rear sprocket bearing $89.00 !!!! (05 640 Adv)

I replaced my sprocket bearing eons ago with a NSK unit that I picked up at bearing supplier... The # on the box is 3205B-2RSRTNGC3....

Most of the answers to my questions were earlier in the thread. Dunno why I missed them

I know for a fact that Loaded specializes in pre-lubed fagina bearings...

Same thing happens to me, all the time...

Hi Meaty

Remember me?

We were lovers once. You still owe me money. When can I have my bike back? :ddog How's my missus?

Write soon wontcha.

Did I finally make it to OZ? Borrow GodSilla's bike, and his wallet? After a luv tryst with the happy couple...

dang, I never remember the best vacations!

Righto, today had a little chat with the warehouse manager for a local bearing supplier; he offered these points:

• Anecdotally, 90%-odd of bearings fail due to contamination, bearings put in water are the worst. The seals are not designed for water protection.
• Bearings do have a limited life, and sealed bearings are lubed for their expected life. Once the grease is gone, the rest of it is in need of replacement, too.
• Pressure washers and water crossings (hot bearing into cold water, sucks the water in as the bearing cools rapidly while immersed) are the enemy of long bearing life.
• The rule of thumb for packing with grease is no more than 30% of the cavity. This is more than the manufacturers put in there, they are more exact. Any excess is pushed out of the seals.
• If the excess cannot be displaced, then it creates friction (drag) hence extra heat which stresses the bearing unecessarily. If you want to pack the crap out of the wheel bearings, remove the inboard seal so all the excess can be displaced happily into the hub. [Which to my mind makes it a waste of effort]
• Although they should be greased and not rusty, steering head bearings will tend to notch as they never turn a full rotation... another case of poor conditions shortening their life. Nothing you can do about it.

Given my wheel bearings have lasted 30,000km or so, my plan is to pack 30% grease in them every 5-10,000km, as the bike does a lot of water crossings.

This whole grease and bearing thing, Hmmmmmmmmmmm.
Has anyone seen evidence of liquified grease pushed out of seals on a wheel bearing cause I haven't and I have been riding since 1963. I guess I raced for 20 years, enduros, motoX, trail riding and RTW traveling.
Maybe in other types of machinery but not in mc wheels in my experience.

I have seen plenty of dirt and water in dirt bike wheel bearings, some failed bearings and rusted bearings.

As for steering head bearings, after you run them for a while without regreasing them they will start to feel notchy!!

Don't panic if they are quality bearings, jack up the front wheel, disassemble just enough to wipe the old grease out of the bottom bearing with toilet paper, remove the top bearing and wipe it out, regrease everything and reassemble.
No need for a complete teardown, do not use solvents to clean out the old grease. Wipe out the old.

I bet you $100 the notchy feeling is gone.
My old BMW R80ST has 150k on the steering head bearings and the same or more on the wheel bearings(front only on the Beemer cause it has shaft drive).

I grease to about 90% capacity.

IMHO.
b

Yep. Packed the crap out of my old sprocket carrier bearing the other day, was curious to see how much rust would come out in the displaced grease. Answer: lots of grease and lots of rust!! And that was only for a couple of fairly short runs. It hadn't come out past the wheel seal yet, all the displaced grease was sitting between the bearing's seal and the wheel seal. But I was quite surprised by how much had been ejected from the bearing in a short time.

Colin,
Trying to remember how the sprocket carrier bearing sits in my Adventure but memory says it only has the sealed bearing seal and a metal washer followed by a spacer to the outside. When I packed mine I pop the bearing seal and finger in as much grease as it will take and then snap the sealed bearing seal back in place. If the grease is gonna come out it will either come out past the metal washer or end up in the cush drive. I have had neither problem so far. Is that how yours is?
bill.

Yep that's right, the metal washer sits flush against the bore part from memory, as a result not much grease came out that side (blocked by the washer). Lots came out the inboard side where it abuts the spacer bushing in the wheel bearing. Was remembering the wheel bearings on my DR-Z(?), they spewed the grease into the gap between the bearing and the seal (single-sided sealed bearings, packed from the open inboard side).

