Gearing for new Audax bike

[frank9755]

I thought I'd update on this in case anyone digs it up in a search and is facing a similar decision.

I've used the triple (26/39/50) until now, doing almost 4,000 miles on it. But I've never liked it. I've had the chain come off half a dozen times, sometimes getting wedged in round the bottom bracket, the front shifting under load is lumpy and, at night, it's easy to forget which ring you are in and end up cross-chaining. It's an audax bike so I don't race on it, so the close spaced gears were not important to me. In fact I virtually always changed two at a time to get a worthwhile shift. My old bike has a compact and an 11-34 and I found myself preferring to ride it. The final straw was on Monday when the chain came off again on a downshift and got wedged in.

So I have just changed it to a compact + wide range cassette.

Stronglight Impact compact chainset (34/50)
LX medium cage rear mech
11-34 SLX 10-speed cassette
+ existing shifters and front mech.
EDIT - the existing triple front mech worked at first then it didn't. Hard to describe but looking at the shape of the inner plate, it slopes in at a particular point which means it struggles to lift a chain from a 34T ring - so I had to buy a double-specific mech.

Basically gives me virtually the same gear range (one less gear at the bottom end) compared to the triple + 11-28 cassette. It's exactly the same as my other bike only it's 10-speed (vs 9) so there are no big gaps (the SLX cassette is 11-13-15-17-19-21-23-26-30-34). No big shifts between any gears, a lot simpler, slightly less weight, and it looks a lot better too. Mostly bits from the garage; just needed a chainring and the new cassette - I should even make a profit it I get round to selling my 105 rear mech and chainset!

I am going to ride PBP on this so feel much happier to have got it sorted out. Final ride on Sunday to test it out in the field.

I can't understand why Shimano doesn't market this combination (in the way that SRAM now does with a similar set-up).

[531colin]

...................... (the SLX cassette is 11-13-15-17-19-21-23-26-30-34). .............

That would be my ideal cassette, if they made it as 9 speed, without the 11.....http://forum.ctc.org.uk/viewtopic.php?f=5&t=54328&start=30

[mattheus]

Glad you're happy with your setup. I hope to see you at SQY!

I'm still a fan of triples. Here's why your logic wouldn't work on me:
- 26-39 is indeed slightly too big a jump - it's given me occasional problems on downshifts too. But you can fit chain-catchers [ormake one!] and ...
- 50 tooth (with an 11) is much bigger than I need. 46t does me OK, so a 26-36-46 would be fine. Or a 28 granny if I'd fitted a 30T or bigger sprocket. I haven't found aything lower of use even on the MC1K, so PBP should be fine.
- 11t sprocket gives huge gears, 50x11 really is massive - I've ridden a TT (only averaging 24mph, admittedly) with 46x13!
- Those 2t gaps woud be annoying in the big gears.
- With a 38-42T chainring I can ride for miles without changing rings, and mostly have a good chainline. With just 2 rings I'd always be cross-chaining, or shifting at the front too much. And finally ...
- its a bit unfair comparing 10sp with 9

You've clearly thought about this, and the above aren't a concern, so good luck to you!

[Gerch]

I bought a dawes audax frame and fitted
stronglight impact triple 48/38/28
stronglight jp 400 bb
tiagra front and rear mechs
BBB 12/27 cassette 12/13/15/17/19/21/23/25/27
Tiagra Shifters
This does me as I am getting on a bit, live in Norfolk, which is considered to be flat. I am really pleased with the stronglight components, which I bought from Spa cycles, who also gave good advice and excellent service

[PW]

My lightweight has a 10 speed triple Shimergo set up; 48/38/24 X 11-28. Ergos & mechs 2,006 Chorus, Shiftmate, Shimano 135mm oln hub, SRAM cassette & chain. Gear range @ 23" - 118" with plenty in the middle and it changes superbly. The compact won't go low enough for an old man in the Peak District but this triple still has the close shifts for a more rolling landscape.

[David Cox]

Thanks for the update Frank glad you've now got a set up that you are happy with and haven't lost a lot of money. I'm coming to the conclusion that there is almost an infinite variety of ways of setting up an audax (or any other bike) given the number of variables and what feels right for you is the only way to go!! Chains coming off and wedging themselves is a right downer and if you are riding into the night reliable shifting is essential. While these debates are fascinating all any of can do I think is pass on what works for each of us!

[PW]

Hear Hear David. If it works for you that's the way to go.

[hondated]

Interesting discussion as I have recently contemplated all of the factors and opted for the triple option but what I cannot understand is that to buy a new racing bike and especially a CF one it is very difficult to buy one with a triple CS because they all seem to be equipped with 50/34 Compacts.

I read somewhere that this because it is the cheaper option for the manufacturers but surely given the number of Sportives there are these days there must be a demand for triples given the routes that these take which can involve some severe climbing so why the problem in buying one.

[mattheus]

Because sportive riders don't want to admit they need a triple.

So they won't buy bikes with triples, and Cycling Weekly supports their choice.

[531colin]

Funny thing, the shop is always full of people who want their gears lower, and their handlebars higher....never the other way round.
They always seem to buy first, them come to us to sort out their mistakes.

But Mattheus is right, its very difficult to sell a comfortable, practical bike against a sleek, sexy bike, even when you can convince the customer to take a decent test ride they will buy the spangly one. ....tyring to put old heads on young shoulders, I guess....

[David Cox]

Absolutely - although really my head feels young enough, its the aging shoulders that ache - along with most other working bits!

[frank9755]

Thanks for the comments. With a new chainset, cassette and chain, it is like riding a new bike

As ever, I have had a few teething problems (which take more time than doing the actual change), which I'll list in case others want to do similar.

- plastic BB cups. Don't overtighten. I ordered Al ones but Spa sent me plastic. After a conversation I was reassured that the only difference was the cups, so I fitted it, but when I was tightening it, the cup deformed and it was a real challenge to get it off. I had some old Al ones in the garage so was able to re-fit with these. From this I infer that I have been over-tightening my BBs!
- 1mm spacer. Shimano 10-speed 'road' cassettes are 1mm narrower overall than 9-speed (and 8 and 7 which are the same). Therefore you need the 1mm spacer inside the cassette to make everything fit snugly. However Shimano 10-speed 'mountain' cassettes are 1mm wider (ie same as 9, 8, 7) so you don't need that spacer. Took me ages of searching to confirm this!
- 105 triple mech used as a double. This worked ok to begin with but after a few attempts it deteriorated and eventually I couldn't upshift. Looking at the shape of the inner plate, it slopes away from the chain at the point where it needs to lift the chain from a 34T ring. I needed to get a double mech. Works well now.

Agree with all the comments about lower gearing and bar height - fashion wins over practicality.

To be controversial, the other one I add to this list is close-spaced gears! Wide-spaced cassettes are unfashionable, like low bottom gears, triples and moderately high handlebars, tyres >23mm, etc.

On my TT bike I feel I do need close-spaced gears but, if I am not racing, I don't see the need! I find I can adjust my cadence and/or my speed perfectly well to accommodate a gap of 2 or 3 teeth without inconvenience. Certainly a 10-speed 11-34 has the extra sprocket but I don't have a problem either on my other bike with 9-speed 11-34.