Word, as I was having a devil of time with calipers. Especially after drinking a moderate amount of scotch.
Ceramic Bearings?
- Thread starter nowlan
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bearings in general is a bad thing for suspension links since the don't do a complete revolution...
besides that, a friend of mine is a pro bmx'er and he shattered a bb and the bearings in his wheels, the bearings simply wore out the races (dunno if its the right word, but the circular case that houses the balls) often it's only the balls that are ceramic and the races(^^) are plain steel, some of the pro roadie teams in tdf got ceramic balls and races, but those bearings are very pricy.
(it wasn't the cheap stuff he smashed, it was ceramic speed, but now he's back on his old ck hubs and bb)
besides that, a friend of mine is a pro bmx'er and he shattered a bb and the bearings in his wheels, the bearings simply wore out the races (dunno if its the right word, but the circular case that houses the balls) often it's only the balls that are ceramic and the races(^^) are plain steel, some of the pro roadie teams in tdf got ceramic balls and races, but those bearings are very pricy.
(it wasn't the cheap stuff he smashed, it was ceramic speed, but now he's back on his old ck hubs and bb)
Ceramic bearings were created for extreme high speed. Something a bicycle doesn't see, especially the bb. Ceramics also were not intended for shock loads. Something a downhill bike sees a lot of, especially the bb. Using ceramic bearings in a bike makes about as much sense as using caviar as grease.
wow, you are one smart engineer. you need to work for a bike company i guess.
since FS MTB bikes were invented until the mid 2000's lots of companies used bushings in their suspension. now almost none do. i guess they dont have cool engineering bearing experts like you working there....
What a well articulated argument. Lmao. Try again slugger.
ok, since you dont understand sarcasm, let me break it down for you:
up until 10 years ago there were a lot more bushings in FS bikes than bearings. now there are almost none. why do you think that is, in your expert opinion?
The cost of bearings has dropped tremendously in the last 10 years due to overseas manufacturing. You can now buy a bearing for about the same price as a bushing, and because most people perceive bearings as a better part(in a lot of cases they are) it makes a better standpoint. Talk to any bearing expert, they will agree that a ball bearing is not the best fit for that application. There is nothing special about a bicycle suspension pivot.
you are absolutely right that its not the best application for a pivot with high load relatively to the size of the bearings and that in some cases only rotates a few degrees.
however
deep groove ball bearings are way better than the alternative: bushings or needle bearings, or angular contact bearings.
bushing suck because they are not sealed at all and get fvcked by mud. and if that wasn't reason enough, if they get just a little bit loose, they will ovalize the bore in the frame/CS whatever in as little as one ride. leaving you with an unfixable fvcked frame.
needle bearings suck because of the obvious reason they cant do side load, and get destroyed by a small amount of dirt.
angular contact bearings in suspension pivots generally suck do to a lack of quality control in factories over tightening the shlt out of them, not to mention clueless owners.
i am not making this shlt up dude, these are the reasons why 90% of bikes use ball bearings in suspension pivots.
too bad they dont teach real world shlt when you get you bearing enjurneer degree....
however
deep groove ball bearings are way better than the alternative: bushings or needle bearings, or angular contact bearings.
bushing suck because they are not sealed at all and get fvcked by mud. and if that wasn't reason enough, if they get just a little bit loose, they will ovalize the bore in the frame/CS whatever in as little as one ride. leaving you with an unfixable fvcked frame.
needle bearings suck because of the obvious reason they cant do side load, and get destroyed by a small amount of dirt.
angular contact bearings in suspension pivots generally suck do to a lack of quality control in factories over tightening the shlt out of them, not to mention clueless owners.
i am not making this shlt up dude, these are the reasons why 90% of bikes use ball bearings in suspension pivots.
too bad they dont teach real world shlt when you get you bearing enjurneer degree....
You can easily seal a bushed pivot. its quite simple. Even without being paired with a seal a sintered bronze bushing shines in dirty environments, thats their biggest use. If installed correctly you wont hurt The frame since the motion is around the bolt or pin. The o.d. of the bushing should be a press fit. Are you trying to tell me construction and excavation equipment dont see dirty or harsh environments? Give me a break.
What he said.
Also look at what MX bikes do people, needle roller bearings, and spherical rod end thingys on the shock.
No shortage of side loadings there, all dealt with nicely with a thrust bearing/ bush setup.
And on another note, dont Turner still use bushings in their bikes, I've not heard any rumblings about bushing wear problems on any of the Turner riders I know. And one in particular does a lot of riding in muddy glop and anything else he encounters on back-country epics.
Oh, and for the record, I R an injaneer, by trade even.
I made a bronze bushing setup for my old Stab which is still going about 10 years on!
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Nicolai is also using a combination of needle bearings and IGUS bushings on their Horst Links:
http://www.nicolai.net/manuals/manuals/11-Fig_Horstlink_09.pdf
And I don't think I have heard people having reliability issues with them.
http://www.nicolai.net/manuals/manuals/11-Fig_Horstlink_09.pdf
And I don't think I have heard people having reliability issues with them.
They suck, they are the only bad part of a Nicolai frame, but they now offer self lubing resin bushes you mention that sound really good as long as the dirt doesn't get in. I'll get them for the next rebuild, not riding seems to make my bearings last a long time.
I don't understand the whole spenshion bearings need to take massive side loads argument, you have a rigid structure with multiple pivot points it can't really just flop around if the bearings don't have any radial play side load shouldn't really be an issue.
I'm unemployed by trade so I'm an expert at everything.
This. Word is back in the day, Turner asked engineers what would be the best bearing for the application, got the answer of angular contact, except that the limitations of design, cost and implementation made those impractical, he asked what would be the best compromise, and IGUS type bushings with grease ports were the answer. This was a well thought out process, rather than many manufacturers that just slap a few skateboard bearings in there and call it good. The big-hit turners like the Highline and DHR have needle-bearing main pivots. The tolerances needed for some off-the-shelf bearings are not all that great, and they are great for marketing purposes (see how smooth it is!, etc). Let's remember those first-generation suspension bikes also had tiny pivots, no matter what kind of pivot it was, with tiny frame members, and they were just poorly executed all around. These days I'm sure bearings are being used due to how cheap they are to implement. There are work-arounds, like doubling up bearings as ventana does, but it doesn't really address the inherent limitations, we only want the pivots to rotate a few degrees, and we want them to be very laterally rigid.What he said.
Also look at what MX bikes do people, needle roller bearings, and spherical rod end thingys on the shock.
No shortage of side loadings there, all dealt with nicely with a thrust bearing/ bush setup.
And on another note, dont Turner still use bushings in their bikes, I've not heard any rumblings about bushing wear problems on any of the Turner riders I know. And one in particular does a lot of riding in muddy glop and anything else he encounters on back-country epics.
Oh, and for the record, I R an injaneer, by trade even.
I made a bronze bushing setup for my old Stab which is still going about 10 years on!
Think about your car's suspension, why doesn't that use ball bearings? Ball bearings are terrible for limited rotation applications, have always been, will always be. Needle bearings for some pivots (which need to be used with a bushing for the lateral aspect), but this debate gets pretty ridiculous.
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