Your deffinately better to size the housing bore to properly fit the bearing than to shim it thats for sure.
Curious what size you made the bore compared to the bearing OD?
Have to think it would be best to use an interference fit between the bearing OD and housing bore, but too tight could be a concern for the bearing, and dont forget there is thermal expansion of the bearing to consider too.
There are various fits or clearences built into bearings so that they can work in a larger amount of applications, and picking the right one for the app will save a lot of headaches later on down the road.
Another thing that needs to be considered is what tolerences were used in the building of the engine. I have seen many instances where products from the better producers or more advanced countries in Asia have used tighter internal clearences in the bearings due to using tighter tolerences than what are normal here. This may or may not have any serious effect because most problems were or are from using bearings with the tighter clearences on machines from here as these machines were needing additional internal clearence by their design.
fx400 ball bearing cranks?
Something tells me cannondale didnt do very much thinking when it came to sizing these bearings. Notice the inner race on the flywheel side bearings are so tight they have to be torched off and the race on the other side was loose and sloppy. It would be great if we could find a roller bearing to fit in the existing bore to eliminate the need for a sleeve. The bearing bore cannot be resized bigger for a different bearing because of the "john deere" bolt in the case.
It is really shocking how they used such as tiny bearing on this side. Most every other engine has bearings of 2 to 3 times the capacity of that little roller.
It is really shocking how they used such as tiny bearing on this side. Most every other engine has bearings of 2 to 3 times the capacity of that little roller.
Since I have never been into one of these engines I am only able to try and work with a visual of what your describing, but dont always discount a smaller bearing as being worse etc.
Except for some very unusual situations and specialty stuff most bearings do increase their load capacity as they get larger, but they also lose their speed ratings.
That goes for the size of the overall bearing as well as the internal moving parts.
I had been looking at some of the info here on the rod bearing failures and I cant be 100% positive that its from a overload situation (partly from the amount of info and pics) and may actually be from an overspeed or even a combo of things (my thoughts are with the combo).
As was touched on before one of the benefits of a ball bearing is its ability to control or handle thrust loads to a certain limit, and this is something you just cant get with a 2 piece roller bearing (there are some that will handle slight side loads but the amount is limited and the size is typically larger id to od and there can be fitment problems due to the difference).
If your able to get the bearing mfg part numbers or any other failure info I would be happy to take a look at whats happening or what other bearings may be avail.
Except for some very unusual situations and specialty stuff most bearings do increase their load capacity as they get larger, but they also lose their speed ratings.
That goes for the size of the overall bearing as well as the internal moving parts.
I had been looking at some of the info here on the rod bearing failures and I cant be 100% positive that its from a overload situation (partly from the amount of info and pics) and may actually be from an overspeed or even a combo of things (my thoughts are with the combo).
As was touched on before one of the benefits of a ball bearing is its ability to control or handle thrust loads to a certain limit, and this is something you just cant get with a 2 piece roller bearing (there are some that will handle slight side loads but the amount is limited and the size is typically larger id to od and there can be fitment problems due to the difference).
If your able to get the bearing mfg part numbers or any other failure info I would be happy to take a look at whats happening or what other bearings may be avail.
Theres really no need anymore . The rod bearing failures were caused by the cage ( see the crank update thread) and the fx400 flywheel is solved by the 02 03 bearing which are highly reliable. Like I said at the begiining of this thead we have already tried the ball bearing but am leary of them because they were rated for over 14,000 rpm.But had almost a 1,000 pounds less load rating than the puny roller that was in there originally.
The ball bearing was just a temporary solution . The original roller bearing is no longer available and has proven itself to be a ticking timebomb.
The ball bearing was just a temporary solution . The original roller bearing is no longer available and has proven itself to be a ticking timebomb.
Ok so it was more concern or theory, and thats fine.
I guess all that would happening then is that if you had the part numbers then the ratings could be compared (you prob did this already anyhow) and I could alert you if there were any same sized bearings with different limits or avail internal clearences etc. (you may have been thru that too).
I can see where you would be concerned with replacing the roller bearing (those bronze cages are actually better than the steel ones, and normally more $$$ too)with a ball bearing, but its all about ratings and the application, and then ultimately trial and error (aka R&D lol)
Whats funny or unusual to me is that when I was in this business I was mostly confronted with people trying to find a less expensive alternative, and since I have been around this sport its usually the other way around. I think thats partly a good thing because we as a group seem to be able to understand the value in getting a quality product, but it also is partly from our being gouged so often we have become numb to high prices.
Anyhow it sounds like you have a good handle on this and only time will tell how well or long the fix will remain reliable, but I would have to think with the higher rpm limits and typical traits of a ball bearing of this size you should be fine.
I guess all that would happening then is that if you had the part numbers then the ratings could be compared (you prob did this already anyhow) and I could alert you if there were any same sized bearings with different limits or avail internal clearences etc. (you may have been thru that too).
I can see where you would be concerned with replacing the roller bearing (those bronze cages are actually better than the steel ones, and normally more $$$ too)with a ball bearing, but its all about ratings and the application, and then ultimately trial and error (aka R&D lol)
Whats funny or unusual to me is that when I was in this business I was mostly confronted with people trying to find a less expensive alternative, and since I have been around this sport its usually the other way around. I think thats partly a good thing because we as a group seem to be able to understand the value in getting a quality product, but it also is partly from our being gouged so often we have become numb to high prices.
