Is it a bad idea to replace square taper crank bolts without removing the crank arms before re-tightening?

I can't think of any reason it would be.

Sorry to barge into Scrod's thread and answer a question he already answered, but I found this pretty interesting. It's an interesting "theory" that I am still not sure about, myself. But it relates exactly to what you are asking about and worth reading (and thinking about IMO).

Installing Cranks by Jobst Brandt

^That is a good read.

It is. But it concerns me and makes me leery about how "much" to re-tighten the bolts after the initial first few shake down miles.

What I took away from it is that the loss of some preload is not a bad thing and that re-tightening isn't necessary. The properly torqued crank is seated firmly onto the spindle and the crank bolt is then acting as a "stop" preventing the arm from moving back down the taper, but not bearing on the crank to the extent it does during installation.

That's what i get too. But............ on a recent build I re-tightened the bolt just enough to where it felt like it was bottomed (and snug) against the crank, but not enough to "move" the crank farther onto the spindle.

That's what makes me curious about what you will choose to do in your situation? Am I correct in assuming that you will just snug the new bolts up as apposed to going all the way to ~ 30 ft lbs again?

The reason I asked is because I'd like to replace the standard RD2 crank bolts with some self-extracting ones (mostly because I think they look waaaay better) so my motivation is purely cosmetic. I may just wait until I put another couple thousands miles on my BB (its less than a year old) and switch the bolts and replace the BB at the same time.

Having dealt with bolt preload in vibrating machinery, I am of the opinion that at least some preload is necessary to prevent the crank arms from working their way loose over time. Also, I've found that good quality crank arms do not move further onto the square taper spindle after they have been properly tightened initially when the bolt torque is reset.

Jobst Brandt was a very intelligent man. He was also an over-thinking lunatic.

LMFAO

What's your take on the "re-tightening" subject?

Just about anything put under the stress of constant loosening and re-tightening will eventually weaken. Blue Loctite on crank bolts FTW.

Do you ever think you would make a shop kit?

Do you mean lycra ? Are you trying to give Scrod a heart attack ?

In the works! Bojac needs something to wear on the track.

Skinsuit ?

I can only imagine how awesome a Retrogression kit would be. Take my money now, I want one.

It will definitely be awesome.

ill take 3.

Seriously, can we preorder? I don't want to miss out.

There will be a pre-order as soon as the design is complete!

I'm not really supposed to let the cat out of the bag yet but the new Retrogression site will be live in the coming months as well, which is sure to be a certified interweb extravaganza.

So what are we talking about here ? Bib short + road pocketed jersey or something else ?

Bib shorts, full-zip jersey and arm screens - sold as a complete kit or as separate pieces.

Pardon my ignorance, but what are arm screens ?

Woohoo!