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

[NetworkMan]

Note to moderator. Is it possible to get Chris Juden's April/May 2003 "Beat the System" article on here somehow? He gives a set of rules for bodging alternative ring sizes with a theoretically unsuitable front changer. I have a copy but I guess it's under CTC copyright.

[pwa]

My Spa Audax (Titanium) was bought as a frameset and built up by me with bar end levers that you sometimes see on tourers but rarely on "Audax" bikes. I run something like 50/39'/30 x 32 largest sprocket (with a road triple chainset) but I can see no reason why a different front mech and chainset, with lower gearing, should not be used. I find it easier with these levers to get things running smoothly with no chain rub. I'd not go back to STI levers. Too much faff.

[whoof]

There is a 12-36 9 speed Shimano cassette available.

https://www.ebay.co.uk/itm/New-Shimano- ... bwRWJaiBvg

12-14-16-18-21-24-28-32-36

[Bmblbzzz]

Note to moderator. Is it possible to get Chris Juden's April/May 2003 "Beat the System" article on here somehow? He gives a set of rules for bodging alternative ring sizes with a theoretically unsuitable front changer. I have a copy but I guess it's under CTC copyright.

Something similar is on the CUK website: https://www.cyclinguk.org/cyclists-libr ... s/shimergo

[The utility cyclist]

If you need an 18" low then why not go with an MTB chainset so you can utilise the smaller BCD on the inner and that way you don't have to have the silly big jumps by having a 36T sprocket? A 20T inner with a 30T sprocket (700x32mm tyres) gives you an 18" ratio exactly.

For me I'd love to run an XT chainset using 11 speed di2 STIs and be able to use an 11-30 but can't justify the cost so I'm going with 24/38/52 + 12-32 so I can use the bike (Sabbath September) for everything from hard/fast blasts to loaded touring.

[NetworkMan]

Note to moderator. Is it possible to get Chris Juden's April/May 2003 "Beat the System" article on here somehow? He gives a set of rules for bodging alternative ring sizes with a theoretically unsuitable front changer. I have a copy but I guess it's under CTC copyright.

Something similar is on the CUK website: https://www.cyclinguk.org/cyclists-libr ... s/shimergo

That is the first article dealing with the rear transmission. What I'm descriing is the second one which deals with the front and I don't think that ever made it to the Website.

[Brucey]

Note to moderator. Is it possible to get Chris Juden's April/May 2003 "Beat the System" article on here somehow? He gives a set of rules for bodging alternative ring sizes with a theoretically unsuitable front changer. I have a copy but I guess it's under CTC copyright.

Something similar is on the CUK website: https://www.cyclinguk.org/cyclists-libr ... s/shimergo

that article still contains useful information (about rear shifting) but it has been badly edited into its current version; for instance it refers in the text to illustrations that no longer exist....

BTW IIRC CJ's own touring bike has a similar gear range to the OPs requirements and he uses a double 2x10 setup, a kind of modern take on an Alpine double similar to the OP's double option. IIRC he chose to use Middleburn cranks.

BITD I've used alpine double setups and they have been OK for touring, less good for faster work. Their chief advantage has always been that they can (with care) use mechs , shifters etc that are more widely available ones meant for more mainstream bikes, even if the resultant gear ratios are not exactly mainstream.

cheers

[geocycle]

Similarly to the OP I have ridden a Rohloff since 2006. There’s nothing to beat it as a workhorse or loaded tourer but i fancied something different for day rides. I went for the Spa Ti audax with a compact double, knowing little of derailleur gears and just wanting something as an alternative to the rohloff. This was a mistake as I needed a lower bottom gear and more importantly the sweet spot for the rolling country I live in between Lakes and Dales meant I was constantly changing between big and small rings. I’ve solved it with a super compact double. However, a triple would probably have been a better purchase with hindsight. It is a good bike to ride and my average is 1-2 mph more than on the rohloff. But, if I could only have one bike it would have a rohloff.

[MockCyclist]

Wow lots of really useful information there, I've got the message about the triple, I'll drop all thoughts about a double. Thanks to all contributors.

tigerbiten, slowster, yes I'm beginning to think the key is to fine tune the sprockets to my usage, maybe dump the 11. I'll have a look at the cassette suggested by Whoof as well.

PH, I take your point about needing such a low gear on a more sprightly bike. Quite possibly 18" is a bit on the low side, although I used my 17" bottom just this afternoon to wind slowly up the steep concrete ramp at Flamborough beach. Which put a smile on my face and a look of astonishment on the pedestrians struggling to walk it. But i wouldn't take the Spa down there.

geocycle, that's my situation. I blow hot and cold over a new bike, my Raven Sport Tour has heavy rims, sometimes I think just get the wheels rebuilt. I have a Sterling I could use if I want to tour again. Also (and this is a peripheral reason) I know that the Raven is twitchy, you can't let your guard down on a fast descent, so I'm hoping for a bit more stability as well.

