[DßR]

Do the seals on cartridge bearings really make any difference? Metal sealed bearings seem to be a bit cheaper, are the metal seals any less effective? Is there any effect on the side-loads that the bearing can take (I realize that on a non-angular-contact bearing, the side loads it can withstand are very low, but still)?

I'm puttin together a big order of bearings for a few pairs of pedals and for my DH bike so I was just wondering....

 

[Repack]

Ususally, the metal isn't really a seal. It allows dirt in. The plastic you see is actually covering a brass washer. B/c the plastic presses into the bearing races, it is sealed.
"Cartridge", "sealed", "loose pack" are terms that can be used in many combinations. For instance, a Shimano XT hub is not cartride, but is sealed. You can also have a cart bearing that is not sealed, a sealed cartridge bearing, and an unsealed loose bearing.
Kinda confusing, eh? Just a few things to be aware of.
And I cannot see the seal type having any effect on strength. I may be wrong, but I believe that the metal sided bearings you are mentioning are pretty (ghetto) cheap. Most cart bearings retail for $10 or less, at least the 6*** sizes (hubs).

 

[DßR]

Yeah I guess "shields" is a much better term than "seals". The price difference between the metal and rubber doesn't seem to be too much in the sizes I'm looking at though.

The main reason I asked is that my SGS has 608 RS in the shock link, and 608 ZZ in the Horst Link/seatstay pivot (only difference being the shield type). Just wondering if there's any reason for doing that or if I could get away with simplifying my order to reduce the chances of the supplier screwing it up.

 

[EBasil]

You guys know those 608's are what's used in skateboard and inline skate wheels, right? You can get 8-packs of the ceramic ball 608's on eBay for 10-15 bucks. The ceramic balls are tougher than the steel ones, and weigh like 300 grams less, maybe even a couple thousand grams. Well, they are far more corrosion resistant, at least. They are oiled rather than greased, so you would be able to service much more easily, too.

They are also deadly fast in a longboard with Flashbacks...

 

[D_D]

Both the plastic and metal shields on cartridge bearings are useless. At least with the plastic shields you can remove them to clean and regrease instead of just throwing the bearing away.

I would only get the metal ones if they are a lot cheaper and you never ride near water or mud.

 

[ohio]

plastic works mildly well to hold grease inside the bearing. Metal doesn't do a whole lot except shield from large debris in industrial applications... usually in an oil bath. You want the plastic seals.

And yes, ceramic hybrid bearings are pretty sweet. I don't know if I trust them off eBay though. Timken is local and supplied us for a project one time, and even the bulk prices on ceramics are nowhere near those prices...

edit: had a look at ebay. Timken's are a dark gray (almost black), so it's something different on eBay... but if it works, it works. I'm ordering a set for my board right now. We'll see how they hold up.

 

[Sir_Crackien]

metal seals ok
rubber seals good but not great
teflon seal great

leard this from R/C cars. also hold true for every bearing application

 

[ohio]

Originally posted by Sir_Crackien
also hold true for every bearing application

No. different applications, different needs for sealing. RC cars run really fast rpms and really low loads. The most important thing is low friction, NOT sealing.

MTBs run low rpms, high loads, and nasty wet environments. The most important thing is load handling and sealing (to keep grease in), not low friction.

 

[Sir_Crackien]

r/c cars need to keep the grease in and they do have very high load part on them. like the crank shaft. one of the engines that i'm using produces 2.6 hp. that is more that any human and the vehical that is in is designed for large jumps. i've seen one like 10' in the air and land safely. also many time people run their r/c cars in very muddy situations do you not think that is high stress than what is. also remember that the bearing in r/c vehicals have to be small.

also answer this question

when you go to buy new bearing the one that are consistered the highest grade are teflon sealed?

 

[EBasil]

Originally posted by ohio
I'm ordering a set for my board right now. We'll see how they hold up.

That's the spirit: real world testing. Let me just tell you that the hybrid ceramics in my longboard wheels suprised the hell out of me. They roll fast. I think I'm going to buy some cheapo bearings I can fill with sand...

One of the cool things about the hybrid ceramic bearings is that the balls can't cold-weld to the race, ie they should be WAY, way more resistant to corrosion and pitting than even the high quality bearings used in MTB pivots. They aren't readily available in all sizes, of course, as I learned with my cranks.

