Why do makers use ball bearings instead of bushings for pivots?

I had a Turner XCE, road 10,000 miles on that bike and never rebuilt the suspension. Never had a single squeak or issue. Turner used bushings instead of ball bearings for all the reasons you mentioned.

In the 90's pretty much all fs suspension was made of bushings.

They flogged out fast, got sloppy and or were stiff providing stiction. You needed to grease and maintain them often.

It was a revolution when manufacturers swapped to bearings. All of a sudden you got smooth supple laterally stiff suspension that didn't flog out anywhere near as quick as bushings.

What bushings did survive in mtbs is in shock eye bushings and within shocks and forks themselves.

I think bearings are far better in applications where you cant submerse the bush is a liquid oil bath and you need l smooth low friction movement with side loading.


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Bushings suck. Only place on a bike I haven't experienced short life spans is on the one shock eyelet that barely moves. Look up banshee bikes from the late 00's and early 2010's. They had so many pivot bushing issues it almost put them out of business. Even if durability wasn't an issue they tend to have a lot of friction. They are cheap, and light which makes them appealing but they suck.

Those of us who have been around are seriously scared from the use of bushing in pivots in the 90s and early 2000s. Maybe with todays stiffer frames and better tolerances they work but bearings are pretty darn reliable nowadays.

Lots of locations of the bike suspension where a properly designed, speced, and toleranced bushing would be the cheaper, lighter, and easier to maintain design over a ball bearing. In the early days when lots of poorly designed bike suspension was out there I feel bushings got an undeservingly bad reputation when poor design was the issue. I think a lot of it is market driven now based upon misconceptions. I think a lot of people see "all ball bearing pivots" in the marketing literature and assume that ball bearings are the best design regardless of the load and rotation the pivot actually sees.

You said they can't become internally contaminated. My experience is grit will find it's way in which doesn't just grind the bushing it can grind whatever pivots inside it. I've worn out a few vault pedal axles because of this. At first I couldn't' figure out why fresh bushings developed play almost instantly then I realized my axles had slowly worn down to the point where fresh bushings still had play. Bearings won't do this even when they are shot. Generally speaking, bearings will grind themselves up to the point of screaming at you to replace them before damaging other components.

Most of the problems mentioned above existed because builders used the wrong types of bushings, shafts, or designed the suspension poorly. Oilite makes sintered and bronze bushings which do not require lubrication. Use these with either chromed steel or hard anodized aluminum pivot shafts (preferably tubular chromed steel), good design, and a simple dust seal and all of the aforementioned problems go away. I mean, I have no horse in this race, but just looking at it from an engineering perspective. For all I know it could be that bearings are used to reduce the engineering and finishing effort required.

BadgerOne said:

Most of the problems mentioned above existed because builders used the wrong types of bushings, shafts, or designed the suspension poorly. Oilite makes sintered and bronze bushings which do not require lubrication. Use these with either chromed steel or hard anodized aluminum pivot shafts (preferably tubular chromed steel), good design, and a simple dust seal and all of the aforementioned problems go away. I mean, I have no horse in this race, but just looking at it from an engineering perspective. For all I know it could be that bearings are used to reduce the engineering and finishing effort required.

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I've used olite self lubricating bushings on DMR vault pedals with chromoly steel axles. I found igus plastic bushings longer lasting. Part of the reason is vault seals suck. More robust sealing would extend life for sure, but I'm still not convinced life span would be as long as bearings. I've never replaced the outboard bearing on vaults but I've gone through countless inboard bushings. I suspect you're right in saying bearings allow for sloppier tolerances which is appealing to manufacturers. The bike industry is notorious for sloppy tolerances. PFBB's creak because of sloppy tolerances. DM rings can creak because of tolerances. Facts are we really don't need exacting tolerances for bikes other than certain places and bearings would be a good way to avoid having to tighten things up. We need to bring back threaded BB's as a standard because the industry has proven an unwillingness to tighten BB shell/bb cup tolerances.

BadgerOne said:

Am I missing something?

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If you use a bushing the internet will tell you are wrong and the bike is crap...no matter how well you designed it or how well it actually works. Some fights are just not worth it.

A bike designed was asked what's better about their new 4-bar suspension vs. their old single pivot and his reply was "nothing". He just got tired of arguing with people about it online and figured designing a 4-bar system was the easier path to take.

Nothing new here. You can replace "bushing" with whatever tech or design element is not fashionable in MTB at the moment and you'll have the same problem. Even if in your particular situation the unfashionable solution works better.

I would assume bearings handle lateral shock loading forces better. Is that even a thing?

BadgerOne said:

Just a random thought of the morning. I can think of whole list of reasons to use bushings instead of ball bearings. In motors they often use Oilite bushings on the armature shaft. I know some makers such as Transition (I think) use a bushing or two. They can't get internally contaminated, they can't get knackered as easily during press/pull, they can't do that weird thing bearings do under rapid succession micro rotations in both directions (forget what it is called), they don't need additional maintenance or lubrication, they are cheaper...really I can't think of single reason to use ball bearings instead, yet everyone does. Am I missing something?

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They are not cheaper because they require higher precision from the frame in terms of alignment and machining, to do them right with grease ports requires additional considerations. Way easier just to slap a couple skateboard bearings in like most companies do.

AndyD66 said:

I would assume bearings handle lateral shock loading forces better. Is that even a thing?

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No.

Bushings handle lateral loads much better.

Jayem said:

No.

Bushings handle lateral loads much better.

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ok.

good to know.

I owned a FS bushing bike once....ONCE. It was a Psycle Werks Wildhare. I liked how the bike rode, but the bushing experience made me swear-off bushing bikes. The Wildhare was set up in a way that the movement of the rear end always rubbed the bushings. Eventually, the bushings ate away at the aluminum frame, which resulted in (what I called) perma-play. It was a headache. Perhaps other bushing designs avoid my problem, but the experience put a bad taste in my mouth.

Pisgah said:

I owned a FS bushing bike once....ONCE. It was a Psycle Werks Wildhare. I liked how the bike rode, but the bushing experience made me swear-off bushing bikes. The Wildhare was set up in a way that the movement of the rear end always rubbed the bushings. Eventually, the bushings ate away at the aluminum frame, which resulted in (what I called) perma-play. It was a headache. Perhaps other bushing designs avoid my problem, but the experience put a bad taste in my mouth.

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That is the kind of thing I was assuming would happen. I guess you can tighten the design engineering to avoid that.

It seems like the apocraphyl engineer's story about the russian space pencils to my amateur ears..

My son had a Giant Reign 26er with bushings. The bushings had to be replaced.
I have a Giant Trance 29 with bearings. The bearings had to be replaced.

MSU Alum said:

My son had a Giant Reign 26er with bushings. The bushings had to be replaced.
I have a Giant Trance 29 with bearings. The bearings had to be replaced.

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Could and average person have replaced one or the other of them more readily by themselves?

When we were younger bike engineering was much less developed - but as a 14 year kid with an avergae set of garage tools I could rebuild replace or repair every moving or distinct part on my bikes. Today it's much more likely that I have to buy a whole new component AND pay to have it installed.

The tools cost more than the parts they service etc etc..

AndyD66 said:

Could and average person have replaced one or the other of them more readily by themselves?

When we were younger bike engineering was much less developed - but as a 14 year kid with an avergae set of garage tools I could rebuild replace or repair every moving or distinct part on my bikes. Today it's much more likely that I have to buy a whole new component AND pay to have it installed.

The tools cost more than the parts they service etc etc..

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The bushings cost $16 to replace. Parts and labor.