I’m sick of expensive bikes being cheapened by rounded off heads.

Just a selection for bottle cages and stems etc.

And I do use a torque wrench!

Better bits for the torque wrench.

Rusty bolts a prob here…..

I’ve bought small volumes of e-bay before. If you search for cap head hex bolts, (but you actually want set screws as bolts have an unthreaded shank, but that tends to be longer ones than you’ll need for a bike) and make sure they specify A2 grade or even better A4 they’ll be decent enough.

http://www.westfieldfasteners.co.uk/

I usually just get ‘em off eBay.

Pro-Bolt

I’ve used this kit below for stems and brakes etc. I purposely tried to round one off as a test and couldn’t.

http://www.ebay.co.uk/itm/215-PIECE-HIGH-TENSILE-M3-M4-M5-M6-SOCKET-CAPS-KIT-SELF-COLOUR-HIGH-TENSILE-HT-/191053969921?hash=item2c7bb43a01

I think they do a mushroom-head set as well.

If you’re replacing you may as well put stainless one. There is a potential issue with tensile strength, but for accessories such as bottle cages, racks, derailleurs, bar mounted accessories etc it is not significant. I’m not even sure that else where on a bike the difference in tensile strength would be an issue.

Halfords stainless steel.

Better bits for the torque wrench

I just got some teng bits. Bolts are soft though.

I’ve used this kit below for stems and brakes etc. I purposely tried to round one off as a test and couldn’t.

That looks a good shout.

Halfords stainless steel.

That looks interesting.

I went into Halfords and couldn’t find any. Are they web only?

http://www.blacksocketcaps.com

Stainless will rust in this type of use on a bike. Look up crevasse corrosion, it’s a problem anywhere stainless is starved of oxygen. Better off with aluminium or ti for the bike.

Stainless is theoretically harder but the cheap stuff on eBay rounds pretty easily, especially in small sizes. If you want properly strong then anything with a rating (eg 8.8 or 10.9) will be pretty decent. Also ditch the torque wrench and learn to do it by feel but that may be too controversial.

Stainless will rust in this type of use on a bike. Look up crevasse corrosion, it’s a problem anywhere stainless is starved of oxygen. Better off with aluminium or ti for the bike

Crevice corrosion usually happens with gaps that have stagnant moisture, not generally stainless. Think you’re thinking of galvanic corrosion, where two dissimilar metals are in contact.

As said before, decent quality bits, and also appropriate lube/threadlock on threads will do the trick.