MTB Gears on Road Bike

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08-24-2011, 12:35 PM
featuretile

MTB Gears on Road Bike

I live in an area with lots of big hills. I bought a slightly used Ruby (compact double) and had problems when the grade got over 10%. I would watch the other club members spin past me or stand. But Shimano did not make a wide range cassette for bikes with 10-speeds. Now, they are finally making 11-34 and 11-36 cassettes in 10-speed, but they made the new derailleur (Shadow) and road bike shifters incompatible with the cassette. Why they did this is beyond me. And they also tell people that it cannot be done.

I went of a bunch of forums to see if anyone had found a way to make this work. Here are some quotes:
Shimano STI: for 10sp road cassettes and chains, the best choice is 9sp Shimano mtn rear derailleurs, though older 8sp might be passable. New Shimano 10sp mtn derailleurs are completely INCOMPATIBLE with any road shifters. Also, the Shimano 9sp rear mtn derailleurs seem to be a fairly tolerant of exceeding the rated max cog size (ie, they were never meant to accept cogs bigger than 34T but in practice they’ll work on a 36T with margin to spare). Again watch the chain capacity. In summary, mega 9 xt rear mech, xt 11-34 ten speed cassette and Ultegra ten sti work faultlessly.

I went and bought these items and brought them to a local mechanic. (I have no affiliation with Jenson, but these were the best prices I found.
http://www.jensonusa.com/store/produ...+Cassette.aspx (11-34 or 11-36) or
http://www.jensonusa.com/store/produ...erailleur.aspx (long cage)
http://www.jensonusa.com/store/produ...0Sp+Chain.aspx (chain)

Yesterday I took my first long, hilly ride with the new lower gears. It worked just great! I go up every hill without stopping and I was not hyper-ventilating. I only need this 34-36 combo on the really steep hills or the really long climbs. I hope this information will help anyone who is struggling with hill climbing. If you are mashing up a hill and there are no lower gears to get into, the phrase 'work your legs harder' (even if you are a 59 year old woman) doesn't make it. I think cycling is going to get a lot more fun, and I am not going to avoid some of the rides that I have been skipping.
08-24-2011, 02:28 PM
goldfinch

I have started to look for a road bike and the gearing options and what you can and cannot do are making my head spin.

Like you, I want mountain bike gearing but one of my road bike options has a compact double. I think that I need to educate myself some more.
08-24-2011, 06:24 PM
smittykitty

I just learned the other day that according to my bike computer, I can walk up a hill pushing my bike at 2 mph! Love the compact double the rest of the time though. Luckily I don't spend too much time on hills and will keep working at it. But in the mean time, I will tell myself not to avoid hills, cuz I'm a good walker!
08-24-2011, 07:21 PM
roguedog

Quote:

Originally Posted by smittykitty

I just learned the other day that according to my bike computer, I can walk up a hill pushing my bike at 2 mph! Love the compact double the rest of the time though. Luckily I don't spend too much time on hills and will keep working at it. But in the mean time, I will tell myself not to avoid hills, cuz I'm a good walker!

hey! it's cross training :D
08-24-2011, 11:24 PM
laura*

Quote:

Originally Posted by featuretile

Also, the Shimano 9sp rear mtn derailleurs seem to be a fairly tolerant of exceeding the rated max cog size (ie, they were never meant to accept cogs bigger than 34T but in practice they’ll work on a 36T with margin to spare).

The 9spd "shadow" RD's are meant to work with with 36t. These would be the RD-M592, M662, M772, and M972. Note that Shimano only announced the 9spd 12-36 cassette after these RD's (well, not the M592) were already shipping. Thus the printed specs give a 34t limit.
08-25-2011, 03:55 AM
goldfinch

Quote:

Originally Posted by laura*

The 9spd "shadow" RD's are meant to work with with 36t. These would be the RD-M592, M662, M772, and M972. Note that Shimano only announced the 9spd 12-36 cassette after these RD's (well, not the M592) were already shipping. Thus the printed specs give a 34t limit.

What are shadow rear derailleurs?
08-25-2011, 10:25 AM
laura*

Quote:

Originally Posted by goldfinch

What are shadow rear derailleurs?

Instead of sticking out to the right, the body of the derailleur tries to hide "behind" the cassette. The intent is to reduce the chance that the derailleur might get snagged on something next to the trail.

The shift cable also is rerouted to eliminate the 180 degree loop entering the derailleur. This also reduces the chance of snagging something.
08-25-2011, 11:15 AM
goldfinch

Thanks Laura.
08-25-2011, 07:46 PM
featuretile

As far as I know, the Shadow derailleurs are 10-speed, not 9-speed. They are not compatible with road bike shifters. That's why I used an older Deore XT 9-speed derailleur with my new 10-speed 11-36T Shimano cassette (and kept my 105 shifters). My bike is a compact double. I would not need quite such a big cassette if I had a triple.

I can't believe how well it works! It shifts with just the tiniest touch, although that might just be because the mechanic is so good.

Today I went on a ride that includes a very long, steep uphill - probably 3 miles with no breaks (fantastic downhill on the other side). I have never been able to get up this without stopping several times, sometimes walking. I rode up the whole thing in one go. My cadence went from 30-35 with the old cassette to 50-60 with the new one. Plus, my quads were not burnt out. I felt really good today.
08-25-2011, 10:43 PM
laura*

Quote:

Originally Posted by featuretile

As far as I know, the Shadow derailleurs are 10-speed, not 9-speed. They are not compatible with road bike shifters. That's why I used an older Deore XT 9-speed derailleur with my new 10-speed 11-36T Shimano cassette (and kept my 105 shifters).

The derailleur you bought is a "shadow" style. The RD-M592, M662, M772, and M972 are the 9 speed shadow derailleurs. The slightly newer RD-M593, M663, M773, and ... M980/M985 are the 10 speed shadow derailleurs.