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TECH NEWS
First look: Does the Praxis Works Alba 48/32 herald the era of the sub-compact chainset?
With this version of its Alba chainset, Praxis Works is in the vanguard of a new trend in gearing, the sub-compact chainset. What’s the idea, and is it the way to go for you?
The chainrings are the feature that separates this version of Praxis’ Alba chainset from similar-looking five arm chainsets. They’re a 48-tooth outer and 32-tooth inner for a slight drop in gearing over more common set-ups.
The bike industry is variously calling this ‘sub-compact’ or ‘adventure’ gearing because it takes the existing idea of the compact chainset a step further, yielding gearing that’s ideal for bikes used across a range of surfaces and terrains. (Praxis calls it ‘Micro-Compact’ which I think is over-egging things a shade.)
For over a decade the compact chainset has been the most common gearing set-up for road bikes that aren’t specifically intended for racing. The concept shot to fame in 2003 when Tyler Hamilton used a bike with 50/34 chainrings in the Tour de France.
Hamilton had broken his collar bone and couldn’t pull on the bars to push a high gear. Sponsor FSA supplied him with a chainset that gave him lower gears so he could spin up the hills. He went on to win a stage and finish in fourth place overall.
The dark side of what should be one of cycle sport’s greatest stories of heroism and willpower triumphing over pain is that Hamilton’s career ended in ignominy after a string of positive doping tests. In the 2012 book he wrote with Daniel Coyle, Hamilton admitted to having received a blood transfusion the night before his stage victory. (That book, The Secret Race, is a truly hair-raising tale of the ambition-fuelled doping insanity of pro racing, and deserves a place on your bookshelf.)
Hamilton’s sins aside, his use of a compact chainset legitimised the idea in the eyes of enthusiast riders who didn’t have the power to easily climb hills in the standard racing combination of 53/39 chainrings.
Since then, your options in gearing have widened even further. The advent of 10- and then 11-sprocket cassettes means you can get close ratios and a wide gear range without going to a chainring as small as 34, and that’s led to the compromise between race gearing and compact, the ‘semi-compact’ 52/36.
And now there’s yet another option: sub-compact, with chainrings that are two or four teeth smaller than a compact.
Why? Well, for starters, gravel/adventure bikes. Dirt roads can be long and steep, so it’s a good idea to have lower gears than are possible with a compact. For its Sequoia adventure bikes, Specialized is using FSA chainsets with the same 48/32 combination as this Praxis set, and we think we’ll see more of this in future.
There’s another thing, though. For general road riding, the gears afforded by these chainsets make a lot of sense. There’s been a trend in the last couple of decades to higher and higher top gears on road bikes. A pro-level road race bike that would once have had a 52x13 top gear now has 53x11, a whopping 20 percent higher.
Mark Cavendish might have use for a gear that high when he’s diving for the line on the Champs Elysees, but you and me? Probably not. Even when you’re descending, the extra speed you can add by pedalling a big gear is very small; you’re better off concentrating on getting into as deep a tuck as possible.
Sub-compact options
Sub-compacts come with either 48/32 chainrings or 46/30. A 46x11 top gear is still higher than that old-school 52x13. What would you rather have, a top gear that you can only really use once in a blue moon, or some lower gears to get you comfortably up an unexpected 20% grade?
If the latter, there are three obvious ways a chainset maker can accommodate you. The old-school answer is a triple chainset, but they’re hopelessly unhip and few shifting systems now work with them; you can’t get a triple-capable left hand shifter above Tiagra in Shimano’s range, for example.
An alternative is to go to a smaller bolt circle. Most Shimano road bike cranks use a four-bolt, 110mm bolt circle, as did five-bolt compacts. Four-bolt mountain bike cranks, on the other hand, have a 104mm bolt circle, allowing rings as small as 32 teeth; five-bolt mountain bike cranks are 94mm, so you could go down to 30 teeth.
Or you could have two bolt circles, as Sugino has done for a while with its OX cranks. These have a 110mm outer chainring bolt circle and a 74mm inner for a huge range of possible combinations down to 40/24. FSA has taken a related approach with its various Adventure cranks. The Tempo has a 110/80 five-arm spider; the SL-K Modular crank has an outer ring that mounts on the crank and an inner with an asymmetrical 90mm four-bolt circle; and the Omega Adventure has 120mm and 90mm four-bolt circles.
Fans of the quaint, old-fashioned notion of standards will be grinding their teeth at the introduction of yet more chainring attachment patterns to the already excessive number that bike shops have to try and handle.
For this five-bolt crank and its 110mm spider Praxis has come up with a clever fourth way: dispense with the chainring nut and screw the bolt straight into the inner ring. That provides the necessary couple of millimetres of extra space needed for a 32-tooth ring.
