I was on the phone with my local bearing shop today ordering some bearings. Just out of curriosity I checked on our crank bearings, and while he was looking them up I asked the ratings.
We have been told for a long time that our bearings are only rated at 11,000 RPM's and speculation was that this was causing us a problem.
Much to my surprise, our bearings are rated at 11,000 rpms
when using grease:mad:
Their rated at 14,000 rpms with oil.
Now I will clarify that these ratings are for the SKF version of our bearing, but I was also informed that all bearings with this part number carry the same ratings.
Just to backup what I was told, I called Torrington and they informed me that they no longer make these bearings.
So what does all this mean? I'm not really sure, but I installed ball bearings in my 450 motor because of this rumor. I did this knowing that the load rating on a ball bearing is significantly less than on a roller bearing, we'll see what happens.
When I install my Falicon crank in this motor, it will be getting stock bearings installed back into it.
Crank Bearings - do we have the correct info?
Another bit of info that some of you may enjoy:
One of the parts shops has reportedly found a better bearing for use in our motors, it is a roller bearing but an NU bearing instead of NJ (stock) bearing.
This information is off of the SKF website NU design
NU design
The outer ring of bearings of the NU design (fig 2) has two integral flanges and the inner ring is without flanges. Axial displacement of the shaft with respect to the housing can be accommodated in both directions within the bearing itself. The bearings are therefore used as non-locating bearings. For manufacturing and maintenance reasons, the two outer ring flanges of large-size bearings of the NU design which are identified by a Drawing No. may not be integral but take the form of loose flange rings.
NJ design
The outer ring has two integral flanges and the inner ring one integral flange (fig 4). The bearings are therefore suitable for the axial location of a shaft in one direction, see also under "Dynamic axial load carrying capacity".
Did the Cannondale engineers know something we don't when they picked the bearing? Do our bearings need the "axial load carrying capacity"?
I won't pretend to fully understand all this, I'm not a mechanical engineer, but it does make me wonder if the stock bearings may be the ones to use.
One of the parts shops has reportedly found a better bearing for use in our motors, it is a roller bearing but an NU bearing instead of NJ (stock) bearing.
This information is off of the SKF website NU design
NU design
The outer ring of bearings of the NU design (fig 2) has two integral flanges and the inner ring is without flanges. Axial displacement of the shaft with respect to the housing can be accommodated in both directions within the bearing itself. The bearings are therefore used as non-locating bearings. For manufacturing and maintenance reasons, the two outer ring flanges of large-size bearings of the NU design which are identified by a Drawing No. may not be integral but take the form of loose flange rings.
NJ design
The outer ring has two integral flanges and the inner ring one integral flange (fig 4). The bearings are therefore suitable for the axial location of a shaft in one direction, see also under "Dynamic axial load carrying capacity".
Did the Cannondale engineers know something we don't when they picked the bearing? Do our bearings need the "axial load carrying capacity"?
I won't pretend to fully understand all this, I'm not a mechanical engineer, but it does make me wonder if the stock bearings may be the ones to use.
Re: Crank Bearings - do we have the correct info?
[QUOTE]Originally posted by Jaybr
Just to backup what I was told, I called Torrington and they informed me that they no longer make these bearings.
Timkin bought out Torrington about a year ago. So Torrington doesn't make any bearings anymore. Might want to give Timkin a call Jaybr, but seemed like all they care about is getting their money back ASAP, so unless you want to place an order for 1,000,000 of them, they might not be much help.
Just to backup what I was told, I called Torrington and they informed me that they no longer make these bearings.
Timkin bought out Torrington about a year ago. So Torrington doesn't make any bearings anymore. Might want to give Timkin a call Jaybr, but seemed like all they care about is getting their money back ASAP, so unless you want to place an order for 1,000,000 of them, they might not be much help.
Timken Roller Bearings
I work at Timken Roller Bearing. If I can help you in any way, let me know. PS I can get the bearings at a discount, and I don't have to order 1,000,000 at a time!!
-
cannondale27
- Posts: 0
- Joined: Wed Mar 10, 2021 10:41 pm
Jay has a polite way of saying that we have been told a big load of B.S. by someone and it isn't the first time (splitting cranks w/55 ton).
That said nobody else in the industry uses a bearing such as ours. (a large needlebearing) The stock bearings do provide a higher load rating but only in one direction which will undoubtably take care of the force from piston being forced up and down. Now imagine if the crank flexed from poor design, case flex and lack of anything from really preventing flex. The forces would not be in one direction anymore. Which will cause the stock bearing to fail.
The ball bearings can take way more uneven loads.
The one problem I see with the ballbearings is that the only thing that is allowed to slide when this flexing occurs is either the inner race of the bearing on the crank or the outer race where it is in the case neither is good. Stock bearings the inner race can slide in and out all it wants problem is it isn't sliding straight out its on an angle. This is a case of pick your evil, neither is ideal.
