Half step plus granny

[smiorgan]

The gears on the new bike aren't right for the kind of riding I will do on it. Currently I have a 50/36 chainset which is fine for the "fast" bike but, surprise surprise, too high for my new Cross-Check with touring-weight wheels.

I've generated a spreadsheet to analyse all my chainring/cassette combos for gear inches. Man, I love spreadsheets.

I've considered ultra-compact doubles (e.g. the 46-30 from Velo Orange) but they're slightly too much of a compromise, plus chainrings will be hard to source in the future. That leaves a triple, but I'm not mad keen on those either because the middle seems too low to be generally useful. Really I want a bail-out gear and otherwise slightly lower gearing than I currently have using 50t with 14-28.

The answer to all of this looks like the Half-Step Plus Granny that I have read about on Sheldon's site and others. It sounds too good to be true because

- it looks great on my spreadsheet - big ring for cruising, middle for town/gentle inclines and a bail out gear. Current favourite is 48/44/28

- I should be able to do it with a Stronglight Impact (my current compact) which is cheap and the rings are easy to source

- I won't even have to change my derailleur (veloce 2011) since these setups prefer a double. And since the campag FD are now designed for compacts and doubles I guess that will help with picking up the chain from the granny to the middle (16t difference)

Is that right? I have a Veloce medium cage rear derailleur. Total capacity needed would be 34t (20 front + 14 rear).

Shifting is friction and I don't have any concern with too little cable pull (there's plenty more lever travel available). Running 9sp rear cassette.

 

[PpPete]

Half step + granny is a rather old fashioned arrangement.
I have it on the tandem (bought second hand) and TBH i don't like it, but don't use it often enough to make it worth changing.

IME better to go with a regular triple and an 11/28 cassette.... and learn to spin.

However you've done the right thing by analysing what gears you have and what you want on a spreadsheet..... If half-step + granny works for you, then go for it.

 

[MacB]

Get in there!!! someone else wanting to play with gears

If you've read Sheldon then you'll see he wasn't afraid of a super compact where, I believe, he used a 22t gap between the two front rings. for example you could get a triple, ditch the outer, put what you want in the middle and then go as low as 24t in the inner slot. I've just built up a 9 speed with a 24/40 up front and an 11-28 at the back. Yes the front change is agricultural but it doesn't happen often and I use a barend friction shifter. I lined the chainset up so that the large ring can hit the whole cassette and I can get the lowest 5 gears from the inner ring without interference. The cassette wasn't my original plan though, I ordered and 11-23 and the 11-28 was a replacement due to stock issues. So as it stands I have 38 to 97 gear inches in the large ring and an overdrive, if needed, of 5 gears covering 23 to 40 inches in the inner ring.

If I had the 11-23 then that would give me 46 to 97 and a lower range of 28 to 40, but you can get to this sort of gearing in a variety of ways. The choice of the large ring at the front needs to be dictated by yhe top gear you want and the smallest cog on the cassette you intend to use. I like the look of a 9 speed 13-25 cassette, if I wanted to keep my top gear around the 100 inch mark then I'd need a 48t large ring and would be happy to go with a 26t inner giving a low of 28 inches again.

 

[jay clock]

Man, I love spreadsheets.

so you need one of these that I got for Christmas

http://ecx.images-amazon.com/images/I/416fL59LI0L._SS500_.jpg

 

[smiorgan]

Wow, 3 replies from Hampshire folks - feels like I'm back home

@pppete - fair comment, although I do prefer to spin and I used to be able to tackle the downhill near work on my fixie with its 69" gear... these days I just use the brakes. Problem is I don't need the top end of my gearing and the chainline is suboptimal as a result, but a half step arrangement should keep the chain in the middle of the block for both town and country.

@macb - yes, I saw your earlier posts when you were going through the same process... I'm familiar with the idea of using inner+middle only of a triple (there's something on that in the Velo Orange blog from a while back), and I have a set of single chainring bolts at home so it's do-able. I guess I can go with the half-step triple and simplify to double if needed - probably need quite a wide BB though to get the right chainline.

As I said, main question is whether my double FD will work.

@jay clock - very nice sir. Although it is trumped by the t-shirt that my friend was wearing yesterday when we were cheering our marathon runner on

http://www.flickr.com/photos/gusset/4555692123/

 

[Crackle]

I've ridden a half step with Granny and I can't say I found it that great (it was a campag which dated from the 50's). It was especially lacking over any kind of rolling terrain and lacking again when you got to long hills. It got swapped for a 50/36 compact which worked fine but didn't give me low enough gears for loaded touring (I used 1 bike for everything then and largely still do).

Now I have a triple with a 46/38/24 and 11-25 10 speed block. This just about covers everything for me and suits my cadence and cruising speed. I top out about 30 on that combo and then I'm freewheeling but I have a 49 to go back on if needed. The 38 and rear close ratio block gives me plenty of gears in the range I use most and if I want to go faster I use the 46. Modern brifters, 10 speed blocks and a triple have transformed how I thought about gearing on a bike.

 

[MacB]

As I said, main question is whether my double FD will work.

Suck it and see there I'm afraid, you have some leeway if it's a band on clamp to raise and lower. I have a MTB front mech but don't like the way it sits between seat tube and rear wheel. But I was being a cheapskate and all the advice I've been given is that I need to use a Tiagra triple FD for any weird and wonderful setups. So that's on the shopping list.

This is the one bit that does get tricky especially if you're using STI type shifting.