Seduced by Ceramicspeed display

[sfscott]

LBS has a nifty little counter stand with CS bb, dr pulleys and wheel bearings mounted. The also have steel versions from Shimano on the stand.

I have read the technical analyses that show the gains from ceramics to be negligible, but damn if there wasn't a large obvious difference. Spin and spin and spin. And oh so smooth

I know the manager fairly well and asked him if they doctored either range of bearings, and he said no. Straight up, no over-loading the Shimanos, etc.

How does one square science with feel?

[rnhood]

On a bike being ridden the bearings are loaded. There is the weight of you and the bike, and the forces associated with the torque you are producing. Under these conditions the differences are likely little. In addition, the typical Shimano steel bearings have a seal to prevent the ingress of water and moisture, road film/dirt, etc. I don't know if the ceramic bearings have this. Some or ceramic bearings do not include this (I believe). The seal causes some minor drag but the benefits outweigh the drag assuming you ride in conditions other than perfect. The drag is so little that its basically moot on a bike underway. Maybe not on a demo display though.

Ceramicspeed is a good company with good products. I think their bearings and races both are ceramic (unlike some of the others). My guess is the aggregate advantage in a bike with BB, drive train and wheels in ceramic is probably on the order of 2-3 watts at the normal speeds we ride like 18-23 mph. Maybe less. Are they worth the added cost? Well, like everything cycling related that's an individualized question. For me they are not worth it.

[Mark McM]

LBS has a nifty little counter stand with CS bb, dr pulleys and wheel bearings mounted. The also have steel versions from Shimano on the stand.

I have read the technical analyses that show the gains from ceramics to be negligible, but damn if there wasn't a large obvious difference. Spin and spin and spin. And oh so smooth

I know the manager fairly well and asked him if they doctored either range of bearings, and he said no. Straight up, no over-loading the Shimanos, etc.

How does one square science with feel?

Ocean tides can generate some pretty strong forces - if you're not careful rip tides can pull boats out to sea or dash them against the shore. In fact, ocean tides are directly pulling on the earth's rotation, gradually slowing down the earth's rotation. Eventually, the tides will slow the earth's rotation entirely - in a few billion years.

The energy and momentum of a bicycle is so large compared to the power loss in the wheel bearings, that even if the wheel bearing losses were completely eliminated, it would be hardly noticeable on the speed of the bicycle - much like the tide's drag on the earth is barely noticeable.

[drewellison]

Eventually, the tides will slow the earth's rotation entirely

That means that we should ride our bikes opposite of the earth's rotation, and the force of the drive wheel will help to counter the slowing rotation of the earth. And if we all installed ceramic bearings, we'd impart more force upon the earth's spin because we'd lose less energy to friction.

I think it's our duty to humanity to all buy ceramic bearings and ride in the correct direction. Sprinting a lot would help too.

Drew

[Mr_Gimby]

On a bike being ridden the bearings are loaded. There is the weight of you and the bike, and the forces associated with the torque you are producing. Under these conditions the differences are likely little. In addition, the typical Shimano steel bearings have a seal to prevent the ingress of water and moisture, road film/dirt, etc. I don't know if the ceramic bearings have this. Some or ceramic bearings do not include this (I believe). The seal causes some minor drag but the benefits outweigh the drag assuming you ride in conditions other than perfect. The drag is so little that its basically moot on a bike underway. Maybe not on a demo display though.

Ceramicspeed is a good company with good products. I think their bearings and races both are ceramic (unlike some of the others). My guess is the aggregate advantage in a bike with BB, drive train and wheels in ceramic is probably on the order of 2-3 watts at the normal speeds we ride like 18-23 mph. Maybe less. Are they worth the added cost? Well, like everything cycling related that's an individualized question. For me they are not worth it.

The ceramic bearings for bicycles all have seals, they would be rubbish in a matter of miles if they didn't, but they have much more refined seals that create significantly less drag than the off-the-shelf Shimano bearing systems. The quoted percentage gains of ceramic vs. steel bearings is usually the purely mechanical friction coefficient, and rarely, if ever, counts the bearing seals into the equation. The aggregate power loss from all the more drag-y seals is definitely tangible on a bike. However, high-end steel ball bearings with similar drag-free seals would also be tangibly smoother on a bicycle, even without the upgraded balls/races. But really we're all kinda splitting hairs at that point...