Why Ceramic Bearings??? (1)

[Hendrik Petoors]

Loose 12 kg in weight and your bike then weighs nothing !!! Zilch..... nada!!!!!! then you can ride with cast iron balls (bearings) if you want!!!!!!!

[Christie]

 Oops! I stuffed up the power of the Spark! It should be 38kw, at 5900 rpm (I should stay away from anything related to cars, I inveriably end up with my foot in my mouth) I dont know if it can sustain it for an hour, though

I think we both agree on the effects of all the big $$ upgrades being small. We disagree on weather some of them makes a difference.

Perhaps we can convince 101% or Marco to ride the Jock on my 10.5kg steel bike & see if it slows them down? We ride the same frame size....

[Johan Bornman]

He he...

[AttieSlabbert]

I'm open to be convinced with proof. Until then - I stand!!

If we can produce something that is different and that makes a difference, then we are moving forward. Otherwise we're going nowhere. Any ideas?

 

My idea - If we toss the seals and the grease- use Q20 instead and replace the bearings after every race, we got rid of most of the friction. And balance the wheels- I mean really balance and true it!!!!

 

I think you have to decide on what change will make the biggest difference. Is it ceramics, or maybe a more aeroframe or carbon or ....? (for some steel is fine) Or maybe just losing weight. Then you have improved you riding. And that is what we ALL want. Some improvements are free speed- but you have to pay for the improvement. ( I'm afraid to call it an upgrade now!) But it is out there and you can buy it!  Another thing also stands- many small improvements add up to a big improvement!!!

 

We do have true ceramic bearings - with ceramic races - but now you're talking big bucks!!

[AttieSlabbert]

Hi Johan,

Just got the word, the coating we use for the races are CrN/Ti.

After all the testing it has never come off or made any indentation.

What do you think?

Attie

[Diesel]

Hi Attie the local agent for true ceramic bearing are ? My local supplier havent been able to supply any ? Bearing bal's and races must be of the same material and hardnes to create the lowest friction coefficient.

[GoLefty!!]

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

 

Anyway' date=' 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

[/quote']

 

 

Ah but this is where I think oversimplify Mr Bornman..

 

Wheels, when accelerated, must be translated [move in direction of acceleration] and rotated and the mass is a function in both.

That is where weigh off the wheels is worth twice off anywhere else.

 

Whether it is significant is entirely up to the rider, and their riding style. Some are smoother and therefore perhaps do not have as many accelerations in a given time.

 

Wheels form a large part of rotating mass on a bike ( about 3.5 Kg with tyres) and hence reduction here is significant (overall as well as rotationally) since the riders Legs, pedals shoes, cranks, all have to translated as well as rotated.

 

Of course making the legs stronger is the number one focus of improvement, wheels are number two.

 

Whether Mavic Crossmax is significantly better than 20gr heavier Mavic X819 with American Classic rims is significant only depends on where the sweet spot for each assembly lies..

 

 

Ceramic Bearings:

 

Yes they work (as Johan says is realy high speed bearings where there is little shock from outside and little heat to contend with) but the savings in a bicycle application are heavily outweighed by other losses.

 

Titanium Bearing races:

depending on the alloy of titanium used these could provide a slight benefit to ceramic balls. These would need to be made of the harder 6Al 4V alloy or one of the Russian alloys such as BT-6 or BT-16 for suitable toughness to prevent damage of the races by the balls.

Titanium Oxide coating is not particularly hard in the world of ball bearings so I believe this to be marketing spin (sorry about the pun) to get titanium in there..

 

for smooth rolling get good cup and cone bearing hubs, forget this ceramic malarky

As Shimano states: The cost beenfit ratio does not make sense.

[The Saint]

 

 

 

Ceramic balls are antimagnetic

Ceramic balls are rounder and smoother

 

 

  Need to speak to my wife about this, Troy McNamara might be in for some business soon.

 

[Johan Bornman]

Attie Writes: Just got the word, the coating we use for the races are CrN/Ti.

After all the testing it has never come off or made any indentation.

What do you think?

Attie

 

Johan: I have no idea what you mean. What testing?

 

JB

[Johan Bornman]

Ah, so we meet again?

 

We'ver been through this before, so I'll do the math if you agree to tell me how many times during a given race you accellerate from what speed to what.

 

I have no idea what an "assembly sweet spot is".

 

You might find that your fancy titanium allows are significantly softer than titanium oxide. Look it up in a materials handbook.

 

 

JB

[AttieSlabbert]

Diesel,

You can contact Triangle Sports at  paul@triangle.cc  or   041 581 7990. They have shops in Cape Town and PE and agents are starting to pop up everywhere.

Keep me updated.

Attie

[GoLefty!!]

Ah' date=' so we meet again?

 

We'ver been through this before, so I'll do the math if you agree to tell me how many times during a given race you accellerate from what speed to what.

 

I have no idea what an "assembly sweet spot is".

 

You might find that your fancy titanium allows are significantly softer than titanium oxide. Look it up in a materials handbook.

 

 

JB

[/quote']

 

What no quotes??

 

Assembly sweet spot = laymans terms for  MOI.

 

Lets see, for a 80km MTB race lasting 4h 30min at an average of 90rpm = 21600 little accelerations + those big Bretjens wannabee breakaways on the climbs

 

say the little ones are 1km per hour difference and the climbs are speed difference of 4km/hr

 

 

Oh and I'd like to know the time saved please. thanks

[Johan Bornman]

Ha ha, that's really funny.

 

You want to accellerate your 80 kg bike plus rider some 21000 times by 0,2m/s^2?  At a cursory glance I can already see that the total energy expenditure is alreay far more than human body can manufacture from food in a  very long time.  Oh dear, it seems as if the premise of constant accelleration at 1 kph per 0,6 seconds is way, way off.

 

JB

[Ivanb]

IS this still ceramic bearings?

 

We are importers of Ceramicspeed bearings. They are superior by far!!

 

Go to www.ceramicspeed.com for all the info you need, tests against the 'chinese' ones, wear, rolling resistance etc etc.

 

Of course they come witha price but not far off the FSA etc. A Rotor SABB with ceramic bearing is R2400.00

 

 

[AttieSlabbert]

Ceramic speed -- nice!! Sounds good.

I checked the website- couldn't find any info - figures, values - about density, Vickers hardness, compressive strength or composition(silicon nitride balls is that  the same as Si₃N₄ ? )

Can you give us a bit more on that please.

Thanks!

 

[Ivanb]

i have a great deal of papers do you have an emailaddress i can send it to.

 

Ivan

 

Info@impressions.co.za