Why Ceramic Bearings??? (1)

[linnega]

I always find cycling pseudo-science rather amusing.  Very little that is said is backed up by solid scientific evidence and ceramic bearings are a case in point.  As for the argument that the pro's ride them - lets give our Hubbers a little credit, even a moron knows the pro's ride what they are paid to ride and FSA are some of the biggest payers in the business these days.

 

Like most of what is out there ceramic bearings offer no significant benefit and certainly no reasonable cost benefit.  A Reynolds 501 steel frame with Shimano 105 geartrain, box rims and 32 straight gauge spokes from DT Swiss is difficult to improve on in terms of performance.  Your high-end carbon frame with Record components and Zipp wheels may look better but the performance benefits will not be significant and certainly not be justifiable in terms of cost.

 

[AttieSlabbert]

If measuring power output, resistance, hardness and so forth in numbers, is not scientific, then I don't know what is. And even morons know that no pro will ride something that makes him slower.

 

SO all upgrades are a waste of money? 

 

Anyone wants a Cervelo? I still have mine- it is for sale. I also have 2 other carbon frames - Oh and an aluminum-carbon one - I'm going retro - steel is the way to go!! I'm dusting off my Western Flyer from way back! I think I'm going to have trouble finding  the box rims though.

No matter-- my performance will not take a significant dip and I'll have more money to go to races !!

 

On the other hand - it feels GOOD , when you look good on a good looking bike. And that  will make you faster!

 

[Johan Bornman]

Hey Attie

Your theory of using a hard ball and a soft race is not in line with bearing design. Titanium is a poor choice, it is too soft and it also galls very easily, unlike steel.

 

Your understanding of what breaks bearings is not quite in line with reality. Hitting potholes does nothing to a bearing. I suggest you investigate bearing behaviour for yourself. find yourself a nice ball bearing race somewhere, from a discarded wheel bearing perhaps. Then don some safety glasses, hide the kids and then place ball on the 1/2 race, keep it there with some Presstick or such, and hit it as hard as you can. Report back to the group what you find. You'll be amazed.

 

Saying something can be measured does't mean it makes a meaningful difference. Nature abounds with examples.

 

Saying that FSA or Zipp or whoever says so doesn't do it for me either. Science is not about democracy or advertising spend. German and Belgian magazines are notoriously stupid when it comes to science (not to mention South African magazines).

 

The fact that pro teams use a product doesn't do it for me either. They ride what they're told to ride. Bicycling is about fashion and the money generated by that fasion. Obsolescence is an inportant driver of this industry.

 

I agree wholeheartedly that it is for the guy on the bike to decide. But this is essentially a scientific debate and like I say, democracy doesn't sleep well with science.

 

[Johan Bornman]

Ooooh!

I love a fellow cynic. We must swap notes sometime. Perhaps I can give you a spin on my Reynolds 501 bike (actually, Columbus Neuron) with downtube shifters (seven-speed of course), if you are really nice to me.

 

You are of course absolutely right, but I've given up fighting this battle, fashion is fashion and superstition is superstition.

 

There is only one area where you can improve your dream bike and that is to build with double-butted spokes. They do have a huge advantage in durability over straight-gauge. But that's for another thread altogether.

 

JB

[Johan Bornman]

Attie, lets not go at this debate with a red herring shotgun. Focus on bearings. Ceramic ones to be specific.

In my world, which cearly isn't the same world as others, cycling is about realiability, duability, affordability and realism. I often say to people, don't show me your bike, tell me about your last ride. LA said, it is not about the bike. But that's just the two of us.

 

Back to bearings. Ceramic bearings roll smoother than steel bearings. That's a given and like you say, that can be measured. However, a bicycle bearing cannot be used without rubber and labyrinth seals. A good hub will at least give you water protection. Unfortunately, the seals have more drag than the bearing itself - even steel bearings. So, measuring bearing drag in a lab and translating that to wheels on Joe Soap's bike is two worlds apart.

 

Further, steel bearings are good enough for me and I suspect you too. They are cheap, reliable, durable and readily available.

 

Yes, one day we will all be riding on plastic bearings, even in our cars, but there is a point where it becomes viable. Before that, it is silly for people like me and like I suspect, you, to spend R20 per ball. But, if it gives you a kick, do so, I really don't care. Some people pay extra because someone spraypainted "Billabong" on their T-shirt. A diverse world is an interesting world.

 

Now, for that Western Flyer of yours. No need to panic. it was fitted with box rims.

 

JB

 

 

[Christie]

I always find cycling pseudo-science rather amusing.  Very little that is said is backed up by solid scientific evidence and ceramic bearings are a case in point.  As for the argument that the pro's ride them - lets give our Hubbers a little credit' date=' even a moron knows the pro's ride what they are paid to ride and FSA are some of the biggest payers in the business these days.

Like most of what is out there ceramic bearings offer no significant benefit and certainly no reasonable cost benefit.  A Reynolds 501 steel frame with Shimano 105 geartrain, box rims and 32 straight gauge spokes from DT Swiss is difficult to improve on in terms of performance.  Your high-end carbon frame with Record components and Zipp wheels may look better but the performance benefits will not be significant and certainly not be justifiable in terms of cost.
[/quote']

 

What a nasty reply! I dont think that was justified. This thread started taking on a nasty tone because of your post.

 

Yes, I also feel that the advantages of ceramic bearings on a road bike are debatable, but at the risk of going off the topic, I dont agree at all that "most of what is out there offers no significant benefit" In some cases the advantages are significant. Getting light, high end wheels for a mtb makes a big difference. On a mtb there are much more accelerations than on the road, and a reduction in rotating mass saves a lot of energy. Secondly, I've got a 6.5 kg road bike and a 10.5kg steel one. I can not climb the same hill in the same time using the same power, and I can measure that for you with my powertap. For me it will be the difference between making the selection in a race or finishing in the second bunch.

