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Bearing upgrade


davem
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How much difference do your bearings make?

 

I am a long distance triathlete. Courses are generally not particularly hilly so bike weight is not a particularly big issue.

 

I have made the decision to race with Gatorskin clinchers as it reduces risk of not finishing but at the penalty of increased rolling resistance.

 

I was wondering what the benefits of better quality bearings are. Given that rolling resistance is just an energy expense, how can I cost effectively improve performance.

 

The areas to target are the hubs and the bottom bracket.

 

My wheels are 60mm HED Jet carbon clinchers which use the HED hubs. When I turn the hub by hand, it does not feel particularly free to spin. When the wheel is on the bike, the wheels spins freely with no signs of friction. By comparison, I also have yachting pulleys that with a light flick will spin for a minute. They also have a 700 kg working load capacity.

 

When I spin my wheel, obviously there is a lot of turning inertia created by the weight of the wheel which I feel discounts the test. With the wheel stationery, should the hub free spin?

 

The same applies to the bottom bracket, my bike has Shimano 105 drivetrain, not sure of the BB model. Can I reduce friction by changing the BB or the bearings? (My knowledge of how the BB fits together is limited).

 

What impact does the type of grease have on the resistance? Being a tri bike, risk of ingress of foreign substances is likely minimal.

 

Please give me your thoughts.

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I overheard a conversation at a Argus expo (~2years ago) The stall holder was explaining to this dude about ceramic bearings and the amounts of watts of energy you can save, using them. It did not make much sense to em at the time but I'm better educated now...

 

so, ceramic bearings should be your answer BUT at the 10x inflated price...i'd rather train a bit harder for the same results??

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Is it possible to purchase loose ceramic ball bearings or do you have to buy the sealed type bearing to get ceramic bearings? I went to Bearing Man and asked if they sell loose ceramic ball bearings and the dude looked at me as if i was high on papagaai slaai.

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You will save about 0.3W if you change to ceramic bearings on your crankset (based on data from FAG). For comparison, changing from Gatorskins to Michelin Pro 2 Race tyres could save about 22W (based on Roues Artisanles rolling drum test).

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Just a comment on the 0.3W saving above: most of those savings came about because FAG was using a new wear resistance, corrosion resistant steel alloy for the races. This, together with corrosion resistant ceramic balls means they can run the bearing with light oil, rather than thick grease as a lubricant.

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Is it possible to purchase loose ceramic ball bearings or do you have to buy the sealed type bearing to get ceramic bearings? I went to Bearing Man and asked if they sell loose ceramic ball bearings and the dude looked at me as if i was high on papagaai slaai.

That should have answered your question. There are other ways of wasting your money. They will probably not last until Christmas.

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Seems bearings are a waste of time. 0.3W is nothing.

 

But 22W on tyres. Hell, thats worth looking at. Edman, do you have a link to the research/webpage.

 

Thanks for the feedback.

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I overheard a conversation at a Argus expo (~2years ago) The stall holder was explaining to this dude about ceramic bearings and the amounts of watts of energy you can save, using them. It did not make much sense to em at the time but I'm better educated now...

 

so, ceramic bearings should be your answer BUT at the 10x inflated price...i'd rather train a bit harder for the same results??

 

That guy is a fraud. It is easy to replicate his experiment. A wheel that spins in the air without any load experiences primarily seal drag (if we exclude air drag for a moment. It'll be apparent why in a second *) and fluid drag from the lubrication.

 

It experiences extremely little rolling resistance from the bearings balls and races itself. Therefore, to make the experiement work, you set up two wheels, one with ceramic bearings in, the other with steel bearings. Now you handicap the steel bearing wheel by a) using new bearings with lots of seal drag B) bearings overfilled with dense grease.

 

The ceramic bearing gets an old seal that's already worn down 9if indeed there is a seal at all) and you take out all or most of the grease.

 

Voila! the one with ceramic bearings spin longer and therefore ceramic is great and you must buy them.

 

The next time I see him I secretly film him and show it on Carte Blanche.

 

Puhleeeze!

 

 

*I've excluded air drag since it cancels out, both wheels experience approximately the same.

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That guy is a fraud. It is easy to replicate his experiment. A wheel that spins in the air without any load experiences primarily seal drag (if we exclude air drag for a moment. It'll be apparent why in a second *) and fluid drag from the lubrication.

 

It experiences extremely little rolling resistance from the bearings balls and races itself. Therefore, to make the experiement work, you set up two wheels, one with ceramic bearings in, the other with steel bearings. Now you handicap the steel bearing wheel by a) using new bearings with lots of seal drag B) bearings overfilled with dense grease.

 

The ceramic bearing gets an old seal that's already worn down 9if indeed there is a seal at all) and you take out all or most of the grease.

 

Voila! the one with ceramic bearings spin longer and therefore ceramic is great and you must buy them.

 

The next time I see him I secretly film him and show it on Carte Blanche.

 

Puhleeeze!

 

 

*I've excluded air drag since it cancels out, both wheels experience approximately the same.

 

Johan if you take the bearing that has no grease in and you fill it with Squirt it will most likely never stop spining!!!!!!!!

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