Saturday, March 7, 2009

Motobecane Grand Touring Teardown

Good progress on the latest addition to my herd, this week. As I mentioned in my last post, I'd started the process of tearing down the Motobecane. And I've been rebuilding individual components and sub-assemblies, and even done a little final assembly work.

I mentioned that the fork is kind of messed up. It's a pretty, crowned steel fork (with some detailing on the crown, and chromed lower legs), but not an expensive one. The dropouts are stamped (not forged), for example, and the legs are welded into the crown (not brazed). The fork is of the French spec, and it's held into the frame with a low-profile OEM (cheap) steel headset that's got some unfixable rust on the chrome. The steerer has been cut unevenly and too short to really hold the locknut, and any replacement French headset of quality I could find would have a taller stack height. So essentially the fork is unusable on this bike, but it could be mounted readily enough in a frame with a shorter head tube. Might be worth a few bucks on eBay.

Replacing the fork will be simple but expensive. I'll need a chromoly fork and a headset of course, and either of these could run $20-$120, depending on how crazy I wanted to get. And while at it, I would make the shift to British specs, which would mean changing bars and stem as well. I'll have to do those two pieces eventually anyway, but let me stick to the frame and fork for a sec.

The frame is of Vitus 172 double-butted chromoly main tubes, and probably a milder steel rear triangle. The chainstays are spot welded and then brazed to the BB shell, and the construction is otherwise lugged and brazed. The rear dropouts have no eyelets (which still boggles the mind, honestly, given the bike's name), but they're nice, forged Gipiemme pieces threaded for axle adjustment screws.

Everything but the headset and the front derailleur mount (more on that in a sec) has been pulled off the frame and cleaned up, and the frame itself has been cleaned up (but not zealously) and waxed. The frame looks to be in good shape, though my eye registers something not quite right about the right rear dropout's alignment. It looks OK clamping in the rear wheel, but I'm still seeing something amiss, and need to figure out how to check that. Maybe take it over to a LBS to check the alignment.

The bike came with Suntour VX pieces originally, but Steve had upgraded most of that. The crankset is the original SR Apex model with the usual specs -- 170mm arms and 42/52 chainrings. The Apex crank is a midrange piece -- nice aluminum arms, but the spider is swaged to the right arm, rather than being formed with the arm as a single piece. I've cleaned the crankset up and rebuilt the MKS pedals (which say VX on them, interestingly enough, so they may have been an OEM part of the Suntour groupset). I'm going to keep the crankset as-is for now, but I prefer the feel of a 172.5 crank arm and may change that up at some point. I've been thinking about putting a compact crankset on the Schwinn, to get a lower low range without having to go to a triple. If I do that, I'll have the Schwinn's 172.5 crankset with 39/52 rings on-hand, and it'd bolt right onto a narrower BB spindle. So we'll see.

The BB has been removed, repacked with new balls and grease, and reinstalled. The races and spindle all seemed fine, and that's a good thing because it has Swiss bottom bracket threading, not French (I have a spare set of French cups, but not Swiss). I'm actually kicking myself a little, because when I bought the Allegro frameset I bought a Phil BB and rings to go with it. Then when I listed the frame on eBay, for some reason I threw the rings into the equation. In any case, if I swap the crankset around later, I'm going to have to buy a set again ($38) and find either a used Phill BB or an old Shimano unit to strip of its cups.

The front derailleur is a basic but nicely engineered Suntour Cyclone II model. It has an interesting mounting system, where there's a band/post combination that you clamp around the seat tube (you can make this out in the top photo), and then you mount the derailleur to that contraption's threaded post. Honestly it seems needlessly complex, but it's a neat piece of engineering, and I bet this simplified supporting the various seat tube sizes that were more common 25-30 years ago than today. The derailleur is blocky in an early 1980's sort of way, but it's nearly all aluminum and looks nicely made.

The rear derailleur is a matching Cyclone part. It's simple and delicate by the standards I'm used to (nearly everything I have wears a Shimano derailleur from the 1990's, which tend to be more sculpted and have more stuff grafted to them). I took it partially apart, cleaned and regreased the cage pivot spring, cleaned and regreased the pulleys (which both feature a bushing, unlike any of my Shimano derailleurs, which have one nice pulley and one crappy one), and lubed the link pivots. It's all clean and pretty, now, and I'm looking forward to seeing how well it shifts.