The chainring bolts screw directly into the inner ring. A conventional chainring nut in this location would overlap the teeth.
The hole in the inner ring is very close to the bottom of a trough between teeth, though, so you can’t go smaller with this trick. And you probably can’t just put the Praxis rings on a 110mm five-arm chainset that you happen to have spare. To make room for the chain on the 32-tooth ring, Praxis has machined a shoulder into the arm of the crank; without it, the chain will almost certainly hit the spider arm and skip.
The lighter, hollow-forged Praxis Zayante chainset also has the cutaway crank spider ends, so you can use the 48/32 rings with those cranks too.
You also get Praxis’ intricately-shaped outer chainring. Praxis claims to be the only manufacturer beside Shimano to cold-forge its outer rings. The advantage of that, according to Rory Hitchens of Praxis importer Upgrade bikes is that “shift accuracy can be detailed into every ring combination for better than great shifting.”
The end of the crank spider is stepped to make room for the chain to sit on the inner ring.
Is it all worth it or would Praxis be better off going for a whole new chainring bolt pattern? For a chainset maker, the big advantage of this approach is they’ve not had to create loads of new tooling. If the idea doesn’t take off, well, the Alba crank will work just fine as a regular compact.
Compatibility is important too. Rory told us: “I would say it’s for better industry compatibility at this time. 110 ring sets are more available in the Praxis range right now.
“If you look at the other 2-D forged crank from Praxis, the Cadet MTB crank, you will see that is SRAM style direct mount for the rings. I would not be surprised if Praxis looked at this system going forward for Alba as you would then have a choice of a single direct ring — very clean — or a direct mounted spider for a 2x set up with the choice to make different BCD options at lower cost.” There’s that cost consideration we mentioned.
The Alba costs £150 for the cranks and chainrings, which includes the beefy-looking 30mm hollow aluminium axle built into the right hand crank. You’ll also need a pair of Praxis M30 bottom bracket cups, which are £34.99 for threaded units or £64.99 for BB30 press-fit.
It’s going on my gravel bike shortly, and I’ll report back in a few weeks on how it all works
John has been writing about bikes and cycling for over 30 years since discovering that people were mug enough to pay him for it rather than expecting him to do an honest day's work.
He was heavily involved in the mountain bike boom of the late 1980s as a racer, team manager and race promoter, and that led to writing for Mountain Biking UK magazine shortly after its inception. He got the gig by phoning up the editor and telling him the magazine was rubbish and he could do better. Rather than telling him to get lost, MBUK editor Tym Manley called John’s bluff and the rest is history.
Since then he has worked on MTB Pro magazine and was editor of Maximum Mountain Bike and Australian Mountain Bike magazines, before switching to the web in 2000 to work for CyclingNews.com. Along with road.cc founder Tony Farrelly, John was on the launch team for BikeRadar.com and subsequently became editor in chief of Future Publishing’s group of cycling magazines and websites, including Cycling Plus, MBUK, What Mountain Bike and Procycling.
John has also written for Cyclist magazine, edited the BikeMagic website and was founding editor of TotalWomensCycling.com before handing over to someone far more representative of the site's main audience.
He joined road.cc in 2013. He lives in Cambridge where the lack of hills is more than made up for by the headwinds.
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37 comments
Wow, maths galore, I have a TA triple, 48, 38, 28, after that I let my legs do the maths!
Any idea if the Hope 30mm BSA BB is compatible with the Praxis cranks?
As possibly the heaviest commenter here, anything that makes getting my chunky butt over gentle hills at over 70 rpm cadence is to be applauded. Smaller chainrings please, hopefully I'm just a member of a silent minority...
Better than nowt and much the waI have gone.I was hop for a msllaer BCD to allow smaller chainring. My main road bike uses MTB 42/28 . I do spin out occasionally on an 11 t rear but steephills just allow a freewheel and I don't like ( or in someways approve of but thats me) going as fast as gravity and pedalling will allow.b double is that they really are using the inner ring and a biggish one in the middle position, The Sugino doe this. Neater than some but still ugly compared with a road ch sets also have a ish Q factor sadly.
Off to look at the FSA
Re: 30/40/50 & a 11-26
Hi AlexB,
I can appreciate your use of the smaller cassette with a wider triple but I find that the 10 tooth front gap ends up with a lot of duplication - as shown below.
