Front Chainrings and The Theory of Relativity

The old rings.
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.

 

 

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170 Replies to “Front Chainrings and The Theory of Relativity”

  1. @norm

    @wiscot

    @Chris


    I was actually referring to the get carter carpark for @Teocalli‘s great carpark climbs of the world.

    I was with you on the Gateshead monstrosity and the get Carter reference (great movie, can’t imagine why anyone thought a Stallone remake was a good idea.) but I thought I’d be pedantic about @wiscot’s song reference.

  2. @ab Everything that comes round goes round as they say – look at mountain bikes.  err – should I wash my mouth out after saying that?

  3. Just to link the Italian Job to the context of this site – what was the bike Michael Caine threw into the substation……(and don’t expect me to know the answer).

  4. @ab

    Will I be immediately excommunicated by the keepers for suggesting a single ring (so lighter with no front mech)? eg 46 up front and 11 / 28 out back? Essentially the same range as my old school 53 /42 with 13 / 28 that took me over European ranges with camping stuff.

    I look forward to my flogging.

    @Teocalli

    @ab Everything that comes round goes round as they say – look at mountain bikes. err – should I wash my mouth out after saying that?

    Like coming right around to the single chain ring/single rear cog aka single speed! I use mine as my commuting machine.

    Speaking of glutes and quads, I ride thru a river valley on my way to work every day: spin down, grind up, both ways. I think this routine has improved my stroke.

  5. @frank

    @unversio

    This is the week to mount up the 54/44. Crank length is 175. Me 6″² 3″³

    The question that remains is: are you built like a rabbit or a horse? And I’m talking about legs, FYI. Crank length has nothing to do with height, but inseam.

    I’m 6’4″³ and only an inch taller than you, but I am willing to bet if I rode your Merckx, I’d raise the saddle by a half meter.

    Crank length has to do with the circle your legs can draw, not the gear you can pull. The analog of this is telling someone which tire width they run and a what pressure, without relaying the weight of the rider and the severity of the tarmac.

    (Ricky Bobby voice) “With all due respect…” Crankarm length (length of a lever) plays a role with enacting more force at the end of the lever. Then your ability to pedal that circle diameter comes into play thereafter.

    Shake n’ bake!

    “That just happened!”

  6. @Chris

    @norm

    @wiscot

    @Chris


    I was actually referring to the get carter carpark for @Teocalli‘s great carpark climbs of the world.

    I was with you on the Gateshead monstrosity and the get Carter reference (great movie, can’t imagine why anyone thought a Stallone remake was a good idea.) but I thought I’d be pedantic about @wiscot’s song reference.

    Yes, although that line doesn’t come from the carpark scene if you want to get really pedantic.

  7. @frank Wile E. Coyote grabs a stick to create a first class lever. He inputs 445 J of work and the output work of the lever is 430 J. Calculate the efficiency.

  8. @freddy Yup that’s exactly what I meant.  He my old retro 5 speed could become modern again!  Maybe I should take off the front double I put on in the 70s

  9. @HamDer

    @johnthughes did you by any chance check out the party at Børneteatret on last thursday?

    In the afternoon we caught some cake at Manefiskeren(I think, huge cake). Then in the evening it was just beers on the patio at Nemo. Everything was so packed. Super fun though, great attitudes, happy people.

  10. @ChrisO

    @Chris

    @norm

    @wiscot

    @Chris


    I was actually referring to the get carter carpark for @Teocalli‘s great carpark climbs of the world.

    I was with you on the Gateshead monstrosity and the get Carter reference (great movie, can’t imagine why anyone thought a Stallone remake was a good idea.) but I thought I’d be pedantic about @wiscot’s song reference.

    Yes, although that line doesn’t come from the carpark scene if you want to get really pedantic.

    Fuck. Picked up by the pedant’s pedant (or should that be pedants’ pedant? I think not). Time to go for a beer.

  11. @johnthughes ahh¨, not bad indeed. i just wanted to know if you attented the party i was spinning records at :) funny ‘lil’ world!

  12. just did the alpine loop in harrisonburg va  on my 53/39 and13/26 in the back  everyone had compact and huge cassette in the back

  13. @ErikdR

    @Mikael Liddy

    @ErikdR

    @Barracuda OK, thanks! Granite Island, eh? Now that sounds like a good place to go for a ride…

    nah it would probably take less than 5 minutes to ride around the whole island…but if you want to try that climb I’m pretty sure our fishy friend has that lined up to start the Cogal in February (should give you enough time to organise flights to escape the Danish winter).

