vosyer

On my forth round of front der's trying to fix a shifting issue on a my Trek 750 project. I guess it's just part of the fun - but frustrating at times. In this case it was a 1991 750 with NOS Specialized touring Cranks (46-36-26) with 8 speed Dura Ace bar ends - started off with new generation FD and working backwords even tried a Suntour. expensive excercise - needed a front der with a totally flat cage - by process of elinination it has come down to a Pre XT Deerhead or a Shimano 600 FD # 6207 which I found online today for $32. This is my last ditch effort before changing out the cranks. I'd be interested in hearing others stories.
mw

Little Darwin

What problems are you experiencing?

However, with the information provided... With those chainrings, you are running a mountain/touring crank, so the Deore (Deerhead) would be a better guess than the 600, which would be a road derailleur.

Actually another point came to mind... Is the front shifter indexed or friction? The cable pull on Shimano front derailleurs are different between mountain and road, so if indexed, there is a difference. But then again, pre-9 speed Dura-Ace were oddball too, but I have read that concerning the rear derailleur, so I have no idea if the same sort of issues impact the front derailleur.

So basically, I don't know. If you are running friction, then I would definitely look toward the deerhead before the 600.

JunkYardBike

I've successfully used a Suntour Cyclone FD, a Suntour Mountech FD, and a Suntour XC Expert FD on a Sugino XD 46/36/26 crankset. However, these were all on 28.6 seat tubes. I assume your 750 has an oversized seat tube, which puts your FD further out. What size BB spindle are you running? You need a longer one for oversized tubes.

vosyer

Little Darwin.

My first leaning was Deerhead - but finding a nice afforable one has gotten challenging. I am hopeful the FD# 6207 will be my solution in reading the spec's is rated for 18 teeth and probably 20 is okay. There are three varieties of 600 fronts - 2 are rated for 14 teeth and on is rated for 18. It really doesn't make a difference friction or index it's the design of the front der. and beveling of of the cage especially more modern ones. My bike knowledge until more recently was campy specific - now I have to access to older Shimano and Suntour part catalogs and know who actually produced private branding labels like Specialized in the 80's. And as it turns out varieties of Shimano 600 were used on mountain and touring bikes pre XT just like Deerhead. It's driving me alittle crazy !!!

vosyer

Hey Junk,

It's not oversized - 28.6 is the right size - your solution was down on my list of solutions because I am I have become a fan of Cyclone 2's . I am using a 122.5 spindle. I glad that combination works there were mixed messages whether it would in the blogs I still need to find out if there is more than 1 variations of the Cyclone . I forgot I tried the Suntour Expert combination with no success. I have the XD2's on 2 bikes and love them. These Retro Specialized cranks were made by Sugino - just a little different profile.

JunkYardBike

122.5 seems long. Is that required to clear the chainstays? I'm running a 107mm on an old Raleigh frame, with a Suntour XC Expert. It shifts beautifully. The XC Expert is much more competent shifting up from the granny ring than the Cyclone was.

By the way, I should have clarified: I was using the Cyclone MkII. It was an NOS item I purchased on ebay, and the box was marked 'Touring' for what it's worth. The cage may be slightly longer than the other MkII?

You never mentioned what trouble you're having...

vosyer

According to everything I had read about this bike it orginally came with a 122.5 and my local LBS tells me it's the right size. I bought a Cyclone NOS MkII rear off ebay sight unseen as well based upon a Specialized Expedition bike out of California that is regularly shown on the BF. You are right I think there are several versions of the MKII because I pretty sure the one I recieved is for a double.
Also several early high end mountain bikes came MKII equiped so I made a false assumption they were all for triples. Now it is just a new addition to my part box!!

JunkYardBike

What problem are you having?!!??!!?!??

If the crank is too far out, that may be causing some problems. FWIW, my Cyclone MkII 'Touring' has a narrow cage and looks like your average double FD.

John E

Since I tend to run smallish outer chainrings (50, 49, 47, even 45) chainrings on my road bikes, I have to be aware of the cage shape. My biggest mismatch is the UO-8, which has a Shimano Titlist front derailleur and 45-42 half-step chainrings. The cage looks a bit odd, sticking way out behind the chainrings, but the combination works quite well, as long as I don't mind trimming the cage position whenever I shift by more than one cog in back.

vosyer

Sorry Junk for lack of clarification,

All of these combination are not allowing for shifting to the lowest chainring without a rubbing the cranks. Most or more modern front der. are beveled or indented to assist in the shifting. The problem as diagnosised by my LBS has something to with the crank design which is some what retro Sugino and more modern Shimano. I have been running into this fairly often recently when I mix and match parts - even those of similar era's - for example a 1985 Miyata Valley Runner and some beautiful AT cranks - frame was not not indented enough for cranks - conclusion after 3 bottom brackets. Or another recent conversion of a Ultegra triple on a 69 Paramount - and the combination of front der a 8-9 Campy Racing Triple which works great. When mixing parts and era of parts "brands" it's alot of trial and error - and all those pesky hard to find and at times expensive parts.