Bicycle Mechanics - Re-inventing the Wheel: Internal Gears

I was riding into work a few days ago, and I started thinking that the old, internal-gear style drivetrain would really suit my purposes. It would be for a commuter bike with no real hills to speak of. I still have to shift a few times; but I always stay on my big chain ring in the front. I began thinking about finding an old bike with said drivetrain to try it out.

Lo and behold - as I'm sure many of you already know - Shimano, SRAM, etcetera, re-invented this wheel several years before *I* re-invented it.

After reading most of Sheldon Brown's site, and a few other sites, I've decided to buy one and try it. I'm probably going to go with a Nexus 7 speed as a optimization between cost and performance.

My real goal is to reduce maintenance on my beater commuter; and as such I'd like to get rid of the smaller front chainrings.

Some Questions:

What is a roller brake? Is it the same as a coaster brake? Drum brake?

What's the difference between the 'premium' Nexus eight speed and the non-premium version?

I have vertical dropouts; so now I need some sort of chain tensioner (don't I?). Where would I get one? Is it just a common derailleur? I'd really like to go to just one front chainring.

Has anyone used the older indexed thumb shifters with the seven speed Nexus? Comments? Is the current shifting mechanism good enough?

When I used the search tool, another thread said that common thumb shifters could be made to work - I think they were XT's. Everything else I've seen disagrees. Does anyone have any confirmation?

Thanks!

My opinion is to avoid the roller brake. I'm guessing it's like a coaster brake, but instead of back peddling to engage it, you pull a hand lever. I do know it's damn near impossible to remove to change a tire or fix a flat and that's why I had the brake removed.

I got the Nexus 8 myself for similar reasons. You'll have to pick a crank (front gear) and a cog (rear gear). To figure which ones, based on the number of teeth, go to Sheldon Brown's gear calculator. First figure out the gear inches on the bike you are currently using. You'll probably have to count the number of teeth for each gear, use a piece of tape to mark where you start so you don't miss count. Then compare the gear inch ranges that you could get with the internal hub model. You're probably going to have to sacrifice some part of your current bike's range. So ride your bike a lot and figure out what gears you can do with out.

I don't know about the thumb shifters and they do have chain tensioners, but I think you'll also going to need non slip washers. Horizontal dropouts will make the whole thing easier.

My real goal is to reduce maintenance on my beater commuter; and as such I'd like to get rid of the smaller front chainrings.

The nexus 8 in my experience required constant fiddling to keep the cable adjusted around 4/5th gear. Weak point for hub.



Some Questions:

What is a roller brake? Is it the same as a coaster brake? Drum brake?

A roller brake is like a coaster brake that is actuated by a hand lever. Shimano models dont work as well as other brands because they have a mechanism that doens't let you brake as hard. Like other poster said, they are difficult for fixing flats.


What's the difference between the 'premium' Nexus eight speed and the non-premium version?

Bearings


I have vertical dropouts; so now I need some sort of chain tensioner (don't I?). Where would I get one? Is it just a common derailleur? I'd really like to go to just one front chainring.

If you have a chain tensioner, you could conceivably go with a tripple. Since wou only want one though, you can use a junky X-mart bike derailler just as a tensioner, or get a purpose-built one, such as a surly singleator.


Has anyone used the older indexed thumb shifters with the seven speed Nexus? Comments? Is the current shifting mechanism good enough?

The pull is wrong. Somebody on here once made some sort of custom doohickey to make them work with bridters. But generally you need the proprietary gripshifter.


When I used the search tool, another thread said that common thumb shifters could be made to work - I think they were XT's. Everything else I've seen disagrees. Does anyone have any confirmation?

Thanks!

Putting a chain tensioner on hub gears kind of defeats the simplicity. Look around for a bike with H dropouts as a hub gear project bike. Older touring and road bikes often have these.
SRAM gears use a click-box which contains all the indexing system and is removable, making wheel change easier but is a bit vulnerable to damage.

