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triple-to-double conversion questions (sorry, kinda long)(7 posts)

triple-to-double conversion questions (sorry, kinda long)TomS
Aug 8, 2002 7:51 AM
I've been reading about various ways to convert my triple to a double - either just ditch the smallest ring and adjust the limit screws, or get a new bottom bracket/double crankset and possibly deraillers.

The main motivation for this is cleaner front shifting, I've started doing faster rides and some group rides and the last couple of times out I've overshifted coming into the middle ring. This doesn't happen on easier more relaxed rides so I think it's an "under pressure" thing.

My question is: if I take the easy route, and just ditch the smaller ring, will I get the cleaner shifting? Or would I have to get a "real" double setup to get that? (I currently have a 2000 campy daytona group, 9sp with a triple)

Also with the triple I have 4 "clicks": small ring, 2 for the middle ring, and big ring. If I adjust the limit screws on the front derailler will I have just 2 clicks (big and small ring) or will I still need two trim positions for the small ring, since I'm not changing the chainline at all? I guess that would be the advantage of getting a double crankset and shorter bottom bracket...?

I've also been toying with the idea of getting a separate "fast" bike next year... and leave the triple on my current bike (a univega modo volare, which is definitely a nice comfortable bike but a little heavy). Or I could do the double upgrade now, then later get a light/stiff frame if I still feel like I want it, and move the double parts to that, and re-install the triple parts on my univega.... But that's a whole different discussion - and if I do decide to upgrade now, there's the whole "should I go 10-speed while I'm at it?" question. ack!
The easy way...cory
Aug 8, 2002 8:04 AM
...would be to turn in the low-gear limit screw until you can't get the small ring. That might clean up your shifting. You could remove the small ring if you want, but what's it going to save? 30 grams? Dunno about the indexing, though--IMO, indexing a double crank makes no sense anyway. It's like indexing a light switch.
You could also find (maybe) a slightly shorter BB spindle to move the right crank in and reduce the Q factory a little, but only you can say if it's worth it. Wouldn't be to me.
Others will disagree, but I wouldn't do anything, especially since you're thinking of getting a new bike. There's a place for triples in the world. Some people aren't convinced 10 speeds is an upgrade, either (personally, I thought seven was plenty). There's something to be said for having a go-fast bike and a bike-path, picnic, ride-to-the-lake bike. Spend $500 on the Modo Volare, and you'll still have an expensive Modo Volare.
That's Q FACTOR, not FACTORY. Jeez! (nm)cory
Aug 8, 2002 8:06 AM
my wife already thinks I have too many bikes though!TomS
Aug 8, 2002 9:30 AM
I have an old rockhopper that I use for commuting, errands, etc. And a new stumpjumper as my good mtn bike, the modo volare as my road bike, an old beat-up 12 speed I keep meaning to get "fixed", and an old bmx bike that I keep around for sentimental reasons... I don't know if I can swing having two road bikes, or if I'm ready to sell the modo volare for a new bike just yet :-)

Hmmmm lots to think about. I'll definitely play with adjusting the limit screws. Thanks for the input!
re: triple-to-double conversion questions (sorry, kinda long)Chen2
Aug 8, 2002 8:23 AM
If you only change the limit screws you will still have a detent (click) between the middle ring and big ring. You may be able to eliminate the detent by adjusting your shift cable, but I've never done that so can't say for sure. With all of the Shimano 9-speed shifters except Dura-Ace, the same shifters are used for doubles and triples. To see a big improvement from what you've got you would need to replace the shifters with D-A, and replace the crank-set, bottom bracket, and derailleurs. From what I've seen the later STI shifters have some trimming available by sliding the levers in, up to about 5mm. This is a separate function distinct from the detents. My wife's '98 Ultegra does not have that capability, my 98 D-A does. I upgraded a friends bike to 2002 105 and it has the trimming capability. But I think a double set up with a perfect chain line should not need trimming.
Depending on your situation it would be more cost effective to leave this bike as is and buy a new complete bike with your choice of components.
~Al
So I'd have to upgrade from campy to shimano? :-)TomS
Aug 8, 2002 9:25 AM
Just kidding... Since I'm running campy daytona now, if I did the parts upgrades I'd probably go to chorus. I priced the parts and it'd be about $400 since I wouldn't need new brakes, cassette, etc. Probably not worth it; if it was any cheaper I might go for it just to play around, but that's really pushing my "just play around" budget.

thanks!
Ooops. I need to read more closely. (nm)Chen2
Aug 8, 2002 9:57 AM