curbowman

Hello there! I want to install a 6-speed Megarange freewheel (14-34) on my old '70s road bike, but I'm concerned about the rear derailleur.

The original 5-speed freewheel is a 14-28 teeth one, and the Suntour Honor derailleur has a 28t maximum limit. However, I was told in my LBS that the Megarange freewheel requires a special derailleur, but I think I might be able to use the Shimano Tourney TX I have in my mountain bike. Should I trust the salesman of the bike shop and buy a their recommended derailleur? Any advice will be useful for me.

Bill Kapaun

With friction shifting, the Tourney will be fine.
I have one shifting a 9 speed on an early 70's Takara road bike.
Useful too, if you need a claw mount RDER.

canklecat

Check the specs for the Megarange freewheel you have in mind. On the 7-speed 14-34T Megarange there's a big jump between the largest 34T and the next largest (28T, I think). It can make for some awkward upshifts and flailing around with legs spinning like propellers.

I have the 7-speed on my errand bike and occasionally need the 34T cog when climbing hills with a loaded bike. But the shift from 34 to 28 is always awkward. I'm considering swapping to the more closely spaced Megarange freewheel. I'll probably buy one of each because they're inexpensive and see which works best for me.

FWIW, my errand bike has an Altus RD but the Tourney and at least one other Shimano RD should work fine with the Megarange.

Bike Gremlin

Now on the errand bike I use an 8 speed cassette with a 28-34 gap as well, and it works perfectly fine with a Shimano Sora "road" RD, short cage version! The B screw needed to be screwed almost all the way in, but that's it. Works fine in both indexed and friction mode.

So my suggestion would be to try the existing RD out, and if it doesn't work, then go for Shimano Acera, as the cheapest quality option, skipping Tourney and Altus if possible. Though they too should work fine.

When using original RD, mind the chain wrap capacity. If using a double, almost definitely with a triple front chainrings, the short caged RD will not work well when on small front chainring and smaller 2/3 of the cassette - unless the chain is cut too short.

xenologer

In my experience (with customers bikes, not my own) cheap Tourney derailers work well with cheap megarange freewheels. Perhaps even moreso than nicer derailers.

I think it has to do with nicer derailers being designed to shift well with actual wide-range cassettes with no need for a megarange jump

Bike Gremlin

If you have a Tourney on hand, then by all means install it. If buying a new RD, I'd rather pay 20 e for an Acera, than 15 e for a Tourney (not sure about US prices though). Acera work perfectly well with megarange, and are probably a better "bang for the buck".

u235

Agree here.. I used a Tourney on a Megarange with no problem until a piece of plastic strapping get twisted up in it and spun it around into the spokes. Replaced with a Deore that was 2x the price but really only $15 USD more.
If it's not broke, don't fix it.

Slash5

You will have to check if the 6 speed freewheel will fit between the rear dropouts. Usually 6 speed has a wider axle than 5 speed.

Bike Gremlin

I think Deore is great quality, probably among the toughest and most durable in Shimano product line.

However, branches, or, as in your case, plastic, getting stuck and destroying the RD, or worse, can happen to any RD, no matter what price, or quality. RD hangers are usually built to let go of the RD - and it ends up wherever - before the frame gets damaged.

curbowman

The rear spacing is 123 mm. I did a test with a 7-speed freewheel and it barely fits. However, a 6-speed does work. I really need the biggest sprocket I can get since I live in the top of a steep mountain.

Ironfish653

You'd be surprised at what friction shifting lets you get away with.

I had a wide-range 5-speed with a ~32 tooth cog (it had skip-teeth so tooth count is an estmate); the Suntour V-GT had no problem motivating a 34-tooth Megarange 6-speed.

The ramps and pins built in to the freewheel, along with a new, modern chain (KMC Z51) do a good job of helping the DR move the chain up and down the gears.

canklecat

BTW, if you haven't already bought what you need, Jenson USA has the best prices I've seen on Shimano Megarange freewheels and Altus and Acera rear derailers. Cheap enough to buy a couple as spares.

ramzilla

Tourney RD will work fine with friction shifters or thumb shifters. Not so well with index shifters.

nfmisso

true.

nfmisso

It was mostly likely a Suntour 14-34 5 speed freewheel, I had one too, on a bike with a V-GT.