Or consider a new bike. The shop I work at sells Electra Bikes & Breezer Bikes. They come in at about $300- 400. When I first started I thought they were out of place among the high-end road and mountain bikes that they sell, but I have begun to appreciate their simplicity. Many of them combine both the 3 & 8 speed Nexus hubs with either coaster or v-brakes for more stopping power.

Pick up a beater frame with horizontal dropouts from a bike co-op and build up a conversion. I think the axle spacing for IG hubs is different than that of freewheel/freehub setups, so you would be best off finding a frame that was supposed to have an IG hub in the first place.

I'd second the get-an-older-beater-frame with horizontal dropouts. It's easy enough to come by old steel frames, that are not bad bikes, have horizontal dropouts (and often not even a derailler hanger!) and aren't too heavy.

Whether you convert a 10speed or not, just mind the spacing and the chainline. Different IG hubs com with different spacing.

Using an old RD for a tensioner has NO significant problems, and you may get lucky if you simply forget the whole thing, and muck around with different chainring, cog, and half-link combinations.

Also, doesn't harris sell Nexus wheels prebuilt?

I'd recommend against the breezer, if you are a 'serious' cyclist. Those things are marketed to people who havent excercized in 30 years, and will be far to heavy and slack for somebody who normally rides every day.

Whether you convert a 10speed or not, just mind the spacing and the chainline. Different IG hubs com with different spacing.

Using an old RD for a tensioner has NO significant problems, and you may get lucky if you simply forget the whole thing, and muck around with different chainring, cog, and half-link combinations.

Also, doesn't harris sell Nexus wheels prebuilt?

I'd recommend against the breezer, if you are a 'serious' cyclist. Those things are marketed to people who havent excercized in 30 years, and will be far to heavy and slack for somebody who normally rides every day.

I respectfully disagree with your synopsis on Breezer bikes. I got to try an "Uptown 8" for two days for my commute and general riding. I am definitely not a casual rider. I found it to be well balanced and strong. The Premium 8 hub worked flawlessly and the many hills around here weren't any steeper than with my 830.

It may be true that people who are not cultic in their cycling knowledge are attracted to these, but that's not a bad thing. They are not avant g'arde, but rather, a return to the era of 3-speeds, but with lighter materials and updated componets. I think 3-speeds were the epitome of utility and that's what a commuter is designed for. I can recommend one for those who don't want a 'project'. Breezer, and some others, got it right. I might have bought it myself except I already have a battlebike.

I am i bicycle mechanic and 1 tip on nexus, if it ****s up and you need to get it fixed DO NOT attempt it yourself, take it to you local bike shop as it is a complete pain in the arse. because of this it may also take some time to get fixed as specific parts are needed.

Good luck, hope you get what you want

Putting a chain tensioner on hub gears kind of defeats the simplicity.

Exactly. I don't want to do that at all - but I was afraid I might be forced to. Having to use a chain tensioner would make this option much less apetizing.

After I posted, I read:

http://www.sheldonbrown.com/singlespeed.html

Towards the bottom he mentions converting vertical dropouts to fixed gear setups; I might try this before trying to find a new frame. I'd rather have to fiddle with gears than get another bike.

Thanks for the help!

What works to get a fixed-gear working with vertical dropouts is not necessarily something that will get vertical dropouts to work with an internal-gear hub. The problem is not chain tension, it is that horizontal dropouts are generally necessary to give a surface to brace against, so the axle won't slip and rotate in the dropouts. You can buy a Rohloff that is designed to work in vertical dropouts. For the lower-dollar hubs, it isn't impossible to get things to work, it's just generally understood to be much more difficult than it is really worth. If you really want to do it, though, Sheldon Brown's page on the Nexus 7 or 8 has a section on modifying the vertical dropouts on your bike to make it work. I will advise you that the method he describes requires a drill and a steady hand! If you decide to go through with it, best of luck to you! Otherwise, I would recommend finding a frame with horizontal dropouts, which will greatly simplify your task. In any case, I applaud you! Internal gears are a wonderful thing, and I love seeing that they are beginning to catch on again.