Categories: The Bikes

Front Chainrings and The Theory of Relativity

The old rings.

Disregarding my Schwinn Typhoon, I started keeping score with my 1976 Peugeot PX 10 LE. It came with a Stronglight 52 x 45 and a 14 x 21 five speed freewheel. I always thought this Peugeot was set up for the pavé of northern France with those gears and wire-wrapped and soldered 3x tubular wheels. Yet according to Peugeot’s advertising, this is what the boys rode in the Tour de France. Chapeau! Since this was my first real bike, the coolness of this Rule #5 rig was lost on me. The uncoolness of Mafac brakes and Simplex derailleurs was not lost on me and over time I swapped out many of the French components for Campagnolo ones but the Stronglight crankset was worthy and it stayed the longest. I found a drilled-out 42 inner ring. Surely Bernard Thévenet would approve of that. It was not such a taskmaster as the 45 and scored very high on the cool scale.

Eventually the 52s went to 53s and the 42s to 39s and there they stayed.

Post-Peugeot I lived on the sandy moraine called Cape Cod. It is rolling, easy-to-ride country; there were no steep, long climbs and the default 39 inner ring was too small for the Cape. Some switched back to 42s but our LBS had a handful of Campagnolo 44 tooth inner rings and a few of us installed them. It didn’t occur to me at the time but I was reverting to a more modern version of my original Peugeot gears. This was not a chainring for the early season but once summer arrived, it made perfect sense. The shifts between the front two chainrings were subtle and smooth. It was all good until we ventured over to a proper climb on the nearby island of Martha’s Vineyard. That climb, known to us as the hill-o-death, started off steep and never eased (this was pre-Garmin world, an estimated 15% grade). It actually was the kind of climb where if you were going to have a heart attack, it would be here. The 44 worked, it just meant most of it was done out of the saddle and the pain cave entrance was lower down. But, it may have been a faster way to get the job done. There was no in-the-saddle spinning going on; it was just more heaving of bike and body trying to turn over the shortest gear the 44 would give up.

I came to Maui armed with the 53 x 39. Earlier on Kauai, I once felt shame and horror as an older dude with stick legs passed me on the Waimea Canyon climb. Those sorry sticks were whizzing over a vile compact crankset. It gave me pause. But on Maui the 53 x 39 got the job done, until I did Maui’s version of the hill-o-death, The Wall. I got up it, but it wasn’t pretty or easy. Something was going to break doing that: knees, heart, chain, pedal, more likely part of me, rather than the bike. I was on Maui for the long haul and the Wall was not going anywhere so I opted for a compact crank.

My above prologue leads me to this, my theory of relativity. The terrain dictates the chainrings. You want a 52 x45 on your bike, stay away from the Pyrenees. If you have a compact crankset on there, there had better be some big ass climbs out your front door. But here at Velominati we like to quantify our suffering. My math is as weak as my VAM but I’m working on a calculation with correction factors which would determine what kind of crank one should have on their bike.

((GLx %Gr) 1/age) Bf x BPf x Df

Where:

GL = length of toughest grade encountered on Sunday ride.

Gr = Steepest sustained section of GL.

B = Belgian Factor, also known as Museeuw. The need to always ride in the large ring, always.

BPf = Big Pussy Factor, inverse of Bf. The inclination when a climb begins to sit when one might stand, to shift down rather than up.

Df = The Dutch factor, this is a terrain correction for sea level riding, as the Dutch do along the North Sea.

 

 

Gianni

Gianni has left the building.

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  • @Barracuda

    Great photograph! Can I ask: Where is this, exactly - and what is that impressive piece of engineering in the far background?

  • @Barracuda

    @piwakawaka

    I'll run a 50×34 when SRAM release their 10t cog for road then you could have a sweet 10-23 to run with it. I would recommend trying bigger tyres for those on compact groups, a 25mm tyre gives you another 109 mm in roll distance.

    Correct, already doing it ! 23 up front 25 out back

    Front and rear for me, feels like more tyre, 'cos there is, run the front at 100psi, rear 110, I'm 77kg really rate the down hill performance with a bigger softer front, seems to track much tighter through turns,feels like there is more grip than the 23's, took a few rides to get used to the bigger gearing!

  • @ErikdR

    @Barracuda

    Great photograph! Can I ask: Where is this, exactly - and what is that impressive piece of engineering in the far background?

