BlueDevil63 

So I am working on a gravel grinder type bike as a winter project (yes it is winter here already, 8" of snow on the ground). It's based on a Melton frame I bought this last January. The frame was evidently intended as a loaded tourer and is built from Reynolds 531 tandem tubing. Very stout. Anyway I wanted to get a wide range double configuration, use parts I had available (mostly) and be at least somewhat vintage. The frame is from the mid 70s I think.

Anyway I had an Electra 50-39 compact crankset I bought on sale $79). It is vintage style crankset reminiscent of the Stronglight 49D with Campy Record crank arm style. I also had a Campy first gen Rally rear derailleur I wanted to use. According to the specs the Rally can handle a wide range freewheel so I ordered a Shimano 14-34 freewheel.

I have the bike mostly assembled. Looks like this:





As I am playing around with it now though it seems like there is no way the Rally can shift onto the low rear gear. This freewheel has a huge jump from the second largest to the largest cog. The jump just seems to big. As the derailleur moves over the derailleur cage hits the large cog and grinds on it. If I shorten the chain a good bit it will pull the derailleur and cage forward and might get the cage clear of the large cog but that would make the chain quite a bit shorter than my usual formula (around largest cog and largest chainwheel and add 2 links) and right now the chain is already about 2 links shorter than my usual formula. I could also pull the wheel all the way back which might help but I don't think much.

Has anyone used one of these Shimano Megarange freewheels or any other freewheel with this big of a jump and if so do you have any tips on how to set things up?

LeicaLad 

I have a very similar set-up, but I have only gone with the 13-32 rear.

I'm using the same 1st gen Rally with a Stronglight 93 (52t/38t). The hyperglide freewheel and new chain let it shift like butter.

Those extra 2 teeth may be the issue.


Here's my setup on this '63 frame:

Jeff Wills

The Megarange freewheels came around about 20 years after the Rally derailleur was current. A contemporary freewheel would have a smaller jump from the large to the next cog, something like a 27 or 28 tooth number-two cog.

I think you would be better off with an IRD 6-speed 14-34 freewheel: https://www.universalcycles.com/shopp...5&category=402

ThermionicScott 

I think pulling the wheel all the way back in the dropouts would make things worse, not better. It would be like turning out the B-screw, when you usually turn it in to clear bigger cogs.

For what it's worth, I like the progression of the 14-32T freewheel a little better, but of course it's the one that's out of stock...

BlueDevil63 

No doubt the IRD would work better but it is $30 more and I have the Shimano already. Just wondered if anyone had some ideas on how I might make it work if indeed it is possible to get it to work.

Michael Angelo 

SUntour VGT, would handle that.

ColonelJLloyd 

I use the IRD 6sp with the smaller jump (there are two configurations with 34t cogs) and a Shimano Crane/LeTour and it works really well. The Crane and Rally are very similar mechs. I suspect a different freewheel will solve the issue.

BlueDevil63 

I've got got a VGT Luxe and an early Shimano Deore so I have other derailleurs to try but I really wanted to use the Rally. I will consider switching to a different freewheel to keep the Rally. I could definitely live with a 32 large cog I just went with the 34 to get the lowest granny gear. I would actually much prefer the IRD gear setup.

zukahn1 

+1 If want to go vintage on the cheap or not the Sutour VGT is the way to go I have one on my current rider running 52/38 and 13-32 on the back with a modified 9speed using running 8speeds of 11-32 cassette on the back and it is great with friction shifters.

Jeff Wills

Yeah, well- the Megarange has that 10-tooth jump from the number-two to the big cog. I think the derailleur cage of the Rally (and the VGT Luxe) wasn't designed with this in mind. The Shimano derailleurs made for the Megarange freewheels would work (naturally) but putting one on that bike is just... eeewwww...

zukahn1 

Another option would would be to go with a modern 13-28 7speed which are pretty common and realitavely cheap both the Shimanos's and Sunraces are better than the IRD's for about half the price. Just add about 2mm spacing to the drive side and they work fine on older six speed setups. Then maybe run one size smaller on one of the front chainrings and you can use the DR's want to just fine.

BlueDevil63 

Yes you are certainly right. The 10 tooth jump is very extreme and I am not sure the Rally can handle that no matter what. Test fitting a VGT Luxe seems to show that it can't handle that 10 tooth jump either though. It may be that only a modern derailleur with the right cage configuration would be able to handle it.

I want to keep the Rally though so I will look to get a freewheel that either has a 28 tooth second cog (which gives me a more usable set of gears anyway) or a smaller large cog (like a 32 or even a 28 if I have to). The Shimano was only $14 so no huge loss if I can't return it. I wasn't paying close enough attention and didn't really realize how large that jump was between largest and second largest.

thirdgenbird

I'm afraid any advice I give you on the drivetrain will be based on aesthetics. With that out out of the way, ditch the shimano freewheel for something more conservative. The rest of the bike looks money.

i know they don't serve much purpose, but I am picturing this bike with a pair of extremely short 10in or so fenders.

BlueDevil63 

Thanks. For what it is worth if I end up using this freewheel I will remove the ugly Shimano logo and crap in the big cog. But still it definitely doesn't look vintage. The problem is I want this to be a rider. Lots of hills around here. I will be riding this off road and there are at least a few short but very steep and rocky sections (between smoother rail trails) where I need a low gear I can spin up the hills while sitting down to retain traction. I'm usually in a 22x30 on my mountain bike on these hills so I need as low as I can get on this bike. I can't go lower than the 39 on the crank I have so I really would like to have something bigger in the rear than a 28.

Michael Angelo 

I used a SUntour VGT with 5 speed freewheel that had a 36 tooth large cog, and worked real good. Nice shifting no problems. PB has the frewheel now, I have no use for that kind of gearing here in Flatland.

pastorbobnlnh 

The problem is international incompatibility and national competition. Japan does not like to play with Italy. If you plan to run the Rally you need a Regina Mega Range.



Actually, I believe your problem is in the fact that the cage on the Rally tends to be a bit bulky and overbuilt. I've had this problem with a 2nd Gen Rally hitting the spoke protector on some wheels and the spokes on other wheels. It just tends to need more clearance than other RD.

LeicaLad 

Given the description you just added of the terrain and gearing you need, I don't understand why you went with the mega-range that leaves you with a 10t gap right in the range you (apparently) need most. It's more like you want a 14-34 with no mega-jump. It's why, on the bike shown earlier in the thread, I went with 13-32 (it was the available from Niagara at the time), and a 52t/38t front.

Still, there are rides that I find this gearing not low enough. This is why I went to the same 13-32 rear with a triple-ized front for the bike below. I went with a 30t front granny, which is not so low, but when I want/need it is just about right. More importantly, I have that range of steps in the rear where the mega-range doesn't. This is a standard Campy NR/SR crank set that was drilled out to accept an inner granny. The original Campy triple is 100bcd and takes only a 36t as its smallest ring. This is drilled to 86bcd.



Actually, I now realize this is the same wheel set as in the previous photo. This bike now has a different wheel set with lighter tires, but the same model freewheel. I like the hyperglide teeth!

ymmv, of course.

BlueDevil63 

I have been unfairly maligning the fine Rally derailleur. I set the chain up a few links shorter than normal. It pulls the cage far enough forward to clear the large cog and it shifts up really, really well.

Much of this is driven by using what I had and spending as little as possible. The crank is the crank I had so I am trying to work with it. A better progression in the rear would be desirable but not available at the $14 price point. And its actually not that bad a setup for my riding.