PKN-10 with a Sugino mountain crank, but since this particular spider already had 110/86 dual BCDs, I used a more conventional 86mm 34T on the inside.)

I know. And I did. In 2011. :D

I was wondering which front derailleurs can handle quads and whether the Q-factor got too outlandish for some folks' knees.

Me too, or at least the FD part!