chico1st

is it possible to use a front deraileur with an IGH? If you had 2-3 chain rings up front the chain angles very little but you use those thick single speed chains with an IGH can it handle this amount of angle? or is that a bad idea?

operator

2 will probably be max.

You'll need some sort of chain tensioner/derailleur to take up the slack as you shift through the gears. I'm not sure if you can make the chainline work or not. You will most definitley not be able to use 1/8 chain. At any rate, a 3/32 chain will handle crosschaining better than a 1/8. It was designed to.

mickey85

If you got a half-step setup (I've got one that's 52/47 for instance), you could probably get away with just using super long dropouts. Might not be the safest thing...Once you go with a tensioner or a derailer that has been fixed in place, you kinda lose most of the benefits of going with an IGH - namely nothing to get gunked up and a clean chain line.

operator

That won't work anyways. The chain tension will be ridiculously loose in one combo. Enough to drop chains.

Panthers007

It would be interesting to design an adjunct to an IGH that can also pick up the chain-slack. But I don't see it rolling down the street for awhile. Thanks for the concept.

Mr IGH

Other folks have done it. The issue is that if you choose an Nexus/Alfine, the gear steps are not consistant (the difference between 1-2 gear is much less than the difference between 5-6 gear). The set-up won't be a half-step, there will be lots of overlap. All you'll do is extend the range 2-3 more gears. If you choose an SRAM im9 hub, the steps are consistant and you can get a wider range with less overlap. No issues on the chainslack, just use a rear dearaillieur...Which kinda defeats the purpose of an IGH....

mconlonx

Shimano makes a double-pulley Alfine chain tensioner for applications with front shifting and there are other tensioner designs out there that would work. A double would make sense, but check with hub mfg regarding minimum ratio before planning on a triple chainring setup--a super-small chainring might overtorque an IGH hub.

ryanwood

you should try an internal geared crank, I am not terribly familiar with them but I have seen them on a few mountain bikes so I know they exist

hartsu

I had double setup last year.
Shimano Tiagra Compact 50-34 and Shimano tensioner, works fine .

JohnDThompson 

Cyclo used to make a 3-speed cluster and derailleur for use on Sturmey-Archer 3-speed hubs to give 9 speeds in total. The system used 1/8" chain so I suspect you could run 3 chainrings and a front derailleur with 1/8" chain as well. But you would need some kind of chain tensioner on the back.

griftereck

I built a few bikes that had igh and mechs.

Lil Blue bike was a kids MTB that I fitted 20" 3 speed Sturmey Archer wheels too. I fitted an old Shimano 3 speed 18t cog to it. As these are pressed steel and can use a narrow chain.
But needed a smaller cog. I had racer 42/52 cranks on it. Could spin out the gears too easily.

Bianchigirll 

I do not have alot of miles on my IGH, but it seems that a triple is a bit overkill as the 28T on mine is usless. atleast here in rather flat So Jersey. I did switch toa sort of halfster with 42/58. I had the triple carnks and wanted to use it plus the vertical dropouts meant I needed a tensioner anyway

tatfiend 

LOTS of ways to go in order to extend the overall gear range of an IGH from using the SRAM Dual Drive to multiple front chain rings with a chain tensioner or rear derailleur adjusted to act strictly as a chain tensioner. Using thin Shimano or SRAM dished IGH rear cogs allows fitting of two cogs to most Sturmey Archer hubs. With careful choice of cog sizes and chain length the chain tension adjustment of most horizontal dropouts should be enough to allow proper chain tensioning with the chain on either sprocket. No changing of chain position possible while riding but a quick stop allows readjusting to the range wanted.

Almost all have the disadvantage of losing the simplicity of appearance and single chainline that the IGH with single sprockets front and rear provide. They also make fitting a chain guard much more difficult. The one exception is the Schlumpf dual drive front crankset or something similar. Expensive solution though. I personally favor choosing a IGH that provides the overall gear range needed to start with. If you need a wide range the Rohloff has a 526% range, the NuVinci has a 350% overall range and the SRAM iM9 has a 340% range.

As already mentioned too, trying to fit too low an input ratio for the hub via fitting a too small inner chainring risks over torquing the IGH unit which risks possible failure. Rohloff, NuVinci and SRAM all list recommended minimum input ratios for their hubs and Sturmey Archer used to prior to the Sunrace take over.

daredevil

I like the looks of this...
https://jamisbikes.com/usa/thebikes/s...ter4_spec.html

tcs

LOL! Here's how to half-step a Shimano 8:

It can't be done with two chainwheels --- but it can with three.

Example: let's use - arbitrarily - a 700x32 and a 23T cog. Our three chainwheels could then be a 42T, 45T and 47T.

Gear progression would be:
1st ratio, 42/23 = 26"
1st ratio, 47/23 = 29"
2nd ratio, 42/23 = 32"
2nd ratio, 45/23 = 34"
3rd ratio, 42/23 = 37"
3rd ratio, 45/23 = 39.5"
4th ratio, 42/23 = 42"
4th ratio, 45/23 = 45"
5th ratio, 42/23 = 49"
5th ratio, 47/23 = 55"
6th ratio, 42/23 = 60"
6th ratio, 45/23 = 64.5"
7th ratio, 42/23 = 70"
7th ratio, 45/23 = 75"
8th ratio, 42/23 = 79"
8th ratio, 45/23 = 85"

tcs

daredevil

^^^is that describing anything similar to that two ringed Jamis mentioned in post #14?

mconlonx

Jamis, assume 18t rear sprocket. 700x32 tires. 48/34 crank.

26.9 34/18 1st
32.8 34/18 2nd
37.9 48/18 1st
38.1 34/18 3rd
43.4 34/18 4th
46.4 48/18 2nd
51.0 34/18 5th
53.9 48/18 3rd
61.3 48/18 4th
62.4 34/18 6th
72.0 48/18 5th
72.4 34/18 7th
82.4 34/18 8th
88.1 48/18 6th
102.2 48/18 7th
116.3 48/18 8th

Rather than a half step, there are a couple ratios on there, right in the meat of where I'm usually at, that are pretty close together. Currently, I'm running 44/18 on a nexus hub, which is just about perfect for my slightly hilly commute--if I lived in real hill country or mountains, I'd be looking for a lower gear. As it is, I'm thinking of a double chainring setup, but it would be more like 48/38 or some thing that would stagger the middle of the range a bit more evenly. Even so, I think I'd rarely be shifting the front, considering it more a hi/lo range, set it and forget it kinda thing, rather than something to be used for hitting half steps along the regular range.

LarDasse74

A couple of months ago I retrofitted an Alfine hub to my touring bike and used the Alfine chain tensioner... the Shimano instructions actually give guidelines for running multiple chainrings and how to size the chain, etc.

Also, the Alfine chain tensioner did not work well with the 1/8" chain - the chain was lightly rubbing on the sides of the tensioner, and I lost the option of using the (still installed) 28 and 46 tooth rings. I have run the bike several times with the other rings, but I just swap it over by hand as I removed the front derailleur and shifter when I installed the Alfine hub.

Mr IGH

Why use an 1/8" chain? All the rear cogs are available in 3/32, the tensioner and chainrings are made for 3/32.

LarDasse74

I thought I was being clever. I have since installed a 3/32" chain and all is right with the universe.