Mid-Life Cycling

Mid-Life Cycling

01 October 2015

Vera Goes Gran Fondo

You tell yourself, "This is it!"

You're not going to buy another bike, you tell yourself.  The bikes you have are "for life".

No more changes, no more upgrades, you say.  You're not going to buy another part unless you absolutely have to replace something that's worn out or broken.  You won't buy another bike accessory, no matter how great it looks or whether you really wonder how you've lived without it. And you absolutely swear not to go to any more swap meets, spend any more time hanging out in bike shops or while away your evenings looking at bikes and parts on eBay.

And you promise yourself you won't lift another allen key or screwdriver, or squeeze your oil can or grease gun, unless you're doing maintenance that absolutely must be done to keep your bike rolling.

But you know, deep down, you're lying to yourself: Once you learn how to tinker with your bikes, you won't stop--no matter how little mechanical aptitude you thought you had before you picked up that first repair manual, that first edition of Anybody's Bike Book.

You always find something to fix, even if it doesn't need fixing.  And there's always some experiment you want to try.



So it is with Vera.  Just before I went to Paris, I had an idea:   I'd turn  her gearing from a typical "compact" road setup (well, with slightly lower gears) to something I'd never before tried:  Gran Fondo gearing.






Turns out, I had everything I needed for the experiment. Well, almost.  The crankset that originally came with Vera--a Shimano Deore triple from the late '80's or early '90's--was sitting in a box, just begging to be reunited with her.  A BBG 46 tooth chainguard/bashguard, also sitting in that same box, would look good on that crank--and on Vera--I thought.   And I had a nice Stronglight 46 tooth chainring I'd been using with my the compact double as well a Shimano UN-52 bottom bracket that, according to the folks at Harris Cyclery and Velo Orange, would work. All I'd need is a 30T chainring with a 74mm bolt circle, which I found easily enough.

I installed the chainguard in place of the outer chainring.  The Stronglight ring, made to be an outer ring for a double or triple, went on the middle position.  And, of course, the 30T ring was bolted on the inside.  

I installed the Stronglight chainring with the logos facing out, as if it were in the outer position.  That meant the chainring fixing nuts wouldn't sit flush with the surface of the ring, as the holes for the chainring bolts are countersunk on the opposite side of the ring.  That didn't seem to matter.  I've ridden the setup about 200 kilometers and it doesn't seem to be coming loose--and the nuts standing proud of the chainring surface doesn't seem to affect the shifting.
In this image, you can see the countersinking of the holes for the chainring fixing nuts.  You can also see a segment of an example of drillium at its best or most extreme, depending on your point of view!



Speaking of which:  I've shifted, well, only to see how it shifts.  I haven't ridden on the 30T ring.  But part of my intention in setting up the gears as I did--and, by the way, I set up the gears on Arielle, my Mercian Audax and Helene, my other Miss Mercian--was to spend most of my riding time on the larger ring and to use the smaller one as a "bail out" gear.

In any event, the shifting was even smoother than I expected it to be.  The Shimano 105 front derailleur from the 8-speed group is made to handle, as most modern road front derailleurs are, a 14-tooth difference between the chainrings.  Part of the reason why I haven't had problems with shifting is, I believe, that I'm using a non-indexed downtube shifter.  I wonder how (or whether) the setup would work if I were using Ergo or STI levers, or even bar-end shifters.


Image result for symmetrical bottom bracket axle
This illustration shows how the right side of a bottom bracket axle was typically longer than the left side.  The drivetrain mounts on the right side.  Today's axles are typically more symmetrical.


 
The bottom bracket's axle is 127 mm long.  The crank is actually made for the old-style asymmetrical axle:  The original bottom bracket is what's known as "121+5":  In other words, 5 mm are added to the right side of a 121mm axle.  Using the modern bottom bracket doesn't seem to affect shifting or my pedal position"  It just leaves more axle showing on the left side than what you see with modern cranks and bottom brackets.  However, if I keep this setup, I might splurge (if finances permit) for a Phil Wood bottom bracket with the asymmetrical axle.



In reality, riding with this setup isn't different from riding with the compact double, as I am using the 46T ring nearly all of the time.  But I think that it will allow me a greater range of gears, should I ever want or need them.

Vera seems to like it.  Truth be told, I think she likes getting the nice old crankset back.

2 comments:

  1. Perhaps it'll wind up like my cyclocross bike - I ride the big ring for pretty much all "on road" riding and the small ring for pretty much all "off road" riding.

    ReplyDelete
  2. Steve--I've always had the impression that a lot of people ride Gran Fondo or Randonneur setups the way you describe.

    ReplyDelete