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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  • @DCR

    @Gianni

    A perfect way to reinforce the n+1

    Does that mean the rule just became n+2 if you have to double up every time?  Nice.  Heather I need to.....SMACK!

  • @Chris

    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.

    He he.  I have a friend out a bit further east from you in Suffolk.  He talks of peaking his local Cols at 50 feet and needing Oxygen at the top.  He suffers somewhat when he comes over to the Surrey Hills.

  • Ha... nice one, Gianni. Your math is impeccable, as far as I can tell: (I suck at maths, so my rule of thumb in such matters is easy: if I don't understand it, it has to be proper and correct mathematics...)

    My 88-year-old dad has decided that his days as a cyclist are over, so he has given me his 30-year-old steel *Moser' to play with. (It's presently my #3 bike). In fact, with regard to frame geometry, it looks similar to that beautiful Masi that @Haldy has put on display in post #66 (but not nearly as pretty and well-groomed, at the moment.) It even has the same lovely saddle (a white Rolls San Marco)

    Anyway: the Moser has a 42-52 chain ring combo, and a 'straight-6' 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.

    By means of compromise, I'm seriously considering fitting a slightly more merciful freewheel on the steel steed (I have a couple of 14-24 blocks lying around, one of which just might fit). That would make quite a difference, I suppose. But the 42 stays for now...

    For the record: my #1 is fitted with a compact - works beautifully around these parts.

  • @Teocalli

    @DCR

    @Gianni

    A perfect way to reinforce the n+1

    Does that mean the rule just became n+2 if you have to double up every time? Nice. Heather I need to.....SMACK!

    Ahhahhah... Thanks mate - that provided a very welcome good laugh this morning. (Wiping coffee off the keyboard here...)

  • @Teocalli

    @DCR

    @Gianni

    A perfect way to reinforce the n+1

    Does that mean the rule just became n+2 if you have to double up every time? Nice. Heather I need to.....SMACK!

    That's quickly becoming n^2. Every time a new bike is acquired, it requires the purchase of a winter version, a matching mountain bike, cross rig, and classic steel restoration.

  • On the subject of big gears and legs/knees, I've always been a spinner - I would regard a 95 rpm average for a ride as normal, and anything below 75 as grinding and only to be endured for the shortest time possible.

    Recently however my coach has been setting sessions building up long periods of low cadence. I'm up to 30 minutes tempo at around 65 rpm. Also sessions with big gear acceleration bursts

    I was expecting it to be leg-shattering but although the first few sessions felt like I'd been doing squats it has been relatively OK since then and I think it is quite helpful in building leg strength.

  • Gianni is becoming the rogue compact-riding, EPMS-toting Keeper here. I like it.

    Judging by his math, my terrain requires a compact. I live at 800m altitude, and from home it's a 600m descent into a valley from which you can only go up. Average grades are between 6-7% on the mild ascents to 15% on the steeper sections. A round trip of roughly half the local climbs (as in, each done only one way) ends with 3200m of climbing, verified. No, it's not the alps, but if you want to keep a solid cadence you could use a compact. hen my group went together up our country's only HC climb, I thought I was fine until the final kilometres. Having had to grind my way up at 30RPM when others spun their compacts, and when the fuse was lit in the final kilometres, I was already spent.

    Sadly, I don't have one nor the budget for a compact these days. In the works: A compact for both my TT and road rig. Why? This is why. If he can go sub-50min for a 40k TT on a 50-39, why should my weakling 61-minute legs need something bigger? For pan-flat road races and TTs, you could always sub in a 52 chainring in case of backwinds.

  • @Chris

    @FNG

    @Chris You don't even know me douchebag, let alone how copious my V account is. Having worked in Orthopaedics for in excess of 10 years, I can assure you that potential knee damage resulting from pushing larger gears is given much more blame for injury than it is due. Other factors are significantly more problematic & causative (weight, prior injury or trauma.) Besides, for me, I'm young (40) only weight around 150, even when I'm Too Fat To Climb, & don't have many monster hills nearby, so 53/39 drills it, plus Pantani rode a 54/42 :-)

    Michele Ferrari was a doctor and look where that got us. And Pantani wasn't exactly playing it by the book medically.

