A
Anonymous
Guest
Come on propflux man, you've quoted me but ignored just about everything I wrote!
and when your a sponser that craps out 500k+ per engine with plains, and close to $1Mil with rollers, do the math..hmmmm, one race...tore down...both can rev to 16k...$500k vs 1 mil.... one race...you get my point there
There's no way a roller bearing crank costs twice what a plain bearing does!!
As for the turbine engine, yes, radial loads are light, seems a PERFECT environment for a bearing which relies in a film of oil to maintain clearance.
There are other factors, as I implied, which dictate the choice of bearing in gas turbine engines. Roller bearings are NOT chosen in this application for their "strength". ( Note I mean ability to take load )
As for a plain crank not wearing much? most automotive engine i see have to have the cranks turned down at EVERY rebuild,
In this country, almost no car engines are rebuilt before the vehicle is scrapped. By far the vast majority of plain bearing cranks will outlast the rest of the vehicle given adequate maintenance. As I said (if you would just READ my posts) and I quote myself:"Would a roller bearing crank have lasted longer? Very possibly, but who cares? The point is that given proper care, a plain bearing crank will last as long as the rest of the bike. "
This is the reasons i am saying that a plain is used for cost-efficiency Vs a roller.
The very first thing I wrote in this thread was: "Main reasons would be manufacturing based, i.e. that plain bearing cranks are cheaper to make and are probably quieter and therefore more easily fit into recent noise regs"
Do you really think there will be alot of these new 15000RPM plus plain bearing superbikes running around 20 years from now WITHOUT having had an overhaul??
No of course I don't!!! I've already said as much. A roller will always last longer, all other things being equal. But the original question was about strength, not decades of durability! I have already mentioned Kent Stotz's championship winning 500bhp Honda Blackbird , and there are literally hundreds of blown Busa's in cars and bikes out there, some with nitrous, proving the strength issue. Very long term durability? Rollers every time. :wink:
One last point: I am rebuilding currently a GS1150 motor for a customer. I have just taken the (roller) crank to my crank specialist to be rebuilt. Why? Because the #1 big end had gone.
and when your a sponser that craps out 500k+ per engine with plains, and close to $1Mil with rollers, do the math..hmmmm, one race...tore down...both can rev to 16k...$500k vs 1 mil.... one race...you get my point there
There's no way a roller bearing crank costs twice what a plain bearing does!!
As for the turbine engine, yes, radial loads are light, seems a PERFECT environment for a bearing which relies in a film of oil to maintain clearance.
There are other factors, as I implied, which dictate the choice of bearing in gas turbine engines. Roller bearings are NOT chosen in this application for their "strength". ( Note I mean ability to take load )
As for a plain crank not wearing much? most automotive engine i see have to have the cranks turned down at EVERY rebuild,
In this country, almost no car engines are rebuilt before the vehicle is scrapped. By far the vast majority of plain bearing cranks will outlast the rest of the vehicle given adequate maintenance. As I said (if you would just READ my posts) and I quote myself:"Would a roller bearing crank have lasted longer? Very possibly, but who cares? The point is that given proper care, a plain bearing crank will last as long as the rest of the bike. "
This is the reasons i am saying that a plain is used for cost-efficiency Vs a roller.
The very first thing I wrote in this thread was: "Main reasons would be manufacturing based, i.e. that plain bearing cranks are cheaper to make and are probably quieter and therefore more easily fit into recent noise regs"
Do you really think there will be alot of these new 15000RPM plus plain bearing superbikes running around 20 years from now WITHOUT having had an overhaul??
No of course I don't!!! I've already said as much. A roller will always last longer, all other things being equal. But the original question was about strength, not decades of durability! I have already mentioned Kent Stotz's championship winning 500bhp Honda Blackbird , and there are literally hundreds of blown Busa's in cars and bikes out there, some with nitrous, proving the strength issue. Very long term durability? Rollers every time. :wink:
One last point: I am rebuilding currently a GS1150 motor for a customer. I have just taken the (roller) crank to my crank specialist to be rebuilt. Why? Because the #1 big end had gone.
