dzinehaus

https://www.nashbar.com/profile.cfm?c...u=18989&brand=

Any opinions / first hand experience / compatibility issues with the Shimano MF-ZH37 MegaRange 7-Speed Freewheel – 13x34T?

I'm using a 105 short cage RD

HillRider

Shimano road rear derailleurs are rated for 27T maximum cogs. Most will allow a 30T and some will even tolerate a 32 but none I've ever heard of will work with a 34T cog. You need an MTB rd.

KLW2

You do need a MTB RD, I run Mega freewheels on my bikes and many Shimano RDs will have MEGA on them to help guide you. Mine are "Deore Mega range" I pick them up as new upgrade take offs from bike shops on e-bay pretty cheap. Sheldon Brown has a listing of the newer ones with specs including max teeth...HERE is one on e-bay now,,,,

dzinehaus

thanks I found the tech specs for the shimano 105 shortcage read derailleur. Says 22t max front difference for the long, so i'm guessing about the same for the short maybe about 2 less. Which kinda sucks.

27t-11t is the max-min I can go with the 105 shortcage with a max 14t front derailleur tooth difference

back to the drawing board or I might have to pick up a mega derailleur for my haro and switch the casette to a mega range. could be interesting.

EDIT:

sorry, change the 'freewheel' on my haro.

late

Umm, a freewheel and a cassette are two different things.

Road Fan

I assume you know whether you need a freewheel or a cassette - can't be both!

I've used Megaranges in friction shift systems with no problems, with Shimano, Campy (on a 14-28, not a 13-34!), and Huret Duopar derailleurs (13/34, beautiful!!!). The tooth design on the Shimanos picks up the chain so readily that you're going to get good shifting with any rear mech I can think of that has a 34 tooth capacity and the ability to wrap chain for perhaps 38 teeth of total sprocket difference. Shimano Deores are famous for handling this sort of range, whether or not they say "mega." You WILL need a long cage design.

Road Fan

operator

Sora Long cage RD = $15. Thread over.

dzinehaus

shimano saint rd 20$ bnwb

dafydd

sora will not handle a 34T cog. play on.

saint derailleurs need saint hub to work. a deore derailleur would be a good midrange choice, but i believe all shimano MTB made in the last few years are designed to work with megarange. be sure of what you have and what you're paying money for.

dzinehaus

I thought all rear derailleurs are non-specific to hubs ? I dont see anything on the shimano saint site stating that it needs to be used in conjunction with the hub but it is suggested to be paired up with it.

HillRider

Not quite. The Sora is a road derailleur and same cog size limitations apply. Thread to continue.

dafydd

it's not so much a suggestion as mandate, the derailleurs bolt directly to the axle.

Hardheadmandca

My Dura-Ace 9 speed will do a 34t, but it's kinda grumbly about it.

operator

My bad. I got temporarily confused with the bottom of the line Shimano stuff.

I meant shimano tourney, long cage.

Thread over.

HillRider

Yours is the first I've seen reported that will do it at all.

rmikkelsen

I'd like to know what kind of experiences people have had RIDING with the Megarange. Do you wish there were some intermediate cogs, or is it enough to have bailout gear for the really steep stuff? I do pretty well on rolling hills with my existing setups (52-42/13-26 6 speed set up and a 53-39/13-28 7 speed), but I'm pretty sure those aren't enough to carry me through the mountains.

z415

It is horrible. My roommate's girlfriend's bike has it, as did his before he upgraded to 9s and the large gear differences don't feel right. Hopping on the the "bailout" cog is quite an experience - no matter how steep the climb I just can't get used to suddenly spinning like a madman, and I keep a pretty high cadence in riding. And then if you slow down your spin, your momentum is so slow it feels like trackstand practice.

I personally wouldn't get it unless I was sure I needed it.

DMF 

Only on the small ring, I'll bet.

dzinehaus

I was thinking it would be worth a try and could be interesting on a 53t dbl. Needless to say they is that it would only work on my mtb.

But the horrible comment on the bail-out cog kinda makes me picture anyone pedaling in the void. funny.

late

Personally, I need that 34T gear. You can get a low gear of 30T or 32T if you want.
Harris Cyclery makes something they call the Century Special. It has a low gear of 30T and will work with your existing short cage derailleur.

ginsoakedboy

Shimano makes that same 7sp freewheel in several configurations that have a 28t large cog. I see several replies that suggest that any of the long cage 105, Ultegra, or DA rear derailleurs will work ok with a 28t max cog, even though they are listed as 27t max cog. Why not go with the freewheel in a 28t max, instead of going with that Megarange that has the 34t large cog. Pair the smaller freewheel with a triple or compact double crank, and that would seem like it would give you adequate gearing range. I'm wrestling with these same issues, as I have an old bike I am restoring that will have to use a freewheel, and I'm looking at what other drive train parts I can get to match with the freewheel.

dzinehaus

I was just gonna cross-post to your posting and say we already covered your issue in my thread. the issue is that the long cage will do it, its a matter of adjusting the low gear pin / screw. the short cage just doesnt have enough reach. I'll probably still pick up the mega-rage for my mtb that im slowly gonna convert to a hybrid/commuter as the frame geometry almost encourages it. Montreal is filled with beautiful climbs and flat roads. The mega-range would be more of a test toy at that point for me for the cost that it sells for on nashbar.com

Road Fan

I rather like it, here in Michigan. You get a fairly close ratio and nicely spaced 13-24, then a bail-out gear. Lately I only use the bail out on steep tired climbs. a 42/34 gear is a lot lower than your 39/28.

I do wish I had a smooth range of gears that bridged sometimes between the 24 and the 34. Lately I want more cadence tuning at slower speed/high cadence, something like a 28 T gear in between the 24 and the 34. So I guess on some rides the 34 is too low, and the 24 is too high!

Road Fan

Road Fan

Century Special is a wonderful product, but recognize it is a CASSETTE, not a FREEWHEEL.

Road Fan

Road Fan

Actually I do this on my Woodrup, it has a 13-26 freesheel and a 52/42/36 racing triple crankset. Works well with a long-cage Campy derailleur, needed to wrap up all that chain.

Road Fan