My new Shimano-hubbed Sunrim Cr-18 wheelset arrived the other day, and to my chagrin – it’s not drilled for Schrader valves, but presta valves (those tall, thin metal ones with threads). Nothing is wrong with presta valves – in fact they actually retain air better at high pressures – but the availability of tubes for wider tires is somewhat limited.

So what does one do to remedy this problem, short of replacing the rims? Well, you drill the valve holes out, of course. Presta valves are 6mm wide, with a 6.4mm (1/4in) valve hole. In contrast, Schrader valves are 8mm wide, and have an 8.3mm (21/64in) valve hole. Luckily for me, the Cr-18 rims are wide enough to accommodate this wider hole; don’t try drilling out thin rims, or those rims with a strongly arched profile, or you may end up weakening the rim significantly.

Flat profile rims; its easily drillable.

 Select a few dill bit sizes for stepped drilling – this will prevent the bits from binding and ruining the rim. I chose 3 bits: a 7/64in bit, a 9/32in bit, and of course the 21/64in bit.

If there is already rim tape, peel it back with a tire lever and commence drilling. Once done, it should be noticeably larger:

 File off the burrs in the metal to prevent punctures, and the job is done.

 Now that I’ve drilled out these new rims, I’m all set to replace the old wheelset. The old Shimano/Araya combo has conducted me very “wheel” over the past 5000km and 5 years, and supported another 5000km or so for the 13years before that. 10 000kms and 18 years later, though, it is time to move, lest something *does* in fact break during our Italian trip.

R.I.P.

$10 Craigslist sale, anybody?

Here are the new beauties: I’ve finally made the switch over to 8 speeds and double walls.