Bicycle Mechanics - Loose ball bb's? Are they a good idea?

My Mech said I have a loose ball bb, he seemed happy about this and seemed to infer that it was easier to maintain and repair?
What are the differences in bb types, and pros\ cons of the different types?
This bb could be as old as 14 yrs! I'm impressed with it, (Shimano @ some point made some good stuff.) and intend to rebuild rather than replace- But I may install a different type- Company recommendations welcome.
This is for a mtb.
>jef.

I agree with your mechanic. There are two styles to deal with.
1: the older conventional cup and cone loose ball type that you can open up and overhaul. I've seen these last for over a decade if maintained.
2: The newer styles of cartride bb's. They are easy to install but you can't adjust the preload on the bearings on most. About all you can do with them is pull the seals and relube.

The newer style BB's are light, stiff and work with the new trick cranks but most people wouldn't benefit or notice a "real" difference with them. Your older style bb will limit you on your crank choices here soon enough.

Can you explain pre-load?
I'm running a single chainring (mm's thicker) to a 7 rear cluster.
I am positioned to put max stroke\ force to the bb, and am very 'hard' on it.

There's basically 2 types of BBs: loose ball and catridge. These days, loose-ball BBs are found only on the cheapest bikes, although that is not to say catridge BBs are found on only the best, or all are of good quality.

With regular maintenance, a quality loose-ball is arguably superior to a catridge. It will almost for certain last longer, as the bearings are servicable. Oem cartridge bottom brackets by shimano and campagnolo are not. Plug and play, throw them away.

Many aftermarket cartridge BBs (most notably Phil wood) are of excellent quality and have replacement bearing units and will provide many years of excellent use. But some of them require a little extra prepping of the BB shell to insure good alignment of the bearings, depending on design.

Reality is, catridge bottom brackets are here to stay and are easier for most consumers and establisments alike. You can expect to use a good catridge for 3-5 years or maybe more under normal circumstances. They're quicker and cleaner to "service," as you don't service them, you find the correct size and replace it once they crap out. You can't order quality loose-ball style BB parts anymore, they aren't made anymore.

As far as cartridge BBs go, it doesn't get any better than phil wood. it also doesn't get any cheaper. The Shimano UN5x and UN7x square-taper BB series are also good, much cheaper.

If you want to stick to loose-ball style, start checking on ebay or LBSs with a history.

Can you explain pre-load?
I'm running a single chainring (mm's thicker) to a 7 rear cluster.
I am positioned to put max stroke\ force to the bb, and am very 'hard' on it.

What he's saying you can't adjust any tightness or play in them. Once they develop play, you can do nothing about it other than replace them.

That's what's nice about a loose-ball BB, if they develop play from normal wear and tear, you can adjust it out and prevent damage from things moving in ways they're not designed to.

What does the 1.37 by 24 T designation mean? the other idents are VIA and PA.?
I believe it's of a good quality as Ritchey chose to install in a race frame.
And it has lasted, I'm probably really the first person to hammer on it.

And thanks for the info folks, it's not toast yet, but I want to make the right choices.
I think I'll have it dissasembled by my mech next week.

Ya, i'm looking at the cartridge bb on my Triathelon frame- Man that thing is TINY.
Its totally inside the bb tube.
Is their less flex @ the bb with the smaller inserted cartridge?

If anything, there's probably more with a cartridge, as there is single bearing on the drive side, and the "cup" on the nondrive side is plastic. i doubt there is much difference between the two in reality. If flex is a concern of yours, the newer splined cartidge BBs and accompanying cranksets in theory have less flex, although many will dispute if it's noticable for the majority of people, plus it's more dough.

If anything, there's probably more with a cartridge, as there is single bearing on the drive side, and the "cup" on the nondrive side is plastic. Not all of them are plastic, and there is a bearing on each end of the cartridge.

Are you sure your mechanic wasn't differentiating between loose ball bearings and bearings in a cage? That's what I thought you meant at first. The nice thing about loose/caged bearings (non cartridge) is that your bb will last longer as the bearings wear out first. Once they get pitted or deformed they begin to wear down the bb. But if you replace them early enough, no problem. It's the same with loose are caged bearing hubs. Now, I was just at the older repair co-op in town and the tech was ordering a bunch of caged bb bearings because we was tired of dropping and losing the loose ones. But I can see how they might wear out faster, being on contact with the cage. Oh, and you still can order these bb parts. We do all the time through the Babac catalogue. The only thing with these is that when you repack them you need to be aware of not making them too loose or too tight. You want no play but no grinding either. So when you tighten the lockring you have to have left the bb a little loose as the lockring will tighten it a bit further. Sometimes attaching the crank arm does too, if it's an old crappy bike. So it's a balancing act. But isn't that the case with most of the bike? Trying to get the thing light the designers make one bit serve two functions, demanding more maintenance, balancing.

