Friday, September 23, 2011

Lemond To Lemon To Lemondazed

I got my new parts last week and set about to putting the Lemond drivetrain back together and enjoying some sweet hill climbing bliss.  I'm a pretty good bike mechanic.  I have an innate sense of how things go together.  Most of my ideas are feasible.  So sometimes I coast on my build resume and overlook the more subtle aspects of the project---little things that can make or break it.  Such was the case this week.  Let me share the process with you.

When I dismantled the 52 and 42 chainrings, the 42 was large enough to slip over the spider arms.  However, upon installing the 39 replacement ring, its smaller inner diameter was just a tad too tight to slip over the spider, so I had to remove the crankarm assembly.  The Lemond uses an ISIS type splined bottom bracket, which is similar to Shimano's Octalink, but they are not compatible.  Having the crank off made installation of the rings much easier anyway.

The first puzzlement was the alignment of the 39 ring as it had a ramp and pin system on the inside that was completely different than the Bontrager part it replaced.  I rotated the ring round and round and finally I figured out it made no difference, as the pins would catch the chain at some point anyway.  The 52 ring is finished much simpler so I just bolted that on.  Lastly I greased the spindle and bolted on the crank assembly.

Next I shortened the new hollowpin chain by 5 links to match the length of the old stretched chain.  Only AFTER I shortened it did it occur to me that the old chain is longer than it should be (because it's stretched, right?) , maybe by 1 link length overall.  Oh well, that would make the new chain 1 link longer than needed, no big deal (?).  I put the new chain on, lubed it with Boeshield lube, ran through some gear changes and patted myself on the back.  Job done!

The Next Day, riding to work.
My initial feeling about the 39 was justified, I can more easily climb moderate grades compared to the 42.  However, the shifting was not so great in the rear, noise, ker-thunks, and balky shifts.  The front derailler was rubbing on the chain in several positions.  I was riding up Park Blvd, adjusting the cable barrel, when I got a rear flat.  This is the 2nd ride up in a row on the Lemond I suffered a rear flat.  At this point I was not feeling the love for the bike, even though it was entirely not the bike's fault---it was society tossing its glass my way, and me, for not taking the time to do fine adjustments on the shifting.  While working on the tire, I noticed on the 52 chainring that it's outside chainstop peg, which is supposed to be positioned so that it stops the chain from jamming between the spider and arm, was like 150 degrees rotated on the crank and just sticking out naked in the air, not doing a thing.  DOH!!  I repaired the tire and noisily climbed to work, but it was not much fun.  I was beating on myself for turning my bike into a lemon.

It was then that I realized that part of the essence of a great ride is having your bike work flawlessly and quietly.  If I have to think about what's NOT right with my bike while I'm riding it, it taints the whole ride experience. But I wondered why the changes to the shifting?

First, I had put a new chain on old sprockets and chainrings.  There are going to be teeth meshing tolerances out of spec compared to new.  Audible proof of this that when pedalling on the 39, the system  purrs like a kitten, but on the 28, it has a ratcheting sound.
Secondly, I removed the crankarm assembly and reinstalled after greasing.  I think I was able to get it further onto the spline than before, and that put the chain a millimeter or two closer to the derailleur cage.

So I put the bike back up on the rack, popped a cold PBR (the hipster's choice), and set to adjusting the front and back shifting.  I won't go into too much detail, the rear is a matter of turning the barrel back and forth until things get as quiet as possible.  The front, that's a horse of a different feather, as you have 3 index stops plus 2 trim stops, 2 limit screws, side to side alignment, plus cable tautness. By no means do I feel that I have mastered the front triple derailleur.  For instance, the Shimano technical bulletin on this part states that the 2 trim settings are for the middle chainring.  On my bike, they only serve the small inner chainring, there is no trim when I select the 39.  All this is controlled by the shift lever, the various stops and trims.  The derailleur itself is a "dumb" slave device.  No way do I even want to attempt to get into the workings of a shift lever.  In this case it is what it is, it works so I'm happy.

Then I took the outer rings off and rotated the 52 so the chainstop peg was in the right place. I laughed at myself.  When I put that on it was truly a "no brainer".

So having made all the adjustments, I rode to work again today, and the difference is like night and day.  The bike shifts well again, its quieter, the chain does not rub, there is a sense of harmony to the ride, which, like I said earlier, is essential to the gestalt.

So now I can say I put the Lemon in Lemond, and when faced with that, made Lemondade.

Ride On and Be Safe Out There My Friends,

1 comment:

  1. I admit I didn't understand anything you said about what you did with your your bike, but I bet your mechanically inclined readers will.

    I am happy that you're happy with your bike. And, I'm very grateful that I know some very helpful bike mechanics at two of my favorite bike stores in Alameda.