Actually, if I can digress for a minute, one of the things I'm really interested in experiencing with this bike is the shifting quality. The teeth on the freewheel are not "shaped" like those on a contemporary Hyperglide or similar rear cluster. And the derailleur is a more or less modern parallelogram design, but an old example of the breed. There are videos up on YouTube that show how different generations of derailleurs shift, from older Campagnolo models to Suntour models only a few years newer than mine to newer Shimano stuff like I normally ride. Some of these need adjustment, but it's fascinating to watch these clips if you're a bike geek.

Oh, gosh -- I just admitted to being a bike geek. Well, I guess that's OK -- you knew.

Anyway, the point is I'm used to drivetrains circa 1995, and I'm dialing the clock back 15 years or so from there, and I'm curious as to how different the shift quality will be. And I suppose someday I'll have to get a new bike to see how current stuff works -- probably ridiculously well.

The shifters on the bike are Campagnolo Gran Sport, I think. They're basic, classic, clamp-on Campy friction units. Pretty and smooth, and a bit of a throw-back. I'm using retrofriction Suntour bar-end shifters on the Schwinn, and like the micro-clicks I get with those. And I've tried the friction settings on my Shimano shifters on other bikes, and not been terribly happy with them. So we'll see how these work out. I can always find a set of Simplex retrofriction shifters at some point, if I don't like the experience. Or maybe the set of Silver bar-ends from Rivendell I've been promising myself for over a year.

Lastly, I picked up a SRAM chain like I have on most of my bikes. That's still in its little box, but it's a chain, so there's really not much to see, there.

The brakes were once the nicest components on the bike (Suntour Superbe), but they've needed/still need some help. For one, the caliper springs are pretty rusty. My guess is I'm going to have to replace them, but I haven't found any online, and need to do more digging. Initially I wasn't too worried about the rust, but in playing with them, it's clear that the small contact points between the spring ends and the calipers need to be treated like bearing surfaces, and that rusty springs won't be healthy for longevity or smoothness. The other issue is that the aluminum adjuster barrels/cable stops were frozen. They popped right out without damaging the calipers, but the adjusters wouldn't turn -- completely frozen up. So I did some research online and found that Campagnolo parts are a good replacement option. For the Superbe levers, I've ordered a set of replacement hoods as well. The levers look to be in nice shape, and they're drilled and quite pretty.

The brake pads are OEM Suntour salmon pads, and my initial approach has been to simply sand down their braking surface to expose fresh pad compound and clean some grit out of them. We'll see how they feel. Easy enough to replace them if they don't bite anymore.

And that goes for the brakes in general, actually. I've toyed with the idea of running a cantilever fork and front brake just for grins, and I may do just that if I don't like the way the Superbe brakes feel or if I just feel like doing something different.

The SR seatpost is a very interesting design, and I'm assuming it's an OEM component. It needs to fit in a French frame, so it's a 26.0-diameter post. It's a two-bolt design, and it's a sort of hybrid between the design of the two-bolt Campagnolo post I put on my wife's Bianchi, and an old side-clamp/straight post design. The inner halves of the clamps are riveted to the post, and the rivets serve as pivots to allow the saddle angle to be changed. The outer halves of the clamps are through-bolted to the post body, and the two clamping nuts are right next to each other, nestled in the center of the post. It's a complex and interesting design. Not light, and probably a lot more expensive to make than a modern single-bolt design. Neat stuff!

Last weekend I put the red Selle San Marco saddle that was originally on Juli's Fuji onto the Paramount, where it coordinates nicely with the red cable housing on that bike. Then I took the old brown Brooks Team Professional that I've had on that bike for a season, and bolted it to the SR seatpost for the Motobecane. The saddle has been pretty heavily oiled this winter, and it showing signs of heretofore unseen softness. This will be the saddle's last chance to serve as a functioning bike part -- at least for me. If it doesn't work out, I'll let it dry out again, give it a few shiny coats of clear shoe polish and put it somewhere as a piece of cycling decor. In that event, I may move the green Brooks from the Paramount to this bike, and wrap the bars in matching green leather tape. I think that combo would work very well with the Motobecane's champagne metallic paint. Then I can use a black or honey saddle on the Schwinn, which might look better with its orange paint.

