albuhhh

hey guys, i have a vintage corsaro cabrio that i love to death. unfortunately, i bent the suntour arx rear derailleur and messed up the chain a couple weeks back. i had it repaired in the shop where they replaced it with a shimano alivio derailleur, which is huge! i found that it shifted smoother than my old suntour, so i didn't give it much thought, but it recently came to my attention that the alivio is meant to be mounted on a mountain bike. is this going to cause any problems in the future if i pursue serious touring? right now i just use it for commuting. i considered going back to the shop and complaining, but i dunno what good that will do considering that i've already paid for it.

lance.house

it should be fine, i have mixed and matched all sorts of gear. shimano uses the same dimensions in road and mountain gearing so it should generally be fine ( as long as 8 goes with 8, 9 with 9 etc)
in fact, if you are thinking of touring the mountain bike derailleur is an advantage as you can use mtb clusters which have a wider range of gears (ie lower low gears) than would be possible with a short cage road derailleur.

lance

Bill Kapaun

It was working so much better than the old one, you didn't realize you were offended?

albuhhh

haha yeah... like i said, it's not really affecting my riding, and i suspect that it won't really have any long term impact. i just found it odd that the most reputable bike shop in my area would do such a thing.

dalmore

If it's not shifting smoothly - that's cause for complaint. Take it back and tell them it's not shifting smoothly. It probably needs a tuneup and they should do so for free.

As for mountain vs road. It's mostly marketing. Don't get hung up it. The biggest diference as lance.house pointed out is that the mountain cycle allows a wider gear range if you switch cassettes. unless you are a weight weenie and then the biggest difference is clearly going to be the extra grams...

Banzai

Ditto.

I use a Deore RD on my road commuter bike. Granted I'm not running a really wide range cassette (12-28) but it's wide enough that I opted for a "MTB" RD anyway. (28t was the outside limit for the tensioner on many "road" RDs.)

Andrew*Debbie

well after you've been riding for awhile you will find the bike keeps pulling to the right. All road bikes with mtn. parts will do this -- they want to get off the road.

Seriously though, that part should be fine for touring or commuting. I mix and match all the time.

Suntour has been gone for years. If you search, you might be able to find a NOS Suntour part somewhere. But the Shimano works better.

There are some parts that don't interchange easily. For example road bars and mtn. bars are different diameters.

bmclaughlin807

Hehe... Mountain Bike dérailleurs are pretty common on touring bikes, as other have said, for the gearing. You're just getting a jump start.

If it runs smooth, ride it!

The biggest advantage is price! Mountain bike parts tend to be cheaper than road parts... Maybe the bike shop is even better than you think... if you were talking about touring and/or talking about budget issues, then the mountain bike dérailleur was the best choice.

huhenio

What is that shifting business you speak of?

hairlessbill

I run Deore XT derailers on most of my bikes including my roadie because they all have triple cranksets and I like being able to use a wide range of gears. Not as pretty or as light as road derailers but they work great. Also cheap to buy. Nashbar is selling a new Deore for $17.00.

Cyclaholic

You have nothing to worry about, in fact what we know as mountain bike groupsets had their origins on the road not on the trail.

Mountain bike groupsets with ultra-low gear ratios predate the advent of the mountain bike, they were called touring groupsets. Their origins are on heavily loaded road bikes, not on the trail. The inventors of the mountain bike were great improvisors and borrowed the technology from the road tourers. With declining interest in touring and the explosion of interest in mountain biking, the marketeers changed the identity of the groupset.

Raiyn

Applesauce. Modern dérailleurs don't care how many gears they shift, so long as they're matched to a shifter compatible with the cluster spacing and indexed cable pull requirements of the dérailleur. But that's if you care about indexing. That same Alivio dérailleur can be hooked up to a friction (gasp) shifter and used to shift anything from an old 5 speed freewheel to a brand new 10 speed system with nothing more than a limit screw adjustment.