Hendo252 

Greetings. I've checked the archives and read a jillion posts on front index shifting issues, but I haven't found the answer to my question, so here goes.

My bike is a 1983 Trek 620. It was originally set up as a triple crank with 6-speed rear (3x6).

I upgraded the back to Shimano 7-speed SIS some years ago, using downtube shifters.

The front is all original -- Sugino AT triple crank, Suntour Cyclone II FD controlled with friction-mode downtube shifter. BB is oritinal Sugino w/asymmetric 3U spindle. Chainline is 45mm.

Now I'd like to move the shifters up to the bars. Not too many 7-speed SIS brake/shifters are available, but I have a set of RSX brifters from eBay and they work the back fine -- I like having the shifters up on the bars and I'd like to migrate the front up there too.

But it appears that the RSX index setup isn't compatible with my crank/FD setup; it doesn't move the front derailler enough to shift across all three front chainwheels.

I expected that, and I can leave the front on the downtube friction shifter for the time being, but I'd like to upgrade it to SIS.

Any thoughts about whether that will take both a new crank (with narrower chainwheel spacing) or just a different front derailler that will give more chain movement for the available cable pull from the RSX levers? I hope I 'm expressing that in a way that is understandable.

If changing the FD will do it, I'll definitely give it a go.

If I have to go with a new crank, anybody have any suggestions for a triple that is compatible with my 7-speed chain and RSX shifters?

I'm not willing to upgrade the back to 9/10-speed at the moment so I'm stuck with the 7-speed setup for the time being.

Any thoughts are appreciated!

-Tom in SoCal

top506

Pretty sure that your RSX shifters won't pull enough cable for any triple crank, regardless of the FD.
Rumor has it that Shimano is re-introducing a 7-speed brifter set that will be triple compatible.

https://www.bikeradar.com/news/articl...rst-look-33204

Top

bradtx

top506, There was a RSX triple group.

Tom, Not much help, but I was able to have a RSX double shifter work with a Suntour X1 FD with a RSX double crankset on my daughter's Volpe. I had to use the B position cable anchor. Good luck.

Brad

HillRider

+1 My son's Trek 1220 came with it and an RSX triple crank and fd. A Shimano 7 or 8-speed triple fd might work if your brtiters are the triple version. If you have the double brifters probably nothining will work.

Possibilities to improve the front shifter location are to replace the dt shifter with a bar end or use a Kelly Take Off with your dt shifter.

Puget Pounder

Does your RSX shifter have 2 clicks? If so, it is a triple and WILL work if you get a shimano triple front derailleur.

These things don't have trim, so they take a little more precision to set up. If the shifting is not to your liking, then getting chainrings that are ramped and pinned would definitely help. However, it'd be cheaper to get new cranks at that point.

Hendo252 

Thanks everyone -- I should have been clear that the shifters I have ARE indeed triple shifters -- two clicks, three positions.

I gave it a try last night, and the FD just doesn't move enough. I'll give a new FD a try and see if that helps. I'm hoping to avoid a new crank etc if I can avoid it.

The FD-3403 appears to be compatible with 6/7/8-speed chain and is reasonably priced; so will probably be my first choice. Any body have any experience with this FD that they can share?
https://www.universalcycles.com/shopp...9&category=529

Thanks again for everyone's thoughts!

shelbyfv

I think your crank should work with a newer triple FD. I have used the Sora double and was surprised at how well it worked. Avoid the newer 105 and up that have deep, sculpted inner plates.