Best place to drill a hole in a tubular pannier rack?

[Richard D]

For reasons of aesthetics, I want to try to destroy my very pricey titanium Tubus pannier rack by drilling a hole in it.

Okay, what I actually want to do is to hide the wiring to the rear dynamo light, and as the Tubus is hollow it has real potential.

It's already open at the bottom of the rack, but where's the best place to drill at the top/rear corner?  At the back of the horizontal rail, at the top of the upright stay, or somewhere along the bend where the upright transitions to the horizontal (and if so, whereabouts?).

I know that drilling *anywhere* is going to compromise the strength of the rack, and it’s not got the greatest load capacity as it is.



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[The French Tandem]

Drilling at the back of the horizontal rail is certainly not a good idea, since this is exactly where all the weight of your panniers will rest. I didn't say that drilling at other places is a better idea!

A

[LittleWheelsandBig]

I would space the hole away from a crossmember by perhaps 2cm. Otherwise, I’m not sure where a significant stress concentration might form. File the opening to a smooth finish, of course.

[hatler]

I would say you want to avoid a hole where there's any bending moment, so I'd suggest somewhere on the straight bit of the upright, where loads will likely be compressive.

[Brucey]

look Ma, no warranty!

But a few thoughts...

is there perhaps already a breather hole in the underside of the cross-member? If so could it be used in some way?

Also, is it worth wiring the rear light using a ground return through the rack? This way a thin single-core wire could be run up one leg, and would only require a small exit hole to be made.  The lower of your two red circles would be a better position I think...?

cheers

[LittleWheelsandBig]

If there is a breather hole in a crossmember, there is unlikely to be a penetration through the side of the longitudinal tube, so I don’t think that is a likely solution.

[Brucey]

If there is a breather hole in a crossmember, there is unlikely to be a penetration through the side of the longitudinal tube, so I don’t think that is a likely solution.

in steel, that would likely be the case. However in Ti, the backside shielding needs to be more extensive, so apparently superfluous holes are not unknown.

In any case sucking or blowing on the open ends whilst blocking off obvious holes will soon show if there are hidden drillings or not, although it may not tell you exactly where they are situated.

cheers

[Richard D]

I’m not sure I could cope with relying on the ground return via the rack/frame.  I’m using SON coaxial cable, so it wouldn’t save a lot of effort.

I’ll go looking for the breather hole tomorrow (it certainly would make life easier) but I’d not spotted one when I last looked.

Warranty?  What’s one of those?  I’d initially thought "but my rack is over five years old; there won’t be any warranty", but I now see Tubus have a 30 year warranty!

[Paul]

In a well-equipped workshop!

Boom! Boom!

Sorry: Christmas spirit and all that.

[Richard D]

Ha!

One option is to drill the hole (it’d be 3mm dia in a 10mm tube) while supporting the tube with a dowel, and then insert a pre-drilled sleeve and glue it in place to give the tube a bit of reinforcement.

Turns out to be a moot point right now, though, as I’m buggered if I can work out the internal wiring route for the front fork!  There’s a port by the dynamo hub on the RH leg, but I’m not seeing a way to get any wire that goes in out through the hose port at the top of the LH leg.