Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

For discussions about bikes and equipment.
MockCyclist
Posts: 159
Joined: 29 Dec 2008, 7:18pm

Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby MockCyclist » 2 Aug 2019, 10:37am

I've been pedalling my heavy-ish Rohloff bike around the plains happily for over 10 years, now I live in the foothills I'm considering a Spa Audax. I've read countless threads about weight, doesn't make a difference, makes a 2Mph difference, it's the geometry, tyres, etc. etc. I'm just going to have to find out for myself. Plus I've got to get my head around gear selection as I'm a lapsed derailleur user.

Obviously gaining a bit more speed would be nice but really I'd just like to be able to bowl along and up the hills a little easier.

I never stand up, always seated, and I don't push big gears. My current top gear is 91". So I reckon I need a range of 18-100 ish gear inches.
At the low end I need 24 chainring, 36 sprocket. = 18".

I could specify the Audax with Tourer triple gearing, which in one configuration would give me 18-108 gear inches as a 9-speed triple, 24/36/44 & 11-36, just about perfect. I don't want to buy the tourer as I want something that's more progress-oriented, just not with the high gears which I won't use.

But I'm wondering if I might benefit from just having a double 10-speed. Can I just eliminate the middle ring? A 24/42 10-speed would get me up to 103 gear inches.

The ratios look widely spaced to me compared to my Rohloff at about 13.6% throughout. The 10-speed looks slightly better in that regard.

My question is, does the saving of the middle ring give rise to other issues ? Is it a pointless saving ? As a triple it would be 9-Speed (as supplied by Spa), as a double 10-Speed. Will it even work at all ? What are the wear issues ? 9-Sp vs. 10-sp ? How many 'non-usable' gears will there be ? Just looking for opinions on either configuration really.

ImageGearing by Mock Cyclist, on Flickr
Last edited by MockCyclist on 2 Aug 2019, 10:55am, edited 1 time in total.

Brucey
Posts: 34868
Joined: 4 Jan 2012, 6:25pm

Re: Audax Bike (Spa?) with Tourer Gearing ?

Postby Brucey » 2 Aug 2019, 10:51am

pros for the triple

- more choice of gear ratios
- smaller double shift
- better chainline (so better efficiency and less wear) in chosen gears

cons for the triple

- fractionally heavier (100g?)
- less choice in components (presently)
- front shifting can be slightly more irksome if parts are not selected with care

FWIW if you don't want a 108" top gear, think about deleting the 11T sprocket, either with a custom cassette or a shortened cassette, fitted to a narrower freehub body. The latter route results in an improved wheel dish, which in turn means you can run lighter weight wheel components for the same duty.

Chainsets that support the (double) ring sizes you want ain't cheap; some (which are the best value) are converted triples anyway, so you can try 'no middle ring' that way if you want. Personally if the gear range is that wide I think a triple is a no-brainer (you don't need to be genius to work out that the tiniest improvement in efficiency more than pays for the footling weight increase....), but each to his own.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

De Sisti
Posts: 709
Joined: 17 Jun 2007, 6:03pm

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby De Sisti » 2 Aug 2019, 11:20am

I have a Spa Audax and bought the following custom chainset from them:
46/34/24. (Paid an extra tenner for it).

I then added a rear (9s custom) cassette of choice:
13/14/15/17/19/21/24/27/30.

whoof
Posts: 1824
Joined: 29 Apr 2014, 2:13pm

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby whoof » 2 Aug 2019, 11:21am

If I already had a bike with double chainset, mech and levers then I might consider an 'Alpine' compact due to costs but if starting front new personally I would go for triple to avoid the big change between chainrings.

ratio.jpg

tim_f
Posts: 240
Joined: 12 Oct 2009, 10:37pm

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby tim_f » 2 Aug 2019, 11:46am

My Spa audax has

Spa 46-34-24 triple chain set

11- 34 9 speed cassette

Sora triple front mech

Alivo 9 speed mountain bike shadow rear mech.

bar end shifters

I like the spread of gears it gives low enough to get up steep hills with a touring load but high enough to go fast on the flat and when unloaded.

I think the read mech would work fine with a 12-36 9 speed cassette

I suspect that a 46-34-24 chainset works better with current shimanio road triple front mechs designed for 11 tooth difference than a 46-26-24 but I expect Brucey can provide advise on what works best together.

As well as gears need to think about match between brake levers and brakes - again best to get Brucey's advise on what works together well.

