Say for example you had an old alloy frame that you love, but you’re not precious about. Next to said frame you have a box with a Di2 groupset in it. Would it be ok to drill two 5.5 mm holes in the frame so I could run the cables internally?

Frame is an old Airborne disc frame so not the lightest. Thinking of one hole on the downtube and one at the mech end of the chainstay. Firey ball of death likely?

My dad drilled and tapped my Zaskar Le frame at some point in the late 90s to bolt on a crud catcher instead of using the elastic bands, m4 bolts probably

Was fine until the headtube parted from the frame in an unrelated incident

Judging from what trials riders do to lighten their frames I’m gonna go with ‘Sure, provided you’re not drilling through the welds themselves’.

All I will say is it’s up to you and you would have to be very unlucky to cause a problem.

Just obviously don’t do it close to any welds and use a decent drill bit (not a Silverline 10 for £1 jobby) and some lubricant if you have some wouldn’t go amiss as it makes for a nicer hole and keeps the bit in good condition. Which reminds me I need to find mine.

Cheers gents, will (hopefully) report back on my findings