I think I'll be popping over to Harrogate soon and riding one.

[horizon]

My Spa Audax (Titanium) was bought as a frameset and built up by me with bar end levers that you sometimes see on tourers but rarely on "Audax" bikes.

Do you know why this is?

[pwa]

My Spa Audax (Titanium) was bought as a frameset and built up by me with bar end levers that you sometimes see on tourers but rarely on "Audax" bikes.

Do you know why this is?

I guess that most Audaxers want a detuned race machine with a few concessions to comfort, whereas I want a faster tourer. In reality those two concepts come very close and perhaps overlap. The second you lose shifting with a bar end lever, or a down tube lever, matters to a professional road racer but not to me. I'd much rather be free of the gearing constriction that comes with the left (front mech) STI lever, and the fiddling required to get front indexing to work with no chain rub. But each to their own.

[horizon]

My Spa Audax (Titanium) was bought as a frameset and built up by me with bar end levers that you sometimes see on tourers but rarely on "Audax" bikes.

Do you know why this is?

I guess that most Audaxers want a detuned race machine with a few concessions to comfort, whereas I want a faster tourer. In reality those two concepts come very close and perhaps overlap. The second you lose shifting with a bar end lever, or a down tube lever, matters to a professional road racer but not to me. I'd much rather be free of the gearing constriction that comes with the left (front mech) STI lever, and the fiddling required to get front indexing to work with no chain rub. But each to their own.

Yes, I have this image of Audax of long lonely rides in the middle of the cold dark night across some blue and long forgotten hills with only the burbling sound of a black and gruesome looking river next to you and the hours stretching interminably into the distance. Suddenly you realise you've got a full hour in hand to make the next gear change as you fidget wistfully with the lever and wish it were now - something, anything, to break the long monotony. In those circumstances I too think that slick-changing STIs are just inappropriate.

[PH]

... 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.

I'm not going to attempt to redefine the Audax bike, you might even consider that any bike that you ride an Audax on is therefore an Audax bike, which in my case is a flat bar Rohloff tourer, which is what I've used for most I've done. In the days when I had a traditional Audax bike the only rides I preferred it for were 100's and flat 200's.
So as an observation rather than in any way a recommendation - There's always been a variety of bikes used, yet when I started probably 80% fell roughly into the type that gets marketed as such, steel, deep drop calipers, guards, drop bars... basically the sort of bike that the Spa Audax is a good example of. They're still there at the start of every Audax I've done, though now it's unusual for them to account for 20%. The rest (Discounting the oddities, tandems, recumbent, trikes...) fall roughly into two camps; Road bikes, hardly any compromise to comfort, no guards, very little luggage capacity, predominantly carbon, 22 - 28mm tyres. The other type is the sort of bike popularised by self supported racing - disc brake, wider tyres, carbon or metal with a carbon fork, often no guards, and any luggage of the bikepacking variety. PBP is coming up later this month, no doubt there'll be plenty of photos and I'd be surprised if the British contingent didn't match what I've just said. (I don't know what's popular in other countries)
I doubt Spa's sales figures are known, but I wouldn't be surprised if over the next year the Aubisque outsold the steel Audax and the Elan the Ti Audax, what we will see of course is how the range adapts. Thorn's latest Audax frame is a disc frame with clearance for 32mm tyres, they were for a long time opposed to the idea of disc brakes so I doubt that decision was anything other than a response to demand.
For myself - I like the idea of a faster bike, but I haven't found anything I can ride 2mph faster on and still be comfortable all day.

[CJ]

I've run triples since the 70s and though I say so myself, I'm good at getting them to work reliably, but doubles DO work better. And having studied them very closely, having written the article on how front shifting works, I know WHY doubles work better.

Front shifting works like this. The upshift works by the mech's inner cage-plate pushing some chain against the teeth (and nowadays also the pick-up pins) on the the larger ring, which it catches on and is carried upwards as it rotates. And the downshift works by the outer cage-plate derailing the chain off the teeth of the larger ring, so it can fall onto the smaller ring. So front shifting is mostly about the relationship between those two plates and the LARGER of the two rings involved in the shift. It matters not not a lot where the smaller ring is, but the larger has to be where the mech is designed to find it. The inner plate has to push chain directly against teeth and the outer has to slice across those teeth as closely as it safely can, i.e. with a clearance of 2 to 3mm.

That's all very well with a double. With a double it's obvious which is the larger of the rings involved and a simple matter to design and set the mech up to work optimally with that.