User avatar
Tigerbiten
Posts: 1840
Joined: 29 Jun 2009, 6:49am

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby Tigerbiten » 2 Aug 2019, 11:55am

Where are you're flat land gears (most commonly used) in both setups ??
There's no point in getting an ultra low first gear, if you're most commonly used gears are virtually unusable because they either have big jumps between the gears in that area or/and are across a gear range.
Once you have your flat land gears worked out, then see how low you can go and only then see where your top gear is.
I'd work backwards with a gear calc to see if custom chainrings and cassette gives you a better setup.
I'd try dropping the 11 sprocket and add one between the 13-34 while move the others around to give you better steps between the gears.
Or even go 14-34 and maybe go 48-36-24, 46-36-24 or 46-34-24 in front.
Once you have something worked out which you think would work, talk to Spa to see if it possible and how much extra it would cost.
If it's not possible, they may may know how to get something very close.
I did that with Inspired Cycle Engineering when I had my bent trike built with very custom gears, 9.4"-176".

Luck ....... :D

slowster
Posts: 822
Joined: 7 Jul 2017, 10:37am

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby slowster » 2 Aug 2019, 12:44pm

http://www.ritzelrechner.de is better at presenting gearing options visually than the Sheldon Brown calculator. In this link I've input your proposed triple and compared it against a Spa 40/24 compact double with a standard 11-34 10 speed cassette.

There are a number of past threads on here describing people's customising of Shimano cassettes to get the gears they want. These tend to address two things:

- eliminating the inefficient 11t sprocket (and/or 12t) and replacing it with a larger sprocket at the other end of the cassette to give a lower bottom gear.

- reducing the first 3 tooth jump in the middle of the cassette to a 2 tooth difference, because many dislike having a large jump in the middle cruising gears, e.g. replacing 17-20 with 17-19 or 21-24 with 21-23. Whilst such large jumps might be something you are quite used to with a Rohloff, especially if you are adopting a relaxed riding pace, on a light derailleur geared bike you too might not like those 3 tooth jumps in what should be your most used gears.

Most of the customised cassettes seem to be 9 speed, and it seems to me that often what they are trying to achieve is available off the shelf with a 10 speed cassette, e.g. the 11-34 10 speed has 2 tooth jumps up to 23t. Given the cost and hassle of customising 9 speed cassettes, I think 10 speed makes more sense (and there is no requirement to use the 11t sprocket). This link compares your proposed 9 speed triple set up with a 10 speed 11-34 cassette.

In short, I would not be influenced by what the top gear would be, and would make my choice based on a sufficiently low enough bottom gear and the combination of cruising gears that (I thought) would suit me best, whether that be double or triple.

keyboardmonkey
Posts: 608
Joined: 1 Dec 2009, 5:05pm
Location: Yorkshire

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby keyboardmonkey » 2 Aug 2019, 12:46pm

The triple, definitely, for all the reasons Brucey states. Then source a suitable 12T - cheap enough - to replace the 11T.

PH
Posts: 7299
Joined: 21 Jan 2007, 12:31am
Location: Derby
Contact:

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby PH » 2 Aug 2019, 1:19pm

Tigerbiten wrote:Where are you're flat land gears (most commonly used) in both setups ??
There's no point in getting an ultra low first gear, if you're most commonly used gears are virtually unusable because they either have big jumps between the gears in that area or/and are across a gear range.

That's my starting point, there's always going to be a compromise somewhere but I'd rather occasionally spin out or get off and walk a short hill (Which I don't mind doing) than spend half the ride searching for a gear that doesn't exist or constantly needing to double shift.
Also consider just how low a gear you need, if you're going to need as low a gear as you have on the heavy Rohloff bike there doesn't seem much point in the new one. I also choose different gearing for different rides, even when they're over similar terrain. If I'm on tour I want it to be easy, I need to stay fresh for the next day and the one after that, if I'm out for a couple of hours I don't mind pushing harder even if that means flopping out in an armchair when I get home. The bike I use for touring has a 20" bottom gear and the one I use for shorter rides a 23", they're both right for me.
And although I know not everyone agrees, IMO the traditional Audax bike is dead, you can get bikes that do everything they do without the tyre size restriction. I'm not at all surprised they're becoming less common on Audax rides, a considerable difference to a decade ago.

User avatar
Paulatic
Posts: 4030
Joined: 2 Feb 2014, 1:03pm
Location: 24 Hours from Lands End

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby Paulatic » 2 Aug 2019, 1:25pm

For me it would be the triple day in and day out 3x9 :D
Although I rode LEJOG on compact 2x10 without problem if ever you stick on a pannier and choose a hilly route then the knowledge of knowing that granny ring is there is priceless.
Whatever I am, wherever I am, this is me. This is my life

https://stcleve.wordpress.com/category/lejog/

keyboardmonkey
Posts: 608
Joined: 1 Dec 2009, 5:05pm
Location: Yorkshire

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby keyboardmonkey » 2 Aug 2019, 1:31pm

PH wrote:
Tigerbiten wrote:Where are you're flat land gears (most commonly used) in both setups ??
There's no point in getting an ultra low first gear, if you're most commonly used gears are virtually unusable because they either have big jumps between the gears in that area or/and are across a gear range.

