Rear Wheel Bearing Problems

I had a rear wheel bearing disintegrate the other day - no problem except that it completely scored out the inside of the hub and they are not cheap to replace!!!

Apparently the spacer that the bearing goes over needs about a mm sandpapered of it as what happens is that the bearing heats up and too much pressure is then put on the bearing race and it goes kaput in a big way!!! Hopes this prevents what happened to me!!!!!

Actually the spacers are made of a soft material. The rubber seal wears a groove in the spacer letting water and dirt into the bearing. There are many companies out there making hardened spacers and double sealed bearings. www.enduroeng.com www.e-rider.com

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TWIST&SHOUT

"Jeeeeeese" I cringe everytime I hear this.

dont buy your bearings from a ktm dealer!!!!!

go to a bearing supply shop in your area and ask for the bearing # that you have. its written right on the bearing.

In canada here a rear bearing from ktm is 30$

but at a bearing supply (koyo or f.a.g.)

only cost about 7 or 8 $.

Originally posted by captain ktm:

"Jeeeeeese" I cringe everytime I hear this.

dont buy your bearings from a ktm dealer!!!!!

go to a bearing supply shop in your area and ask for the bearing # that you have. its written right on the bearing.

I agree with this and the WER spacer post. The number is also listed in the parts book.

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John Brunsgaard

jejb@att.net

01 400 EXC, 99 250 EXC (gone), 99 200 EXC, 98 125 EXC, 98 380 MXC (long gone)

always buy quality bearings. i will only buy bearings made in usa, germany or japan. i have seen eastern block bearings with .010" machining errors.

I had just checked mine last week when I fitted a new tire and sprockets/chain. Now the rear bearings are bad!

I guess new bearings and hardened bearing spacers?

William Ow

2000 400 EXC

Chain adjustment Chain adjustment Chain adjustment. The chain should look like its too loose. Otherwise you'll stress the bearings on the sprocket side and they'll fail. When oh when is this gonna get thru.

Originally posted by Greg in Oz:

Chain adjustment Chain adjustment Chain adjustment.

Equally important is the spacer with the steel ring. Aluminum spacers will groove quickly and give you wheel bearing problems, too.

Check that your chain is not to tight(This is 90% of wheel bearing failure) the chain should be loose enough that it's almost touching the top of the swingarm when the bike is ont the stand.

Originally posted by Krank it with your wrist:

Check that your chain is not to tight(This is 90% of wheel bearing failure)

Where did you get this number that you seem to state as fact?

IMO, the majority of wheel bearing failures come from grooved spacers and/or neglected bearings.

Actually, jeb, I run the race team for a KTM dealer and the bearing failures we see are mainly on newer mxers particularly where the owner has had jap bikes previously. The trail riders who do lots of miles seem to have the adjustment thing right. We don't get many grooved spacer issues, but most of our customers turn over bikes fairly quickly so they might turn up on used bikes at other dealers.

Greg,

Couldn't those still be issues with neglected bearings? I pull all the bearings out of my bikes when new and once a year to clean and pack them. I pop the seals off the sealed ones and do the same, then reinstall the seals. I check my wheel bearings every time I change a tire by popping the outside seal off and forcing more grease in if needed. The majority of the time, they don't need anything but it's cheap insurance.

Hmm,

Sealed bearings, 2month old bikes??? Don't think so. Seriously, though, the vast majority of failures we see are chain related. We even had a destroyed hub. Guy had his chain too tight , busted big air and landed on the flat. Just collapsed the thing.

I sew another cause for bearing destruction that is very common : too much tightening torque at the rear wheel collar nut spindle. The correct torque to this nut is 80nm, we see bikes with 130 nm all the time. This causes the bearing and spacer damages.

Originally posted by Greg in Oz:

Hmm,

Sealed bearings, 2month old bikes??? Don't think so. Seriously, though, the vast majority of failures we see are chain related.

Sure. I've taken apart new bearings and found them almost dry. How can you tell if they're chain related? I'd guess because there's still grease in whatever's left of the bearing? Every bad bearing I've seen was dry and crusty.

We even had a destroyed hub. Guy had his chain too tight , busted big air and landed on the flat. Just collapsed the thing.[/QB]

I'm not saying running the chain too tight can't lead to problems. I run mine loose per the current spec, too. I think, but it's certainly not anything beyond my opinion, that the tight chain is harder on hubs than bearings.

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