 

[DßR]

Does anyone know if it's worth it to buy the really expensive cart. bearings for the pivots in a DH bike?? Mine were roached after a season, which is fine, I have no problem with that, but just wondering if I bought some of the $50 bearings, if they'd last significantly longer. Or is it just that DH bikes are a poor application for cart. bearings?

 

[Repack]

Originally posted by DßR
Does anyone know if it's worth it to buy the really expensive cart. bearings for the pivots in a DH bike?? Mine were roached after a season, which is fine, I have no problem with that, but just wondering if I bought some of the $50 bearings, if they'd last significantly longer. Or is it just that DH bikes are a poor application for cart. bearings?

I would say that there would be a difference, but it is tough to say just how much. One observent complaint that I have heard about cart bearings is that they do not handle side loads well (its a fact). This is one of the main reassons that Shimano has been hesitant to put cart bearings in hubs. Have you ever looked at hub cups and cones? The interface between the races and balls is angular. Thats why people make such a big deal about angular contact bearing equiped headsets. The angular aspect of them lets them support loads along most (maybe even all?) axis. One limitation of such bearings is that they take up more space. I am sure thet some bearings last longer/better than others, but the fact remains that standard cart beraings are not the ideal type of bearing to put in suspension pivots because of all the side loads they incur. BUT, cart bearings are far better than any alternative currently available.
I don't know if this really answered your question, but I hope this at least helps.

 

[Sir_Crackien]

as for super high quality bearings i know that a company named Boco or Boca make some if the best bearings in the world. but i don't remember the price or size avaliablity. but these bearing sould last for seasons. as for putting cartrage bearing in suspendion desings is an ideal application because the rotation of the swing arm will load the bearing in an up down forward backward direction and not laterailly. look at it. it makes common sence whne you think about it.

 

[Repack]

Originally posted by Sir_Crackien
as for putting cartrage bearing in suspendion desings is an ideal application because the rotation of the swing arm will load the bearing in an up down forward backward direction and not laterailly. look at it. it makes common sence whne you think about it.

Rear suspension bearings take loads in every direction. Every time you turn your bike, you are twisting the frame members, putting side loads on the bearings. Everytime you sprint, the same thing is happening. Everytime you stuff it into a berm, the frame is twisting. Have you ever gone so far and hard into a turn that the tire rubbed the stay? Thats also the frame being twisted and the bearings being side loaded.
Think about it this way. Imagine a hub and a pivot point take the same grade bearing. The hub feels fine after a year, the pivots feel like junk. What are you willing to bet that the hub bearing has probobly made at least 10,000 times the number of revolutions as a pivot bearing?

 

[ohio]

Originally posted by Sir_Crackien
r/c cars need to keep the grease in and they do have very high load part on them. like the crank shaft. one of the engines that i'm using produces 2.6 hp. that is more that any human and the vehical that is in is designed for large jumps. i've seen one like 10' in the air and land safely. also many time people run their r/c cars in very muddy situations do you not think that is high stress than what is. also remember that the bearing in r/c vehicals have to be small.

also answer this question

when you go to buy new bearing the one that are consistered the highest grade are teflon sealed?

I doesn't matter how much power the cars are outputting, the bearings are NOT seeing high radial loads. I didn't say it wasn't "high stress" (although it isn't high stress, according to the engineering definition) I said it wasn't high load. It is a different application.

Also, I can't answer your question because I can't understand it. Is it even in the form of a question?

 

[ohio]

Originally posted by Sir_Crackien
as for putting cartrage bearing in suspendion desings is an ideal application because the rotation of the swing arm will load the bearing in an up down forward backward direction and not laterailly. look at it. it makes common sence whne you think about it.

no. there is a ton of lateral (z-axis) loading in bicycle suspension, in addition to the radial loading. fortunately almost all the cartridge ball bearings you purchase are angular contact, which means they can handle the load.

DBR, yes, better bearings will last longer. Whether it's worth the $50 is up to you, but have a look at McMaster.com and you can see the difference in load rating vs. bearing grade and material. It's not a cheap supply house though, so it may make sense to order from elsewhere.

 

[Repack]

Originally posted by ohio
fortunately almost all the cartridge ball bearings you purchase are angular contact, which means they can handle the load.

Are you sure about that???

 

[ohio]

Originally posted by Repack
Are you sure about that???

skateboard bearings are. otherwise they would fall apart every time you tried to turn.

doesn't necessarily mean they support HIGH thrust loads, but they'll support some.

you can buy either, but you'd have to screw up to NOT get angular contact bearings for your bike or board.