But a triple? Here we have two shifting pairs, outer/middle and middle/inner. So the mech wants a cage that mates closely with the teeth on two rings of widely differing sizes! Back in the seventies nobody in the cycle industry seemed to realise that and although you could get triple chainsets - even quadruple (though I only ever saw pictures of those) - the mechs were all designed for simple doubles and middle/inner shifting was rubbish in both directions. Unless you made the middle nearly as big as the outer: then, given how the mech swings down as it swings inwards, the middle ring had a similar relationship with the cage as the outer ring had and so-called half-step triples (because the outer/middle shift was half the average ratio between adjacent rear cogs) worked well.

When the MTB arrived and made triples mainstream, triple shifting got some attention at last. The upshift was relatively easy to improve. The inner cage was made deeper so the bottom part was low enough to push chain directly against the teeth of a middle ring some 10T smaller than the outer, but not so low that it fouled those teeth when the mech shifted further out to engage with the outer ring. But change the difference in size between those two rings by more than one tooth and the system no longer works as intended. Want a bigger outer? You'd better get a bigger middle too!

But what about the downshift? You can't make the outer plate any deeper than it already is, since has to completely clear the outer ring. So the mech will always be working at a severe disadvantage when it comes to deflecting the chain off the middle ring, because it can't possibly get as close to the action as it really needs to be! And the middle to inner shift is THE MOST IMPORTANT shift a tourist ever makes, it's the "Goodness me this hill is steeper than I expected" shift, the leg-saving "{FFE - family-friendly edit } give me some lower gears" shift and the "Oh no I've left it too late" shift! So it's no good when the only way this shift works is with the pedals spinning fast with zero pressure on them, because neither of those things are going to happen on an unexpectedly steepening hill!

The way Shimano found of making that almost impossible downshift work, is to make the middle ring teeth so short, twisted and gappy, that the chain is on the point of falling off to the left already and only needs a little nudge to make it go. In fact, the inner plate of the front mech now plays the role of preventing it falling off spontaneously, which the chain will be trying to do whenever you engage middle ring with the biggest rear cogs. Try riding a Shimano triple without a front mech and you'll see what I mean. One downside of this is that middle-bottom (and sometimes also next-to-bottom) runs a bit rough, which is bad because "the lowest you can get without resorting to the crawler ring" tends to be a much-used gear - and used hard! The other disadvantage is those pre-worn stumps of teeth don't last so long, which is bad since middle is already the most used ring on any triple-equipped bike.

Like I said, I'm good at getting triples to work pretty well in spite of their unavoidable disadvantages, back in the day when we had only five or six cogs in back, we NEEDED three rings in front to get the range and the number of gears to tour in mountains, in comfort. Now we have nine or ten in back, we don't. Especially now those nine or ten - or even eleven - can cover a range of 3 or 4 : 1 by themselves! It cannot have escaped your notice that mountain-bikes of all things, often come with just a single ring nowadays. That's IS a bit daft IMHO, especially since they then have to do all sorts of expensive things to stop the chain falling off that single ring, that a front mech already does for free, but you get my point: if one can suffice for mountain-biking, two is surely enough for anything.

In another thread I've described the 42,22 by 12-36 9-speed setup on my tourer. It works very well for me, providing a 17 to 95in range. And with a 36 sprocket in back, my not-very-big ring goes down to 32in already so the crawler-ring isn't needed at all on some rides. And when it is I've perfected the knack of shifting front and rear simultaneously: one ring and three sprockets delivers an immediately useful next gear in either direction.

Meanwhile on my audax bike I had this 105 triple that wasn't shifting great since the middle ring got a bit worn. And I seldom used the outer, so I got to thinking that if only the middle were a little bigger I'd never need it at all. So I replaced the middle with a 42 made by Stronglight - with proper toothy teeth - and replaced the outer with a plain disk - as a chainguard and to neaten things up. With the much smaller outer the deep triple mech fouled the chainstay, so I had to swap that for a double mech. This works perfectly in spite of being designed for something ten teeth bigger - though I daresay the chainguard-ring helps. I already had a 26 crawler ring (instead of the original 30) and with an 11-36 10-speed cassette I have gears from 19 to 101 inches. And they work brilliantly, the mech slices the chain off the outer ring and delivers that crawler gear immediately, whenever I want it. Oh and 'big-bottom' is 31in on this setup (due to thinner tyres on this bike) so even less need to use the crawler-ring. Except that I now live halfway up a 1:5 hill in the Peak District!

[Mike_Ayling]

I don't know what the OP'S budget is but I love my Thorn Mercury with Rohloff. Mine is the flat bar version.

Thorn market this among other uses as an Audax bike.

Mike