Grease them tapers?

[bomberz1qr20]

On a square taper BB, does one grease the faces of the taper? Why? Why not?

[Shibby]

hey, i don't do it on my own rigs, so i vote no

[gravity]

yeah grease em, it stops em creaking. as well as preventing metal fatigue from direct contact.

[edoz]

I can't believe you guys even consider greasing them!

[johnbryanpeters]

molybdenum disulfide-based grease.

[BMXman]

Originally posted by gravity
yeah grease em, it stops em creaking. as well as preventing metal fatigue from direct contact.

any mechanic worth his carbon knows this....a little grease never hurts.....D

[RideMonkey]

Originally posted by BMXman


any mechanic worth his carbon knows this....a little grease never hurts.....D

Not in this case. The taper on a BB spindle and crank is a press fit mechanism. The friction between the crank arm and the spindle causes the arm to slide on so far for a given amount of torque on the crank bolt. If you grease the spindle, the crank arm can slide farther onto the spindle, farther than it was designed to. The result is that the taper on the spindle forces the taper on the crank to expand. Multiple installations like this will cause the crank to move closer and closer to the BB shell, altering chainline and eventually ruining the crank when you pull the spindle all the way through the arm.

[BMXman]

Originally posted by ridemonkey



Not in this case. The taper on a BB spindle and crank is a press fit mechanism. The friction between the crank arm and the spindle causes the arm to slide on so far for a given amount of torque on the crank bolt. If you grease the spindle, the crank arm can slide farther onto the spindle, farther than it was designed to. The result is that the taper on the spindle forces the taper on the crank to expand. Multiple installations like this will cause the crank to move closer and closer to the BB shell, altering chainline and eventually ruining the crank when you pull the spindle all the way through the arm.

It's a poor design... I know, but I still think a little grease is ok and a torque wrench is mandatory so you don't over tighten and cause the problem you mention above.....D

[oldfart]

It used to be that this was a dry fit. No grease at all. But current thinking is for a t-h-i-n layer in there. I believe in the old days it was believed that greased tapers would allow the crank arm to be driven on too far and be damaged. Kept up over the number of bb overhauls needed in those days and the crank hole would be so big that the bolt would bottom out. Today you get torque settings so this won't happen and materials are better than then. Better yet go splined, grease the thing well and don't worry about it.

[Brian HCM#1]

Never ANY grease, ever!!!!!!! It will allow the crack arm to slide up the taper too easily. Allowing you to bottom the bolt out. I have never had my cranks creaking from not using grease.

[edoz]

Originally posted by oldfart
Today you get torque settings so this won't happen and materials are better than then.

Actually, greasing anything will afffect torque readings. You will get different readings on greased and dry bolts, too. I have checked the Barnett's and Sutherland's manuals as well as the Campy book at work and they all say no grease. I can't think of any more reliable source than that.

[edoz]

Originally posted by Brian HCM#1
It will allow the crack arm to slide up the taper too easily.

The CRACK arm? I don't grease my crack pipe cause it tastes funny. I don't know about a crack arm, though. I don't put grease in the meth\crank, either. It tends to make the lab more explosion friendly.

[oldfart]

Race face recommend grease and I think Shimano now too, but not much. In the past I always cleaned the spindle and the hole. But now I use a very thin aplication. I never had creaking either but its what they recommend.

[diesel]

Id hafta agree with oldfart on this one. pat gauss always says follow the dealer manual, same thing goes for cranks. if raceface designed your stuff and says you should greeeese em' i say grease em.

[bomberz1qr20]

Originally posted by oldfart
Race face recommend grease and I think Shimano now too, but not much. In the past I always cleaned the spindle and the hole. But now I use a very thin aplication. I never had creaking either but its what they recommend.

Race Face recommends it on square tapers? Or on ISIS? I couldn't find tech info on either site, and I have no literature or install manuals for Race Face or Shimano stuff.

Where did you get this info?