    Victor Harbor - South Australia, Waitpinga Hill Climb, Granite Island Causeway in the background

  • @Gianni

    @Nof Landrien

    All compact (50×34), all the time since 2002. (Although I've stopped with the EPMS.) 50×34. Rule of thumb for the rear: >3,500 metres climbing in a day slap a 12-27 on; more than 2,500m climbing in a day put the 11-25 on; otherwise an 11-23 does pretty much everything.

    If the smallest cog on your cassette has more than 26 teeth (gear inches with a 39 inner ring = 39.5) then I suggest you come out of the glasshouse before you start throwing stones at compact users.

    I climbed the Giant of Provence with a 53×39 11-23 in 2000. It wasn't heroic, it was just stupid.

    I feel like I imagine Luther felt at the Diet of Worms.

    +1 beauty!

    A friend of mine climbed Ventoux this year on a 53x39 11-25 and had a similar experience of arriving at the summit 20 minutes down on me (52x36 12-27) and another fellow rider (50x34 12-28).  We lauded him for his hard man efforts but the response was that it wasn't heroic, just stupid (slightly over the "right amount" of dumb?).

    The next day he swapped in my 12-27 and I completely cracked trying to stay with him from Bedoin to watch the summit finish.

  • @Bianchi Denti

    @Chris

    @Beers No offense taken. If people being wrong on the internet bothered me, this is the last place I'd come to.

    I will give it a go, my climbing does need a bit of refinement. It'll have to be hill reps though, it's pretty flat round here.

    It might also be that your glutes are stronger than your quads. Some quad exercises for a few months may help increase your standing pedalling power.

    Another option is that you quads get tired much faster than your glutes, so you run out of standing power quickly. This could be a position problem, or a physiology problem.

    I'm only chipping in because I was the other way round for years (standing = faster, sitting = much slower), until I got my glutes firing. My massage therapist mate @Josh figured out how to help my glutes work through the duration of a ride, rather than seizing up at the first sight of a hill.

    It may be contrary to Velominati instincts, but I spend much more money on body maintenance than I do on bike parts these days.

    I think there's a lot of sense in what you're saying. Since switching from messing about with mountain bikes (largely a gravity assisted avoidance of climbing type affair) to road bikes, I'd say that a lot of the serious work to I've put into upgrading my guns has been on the rollers which, at my skill level, is entirely in the saddle. It's probably also left me low on grunt and relying on a high cadence. When the sufferfest session tells me it's time for an 8/10 effort at 60 rpm, that simply cannot be done on the rollers, there isn't enough resistance.

    Quad exercises are certainly required as are more low cadence sessions. Now is also the time to start if KT14 is going to be done properly.

    @Bianchi Denti

    It may be contrary to Velominati instincts, but I spend much more money on body maintenance than I do on bike parts these days.

    This is true but bike parts are just so much prettier and shiny.

  • @Chris

    ....... that simply cannot be done on the rollers, there isn't enough resistance.

    Quad exercises are certainly required as are more low cadence sessions. Now is also the time to start if KT14 is going to be done properly.

    I mix my winter turbo sessions with intervals on the rowing machine and have the two side by side.  It seems to help give me a bit more zip (that being an entirely relative term I hasten to add) when I need the power and it's also good for core strength which you don't really get turning over the turbo on a static bike.  Also helps to break up the sessions with a bit of variety.

  • @Teocalli I hate those things. It's not that they aren't any good, quite the opposite but there only seems to be two intensity settings, vomit or pass out. There also doesn't seem to be anyway of taking your mind off the task at hand (other than hypoxia), anything more than 10 minutes listening to the doubts in the back of my mind would be torture. At least on the rollers I've got balance and form to think about.

    Besides, if I had the budget for a rowing machine...

    (Just in case there's some rowing nut about to say that form is all important, I know but I just don't' care it's too boring and proper rowing is a sport for people who can't handle the future)

  • @ErikdR

    Anyway: the Moser has a 42-52 chain ring combo, and a 'straight-6"² at the back (13-18). Perfect for the pancake-flat Dutch 'polder' landscape it was made for, then. Here in Denmark - and more specifically, Eastern Jutland with its relatively short but steep climbs, it's a different story. Until now, I've been riding it with that same, original gearing, because I think it looks so fucking cool. But, as my knees keep reminding me every time the road points up, I am an idiot.

    And to be honest: the bike may look cool, but the way I have to wrestle it up the nastier inclines, out of the saddle and weaving from side to side, most probably doesn't.

    Yeah I remember when we were driving around the forests outside Aarhus with my uncle a few years back, all I could think was that it would be awesome countryside for riding in...

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