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I measured the wear on a bearing race today. This one looked like it had a lot of wear. The grooves are .001" deep. I used two different indicators one with a .020" ball & one with a point and they both measured at .001"
 

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I measured the wear on a bearing race today. This one looked like it had a lot of wear. The grooves are .001" deep. I used two different indicators one with a .020" ball & one with a point and they both measured at .001"
Wow, it looks much worse than .001. A human hair and a piece of paper is about .004
 

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You could easily grease them up and re install with correct torque. I'm sure they would be fine. The LT is not too precision. >:) Or you could pay for a new set, only available from bmw......:frown:, and put them in. Grease once and a while and correct torque might extend their life but the do wear out. GS bikes kill them. Personally I would go with new. I bet when you took things apart the torque was off. When this series bike first came out it was specked to check the torque on this right side pinion quite frequently. I would suggest doing it at 12K intervals. No one checks.
 

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I've rebuilt over 100 of the Final Drives and most of them had nowhere near as deep of grooves as this one. This one I replaced. Almost all of them I buff the races on a buffing wheel with white rouge buffing compound in both directions & install the race with the most wear on the inside.
 

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Wow, it looks much worse than .001. A human hair and a piece of paper is about .004
Keep in mind though that the issue isn’t so much the absolute number, but the number relative to the thickness of the race. If the race is 0.1 thick, then this groove is 1% of the race thickness. Look up the stress required to compress the steel in a race by 1%. I am not sure what steel is used in these bearings, but I will bet the stress required to compress this metal 1% is quite significant. Each time the FD rotates, it is roller the bearing from the low spot towards the high spot and thus apply stress to the race as it bearing roller climbs the slope from the divot to the original surface.

Having said that, after experimenting with the bronze bushings, which looked good in theory, I am back to BMW OEM. My bearings just arrived and my pins were just shipped so they both should be waiting when I return from my business trip. I think the stress applied to the FD and swing arm from the dried out bushings likely FAR exceeds the stress applied by the rollers climbing up out of a groove that is 0.001” deep or less.

So, back to OEM for me and periodic clean and regrease. I think it is the lesser of the evils. The Beemershop solution may be better, but I will remain skeptical until someone has at least 50,000 miles on them and takes them out for close inspection. So, John and Gordon, get out there and ride a little more! >:)
 
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You could easily grease them up and re install with correct torque. I'm sure they would be fine. The LT is not too precision. >:) Or you could pay for a new set, only available from bmw......:frown:, and put them in. Grease once and a while and correct torque might extend their life but the do wear out. GS bikes kill them. Personally I would go with new. I bet when you took things apart the torque was off. When this series bike first came out it was specked to check the torque on this right side pinion quite frequently. I would suggest doing it at 12K intervals. No one checks.
Actually, there's another source that forum member 'Sailor' posted , but now that I try it, shows 'out of stock' and the price has jumped to $60. When sailor posted that link I bought mine for $40,...supply and demand I guess..

https://www.euromotoelectrics.com/product-p/fdbearing091.htm
 

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