That said nobody else in the industry uses a bearing such as ours. (a large needlebearing) The stock bearings do provide a higher load rating but only in one direction which will undoubtably take care of the force from piston being forced up and down. Now imagine if the crank flexed from poor design, case flex and lack of anything from really preventing flex. The forces would not be in one direction anymore. Which will cause the stock bearing to fail.
The ball bearings can take way more uneven loads.
The one problem I see with the ballbearings is that the only thing that is allowed to slide when this flexing occurs is either the inner race of the bearing on the crank or the outer race where it is in the case neither is good. Stock bearings the inner race can slide in and out all it wants problem is it isn't sliding straight out its on an angle. This is a case of pick your evil, neither is ideal.
Thanks 27,
Like I said, I'm no mechanical engineer and I figured this topic would bring some good discussion.
Another thing I was told yesterday by Falicon is that our stock cranks that have been balanced, are not balanced at all and wobble very bad when spun on a dynamic balancer.
Someone apparently sent them a couple balanced cranks, the ones with the plug added to the hole on one side, and they have been doing some testing.
I questioned the whole engine balance vs crank balance several months ago and never really got a good answer, until yesterday. The weight was added to the crank because the factory discovered the '03 rod was lighter than the '02 rod and threw things out of balance. To correct this they (and others) added weight to the hole on one side of the crank. According to the guys at Falicon, that side of the crank was already heavier and the weight actually needs to go on the other side.
So, with one side of the crank heavier than the other the crank wobbles and puts excessive strain on the rod bearings and pins.
So how would roller bearings react to this wobble vs ball bearings?
Not that I would want my crank wobbleing, I'm just wondering if there would be a difference.
Like I said, I'm no mechanical engineer and I figured this topic would bring some good discussion.
Another thing I was told yesterday by Falicon is that our stock cranks that have been balanced, are not balanced at all and wobble very bad when spun on a dynamic balancer.
Someone apparently sent them a couple balanced cranks, the ones with the plug added to the hole on one side, and they have been doing some testing.
I questioned the whole engine balance vs crank balance several months ago and never really got a good answer, until yesterday. The weight was added to the crank because the factory discovered the '03 rod was lighter than the '02 rod and threw things out of balance. To correct this they (and others) added weight to the hole on one side of the crank. According to the guys at Falicon, that side of the crank was already heavier and the weight actually needs to go on the other side.
So, with one side of the crank heavier than the other the crank wobbles and puts excessive strain on the rod bearings and pins.
So how would roller bearings react to this wobble vs ball bearings?
Not that I would want my crank wobbleing, I'm just wondering if there would be a difference.
..I remember who told me ""We have been told for a long time that our bearings are only rated at 11,000 RPM's and speculation was that this was causing us a problem"""
I also know who told me that our holes in the case and crank plate weren't lined up perfect, causing issues..
..I find it funny, well not really but..so much Cr** is coming out of the bag now..it's almost like "they've" all lied to us owners to get our bizz..
I also know who told me that our holes in the case and crank plate weren't lined up perfect, causing issues..
..I find it funny, well not really but..so much Cr** is coming out of the bag now..it's almost like "they've" all lied to us owners to get our bizz..
-
cannondale27
- Posts: 0
- Joined: Wed Mar 10, 2021 10:41 pm
I remember the static vs dynamic balancing discussion. I agree the job was only half done when putting the weight there. The proper way to do it is to figure out the weight needed and then figure out where to put it. I never saw a balanced stock crank. Must be really rare.
What does Falicon say about case and crank flex? How is that going to be addressed? I believe that is the real reason behind the .015 rod side clearance. Every crank I have seen even early '02 style had this big clearance. Get rid of clearance and rod will bind.
What does Falicon say about case and crank flex? How is that going to be addressed? I believe that is the real reason behind the .015 rod side clearance. Every crank I have seen even early '02 style had this big clearance. Get rid of clearance and rod will bind.
-
cannondale27
- Posts: 0
- Joined: Wed Mar 10, 2021 10:41 pm
claas
I think more is to come down the road. There are reasons why Cannondale was designing a practicaly new motor. Then again some have accused me of looking for "conspiracy theories". I figure it is going to take another year or two for all the ugly issues to become commonplace. I don't believe for a minute that Cannondale didn't know of our present and future problems. Hopefully the root cause of these problems is the crank.
All the problems and it is still worth owning them to me. Things could be easier though. Steep learning curve and $
I think more is to come down the road. There are reasons why Cannondale was designing a practicaly new motor. Then again some have accused me of looking for "conspiracy theories". I figure it is going to take another year or two for all the ugly issues to become commonplace. I don't believe for a minute that Cannondale didn't know of our present and future problems. Hopefully the root cause of these problems is the crank.
All the problems and it is still worth owning them to me. Things could be easier though. Steep learning curve and $