Anyhow it sounds like you have a good handle on this and only time will tell how well or long the fix will remain reliable, but I would have to think with the higher rpm limits and typical traits of a ball bearing of this size you should be fine.
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cannondale27
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- Joined: Wed Mar 10, 2021 10:41 pm
Actually it was only the first motors 01 fx400 and real early Cannibal that had a roller with bronze cage.It was also alot narrower than the later factory bearing which also is a roller bearing with a plastic type cage.Only reason ball bearing bearing was put in was because it was all that would fit the early motors without mods.Some of us also switched to ball bearing bearings in our late motors because we thought wrongly that the stock bearing was underrated speed rpm wise.The ballbearings didnt last anywhere near as long as stock rollers.If you could find another source for our stock bearings and the inner race which has a lip it would be very beneficial.Here is a excellent post of someone who did do some research on our mainbearings.
http://www.cannondaleriders.com/vbb/showth...&threadid=10052
http://www.cannondaleriders.com/vbb/showth...&threadid=10052
Sorry for the delay in posting but I will check out the info in that thread and get back with what options there may be in this thread.
Only had time to read the first few posts and felt bad with all the typical BS the bearing people were throwing at everyone.
Guess there are bad as the yami and honda loyalists, and only their preferred brand bearing is worth a crap
Let me know if there is any room with the boundry dimensions for a larger bearing etc.
Thanx
Only had time to read the first few posts and felt bad with all the typical BS the bearing people were throwing at everyone.
Guess there are bad as the yami and honda loyalists, and only their preferred brand bearing is worth a crap
Let me know if there is any room with the boundry dimensions for a larger bearing etc.
Thanx
Ok it was simpler than I thought, but I hope I am not missing something.
First off these guys were all looking for the wrong bearing (if they really wanted the flange on the inner race) as the number listed does not use one.
I know there have been a few mergers and buy outs since I left the industry but I know the part numbers they are discussing very well, and can supply honest info on them all.
Now I have a couple quick questions.
Will the bearings (the nu205 and nu305) their discussing in the other thread work if they have the lip on one or even both sides of the inner race?
Will these work for both the newer and older cranks?
Lastly let me know if any of the failures or even most of them had one cage type, and if there is a preference in cage material.
I know the phenolic cages are capable of higher speeds than the steel ones, but there have been problems with them when bearing temps get too high, so I want to be sure what I am lookin for etc.
First off these guys were all looking for the wrong bearing (if they really wanted the flange on the inner race) as the number listed does not use one.
I know there have been a few mergers and buy outs since I left the industry but I know the part numbers they are discussing very well, and can supply honest info on them all.
Now I have a couple quick questions.
Will the bearings (the nu205 and nu305) their discussing in the other thread work if they have the lip on one or even both sides of the inner race?
Will these work for both the newer and older cranks?
Lastly let me know if any of the failures or even most of them had one cage type, and if there is a preference in cage material.
I know the phenolic cages are capable of higher speeds than the steel ones, but there have been problems with them when bearing temps get too high, so I want to be sure what I am lookin for etc.
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cannondale27
- Posts: 0
- Joined: Wed Mar 10, 2021 10:41 pm
Will the bearings (the nu205 and nu305) their discussing in the other thread work if they have the lip on one or even both sides of the inner race?Yes need a lip on one side only.
Will these work for both the newer and older cranks?
Depends on the case.Will fit all cranks
Lastly let me know if any of the failures or even most of them had one cage type, and if there is a preference in cage material.
The brass caged older bearing had lots of failures and factory silent recall dont know if fault was with cage or smaller bearing.New stock cages on mainbearings have been very reliable.Only one failure(meltdown)of cage that I have seen.
I know the phenolic cages are capable of higher speeds than the steel ones, but there have been problems with them when bearing temps get too high, so I want to be sure what I am lookin for etc.
Will these work for both the newer and older cranks?
Depends on the case.Will fit all cranks
Lastly let me know if any of the failures or even most of them had one cage type, and if there is a preference in cage material.
The brass caged older bearing had lots of failures and factory silent recall dont know if fault was with cage or smaller bearing.New stock cages on mainbearings have been very reliable.Only one failure(meltdown)of cage that I have seen.
I know the phenolic cages are capable of higher speeds than the steel ones, but there have been problems with them when bearing temps get too high, so I want to be sure what I am lookin for etc.
I have noticed on some of the inner races of the 205 bearing that there is occasionally flaking or spalling of the metal. Only in localized places and its not in the center but on the edge of where the bearing rides. These bearings are rated c4 for tolerance . I just found some skf bearing rated at c3 which is a little tighter. These are the first ones Ive found of a different brand.
And Ive heard others were using ball bearing that are direct replacements for the rollers. The 6205 ball bearing is half the dynamic load rating as the 205 roller. I can see why they dont last very long.
And Ive heard others were using ball bearing that are direct replacements for the rollers. The 6205 ball bearing is half the dynamic load rating as the 205 roller. I can see why they dont last very long.