11 12 13 14 15 17 19 21 23 26
30 || 73.6 | 67.5 | 57.9 | 50.6 | 45.0 | 40.5 | 36.8 | 32.4 | 28.9 |25.3
40 || 98.2 | 90.0 | 77.1 | 67.5 | 60.0 | 54.0 | 49.1 | 43.2 | 38.6 |33.8
50 ||122.7 | 112.5 | 96.4 | 84.4 | 75.0 | 67.5 | 61.4 | 54.0 | 48.2 |42.2
30 X 11 = 40 X 14 = 50 X 17 e.t.c
I couldn't find a campag 10 speed so I used SRAMs PG1070 as a guide
This reminds me of the 46/36T cyclocross crankset my bike came with stock. For a lot of urban riding, a 46T big ring is very usable, and the tight 10T gap to the 36T small ring meant minimal shock to my knees when shifting at the front. I had mine paired with a 12-30T cassette.
That said, I later switched to a 50/34T crank because I wanted both a higher peak speed and an easier ring to climb with. I sure do miss using all combinations of my gears though.
My only beef with Praxis' cranks is the 30 mm spindle. Why they can't make the 48/32T crank concept work with 24 mm spindles, I don't understand. For bikes that use BB86 bottom brackets, smooshing a 30 mm spindle doesn't leave enough room for good bearings to spin.
Where will this STOP?! Gears getting easier and easier until all challenge is gone out of bicycle riding. We know real reason manus are pushing this is because they need to make less teeth and use less metal but price will be same. Riders will LOOSE
Is this a sarchastic comment, or a stupid one?
We don't all have legs of steel or want to ride at high speeds. I rather like the idea of lower gears, particularly on my cross/gravel/allroad bike, and espcially when it's loaded up. For this reason I blew quite a lot on a middleburn 46-30t crankset.
Just need Shimano to bring out a similar crankset as then they'll also introduce a front mech that actually works properly with the smaller rings (before anyone says anything, the shimano 11sp mechs work, but not perfectly, as they are not designed for rings smaller than 34t).
I think it's a stupid one. Anything that enables more people to bike more often can only be a good thing. Of course some riders love and live by Harder, Faster, Stonger. I'm a bit guilty of that myself but there is the other side to cycling, the side where you embrace other riders and the joy of the community of cycling. I personally believe that if everyone cycled then the world would be a happier and better place to live. If the sub-compact groupset gets people out who thought that they were unable to grind out the power needed to get up a hill then this can only be a good thing. To enable is to empower.
On your other point, how much money do you think the manufacturers would make if they knocked a couple of teeth off? They have to design and manufacture a new product but keep the same standards, If anything the demand for a new product will cost them money in the beginning.
The challenge is not the gears, it is moulding yourself into a better person.
Not sure if serious or trolling?
P.s. it's LOSE
It's a shame that, now the manufacturers have decided what's best for us, it's no longer (easily) possible to put together a half step & granny gear combination. I found that for touring a 2 tooth step at the front made for a very useful overdrive/underdrive type of gearing and ,even ye olde front mechs, behaved flawlessly with such a small gap.
When I last used it I had bar-end shifters which worked well, modern 'brifters' would be all the better. The combined front/rear shift can happily be accommodated in one action
Front: 44, 42 & a 28 (or 26)
Rear: 12,13,15,17,19,21,23,25,27,30
gives:
12 13 15 17 19 21 23 25 27 30
28 || 63.0 | 58.2 | 50.4 | 44.5 | 39.8 | 36.0 | 32.9 | 30.2 | 28.0 | 25.2
42 ||94.5 |87.2 |75.6 |66.7 | 59.7 | 54.0 |49.3 |45.4 |42.0 | 37.8
44 ||99.0 | 91.4 | 79.2 | 69.9 | 62.5 | 56.6 | 51.7 | 47.5 | 44.0 | 39.6
Half-step plus granny makes a lot of sense if you have big steps between gears, less so if the ratios at the rear are a little closer - in that case you'd be better off with a triple.
My Campag triple (50,40,30) matched to an 11-26 cassette gets a lot of use right across the range at both ends. I spend a lot of time cruising along on the 50t with the chain somewhere in the middle of the cassette (changing up or down as required to maintain cadence), that seems to be a good combination for flat, fast roads, so the 50t isn't only of use for sprinters.
run a 50/36 - only because the 34 wore out and i couldn't find one !
now love the combination, especailly with a 28 rear
but this .... hhmmmmm - where's
me wallet gone ...
48/32 and 46/30 have been around quite a while.
I think Middleburn did one but it was quite pricey, then Sugino brought out the 601 series.
I got a Sugino at enormouse expense from the USA as no one in UK stocked them. Got lamped for a load of customs duty, (we're going to have to get used to that.) It worked well with a Shimano CX70 front derailleur and 10sp cassette. It's a hollowtech bottom bracket so you can use Shimano or Hope or similar bearings. They did a product recall on the original, which has now been modified. I think it is now available in the UK.
I've gone back to 105 Triple but the double 46/30 was really more elegant.