My sprocket bearing was out, seals off both sides, and very thoroughly packed with grease from either side. ie pretty much packed full, just to see what would happen knowing the bearing was already toast and about to be replaced.

Some beer-coaster maths: 100km/h on a wheel around (ha ha) 2000mm diameter = roughly 800 rpm... about 1/10th to 1/15th the rating on the bearings. Speed in itself is unlikely to overload the bearing. Over-heating from too much grease? At best, it'll just make a mess and waste grease.

The wheel bearings on my Triumph Trophy covered 175,000km in 12 years, without being touched, and are still going. Quite a bit of dirt roads, lots of riding in the rain, no jet-wash and almost no water crossings (some flooded roads, but that was in torrential rain so the bearings were probably water-cooled before being immersed in the floodway). This adventuring lark is much harder on machinery...

Your newly lubed steering head bearing is floating on a film of grease, but the notchy-ness you felt before lube is damage to the race. Some will be happy (like me) with thoroughly greased but damaged steering head bearings. Some will not. Put another way: Some will call it fixed when the bearings are lubed and smooth, some will call it fixed when the damaged bearing is replaced.

I re-grease my bearings too. I agree with the sentiment in this thread that contamination likely kills most bearings. If you can get the contamination out and new lube in before failure you can extend the life of the bearing. Of course this can only happen as preventative maintenance on high speed full rotation bearings since the ways to detect a problem also indicate failure.

The thing is you can inspect the races when you drop the steering stem to clean out the old grease. So just look at them? I am betting they will look good, run some scotchbtite around if need be, regrease and go, sometimes I have to adjust the bearing set a second time cause I get it too tight or too loose. When the machine is up on the centerstand easy to check for notchyness anytime/all the time, I do. I think it is almost impossible to ruin steering head bearings if you relube every 10k.

I think it's always worth a shot to regrease but I get your point. The only bad steering head bearings I ever changed were on my son's BMW 650 single. They were made in Bulgaria. You could see and feel damage to the races.
b

Is this $$$$ bearing a double sealed unit? I just put one in my Yamaha hub and it was sealed on one side only. If you guys are swimming with your bikes more often that riding them I would recommend getting a double sealed units. And pack the seal around the axel with lots of grease.

An old thread...

I was changing out the rear sprocket carrier bearing on a 2007 LC4 Adventure. Many parts fiches show that the bearing is supposed to be the same unit as on various other (cush-hubbed) KTM's, namely 3205-B-2RSR.

I was quite surprised to find that the sprocket carrier contained not one, but two bearings, both marked as 6005. This seems to be a common KTM wheel bearing, used extensively on non-damped rear hubs. These two bearings were about 47mm in outer diameter, 25mm in inner diameter and 12mm in height, each. The spare 3205-B I had laying around measures 52x25x20.6.

There is something very strange with this, as none of the part fiches recognize this discrepancy. The 3205-B angular contact bearing will obviously not fit into this rear sprocket carrier. I think KTM specified an angular contact bearing for a reason, the chain imposes a different type of load on the sprocket carrier side. The 6005 is just a plain vanilla ball bearing.

I searched for references about this 6005 bearing, and I only got one relevant hit here.

On closer inspection of the part fiches, the part number for the actual sprocket carrier changes between for instance a 2003 and a 2007 Adventure. I guess this is to facilitate the different size bearing bore for the two 6005 bearings. The only problem is that the rest of the documentation was not changed accordingly.

Any similar experiences or words of advice?

Cheers,

Tseta

Tseta,

there have been accounts from time to time of KTM's switching parts and such within a model year, and I guess they missed that change on the parts diagram.

You seem to be implying that you think the bearing is inappropriate for the job it does in that position - no?

Hi Meat,

I gather from the lack of input from the "crowd" on this issue that I'm dealing with something either very poorly documented or marginal. Worst case, both. :huh

When I was first taking the old bearings out of the 2007 Adventure sprocket carrier, I immediately thought that "this is some shadetree engineering!" Perhaps somebody had ruined the original sprocket carrier and found an "alternative" cush drive to use, with a different size bearing housing. (This was not the case, as I was to find out later.)