What does the 1.37 by 24 T designation mean? the other idents are VIA and PA.?


1.37 by 24T is the (BB shell) threading. In this case, English thread

VIA is some sort of organization of Japanese businesses (perhaps for mechanical standards, etc.) of which Shimano belongs.

PA is probably the Shimano date code, PA = January 1991
http://www.classicrendezvous.com/Japan/Shimano_date_codes.htm

I will mention the Babac cataloge, my mech didn't mention obselecence so I guess he has a parts supplier. Hey- yet a new question- is it possible to put in a new square taper axle that: makes my crank arm be say 2-4 mm further out?

Would it be expensive as a part and to install?

1.37 by 24T is the (BB shell) threading. In this case, English thread

VIA is some sort of organization of Japanese businesses (perhaps for mechanical standards, etc.) of which Shimano belongs.

PA is probably the Shimano date code, PA = January 1991
http://www.classicrendezvous.com/Japan/Shimano_date_codes.htm

Right on! Thanks, I dated the frame to 1990, by metal and serial, so 91 sounds right. I'm in Victoria too.

victoria, BC?

Recyclistas Bike Coop, 25 Crease Ave, Victoria BC, V8Z1S4 CANADA. Tel: 250-418-8867. Teach bike repair classes, let people use tools for an hourly $$$ rate and have a lot of parts.

I love this game :)

I will mention the Babac cataloge, my mech didn't mention obselecence so I guess he has a parts supplier. Hey- yet a new question- is it possible to put in a new square taper axle that: makes my crank arm be say 2-4 mm further out?

Would it be expensive as a part and to install?
Yes to the first question. There may be another number embossed/etched on the spindle that relates to its size.

No to the second. But because cartridges are becoming the standard, some bike shops might not have them in stock for you to pick and choose. Referencing the number related to spindle size.

Cup-and-cone bearings are so good that the highest level competition stuff is... cup and cone, so the loosest possible preload on the bearings can be achieved, and hence the lowest friction.

The major problem is the fact that the lower level ones aren't sealed, and therefore grit and water find an easy entry into there. However, maintenance is not too difficult, once you have achieved the art of preloading the bearings. Major maintenance problems are brinnelling of the race surfaces, breakages of the ball bearings, mangling of the ball cage (which you can probably dispense with anyway) and cracking of the cup. The spindles very rarely give any problem.

You could conceivably use a C&C bottom bracket forever. Mass produced cartridge BBs generally can't be stripped, repacked and adjusted... you just turf them.

FWIW, I don't think Shimano stuff is bad at all... they still make pretty good stuff, even in the lower grades.

victoria, BC?

Recyclistas Bike Coop, 25 Crease Ave, Victoria BC, V8Z1S4 CANADA. Tel: 250-418-8867. Teach bike repair classes, let people use tools for an hourly $$$ rate and have a lot of parts.

I love this game :)

Yep Vic, B.C.... maybe I'll go there and do the bearings myself, I'd heard of those folks >thanks B.

Thanks Rowan, I need to get a second plate\ guard to sandwich my chairing- I run a 38T ring mid triple so I have little space 'tween the ring and chainstay. Also it will correct the chainline even more.

I love custom bikes!

Right on! Thanks, I dated the frame to 1990, by metal and serial, so 91 sounds right. I'm in Victoria too.

Cool. I do my own work at home (used to work in a LBS so I've got a lot of tools at home) but if I'm lazy I take my bike to Reckless... but it's nice to know about that place on Crease.

Cool. I do my own work at home (used to work in a LBS so I've got a lot of tools at home) but if I'm lazy I take my bike to Reckless... but it's nice to know about that place on Crease.


I let Jeff @ chainchainchain do my mech, my bikes kinda weird, a few handmade parts, Ha, I even have a 140mm tandem axle on a 16 inch seattube frame mtb? ??

I need a dremel to start drilling speed holes in my parts!
Kinda deter theft and be speedy! :p.

