vintage BB woes - Fisher MTB

[d_douglas]

Hi folks,

I commute on an old steel Fisher MTB with the 'cool' press-in bearings and axle, like similar Merlins and Fat Chances of the day. About one year ago, the bearings seemed loose, so my LBS with a very good mechanic (who has been around since this vintage of bike) popped out the bearings, and reinstalled new ones - all done.

A year later, I notice theyre wobbling again, so took the bike to a shop nearby to my work with another excellent mechanic. He said that it was a flawed design that really couldn't be fixed. I just asked him to reinstall with lots of Loc-tite and do his best. The wobble is now back.

SO, I heard that Velo Orange makes a BB for threadless or damaged shells and it seems that it wont work on this type of frame. With this information, can anyone advise another option for resolving the case of the loosening crankset? It is a great commuter, but pretty trashed, so I am not keen on any expensive solutions (the $70 VO BB was pushing it, but if it worked perfectly, I might've done it!)

I know Mavic BB's might work, but any other thoughts? The BB spindle is massive - about 130mm long, FYI.

Thanks for any advice...

[icepick_trotsky]

What's the diameter of the shell on your frame? The VO cartridge one states it doesn't work on most MTBs because the 73mm diameter is too large.

[cmbicycles]

Like Icepick said above, you need to measure the width of your Bottom bracket shell. If it is 68mm, the VO might work. If it is 73 you may be looking on craigslist for a cheap beater frame.

Did the mechanics who looked at your bike say the BB shell on yours is no longer round or that the bearings are fitting tightly? This was press fit before press fit was the latest/greatest, so it is just as flawed a design as today's press fit systems... except the WTB system usually had a grease port to flush the bearings with new grease and they would last a long time. They actually worked pretty well, at least on the Merlin's that I have seen still in the wild, but parts are harder to come by so not as practical.

[Repack Rider]

That bearing is a 10x17x35mm bearing originally made for garage doors, but a perfect size for Tom Ritchey to use in his BB. You should be able to get them for about $2.50 apiece. It was the least expensive component on a Ritchey bike.

Remove the circlips and tap out the spindle, leaving one bearing in the shell. Then tap out the other bearing from the inside.

In the shop, Gary Fisher used a 34mm deep socket and a ball peen hammer to drive the bearings in, but you can use an arbor press if you have one..

[d_douglas]

I love the expert feedback !!

To be honest, these two mechanics who have worked on the bike are experts, I would say. I think one even has a Fat with the same setup. They basically concluded that there is play that they can't get rid of in this setup.

Perhaps I am doomed?

[ColonelJLloyd]

The fact that were able to find not one, but two mechanics who knew what to do and did it is kind of impressive.

[d_douglas]

One wrenches occasionally on the World Cup circuit for Team Canada I believe, and the other used to do the same, but now works on all the Parlées, Moots and Colnagos in the city. Oh, and beaten old Fishers

[pdonk]

Is the wobble in the spindle or as asked above is the bearing wobbling in the frame?

If it's just in the axle you can try spacing like with the Cook Bros BB by using washers on the spindle between crank arm and bearing. It adds a tiny bit of drag and preload but does work. Or try locking collars instead of clips. Good luck finding collars.

[oliver1850]

If it's the bearings loose in the shell you can tighten them up with a center punch. Make a row or (preferably) two of shallow center punch dimples around the diameter where the bearing races seat. If they are too deep you might not be able to press the bearings in, so be conservative initially.

[moobikes]

The VO BB is not going to work.

Play in the axle is a very common occurrence with cartridge bearing systems in hubs and BBs that have no provision to provide some preload. It doesn't mean that the bearings are totally dead.

[d_douglas]

Hmmm, I think the whole crankset is wobbling. ie., the bearings are secure but not tight enough together? I think one mechanic said the BBshell has been grooved where the bearings sit, so there is an unavoidable degree of slop now.

[moobikes]

Are the bearings sitting tightly in the BB? In other words, can you see the outer diameter of the bearing move against the BB?

Is the BB axle itself tight against the inner race of the bearing? If the axle is shoulder-less and very worn, it may be sliding side to side.

The inner race/ smaller diameter ring of the bearing, will move a tiny bit side to side. It's just how it is after the bearings gets some use. This is what you are describing when the cranks themselves move a little bit. Unless the entire bearing is also moving.

[Tandem Rider]

If the bearing is moving in the BB, you can try some Loctite stud and bearing mount, one type will fill small gaps. I don't remember the number right off the top of my head, but any really good bearing supplier should have it for you. Caution, you probably will need a press to get them back out after they are worn.

[moobikes]

If bearings are secure then you just need new bearings.
If BB shell is worn, bearing will be loose.
Your mechanic could be describing machining marks in the BB from cutting a shoulder for the bearings to butt against. That's probably not the cause of the cranks' side to side movement.

[charliedid]

If you need a new spindle:

http://www.philwood.com/products/bbpages/spindles.php