[ibike4fun]

I currently have a Shimano M700 deer head derailleur and need to install a 34t cog. The rear derailleur is to short and binds up on the gear. Someone told me to buy a derailleur with jumbo gears. Why? Any recommendations?

My bike is 1986 Ritchey Ascent.
Thanks

 

[filegiant]

I currently have a Shimano M700 deer head derailleur and need to install a 34t cog. The rear derailleur is to short and binds up on the gear. Someone told me to buy a derailleur with jumbo gears. Why? Any recommendations?

My bike is 1986 Ritchey Ascent.
Thanks

One option if you're trying to keep the bike period specific would be to find an old '85 to '86Suntour LePree triple-pulley rear derailleur. These were made to work with up to 34 tooth rear cogs and 42 teeth worth of chain wrap. They look cool too.

Here's an eBay link showing the rear cage:http://cgi.ebay.com/NOS-Vintage-3-P...QQitemZ6624515455QQcategoryZ420QQcmdZViewItem

I think what the person you talked to was referring to was Shimano's inexpensive derailleurs for use with the "Mega-Range" cassette, which had a huge 34 tooth "bail-out" gear. These derailleurs do have huge red pulleys, but I don't know that this would fix your situation.

Have you tried installing a few more links in the chain?