internal gear hubs
 

Aside from weight, what are the downsides? After much frustration with derailleurs, I'm thinking that hte next bike I get may very well have an internal gear hub.

Internal gear hubs have higher operating friction than derailleur systems, but lower maintenance issues.

Pick your poison.

Depending on the IGH chosen, the steps between gears are usually a bit larger to considerably larger than found with road bike gearing. No duplicate gears however as found on most current derailleur geartrains.

Modern ramped and pinned derailleur gear trains are also better at shifting under high power.

I have the Sram 9 speed. Yea, it's heavy.

It is not anywhere near as crisp as regular derailleurs. It seems like the clutch is looser... It takes more of a pedal rotation for the gear to engage. I'm not too impressed. It was a great thought but I prefer traditional gearing.

Although a Rohloff hub costs as much as what I earn in 3 weeks (and weighs 1.7kg!), I bought one and hooked it up to a Surly Cross Check. The end result is thoroughly enjoyable.

However I had a few hiccups to start with. The hub used to occasionally slip, and so I found out from forums like this one that 1 or 2 out of every 100 Rohloffs have an assembling error which they'll fix up at no cost. So I had to ship the rear wheel to their local service center (in Australia), they fixed it and shipped it back to me.

Despite all this I like the ride quality and it gets used everyday as I'm car free. Couple of weeks ago I did a 60mi ride on it – have to do a century fairly soon!

I have a Shimano Nexus 8-speed hub.
The downsides-No quick release, limited shifter options, you have to put some thought into chainline and chain length.
But I feel I have to mention some other benefits.
Yeeper mentioned clunky shifting with the SRAM, but my particular hub shifts much smoother than derailleur systems.
With a 1/8" chain, ring and cog, it's much more durable.
For city riding with many stop lights, I can shift while stopped.
I never have to worry about cross chaining or the chain dropping off the rings.
The setup has a very low Q-factor.
There's one less cable and two fewer mechanisms to deal with.
My particular hub is weather proof.
One benefit that some may seem like downsides-you aren't going be able to build up low spoke count wheels. But 36 spoke, large flange hubs make for stronger wheels.

i/m thinking an eight speed shimano with belt drive for my next bike. like someone else mentioned one downside is changing a flat i.e. no quick release. i think the belt drive would more than makeup for extra weight of hub. i think treks soho uses this setup on what they call an urban bike.

I've heard stuff though, like how you can't stand or something while pedaling? Has anyone also installed like a front derailleur? (seems like front wouldn't get as gunked as a rear).

I run a Nexus 8 hub.

You can certainly stand while pedaling. Only thing stopping you from running a front derailleur and chainring setup is some kind of tensioner in back. I asked over on the folding bike forum and was told that the Shimano Alfine tensioner will work for this application. Only thing is, once you add all that back into the system, you're really adding weight and taking away a lot of the reasons you might go IGH in the first place. SRAM makes a hybrid system with a 3sp hub that will take a cassette for a rear derailleur only setup where the 3sp hub takes the place of a 3 chainring system up front.

With the Trek Soho, you'd better like the ratios, because unlike with a chain setup, you cannot stray with the 50/24 ratio it comes with... unless you want to gear it up a bit with a 22t rear cog. Either that or switch to chain drive for a lower overall gear ratio range.

One other downside is that flats and tire changes are slightly more involved, threading the shifter cable around the shifting unit at the hub, and it's twice as difficult if you're dealing with a torque arm on the other side with either the roller or coaster brake options. I hear it's a bit easier with SRAM hubs.

I run a SRAM S-7 and outside of the weight issue (which isn't a big deal unless you are a racer) the only other "oddity" is that you have to stop pedaling to shift. It isn't hard to break stride for a second to shift but you have to sort of retrain yourself to do it after years of feeling like I _had_ to keep pedaling to shift. Overall I really like my setup; I rode a little over 50 miles on it yesterday alone.

The hub:
http://i64.photobucket.com/albums/h1...ssenger7-1.jpg

Custom welded shifter mount:
http://i64.photobucket.com/albums/h1...ssenger7-4.jpg

The bike:
http://i64.photobucket.com/albums/h1...n/IMG_0949.jpg
http://i64.photobucket.com/albums/h1...n/IMG_0926.jpg
http://i64.photobucket.com/albums/h1...n/IMG_0984.jpg

Belt drive won't save weight since the wider pulleys on both the crank and rear wheel will be heavier than a comparable cog and Al chainring even if the belt is lighter than a chain.

The more serious problem is that an endless belt can't be "broken" for installation so the frame has to be purpose built to accept it. This is usually accomplished by having a removable drive side dropout to allow the belt to go through the rear triangle as Trek does with the Soho. You can't install a belt drive on a conventional bike.

There's only a few derailleurs left in my house. Single speeds or IGH are how we roll. IMHO, the negatives don't add up to a hill of beans, the upside is no hassles. I was mountain biking overseas with no back-up, just me and my Alfine riding all mountain trails. My Alfine was able to handle it, by the end of the week, every deraillieur bike had issues. Broken chains, bent hangers, muddy chain screwing up the shifting. Rode through streams that submerged the hub, hosed it down every night. Cracked the hub when I got home, no water intrusion...I'm never going back.

The bike in my avatar has the Shimano Nexus 8 speed hub. It's a 40-odd pound Schwinn, but the extra gears make the hills much easier. As has been mentioned, the gears can be shifted up or down when the bike is stopped. Shifting (even when standing on the pedals) is smooth, and with no surprises or hiccups.

I put a Nexus 8 on an old Fuji road frame and 3500 miles later I have to think you'd be pretty happy with it.

THis is 100% not true... unless there is something seriously damaged inside the hub.

You can install a front derailleur, but it isn't practical because you need some sort of dynamic chain tensioner - like a rear derailleur - on the underside of the chain to make it work with differently sized chainrings and deal with chainline issues. Sram (previously a Sachs product) actually makes (or used to make) an IGH that accepts a multi-cog cassette.

Older Sturmey Archer AW 3 speed hubs had a false neutral between second and third gears which could cause problems either if the shifting cable was not perfectly adjusted or on a hub wth worn internal shifting dogs. All current SA hubs, and those from others so far as I know, do not have this problem.

Well, after building us up for a big splash with the iMotion hub, it sort of landed with a splat. I'm not real impressed with mine either as far as the shifter and shifting is concerned. It certainly doesn't measure up to Shimano or Rohloff in that department.
Who knows, though, it may turn out to be the most robust and durable gearhub on the market. We just won't know that for quite some time.