Bars and Stem
Lots to do up here, as I started to touch on earlier.

The bike came with a set of steel MTB bars threaded through a steel riser stem (I think to the old US/BMX steerer spec, actually, so it fits the French steerer, but not tightly), with a set of inexpensive Shimano MTB levers on it. The bar actually started life as a nail-polish pink, it seems, and had been resprayed. In any case, it's not quite what I was looking for.

Steve supplied the original Pivo stem (sans quill and quill bolt) and Pivo drop bars, with the original Motobecane plugs(!). The stem is in nice shape, and for someone with the right parts to complete it, might be a useful spare. But I don't have the right parts. The bars have a nice enough bend, but they're scored where they rotated at some point in the clamp and I don't trust them. But I'm going to use them in the MTB stem for a test ride, and then recycle them when I replace the fork (these are not an eBay candidate -- I don't need to get sued).

I have a set of Belleri bars waiting for installation on the Schwinn, and I'll set aside a half day to do a massive bar/stem swap. I'll move the Nitto bars from the Schwinn over to the Motobecane. I also have an '80's Nitto stem I can use, once the fork is replaced to British specs. I'll probably leave the steerer tube long and add spacers under the headset's top nut to let me raise the bar up a bit. Alternatively, I can go with a threadless setup, but there's more to buy in that case. In any case, the frame is bigger than the Kestrel's, but smaller than the Schwinn's so a bit of rise in the bars will be helpful.

I have a V-O decaleur mount that I'll also install. This one is different than the one I have for the Schwinn, in that it doesn't bolt to the bar clamp on the stem, it mounts as a headset spacer/washer. Depending on what I decide to do for a fork and/or for brakes, I'll have some options for a rack to support the decaleur-mounted front bag from underneath:
  • If I go with a cantilever fork/brake setup, I can run a Nitto M-12 rack up front and that will be more than strong enough for heavy loads up front.
  • If I stick with the Superbe brakes, I can use any number of front racks, depending on what the fork supports -- Velo-Orange has a few models that mount either to P-clamps or eyelets on the fork blades, or down at the dropouts through eyelets, and Rivendell offers a couple of Nitto Front racks (the Mini front and Mark's Rack) that'd work just fine as well.
  • If I decide to retro the bike out a bit, I could use a set of Mafac brakes with a little Mafac rack I have for those brakes.
Lots of options, in any case, and that's part of what's making this a fun project!

Either way, I need to fit my decaleur mount to my new handlebar bag. I didn't bother last season, because I got it very late and needed it for a camping weekend I did. But it's time to do that. Since I'll be using it on two bikes, I may need to do some fiddling/refitting to find a position that will work for both, and I may not be able to pull that off, given the bikes are different sizes -- I'll find out. I'll also have to remove the bag-side part of its plastic quick-release mount, since that'll be in the way.

For the rear, I'm planning to re-use the Viva bag support that was on my wife's Bianchi until recently. Alternatively, I might use the Rivendell Hupe I bought for a friend. It fits on the frame it was intended for, but not well, and we're going to experiment with the two racks to see which works best for each frame. We'll re-gift appropriately, as needed.

I'm still really digging the new Rivendell Sackville bags, particularly the medium one. The price tag is a a pretty big investment in a bag (for a Yankee like me, anyway), but at the same time, it'd probably last forever, and I could move it between the Motobecane and the Schwinn as needed. And if at some point Rivendell makes a handlebar bag (to match, mind you), that might be a nice investment as well.

Hopefully by next week I'll be able to share some riding experiences, rather than just doing a show & tell about parts.

All for now,



qwerty said...

Great.Picked up same bike t flea market ($75) Love the bike. Thanks for the article

John said...

Enjoy it! It continues to be a favorite ride of mine, despite its issues (largely age-related)