Mr IGH

I've been messing around with gears in an attempt to improve things and here's what I've arrived at:

- With a 9 speed triple I have three sets of gears that allow me to make single shifts with small steps between gears. On the flats I run the middle chainring, downhill/with the wind I run the big chainring and whilst climbing I use the small chainring.

- I'm still running 9 speed. If I want a big cog on the cassette, conventional 9 speed cassettes go wide range, most start with an 11T cog. I dislike the large 14% to 17% steps and the silly high gear that comes with an 11-32 cassette. A 50x14 or 50x15 is plenty of gear for me, esp whilst touring.

- For loaded touring I want 24x32 for my lowest gear. If I start the cassette out with a 15T I'll get rid of the unusable 11/12/13/14 cogs and can have smaller steps between gears. I run an old MTB front derailleur and a Deore 9-speed, wide range MTB rear derailleur with indexed Shimano 9 speed barcons.

- Shimano road triples are a mixed bag. The some of the newer triples use a weird, unsupported BCD on the inner ring (92mm?), there's no way to change it to a smaller size. The older Tiagra 4503 has a 74mm BCD, the newer 4603 has the stupid 92mm BCD that forces one to have a 30T minimum inner chainring. I just bought a Shimano 105 5703 crankset and it has a 74mm BCD on the inner ring. The 74mm BCD allows easy-to-source 28T, 26T and 24T chainrings, ideal for touring!

For my touring bike gears I have a Tiagra 4503 crankset with 50/39/24 (came stock with 50/39/30). I built a custom cassette using a Shimano HG400 9 speed cassette 12x36 and bought a Miche 15T first position cog, a 17T middle/final cog and a 19T middle/final cog. I broke up the HG400 cassette and made a custom 15, 16, 17, 18, 19 21, 24, 28, 32 cassette. Here's my gears:

24 39 50

15 43.2 70.2 90.0
16 40.5 65.8 84.4 7%
17 38.1 61.9 79.4 6%
18 36.0 58.5 75.0 6%
19 34.1 55.4 71.1 6%
21 30.9 50.1 64.3 11%
24 27.0 43.9 56.3 14%
28 23.1 37.6 48.2 17%
32 20.3 32.9 42.2 14%

timdow

Your gearing seems very good for a touring rig. I went with Miche 14 first position cog, and 22/32/42 mountain but am considering changing to 24/36/46 or 48.

Do you like the 39/50 middle/big, or do you think 36/48 would serve as well or better?

escii_35

Yes I too find the 11t kinda silly for anything but a modern MTB crank.

The two things I would worry about is how aggressively you can shift from the 24 to the 39 and can the shape of your rear dropout to seat stay tube interaction handle a 15t inner.

Moving to a 14t inner from a 13 proved problematic on my late edition cdale.

bikemig 

That looks good. Personally I don't tend to think much about the inbetween gears and focus simply on the low and high gears.

When I did a cross country in '97, I ran a 3 x 6 on a 1983 Trek 720. I custom built a 15-30 freewheel for the tour. Not as sweet as your custom 9 speed 15-32 cassette but it was the same basic idea--who needs a big top gear on a touring rig.

The bike I currently use for touring is a 3 x 8. I'm running a mtb crank (44-32-22) and a stock 8 speed cassette, 11-28, on the rear. I like this gearing a lot.

Cyclebum

That^^^^. You'll occasionally run out of high with a strong tail wind or on steep downhills. But not often enough to matter.

Mr IGH

If you already own a crankset that can run 24/36/48, I think that's ideal and I'd look at using it.

Back-in-the-day, when 6 speed was all there was, half step was needed so that we could have wide range and small steps. Front and rear choices had to be carefully balanced, with a 9 speed cassette, not so much.

24/36/48 is better, I have a Shimano 50/39/30 as the starting point. It's easy to find low cost Shimano triples with this arrangement and my intention was to show these work fine once a 9-speed is in the mix.

Mr IGH

Good points!

I'm running a Deer Head Deore MTB front derailleur, it shifts the 24 to 39 very well. It's been my experience that if a modern (post 1980), wide range front derailleur is properly installed it'll work better than expected. I'm running a Tiagra 4500 series 3x front derailleur on my road bike with a 26-39 step and it shifts perfectly.

I have a Soma Saga Disc frame with dropouts that have plenty of clearance but you're right, some frames may not fit a 15T (or even 14T!) for the first position cog.

Mr IGH

Yeah, back in 1982 I rode cross country with a home-made Dura-Ace 50/45/28 triple and a custom 6 speed, 15-28 Ultra freewheel (on a 1982 Trek 520 with ton's-o-braze-ons). That's when you had to know what you were doing, 8/9 speed cassettes really make it easy!

fietsbob

6 speed + triple, 14~34 , 50,40,24 , 622-35 tire/wheel Has worked fine for many years ..

Recently I use a 13~34 because that's what they sell .


Though My Rohloff hub in a 26" wheel 16:38t primary drive_ works Great.
as does the 16:53, 20" wheel .

Tourist in MSN

I am trying to figure out why someone with a screen name of Mr IGH is looking at derailleur gearing.

Mr IGH

Mr IGH is a renaissance man with respect to gearing, and he speaks in the third person, bask in his awesome glow!