[Christie]

Your theory of using a hard ball and a soft race is not in line with bearing design. Titanium is a poor choice' date=' it is too soft and it also galls very easily, unlike steel. 

[/quote']

My field of specialization is not metallurgy, but in the engineering field I've seen some high end cutting tools with some sort of titanium coating, so there may be some merrit to using this material for the bearing races. It is clear that the scientific principles have not been suffieciently covered here, so I'll take a stroll down to out metallurgical labs later today and ask somebody to explain the theory to me. I'll post it a bit later today.

[Johan Bornman]

I think you read to much into Linnega's reply. He was pretty straightforward and didn't attack anybody.

 

Anyway, you state that "On a mtb there are much more accelerations than on the road, and a reduction in rotating mass saves a lot of energy."

 

I think you fool yourself about a bicycle's supposed constant acceleration. A bicycle accelerates like a slug and no matter what type of race you're riding, the acceleration you imagine is very, very small.  Measure it for yourself with an all-out effort and you'll see you'll struggle to make 0,5g.

 

As for rotating mass. This little myth has been repeated so often by bike magazines and their avid readers, that they believe themselves. Rotating mass, on a slow-accellerating item like a bicycle is just mass - it has no magic properties. Often people say mass saved on wheels is worth X-times mass saved elsewhere. That's nonsense. On a bicycle (because it accelerates so slowly), mass is just mass. Let me put it another way: Whether the weight is on the wheels or on the rider/bike, it makes an extremely small difference.

 

JB

[dirtrider]

A few weeks ago me and Daemon stopped next to a Yamaha R1 at the robot . I nodded at the rider and as he returned the nod I knew the race was on . I knew he would try and make his get-away using 1st gear therefor I selected one up and 3 down at back . HE dropped me 10cm from the start ! Ok so I need to work on my acceleration .

[101%]

Easy solution!!!! stuff the cermaic bearings!!!! ride your bike more often...it will make you faster!!!!!

[IanJ]

A few weeks ago me and Daemon stopped next to a Yamaha R1 at the robot . I nodded at the rider and as he returned the nod I knew the race was on . I knew he would try and make his get-away using 1st gear therefor I selected one up and 3 down at back . HE dropped me 10cm from the start ! Ok so I need to work on my acceleration .

 

Yes  but the question is does the Yamaha R1 have ceramic or steel bearings ???

 

[Johan Bornman]

I can save you the trip. The material is titanium oxide. Like aluminium oxide, it is pretty hard. But I was being naughty here, Attie mentioned Titanium and I argued Titanium.

 

It would be interesting to find out though if it makes for good bearing races. The fact that it is hard doesn't make it better for X application.

 

JB

[TNT1]

 

A few weeks ago me and Daemon stopped next to a Yamaha R1 at the robot . I nodded at the rider and as he returned the nod I knew the race was on . I knew he would try and make his get-away using 1st gear therefor I selected one up and 3 down at back . HE dropped me 10cm from the start ! Ok so I need to work on my acceleration .

 

Yes  but the question is does the Yamaha R1 have ceramic or steel bearings ???

 

 

Doesn't matter... R1 has around 135Kw.... Maybe dirt-rider needs to train more to get close to that?

 

[Diesel]

True ceramic bearing use ceramic races. Ceramic bals with steel, titanium coated races is n hybrid bearing.

[Christie]

I think you read to much into Linnega's reply. He was pretty straightforward and didn't attack anybody.

 

Perhaps Im overly sensitive' date=' after getting a lot of stick as a TCS member a week ago. His reply upset Attie, though.

 

 

Anyway, you state that "On a mtb there are much more accelerations than on the road, and a reduction in rotating mass saves a lot of energy."

 

I think you fool yourself about a bicycle's supposed constant acceleration. A bicycle accelerates like a slug and no matter what type of race you're riding, the acceleration you imagine is very, very small.  Measure it for yourself with an all-out effort and you'll see you'll struggle to make 0,5g.

 

 

But the power available is also small. To hold 300w for one hour on a bike is hard. This will burn a single household light bulb for an hour. Some of the top pros can hold 700w for an hour. This will burn 2 light bulbs for an hour. Small gains may be worthwile for a cyclist.

 

The chapest car in SA is the Chev Spark, with a 796cc engine. It can generate 5900000w.  A 5w power gain will not mean anything to the driver of the chev, but will mean something to a cyclist.

 

I also dont believe that road bike wheels are accelerated a lot. The varience in speed during a road race is small, and a reduction in rotational mass only saves energy when the wheel accelerates. A speed graph during a mtb ride is a totally different thing. A mtb changes speed much more frequently due to terrain etc. This means it is accelerated more frequently than a road bike. As jou say, these accelerations are much smaller than an F1 car or jet fighter, but the energies applicable to a cyclist is small, and there will be a small energy saving for each acceleration.

[Johan Bornman]

I am sure Attie can take a bit of punch. After all, he posts here with what appears to be his own name. That means he tells it like it is and he stands behind what he says. It's easier if you hide behind a nom de plume .

 

 

Household lightbulbs of the soon to be illegal kind burn between 60 and 100 watts.

 

A Chevy Spark developing 59 kw? That translates to only 59000 watts.

 

A Chevy Spark developing 5900000 watts will annoy BMW M3 drivers endlessly.

 

Now, as for a MTB's accelleration. More than a RB but still insignificant considering the reserve power we have when finished with a race. It certanly isn't enough to start weighing wheels.

 

JB