... And although I know not everyone agrees, IMO the traditional Audax bike is dead, you can get bikes that do everything they do without the tyre size restriction. I'm not at all surprised they're becoming less common on Audax rides, a considerable difference to a decade ago.

That’s interesting. If it’s okay to have a little thread drift what is replacing the traditional Audax bike? I’m a bit out of the loop.

User avatar
Cugel
Posts: 2212
Joined: 13 Nov 2017, 11:14am

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby Cugel » 2 Aug 2019, 1:51pm

The advantage to a triple chainset, as I see it, is that it provides three ranges of gears from the cassette, which you choose from depending on the prevailing road-terrain. If it's flat, fast, wind-behind etcetera: big ring. Most everyday speeds of 10-20mph, say: middle ring. If it's generally going up for a few miles, including some proper up: small ring.

You can then choose or make a cassette with appropriate sprocket-teeth for you, to match the triple. Generally, you can have close ratios as the wide range is provided by using the triple for the terrain-type, as mentioned. For me (and for many experienced cyclists perhaps) the ideal is close ratios yet a wide range of gears.

I have both Shimano triples of the 52/39/30 "standard" and Spa of the 26/36/46 kind. I match cassettes of 10-speed (one 11-speed) to these, ranging from 13-30- to 15-36. The highest gear I have is 52/14 and the lowest is 26/30 - on different bikes, though.

The middle rings are used most: 80-90% of the miles, as they can often be used with all the sprockets without cross-chaining - assuming the middle ring aligns with the centre-line of the cassette. It might be more problematic with very short chainstays but most bikes other than pure race or TT bikes have longer stays these days.

It's possible to use a Shimano 9-speed MTB rear mech with a long arm (big capacity) with a 24/34/44 chainset and an 11-36 standard 10-speed cassette & STI levers. That's a big gear range although myself I would start with a 12 or even 13 sprocket rather than an 11, to ensure the highest gear ratio jumps are as small as possible.

Unless you're in a race and fit enough to be so, high top gears over 100" are not that useful really. Gravity and a crouch down is often faster than pedalling down a slope for most of us.

Cugel

Brucey
Posts: 34868
Joined: 4 Jan 2012, 6:25pm

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby Brucey » 2 Aug 2019, 2:16pm

keyboardmonkey wrote:... If it’s okay to have a little thread drift what is replacing the traditional Audax bike? I’m a bit out of the loop.


all kinds of bikes have been used to audax but if you say 'audax bike' most folk have thought of a bike with a vaguely sporty riding position, lightweight, not meant for load-lugging (but will take alight load of course), with frame clearances for ~25mm tyres with mudguards and ~28mm tyres without.

Now there are bikes with larger clearances (often with disc brakes) that are still lightweight and sporty (rather than touring/loaded touring oriented). For example so-called 'gravel bikes' (although these may accept a load) and endurance road bikes (which may not have mudguard eyelets even if they have clearances for them) are amongst those which blur the boundaries.

Nothing wrong with a traditional audax type bike, of course, but nor is there anything wrong with having more choices too.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Bmblbzzz
Posts: 2734
Joined: 18 May 2012, 7:56pm
Location: From here to there.

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby Bmblbzzz » 2 Aug 2019, 2:19pm

whoof wrote:If I already had a bike with double chainset, mech and levers then I might consider an 'Alpine' compact due to costs but if starting front new personally I would go for triple to avoid the big change between chainrings.

ratio.jpg

This is pretty much my feeling. In fact my "tourer" has a Spa super compact double (about £65), which is a Stronglight(?) triple with the outer ring removed. It works pretty well but sometimes I think about buying that extra chainring and running it as a triple. The only other things I'd need would be a triple mech, triple shifter, possibly a new rear mech to cope with increased capacity, new middle and inner rings to make sensible ratios... actually it's not worth it!

But if I were starting from scratch with a touring bike, yes I'd probably go for a triple. Think about which rings you want to use most: do you want your "normal" ring to be the outer with a hill-climbing ring and a bastard-steep-hill ring? Or do you want to spend most time on the middle ring with a hill ring and speedy ring?

NetworkMan
Posts: 560
Joined: 25 Aug 2014, 11:13am
Location: South Devon

Re: Audax Bike (Spa?) with Tourer Gearing & Double vs. Triple

Postby NetworkMan » 2 Aug 2019, 3:27pm

Only two advantages I can think of for a double over a triple:
1. Tiny saving in weight and cost.
2. If you don't have an indexed front then a double is easier since you don't have to estimate or fiddle the shift onto the middle ring.
Other than that it's a triple all the way. You can choose the middle ring and cassette combination so that the chain runs nicely aligned most of the time. Almost by definition, with a double it will be missaligned since the big ring is chosen by how high you want to go and the small one by how low; there are just not enough degrees of freedom to get the middle right as well.