[justinb]

So, in an effort to bring only one bike to my parents for the holidays, I loaded up the 'cross bike and a few parts to make the conversion from single ring 42 to 50-34 compact. Alas, after I got the new crankset, chain, front shifter, and cable on, I realized I had removed the pulley that allows you to run a bottom-pull derailleur with top-tube cable routing. It's back home, hundreds of miles away.

I can adjust the derailleur using the limit screws such that I could use only the 50t for road rides and only the 34t for singletrack. Or I could remove the derailleur all together and shift by hand, but based on my experience with single ringness, I'm concerned that it's serving an essential chain-keeping function. Obviously, though, the best option would be a rigged replacement pulley that would allow me to use the shifters.

Anyone got a convenient fix I haven't thought of? I've got a hardware store at my disposal, but the LBS isn't open on Xmas eve. TIA.

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[jfmckenna]

I modified a hose clamp by drilling a hole in it to fit a female threaded adapter to accept a bolt through a pully. I can't remember exactally what the female threaded thingie was but I basically found it by rummaging through a hardware store. The only thing you want to make sure to do is to line the hose clamp with at least two layers of an old tube so you dont mar your seat tube.

It was ugly but it worked.

[nitropowered]

The boss is usually threaded M5 so you can get a bolt pretty easily. I guess look for anything round with a groove in it (or grove it yourself) and drill a hole in it so you can pass the M5 bolt through it.

I'm sure you can find something at the hardware store or at your parents

[justinb]

Thanks for all the help guys. I found an M5 bolt and a track pulley for a sliding door. It's shifting fine now.

[jfmckenna]

Ah I assumed you did not actually have a braze on pully bose but rather used the clamp on type. Should be easier for you with the braze on.

[DinoShepherd]

I always thought those pulley were kind of hokey. My current frame had one that I removed because I too was on the single ring program.

If I ever go back to a double I will run a top pull MTB front Der.

Glad you made it work.

-Z

[jfmckenna]

Dino my top pull XTR FD did not change as well on my cross rig as a road FD designed for a double YMMV. And it's next to impossible to find a top pull double FD these days.

[MIN]

Somewhat of an inelegant solution but I hear this works great for cross single ring applications. It is designed by Rolhoff for use with their internally shifting SS hub.

http://www.universalcycles.com/shopping/product_details.php?id=16800

[lordconqueror]

I modified a hose clamp by drilling a hole in it to fit a female threaded adapter to accept a bolt through a pully. I can't remember exactally what the female threaded thingie was but I basically found it by rummaging through a hardware store. The only thing you want to make sure to do is to line the hose clamp with at least two layers of an old tube so you dont mar your seat tube.

It was ugly but it worked.

do you have a picture of this? i am using my cross bike for road riding right now, and have had to take the bar end shifter i was going to use for time trialing to shift my front derailleur because the pulley setup on my bike sucks.

[jfmckenna]

do you have a picture of this? i am using my cross bike for road riding right now, and have had to take the bar end shifter i was going to use for time trialing to shift my front derailleur because the pulley setup on my bike sucks.

No I don't have a pic and I don't use that set up anymore. It was ghetto at best but it worked. If you don't have a braze on for a pully you can buy a clamp 'braze on' here: http://cyclocrossworld.stores.yahoo.net/handlebars.html it's a bit pricey but gets the job done right.