Yay - FSA 48/32T & 46/30T at various scaled price points
Nay - Proprietary BCD combos tying you into their chainrings
Direct mount chainrings/spiders borrowed from the mtb world is the way forward. 1x, 2x, standard/disc chainline, etc. John - might be nice to give a nod to Middleburn(BETD) in this article seeing as they've been doing just that for quite a while now?
Sadly Middleburn are no more, there was talk of someone resurrecting the brand but I'm still waiting. I run two bike with MB rings for this reason. Personnally living on the edge of the Peak District, having kankered knees and a partner from Switzerland plus lots of elderly/touring customers it is long overdue. Roll on the "invention" of the triple!
For road, I am now generally happy with 50/34 - that gives me a very wide range of gears, and I don't lose out on much at the top end. (In my 20s I used to be able to descend at nearly 80km/h on a MTB with a 46/36/26 chainset.)
What I would really love for commuting is a 50/39 chainset. 48/39 would probably be even better. I tend to be at the range of speeds that is at the top end of what you can do with a 34 (or just above that) or the low end of what you can do with a 50.
Well . Before long someone somewhere is going to invent a 26/36/46 mountain bike triple . De je vu then !
Good idea; if you were spending a week in the Alps grinding up HC climbs, then this would be ideal. Was staying in a place near Alp d'Huez a couple of years ago and someone in another group had a super-light custom carbon bike with disc brakes and sub-compact gearing. Could have climbed all day on it. Went into a small bike shop in the Vosges and every bike was a triple. These people live near proper hills and seem to have a different attitude to gearing. I think we should all be getting bikes that suit our riding style, fitness, age, aspirations etc rather than trying to look like a pro.
Personally I have lotsa low gear configurations atwirl below the knees. Two bikes have triple chainsets, all have dinner-plate sprockets and the MTB has a 27/42 chainset with a 36 tooth sprocket at he back.
I have no bike with a gear larger than around 100" (in old money). As the article mentions, I spent years road racing and TTing with a highest gear of 52/13 - used only in sprints and on those wind-ahind days. Wot are these 11 tooth things for? (Posing).
But there is a problem with many modern frames in fitting a chainset with a big ring that isn't (that big, I mean). Those road frames with a braze-on fitting for the front mech are often configured so that the smallest possible big (outer) ring is 50 teef. The front mech will not slide lower - although you can slide it higher for your 55 toofer (wanted only by Cav).
This is a nuisance when you desire a 44-30 on there.
Cugel
Finally, manufacturers are making gearing for people who aren't pro-level fit, like to ride up hills, and don't like to destroy their knees!
About time too!
And I won't be buying one just so that I can run a clsoe range cassette! I'll probably still run 30t or more on the cassette!
I don't get it, if you're a leisure cyclist get a triple chainset. They never stopped working, and you've got plenty of low gears along with some high ones if you need them. These look like they're just aimed at folks who want to look like they're "serious cyclists" without having to do any hard work with it
Not a huge amount of choice for triple systems though and this approach means you only have to change your cranks - not your shifters and mech as well. Each to their own.
I'm hoping Cannondale make a 48/32 spiderring so I can just swap that bit out.
My touring bike has a 46x11 top gear and even on a very steep downhill you're never spinning out, if anything you're probably at a better cadence to go even faster. I took it up and then down Ventoux from Malaucene and I had no problem overtaking campervans and lots of cyclists on the way back down.
A smaller top ring also makes sense as far as not having a huge jump to a sensible small ring for loaded or off road riding.
40/28 mated to a 11-40 Cass will give 95" at the top and 18" at the bottom or 25mph @90rpm cadence down to less than 5mph at the same cadence.
How many riders will be moving at 25mph on the flat outside a racing situation and who are older and need low gearing for mountains, very few?
I have ridden with 53/39 cranks and 50/34, both have their uses but I always find I can't use the whole range of gears and stay in my cadence comfort range(90-100) With 40/28 I will use all the gears. This is my setup on my new sportive/ tourer build.
I say fit whatever rings you like. It's why I ride a very unfathomable 50/39.
It does however annoy me that Shimano now make their rings 'matched' as pairs whose shifting performance is reduced if you abandon their oriental wisdom.
48/32 sounds like a perfect set up for somwhere with lots of hills.
Well maybe the 2x doesn't make that much sense. For me it is 3x or ditching the front derailleur and live a simpler life if crosschaining doesn't get too bad. It is a pity that 3x setups are so rare. With my 26/36/48 setup I will use all 3 rings during my daily commute and they are crucial for my loaded tours!
Have these people never ridden up a 25% hill or a mountain like the Mortirolo?
And is it only me that needs a 26 chainring and 30 rear sprocket?
No, it's not just you. I'd happily run 46/30 with a 32 at the back and my average speed wouldn't suffer.
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