TimArchy

I've got a cross bike that I want to make a little more tourable. I'm going to switch the double to a triple and get a 11-32 rear cassette. The problem is that I'm getting a little confused about what derailleurs I need to get. Right now the bike is all Tiagra stuff, STI with the brake/shifter combo. Shimano has a triple taigra front der but the crankset I'm going to get is 46-36-26 and sheldon brown warns against using a front der with a big ring that is a lot smaller than what its designed for. I'm also not sure if the rear tiagra der can handle the 11-32 cassette with a triple up front.
anyone done this before who has ideas for me? I e-mailed Sheldon Brown but haven't gotten a response in a few days. I figure he's buisy but I thought I'd post here just to get a few more opinions.

thanks
tim

HopOnPop

Hi,
Ask your LBS if your STI can handle new chain rings. I'll bet they can't- but I am a newbie.

Revtor

I went to a 28 38 48 up front and my 105 triple couldnt hang.. I had to go LX up front instead to cope with the rings.. I used an XT rear for my 11-32..

hope this helps
~Steve

anneslam

Why not look at the new compact cranks? Nashbar sells their own version of this 110bcd for $67 right now. You can use the 50x34 or even go smaller as long as you find a ring that is 110bcd. Then you could run a 27 cog in the back and with a 34x27 that should be enough gears to get you up hills in touring.
Of course I may be way off because I tour with my road bike and my smallest gear is a 39x25 but I am coming out of competitve cycling. I use a BOB trailer and I can stand on all climbs.
I am looking at outfitting my road bike with a compact to go to lower gearing.
Its just something to consider because the most you have to change is the cranks and BB. Better then changing both derraileurs and shifters.

RainmanP

I have used both 105 and Dura Ace front ders with small chainrings. Right now I have an experimental setup using a 110/74 BCD triple crank with a 28 small ring, 44 in the middle, and a chainring guard. Properly adjusted the DA front der handles this just fine. This is a clamp on der so I was able to lower it to accomodate the smaller rings. This probably would not work with a braze on. This is all working with DA STI shifters as well.

I have a pretty conservative attitude about gearing, particularly when headed into very hilly or unknown areas. It's better to have lower gears than you think you might need than to not have them and wish you did. Think about how you ride. On flat terrain you probably only need one gear so you have a lot of others to play with. Why not use the top couple to give you some insurance?

TimArchy

thanks for all the advice. I've got a bead on a used crankset that has 50-40-28. That should be good matched with a 12-32 from what I hear. I figure I can get a tiagra triple der. up front and a wide range shimano in back. Am I correct in thinking that all indexed shimano rear derailleurs will work with all of their STI shifters? (specifically deore or XT with my tiagra shifters) I read something like that in my bike repair book but wasn't exactly sure thats what it meant.

tim

Revtor

Yeah, I have an XT rear long cage der. and my 105 sti's shift it just fine.
Anyone wanting a compact crankset, Here's a plug for the Nashbar one (now at $67!? dam I miss all the sales..) anyway, its ISIS, nice forged arms, basic and duty for touring. Get it for next season or winter while its cheap!! And of course the 74/110 sizing lets you play the chainring game till youre blue in the face..

28,38,48 11-32 Got me through Vermont with a full load! (next season Im going with a 26. . )

~Steve

TimArchy

sweet! exactly the answer I was looking for. I may even be able to do the whole conversion for under $100. More money for a nice rack and panniers.
Is there something special about ISIS? I was going to get square taper b/c I figured it'd be easier to replace a BB or crank arm at a smaller shop in the middle of nowhere that way.

tim