smontanaro 

I have a couple bikes with Cinelli 1R stems. I've always been afraid to really honk on the allen bolt for fear of breaking the little internal clamp part. Consequently, they sometimes slip, always when I'm braking on the hoods and you get that back-to-front weight transfer. No problems so far, but it gives me the willies when it happens. I worry about it slipping during a hard stop (like, to avoid ramming a boneheaded driver who cuts me off).

It occurred to me that maybe I could increase the friction a bit. Don't the carbon fiber geeks use some sort of assembly paste for their seat masts (and maybe cf handlebars) to reduce the amount of torque they have to apply to their bolts? Alternatively, might a little drop of oil on the surface between the nut and the clamp piece improve transfer of torque from the bolt through the clamp to the bar? Where the red dots are in this image.

gioscinelli 

Hi Skip, Here's what I used to correct the slippage on the Cinelli 1R stem:

https://www.amazon.com/Safety-Walk-A.../dp/B001NH3WZ4

See you on the road, Mike

SJX426 

@Drillium Dude likes 1R stems a lot. He may have a suggestion. I think you could easily grease the mating parts as well as the fastener. The later may back out but give it a try. Note that the torque will be reduced with increase in applied pressure to the bar.

easyupbug 

I keep carbon paste around for just such situations, works great, takes very little. Much better than in the old days mixing valve grinding compound and grease.

due ruote 

Are you saying it was applied to the red dot areas? Or somewhere else, like maybe the clamping face? I'm a little surprised that there would be that much room in there, but it's been a while since I had one apart.

IVARR

my suggestion was going to be a thin sandpaper given a single wrap around the bar between it and the stem.
a 1000 or 1200 grit wet paper should fit. if you work it down a bit, but you might get a 800 grit in there.

it works ...