I need a dremel to start drilling speed holes in my parts!
Kinda deter theft and be speedy! :p.
Speed holes in the bottom bracket spindle. Cool!

Speed holes in the bottom bracket spindle. Cool!

Crank arms, spyder, under my grips, the seatpost tube inside the frame....not top, bet it would whistle downhill...umm in the bashguard (which I made and filed rock mounting teeth, kinda like waves.) oh and in the clamps for my handlebar brace.
lots of work for little weight, but it'll be fun.

GOSPEEDRACERGO!

oh yeah, I guess you could make a bashguard out of an old chainring. Duh! I was thinking of buying one or fabricating one from scratch, but it would be pretty light just to use a burned out ring. And free! And no real work! How well does that work for you?

oh yeah, I guess you could make a bashguard out of an old chainring. Duh! I was thinking of buying one or fabricating one from scratch, but it would be pretty light just to use a burned out ring. And free! And no real work! How well does that work for you?

Bikes light, me too so It's o.k, a big boy and bike would need a heavier go.
You need to match the size minus the teeth. I only had a 46, 44- would be nicer over my 38T.
Clip the teeth before grinding ( I took 2 cm off the grind wheel!)
It was o.k as a guard- then after trying it out and slipping on logs I decided to cut teeth into it for traction when hung up.
I started with a dremel (quit after second cut.) then went to jewelers diamond files, I cut 5 sets of 5 teeth where the ring struts are.
The teeth get smaller as they roll onto the thin part of the ring and the first big tooth is where the first strut starts for max strength.
I then smoothed it all out so it will not hurt my leg if impacted.

My first road bike had loose BB bottom bracket.

I went to a bearing supply house and bout some precision balls the same size as in my BB (1/4" I believe) came in a box of 100.

I then took some of the finest valve grinding compound I could get and packed the bearings with this and rode for 50 miles, This polished the races.

The I cleaned the bajebus out of it and put it back together with more of the new Ball Bearings. Smooooth.

If I do not use cages, do I then use more bearings and thus decrease the load? Sounds better.

Can I get those 'made in zero gravity' perfectly round ones? Is there a top steel alloy bearing or a specific 'hardness' or quality I should look for?

Thanks.

Karlfitt, that is soo cool you used your bb as a polisher for the races, not sure if I'm that brave, but it certainly is an idea to consider. Do new races and bearings always need post finish\ pre install polishing?

karlfitt, that's su-weet! Now, what's valve grinding compound? Where do you get it? How much did you use, etc. I really like this idea. Could you use this technique on a hub or bb that has a bit of wear in it, or is it only for minor wear?

I've always used the same number of loose bearings as in a cage. If they're loose you fill it right up, take one out. About hardness, I'm thinking you wouldn't want your bearings as hard or harder than the bb or hubor headset itself since if you're going to have wear you want it in your bearings, which are easy and cheap to replace. It, like most things with bikes, is a balancing act. Go too soft and they're deform and pit quickly, then begin to wear out the cup/cone/race, go too hard and they want get damaged, but the rest will, or they'll all wear out together. Maybe it depends on how well you keep on top of maintenance. If you don't cartridge makes more sense. If you sort of do, then hardering bearings, if you're careful, softer bearings. What do you think?

Ya, better the balls than the races. My consideration of hardness is really the mashing I give the bb and wanting to not have to replace them often.
The ball buster I think I am ;) But you makes sense. The same or softer hardness than the race.

Do you order bearings with hardness level?
Is there a hardness range I should stay within?

Valve grinding compound is for polishing valves in motors. It can be had at some auto parts stores.

Be careful though, it comes in different grits, you want the finest they make. I did a quick search on line and did not find what I used, don't know if it is still available. Sears carries it too, but not grits listed on the web site. It used to be graded like sandpaper, but all i found in the quick searh was "fine". I used 2000 grit.

I packed the bearing like with grease. BTW, it was not new, I bought a used bike and went through it. Polished the BB and the hubs the same way, different size Bearing though.

It polishes the races and the shaft at the same time.

If I wasn't sure the compound I was using was 1000 of finer, I wouldn't do it again, might undo what the factory did.

Then again if you were really wanting to do it, there are other grinding and polishing compounds out there. :D . It just depends on what your hobbies are where you would start looking for them.


Final warning, you must clean it ALL out before putting the next round of new bearings in with your clean grease. Any grit you leave will accelerate wear on your BB or hubs.