Roypercy

Hey all:

I'm a longtime rider, but really trying to learn to diagnose and fix my own problems as I'm getting more and more into vintage bikes. I'm having one of those can't-quite-put-my-finger-on-it issues with my "new/old" bike and could use some advice.

I just bought a 1984 Motobecane Grand Jubilee, a really nice bike, but this example hadn't been maintained or ridden in quite a while. Because it needed new tubes and wheel truing I took it to my LBS for a basic tuneup (and won't go there again, but that's another story).

I took it for a test spin last night after work. The bike fits me great, the frame is straight and in good shape, the Campy derailleurs shift like butter, it should be a great ride. But there's some kind of issue going on.

The bike has a Maillard Helicomatic hub and cluster. I noticed when riding last night that the pedaling just seemed more - well, effortful than it should have. I'm used to the feel of a '74 Raleigh Super Course MkII, which is a relatively smooth bike. On the Moto I felt like I was losing a lot of the energy I was putting into the cranks. In addition, I noticed a troubling amount of distension (is that the right word?) on the rear wheel as I pedaled. At moments under effort the rear wheel would rub against the frame slightly, although when I stopped it seemed the rear wheel had returned to its normal spacing (so it wasn't set loose in the dropouts and just sliding forward). And when I hold the rear end of the bike up and spin the back wheel, it seems to spin freely - no obvious obstructions - but seems to spin down to a halt rather more quickly than when I do the same thing with my old Raleigh, which seems to spin quite a bit longer (a very unscientific test, but there you have it).

I'm thinking the rear hub may be shot, that what I'm experiencing is bearings going bad and allowing for so much slop in the wheel. Does that make sense? Or should I look elsewhere for the problem? IS this something I could address by cleaning and repacking the bearings? How would I tell if the hub is salvageable?

I'm planning on getting a new rear wheel anyway, with a conventional freewheel. Given the Maillard's bad rep, I'd just feel easier on long rides having something more durable, more familiar that is easier to get serviced at bike shops. But I'd like to service the Helicomatic if possible and keep the wheel intact as a backup. And I'd just like to learn how to do these things for myself.

Any help is greatly appreciated!

Roy

Bianchigirll 

My first peice of advice is to post pics!!! OK did you take the wheel out and reinstall it and close the QR yourself? while the wheel is out grab both ends of the axle and check to be sure it is not broken. take the skewer out and check the threads to be sure it is not slipping.

how is the gearing compared to the Raleigh? did you try the wheels from the Raleigh in the Moto?

David Newton

Well, don't ride it like that!
Check all the frame joints, one of the rear stays could be loose at a joint, or cracked.
For it to be rubbing on a stay, then spring back to place when at rest, something major is amiss, if it is not a slipping QR.

Ex Pres 

I'm with BG and would check for a broken axle first.
Check the overall bearing settings. Loose cones will let the hub "flop around".
Then check spoke tension. Just pluck 'em all around the wheel. You'll be able to tell if some are too loose.
Then grab the sprockets and see if the freehub seems loose on the hub.

khatfull

+1 to all...

1) Check for a broken axle.
2) Examine the bottom bracket shell and all the junctions of the stays for cracks or other issues.
3) If you have relatively large tires on it on HARD efforts you might be flexing the frame enough to rub, that wouldn't be unheard of. How much of a gap is between the tires and chainstays at rest?
4) Do check for loose spokes but if some were so loose as to cause this CERTAINLY the LBS would have caught them in the truing.
5) Pick the rear of the bike up off the ground, grab the wheel and wiggle side to side, there should be no play.

Let us know how it turns out.

Roypercy

Thanks for the replies, everyone!

Out the door on my way to work this morning I did inspect the stays, there aren't any flaws I can see. I wasn't able to make it flex by hand (for what that's worth). The frame also does not seem to be bent at all, unless it's so subtle that I can't see it. I didn't have time to pull the wheel and check the skewers and the axle.

However, the PO did install pretty chubby, high-profile 27 x 1 1/4" tires rather than the 27x1" that would have come with the bike. And even when locked down, the hub seems to have some play in it. This problem was happening under effort when the chain was on the outer (smallest) sprocket on the back, so is it possible that this is aggravating whateve rdish is inherent in the hub? I had a 1980 Moto Grand Record back in the day, and I do remember that even with skinny racing tires, there was some art to placing the rear wheel properly after taking it off, to prevent the tire rubbing on the stays. It could be that with whatever flaws the hub is showing, plus the larger tires, the wheel just can't meet the slim tolerances for the frame. I have heard that the old maillard Helicomatics are bad about excessive dishing.

I will try pulling the tire and checking all the things that were mentioned, and I will also try putting on the rear tire from my Super Course on the Moto to see if there's a difference - thanks for the suggestion, Bianchigirl! I can't believe I didn't think about that (d'oh!) The gearing on the Raleigh is similar; the Moto is 13-26, the Raleigh might be one or two higher on either end, (don't remember off the top of my head) but not enough to have accustomed me to different gearing enough to make the difference.

The adventure continues. Thanks for the help, everybody, I'll keep you updated.

dbakl

Grab the wheel at the top and see if it moves side to side: could be a loose hub. Squeeze a few pair of parallel spokes: should be pretty firm.

3alarmer 

+1.....whenever I've seen this it's almost always either very low spoke tensions
or more often too much end play in the axle within the bearing assembly.

Otherwise, I got nothin'.

Roypercy

Okay, the plot thickens...

So I tightened up and repositioned the skewer on the back wheel, and seem to have gotten it properly centered... no more tire rubbing, although the rear tire seems to be awfully close to the seat post and the stays in its "normal" position. But in working over the bike and checking the seat stays for cracks I discovered two dents on the underside of the down tube - one about the size of a dime, the other smaller - I hadn't seen them when I looked over the bike before purchase because the paint is not compromised at those points, but I can feel them when I rub my hand along the underside of the down tube. I'd say the depth is a few mm.

I took a decent-length ride on Saturday and the bike did... okay, but still feels kind of wonky. I'm having trouble adjusting the FD to keep the chair from rubbing at one point in its revolution when on the larger chainwheel. I wouldn't be surprised if the BB needs to be overhauled, but don't know if that's causing the problem.

So now the question is: is this frame safe? Do you think it's been compromised by whatever caused the dents? I can't see any cracks anywhere, and the frame looks straight. I'm seriously bummed about the dents, but if the bike is otherwise ok I'll just write it off to my eagerness to get that model, and continue refurbishing the bike. If the frame is compromised I need to contact the seller right away and try to get my money back. I didn't really want this much of a project bike, and if it needs serious work I've spent too much on it already to justify that kind of expense.

Any advice? And thanks for the advice so far.

Roy