Otter2

I received an 86 Ironman centurion from a neighbor and am tearing it down to clean up, modernize a bit and put back together. I already have all of these parts on hand but not sure if it will all fit together.

Shifters - 2x7 micronew (micro shift knockoff) brifters to replace the original down tube shifters. I am not a fan of DT shifters.
Front Derailleur - original Shimano 600 fd-6207.
Front Sprockets - 53 and 38 tooth, not original, in good condition.
Rear Sprockets - 7 speed 13-28 tooth freewheel, original was a 6 speed but the 7 speed has been on it for awhile. In decent condition but haven’t been able to budge it to get it off.
Chain - 8 speed chain
Rear Derailleur - Dura Ace Rd-7800 10 speed, looks like a short cage.

For the rear derailleur the pull ratio is the same as 7 speed, and I’ve seen from other posts the chain should fit fine. I’m concerned the limiting screws may not have enough range and I am just outside the Shimano provided specs by a tooth (smallest 11, largest 27, max capacity 29, max 14 tooth front sprocket diff).

I might be able to rebuild the rough original rough rd-6208 but the rd-7800 is just sitting in my parts bin except I have to find a replacement jockey wheel. I would also be willing to spend about $40 on a better fitting new/used rear derailleur.

10 speed rear derailleur on 7 speed freewheel

icemilkcoffee 

The FD62** won't work with the brifters though. You'll need FD6401 and newer

jetboy 

you will be fine. just adjust the position in your drop outs further to the rear- this gives you a bit more distance from the RD to the freewheel and take care of the shimano numbers- which are conservative to the worst case scenario. you have room to negotiate.

seypat

The FD will work both with Microshift 2X or or 3X brifters. The FD-6207 is the go to FD when it comes to shimano FDs. Heck, most any FD will work as long as it's a bottom pull. Doesn't matter if it's indexed or not. The original RD will take a 28t also. If you go to the IM thread, somewhere in that thread during the pandimic year I go over in detail(with pics) the gear options/limits of an IM. If you need a cheap RD, pick up a Deore from that era off the Bay. I've got one bike with a 52/42/30(9/10 speed chainrings), Microshift R9 3X, Suntour X-1 FD(7 speed), Deore RD and a 9 speed cassette.

Classtime 

6200 RD get worn and loose and I don't think you can rebuild it for dependable indexed shifting. The 7800 is good.
The '86 IM is the best year.

jetboy 

https://www.bikeforums.net/classic-v...aint-jobs.html

post to this thread and you will get all you need to know. the beauty is that I have never met an IM fan who was not up for helping a brother or sister.

Otter2

Thanks for the responses!

Great to hear about that the rear derailleur should work fine after replacing a jockey wheel, but I’ll take a look at at seypat’s post to get some more info.

For the front derailleur, I picked this project back up after several months and after seeing the comments I remember I was searching for a new FD because of some incompatibility issues so I’ll take a deeper look.

I thought the IM thread was more for finished bikes but if I have any other issues I’ll try posting there. I feel like I need to actually ride it first before joining the IM cult.

markwesti

Otter2 , did you check your PM's ?