External bearing drag?

[Spalls]

I just installed a Shimano LX crankset (M580) on my Trek STP 400. Followed the directions to the letter. Before putting the chain on, I gave it a spin with my finger. Drag. This thing does not spin nearly as freely as any conventional inboard sealed bearing or loose bearing bottom bracket that I have ever used. Is this typical?

[rockyrider]

Yes it is. The combination of the preload to prevent lateral free play and the extra drag of the bigger bearing seals mean they usually get about 1 rotation before stopping when new, they do break in a bit though.

The only X type cranks I've seen that still spin like a top when installed fresh are the new XTR which have the adjustable sideload feature so you can take out all the side to side free play and leave the bearings to spin. Like buttah!

[Spalls]

Rocky: Thank yuh, thank yuh vurrry much! I feel better now. I could not think of anything to do as far as adjustments go to improve the situation.

[rockyrider]

Once you're riding in the mud on tires with 50-50 durometer rubber you won't even notice the bearing drag. :D

[hairygrump]

If it's really killing you and you've got a steady hand and a sharp knife you can trim those seals a bit.

Road bike racers do it, I know. I think it might be as much a psychological benefit as anything though...

[RickB]

I just installed a Shimano LX crankset (M580) on my Trek STP 400. Followed the directions to the letter. Before putting the chain on, I gave it a spin with my finger. Drag. This thing does not spin nearly as freely as any conventional inboard sealed bearing or loose bearing bottom bracket that I have ever used. Is this typical?

Contrary to popular belief, these bearings and seals *can* be replaced and upgraded. The high end option is ceramic bearings, which roll like buttah and last a long time, but are pricy. The "enduro" bearings are a good upgrade over stock, at a reasonable price. Many shops now now have the special tools needed to pop out and press in the replacement bearings into the original shimano (or FSA) cups.

- Rick

[Spalls]

I love being surrounded by knowledgeable people. Now, how about some stock picks?

[RickB]

I love being surrounded by knowledgeable people. Now, how about some stock picks?

Anything involving guns or oil...

[ovlovder]

Contrary to popular belief, these bearings and seals *can* be replaced and upgraded. The high end option is ceramic bearings, which roll like buttah and last a long time, but are pricy. The "enduro" bearings are a good upgrade over stock, at a reasonable price. Many shops now now have the special tools needed to pop out and press in the replacement bearings into the original shimano (or FSA) cups.

- Rick

We regularly swap external BB bearings. Even the -less than $20- enduros are proving to be better than stock... I think it winds up around $50 with labor...

[ss29mtb]

Before you invest the $$$ on ceramic bearings i suggest you do a little research on them.

I recomend NOT going to the websites that stand to benefit from selling ceramics.

also just because the BB doesnt spin easily in an unloaded situation ie. bike in the rack, does not mean that they are not superior when you are standing on the pedals, and riding.

IMHO ceramic bearings are a scam, at very best IF you believe the hype they are worth a few seconds in a 40k TT

[RickB]

Before you invest the $$$ on ceramic bearings i suggest you do a little research on them.

I recomend NOT going to the websites that stand to benefit from selling ceramics.

also just because the BB doesnt spin easily in an unloaded situation ie. bike in the rack, does not mean that they are not superior when you are standing on the pedals, and riding.

IMHO ceramic bearings are a scam, at very best IF you believe the hype they are worth a few seconds in a 40k TT

I agree that ceramics aren't probably worth the incremental cost (at present), but the research I've seen indicates that they do roll better and wear longer. The "roll better" seems to do more with the fact that they can be produced to lower tolerances for size and "roundness", rather than something magical about the material itself, though I would think there would be some inherent additional corrosion resistance (since we all know that there's no such thing as a "sealed" bearing).

The enduros are definitely worth it when your stock bearings wear out or get grunchy.