    I had a quick look at ‘Google Maps’ to check the place out – it did, indeed, look somewhat under-whelming. I’m puzzled, though: if the island is that small (and there’s not all that much going on, from the looks of it – apart from that Café and gift shop on the East tip), why have they built that whopper of a causeway? is it a huge tourist attraction of sorts, by any chance?

    Despite the way it looks in the photo, the causeway is similarly underwhelming. Basically it exists purely for a horse & cart to take tourists back and forth from Victor Harbour, the gap it spans would be less than a kilometre. Based on the island name I assume it may have been there originally to allow mined granite to be carted off the island…

  14. @ab

    Will I be immediately excommunicated by the keepers for suggesting a single ring (so lighter with no front mech)? eg 46 up front and 11 / 28 out back? Essentially the same range as my old school 53 /42 with 13 / 28 that took me over European ranges with camping stuff.

    I look forward to my flogging.

    No flogging sir. Sorry to disappoint. This is the road version of Britt’s enduro bike. I like to hear of people screwing around with their equipment. I remember Rob taking his front derailleur and large chain ring for a race up Mt Washington but never considered it as a possible solution for all riding. Bravo!

  15. @frank

    I realize that going small is in vogue and that the world is overpopulated by pussies and people who pay attention to “facts” and “science”. That said, that science is clouded by doping and all other manner of skewed data.

    This is an excellent point, Frank! Why are there so many pussies? No standards, I say.

    I was sub teaching 10th grade last week at a local, expensive, respected private school where most of the teachers have Ph.Ds. In a world geography class groups were presenting on communal work/living experiments around the world. A group was presenting on lobster farming in Mexico. I asked where, considering that whole two ocean thing.

    One student told me I was “doing it wrong” and that their regular teacher didn’t do it that way, making them oh, you know, look at a map or anything. Then all her classmates started chirping in as well, telling me the location didn’t matter. Fucking hell. High school world geography and any mention of a map/location is “doing it wrong.” Little fuckers.

    (I discussed with the regular teacher and he confirmed what I knew; he tries to not make the focus strictly on maps & facts, but all the groups should have indeed known where on the globe their community lived.)

  16. @Mikael Liddy

    @ErikdR

    @Mikael Liddy

    @ErikdR

    @Barracuda OK, thanks! Granite Island, eh? Now that sounds like a good place to go for a ride…

    nah it would probably take less than 5 minutes to ride around the whole island…but if you want to try that climb I’m pretty sure our fishy friend has that lined up to start the Cogal in February (should give you enough time to organise flights to escape the Danish winter).

    I had a quick look at ‘Google Maps’ to check the place out – it did, indeed, look somewhat under-whelming. I’m puzzled, though: if the island is that small (and there’s not all that much going on, from the looks of it – apart from that Café and gift shop on the East tip), why have they built that whopper of a causeway? is it a huge tourist attraction of sorts, by any chance?

    Despite the way it looks in the photo, the causeway is similarly underwhelming. Basically it exists purely for a horse & cart to take tourists back and forth from Victor Harbour, the gap it spans would be less than a kilometre. Based on the island name I assume it may have been there originally to allow mined granite to be carted off the island…

    OK, I see – Cheers!

    As for the Cogal in Oz in February: I would sure like to try something like that at some point – but ‘unfortunately’ I have a 4-week-long ride lined up in the USA in the summer of 2014. I fear that most of my holiday time (and budget) will have to be earmarked for that little jaunt. But 2015? Who knows…?

  17. @HMBSteve

    @Teocalli – That is a great pic and reminds me of many of the rides out here in the Bay Area. Awesome that @johnthughes took the shot while butterflies were flutterring through his spokes. And, no, you are not hte only one. I really enjopy the climbing scenery and have regretted not stoppoing for a pic on many occasion – the potential onset of the Man with the Hammer just keeps me motivated to move forward. Here is one I had to stop for, however; just before the final descent (into the abyss?) on an early morning warm up on the coast between SF and SC. (BTW – I use a compact)

    Is this the coast-side of West Old LaHonda?

  18. It had Campagnolo Super Record, the Tesch 101.  We had a circuit race at the Zigurat in 1987.  It had a small hill every lap.  I made the mistake of working on it the night before.  But it must look pretty, precious.  And I didn’t have a girlfriend, so I occupied my time by working on my bike and riding.

    The Campy SR front der was cool. But I stripped the fixing bolt at 10 PM the night before the race.  I actually had a Dura Ace front der in the bin, and I saw it had a threaded insert whereas the SR was thread aluminum. But a DA part along side Campy?

    Still, that hill was likely small, so I figured I do without the 42 chainring.  Just left off the front der and put the chain on the 53.

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