zandoval 

OK - Still messing with my Campagnolo Rally Long Cage derailleur. I mounted it on my PR-10 that had a simplex mount. I did that by filing the Simplex mounts width down to match the dropout width and then just threaded it to mount the Campy derailleur. I have been having problems with getting into my largest 34T cog and keeping it there. In close observation I noted that the derailleur pulley was so close to the 34T cog it was often skipping over its teeth and then dropping the chain. My possible solution is to try a derailleur hanger extender. I did not anticipate having problems with mounting the vintage Rally to the hanger extender and have found the retainers and bolt will need me to do a little filling and fitting to get the derailleur mounted on the extender.

I would like to know a little more information on how this derailleur normally mounts before I start modifying the hanger extender. The first picture shows the derailleur mounted to the simplex hanger. There is a metal tab at the front of the retainer bolt that keeps the derailleur in place. Let me know if more pictures are needed. I am pleasantly confused with this little bugger. I am sure there is something I am missing...

Andrew R Stewart 

While for it's time and the company that made it, this der was considered a pretty cool item. Excepting the weak upper knuckle casting which would easily crack. Version 2 (the image looks to show the V1) had some reinforcement added but still was sub standard so to speak. The lack of a B pivot spring adjustment meant that it was ether the axle's location within the drop out slot (and these ders were made when horizontal slots were the norm) or the chain length that determined how large a cog could be used. This was a common trial and find out process that shops used to do often with the various ders back then.

My experience with the hanger extenders (like the Worlf Tooth) is that what they offer for large cog capacity they take away with sluggish shifting on the middle and smaller cogs, due to the now greater amount of open chain between the cogs undersides and the guide pulley.

back in the day I ran the Rally (still have it on my shelf) , SunTour's VGTs, Shimano's Crane GS (precursor to the 600 then Ultregra) and Huret's Duo Par. I even swapped out some of their cages with each other just to play around. The Rally in it's best set didn't shift as well as the Crane did. The Duo Par beat them all but just don't back pedal with one

If a really good shifting der and long term reliability are your goals I suggest moving away from the Rally. BTW Simplex had some really nice shifting wide range ders that are very underrated. Their all AL models rival the best Asian ders of their time. If you're assembling a wall hanger then the Rally will certainly get some points. Andy

bikemig 

The long cage Simplex derailleurs aren't bad. You also might be surprised by how large of a cog many short cage simplex rear derailleurs can handle. The simplex criterium that came stock on your PR 10 for example is rated to 34 teeth (!):

VeloBase.com - Component: Simplex Criterium

I have a later short cage simplex handling a 30 tooth cog no problem and it shifts better than a campy NR RD with the simplex double spring design:

https://mariposabicycles.ca/2016/01/...ng-derailleur/

I don't have personal experience setting up a campy rally on a simplex RD but in theory you should not need to file a stop as the campy rally as well as the shimano crane have a stop. That of course is what you did as you simply threaded the drop out. Here is a thread on that:

https://www.redclovercomponents.com/blog/1

It can be a pain to set up an old school RD that lacks a b screw with a big freewheel. The dang thing will often bump up against the largest cog which is what you are experiencing. Personally I'd take out 2 links and see if that helps. Also I'd post this question on the C&V forum as there must be folks there with experience getting this to work.

Alternatively, file a stop and run a long cage suntour VGT RD. You can then sell the Rally to someone who appreciates industrial jewelry. The suntour VGT is period correct for your PR 10 but I certainly understand why you might not want to run a Japanese rear derailleur on a French bike. That said, the best long cage RD of its day was the suntour with the shimano crane (which also does not need a stop) likely coming in second.

zandoval 

So did I but the old Campy Rally has a different attaching mechanism as I found out. It has a little tab that provides a stop. All I had to do was re-thread the simplex hanger to 10mm. That's part of the problem. That little tab/stop thing-gi puts the derailleur out about 3mm and makes it difficult to get to the larger gears...

Great information Andy. This Rally is a bugger. The bike is not really a wall hanger. I could not afford that. Now that I know the problem is in the derailleur itself I can concentrate on alternatives. I knew I was missing something here and its not just the deraileur extender. I am going to go back and make some more accurate adjustments.

OK... Got it... I am going to investigate. I will keep the Rally RD. Its pretty and picky but I'll handle it. Kinda like an old Ranch Truck transmission where you have to double clutch, match RPM and gently pick up the stick shift to drop it into the appropriate gear. I can do that. I'll stick with a 5 speed freewheel possibly with a 30T cog which will give me room to adjust the position of it on the threaded hub. I am going to try my best to avoid a Spoke Protector Dork Disk, but if I have to I'll dig one out. Will keep ya-all posted...

bikemig 

A 30 tooth freewheel will likely help. By the way, does your PR 10 still have it's original crank? That was a stronglight 49d. The outer ring as set up for a 122bcd inner which means you likely have a 40 on the inside.

There are two things you can do that crank. One is you can buy a 37 122bcd inner. That's not cheap but it is available.

https://www.redclovercomponents.com/..._37_Teeth.html

The second (and that's what I'd do) is convert that thing to a 50.4 bcd crank (in effect a TA copy). At that point you can run it as a compact crank (say a 46/30 or something different). New TA rings are available via eBay at non-crazy prices. Alternatively pick up 46/30 50.4 bcd rings from velo orange with the right hardware.

With a bit of elbow grease, you can avoid the dreaded ranch truck double clutch transmission syndrome which can happen on old bikes when you over tweak the gearing,

Mad Honk 

Zandoval,
I think I might try moving the wheel in the drop outs a bit farther forward and see if you get a bit more room to fit the larger cog. With the wheel pulled all the way back the clearance room is a bit tight. Not foolproof but it may help a bit. Smiles, MH