    You don't know me so you've no idea how deep my douchebag account is. I'm sure you've got so much V it's oozing out of you but in my experience there always someone out there with more.

    Your little rant doesn't stack up. You tell us that it's deeply anti V to ride compacts but go on to say that you ride a standard because you're a skinny little fucker with no hills nearby. That suggests that you'd switch to a compact if you were somewhere hilly.

    I'd suggest you are probably spot on when you highlight "significantly more problematic & causative" issues (weight, prior injury or trauma) as a contributor to knee injury but it would seem me that if you're suffering from those a compact would be a good way to go towards minimizing the risk of future injury or long term damage.

    So, what shall we cover next. How wimpy it would be not to slam your stem if you've got back problems?

    I do look forward to these mornings where some new brave young thing pops up, citing their experience or relative riding abilities and preaches to the world before signing off again.  We should come up with a Lexicon Entry for these people.

    I mean calling yourself FNG (Fucking New Guy for those not familiar with the colloquialism) and then ranting is either cleverly ironic or a very poor Troll cover, I'm betting on the latter....

    Still it has kept me chuckling for the first few minutes of the day.

    What about calling them Velopandas....i.e. Eats Shoots and Leaves...

  • @tessar

    Gianni is becoming the rogue compact-riding, EPMS-toting Keeper here. I like it.

    Judging by his math, my terrain requires a compact. I live at 800m altitude, and from home it's a 600m descent into a valley from which you can only go up. Average grades are between 6-7% on the mild ascents to 15% on the steeper sections. A round trip of roughly half the local climbs (as in, each done only one way) ends with 3200m of climbing, verified. No, it's not the alps, but if you want to keep a solid cadence you could use a compact. hen my group went together up our country's only HC climb, I thought I was fine until the final kilometres. Having had to grind my way up at 30RPM when others spun their compacts, and when the fuse was lit in the final kilometres, I was already spent.

    Sadly, I don't have one nor the budget for a compact these days. In the works: A compact for both my TT and road rig. Why? This is why. If he can go sub-50min for a 40k TT on a 50-39, why should my weakling 61-minute legs need something bigger? For pan-flat road races and TTs, you could always sub in a 52 chainring in case of backwinds.

    Hmmm - I quote "There are a lot of variables, but a 50x11 is a bigger gear than Eddy Merckx ever had."......Discuss, over to "the panel"......

  • @Teocalli

    @tessar

    Gianni is becoming the rogue compact-riding, EPMS-toting Keeper here. I like it.

    Judging by his math, my terrain requires a compact. I live at 800m altitude, and from home it's a 600m descent into a valley from which you can only go up. Average grades are between 6-7% on the mild ascents to 15% on the steeper sections. A round trip of roughly half the local climbs (as in, each done only one way) ends with 3200m of climbing, verified. No, it's not the alps, but if you want to keep a solid cadence you could use a compact. hen my group went together up our country's only HC climb, I thought I was fine until the final kilometres. Having had to grind my way up at 30RPM when others spun their compacts, and when the fuse was lit in the final kilometres, I was already spent.

    Sadly, I don't have one nor the budget for a compact these days. In the works: A compact for both my TT and road rig. Why? This is why. If he can go sub-50min for a 40k TT on a 50-39, why should my weakling 61-minute legs need something bigger? For pan-flat road races and TTs, you could always sub in a 52 chainring in case of backwinds.

    Hmmm - I quote "There are a lot of variables, but a 50×11 is a bigger gear than Eddy Merckx ever had."......Discuss, over to "the panel"......

    Factually probably correct - I don't know every gear he ever had but his Hour 52x14 is 100 gear inches, which is significantly smaller than 50x12 (112) and 50x11 (122).

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