This issue has bothered me much, as none of the fiches recognize this discrepancy.

So, I went on to find out about it myself.

I had a discussion with a bearing expert, who basically confirmed my suspicions about the performance of two deep groove ball bearings stacked vs. an angular contact ball bearing. In this application, the angular contact ball bearing will support higher axial loads than (even two) regular ball bearings. Now, how much axial loading is actually imposed by the asymmetric chain drive? Is this axial load over the design specification for two regular ball bearings? These questions cannot be answered without further analysis and calculations. The alternative would be to get in touch with the design engineers at KTM and ask them directly.

I then talked with someone who has access to the dealer fiche tools. In that fiche, the same mistake was found: the rear sprocket carrier bearing for the 2007 LC4 Adventure is specified as 0625032057 GROOVED BALL BEAR. 3205.B.2RSR. However, searching with the VIN code of the bike, a different number was found for the sprocket carrier bearings: 0625060058 GR.BALL BEAR.6005 DDU2CG23S6NM.

Some more fiche work on both sides of the counter produced the following. The 3205 bearing (and consequently, the 58310050144 SPROCKET SUPPORT CPL. 03 sprocket support) was used from 2003 up to the 2005 LC4 Adventures. The next iteration of the sprocket carrier (58310050244 SPROCKET SUPPORT CPL. 05) is in some fiches shown to fit 2006 625 SMC's. The fiche for this SMC also shows (correctly) two of the 6005 bearings in the cush drive. The third iteration (58310050344 SPROCKET SUPPORT CPL. 06) is shown to fit 2006 and 2007 LC4 Adventures, but unfortunately these fiches incorrectly show one 3205 bearing in the cush drive.

So, why did KTM go and change the cush drive design? Was the switching from an angular contact bearing to two ball bearings done in search of a performance increase or a cost reduction? This one is not too difficult to guess...

All in all, it remains that the (public version of the) spare part documentation could do with some updating and error-correcting.

I don't know whether the new bearings are inappropriate for that position. The 2007 ADV has about 15tkm on it, and the sprocket carrier bearings were crunchy, which started this whole saga. My 2003 ADV has 30tkm on it, no problems with the sprocket carrier angular contact bearing. However, failed 2005+ LC4 ADV cush drive bearings do not seem to be making headlines here or on other forums.

If the newer sprocket carrier design allowed for easy switching to angular contact bearings (with a similar dynamic load rating as the 3205), I would probably consider it. As it stands, though, the stock double 6005 setup will be tried again, until the next failure.

Cheers,

Tseta

The biggest cause of MC wheel bearing failures is river crossings , The seals on bearings are good but not that good . When I install new bearings I pop one seal and pack the bearings with hitemp very high load grease . I have not had a bearing failure since using this procces . 35,000 + on my 950 bearings . The first time I change tires on a new bike I treat the wheel bearings the same way . This can be done without removing the bearings from the wheel . If you have two bearings installed together you can pop both inner seals and pack the intire cavity with grease . There seems to be a few people out there that thinking packing a bearing full of grease is bad . For short life high speed use they may be right . For long life in adverse envinromental conditions they are flat wrong . If the bearing is packed full of lube no water can penetrate , and water sucks as a lubricant . SEYA

I have found a few cases, when dealing with '95 RXC engine parts, that often the superceeded part number is not updated on certian fiches or diagrams. When I went to order the part (cheapcyclepart) they found the cases where the part number was superceeded when ordering the part.

KTM parts diagrams is the worst part of owning a KTM. What really drives me nuts is that the 400 LC4 and 620/640 LC4 show up on the same diagram. The rods are diffrent, and are both on the diagram but have no description...

Nice detective work, and thanks for the write-up.

Just this week I was talking to an experienced m/c technician about it, and his comment was that the nice thing about KTM is occasionally the engineers win over the accountants, and you get good components like that angular contact bearing - despite the expense.

dwayne, I think I'd rather have the KTM parts book in my hand, with the occasional error, than not.