fitting a Terracycle pannier rack to V 1.0 or V 2.0 Silvio

[super slim]

what is the wall thickness of the v 1.0 and V 2.0 frame under the seat bottom, to install Open ended knurled Aluminium threaded insert M5 for 0.5 to 3.3 mm sheet thickness or 3.3 to 5.7 mm. These compress down like a rivet to hold the nut solidly.

http://www.totalfasteners.com.au/browse/nut-threaded-inserts-and-tools/202003586

It would be for a set of Terra Cycle Underseat racks without the cross hangers, using the M5 threaded nut inserts in the frame.

http://t-cycle.com/easy-reacher-underseat-racks-c-12/volaehaluzak-rack-p-122.html

Would it be better to use M5 allthread through both nuts inserts (With the thread drilled out on one of them ) to allow external nuts to compress the two nut inserts and hold the clamps to the frame.

regards

Super Slim

 

[John Tolhurst]

Silvio 1.x, main tube wall

Silvio 1.x, main tube wall thickness is (from memory) 1.8mm
Silvio 2.x, main ?tube wall thickness varies along the length and around the girth due to the multiple forming processes. Under the seat, 1.8mm, less 0.4 on the underside, plus 0.4 on the top side.

In either case restrict any holes to the central axis of the tube, where there is neither compression nor tension and where the possibility of developing a crack is lessened (but not guaranteed safe). Do not drill the upper or lower surfaces.

 

[BentBierz]

John...so as to understand

John...so as to understand your answer (because I am looking at some potential small drillings/grommets) by central axis do you mean on each side of the main frame (logo sides) --and-- to keep any drilling as much in the center of each side i.e. try not to drill high or low on the sides? Thank you.

 

[John Tolhurst]

Far be it from me to suggest

Far be it from me to suggest drilling holes in frames, but yes, looking from the side, somewhere near the middle line down the length of the tube, is what engineers call the 'neutral axis', When subjected to bending loads (sitting on the bike, the main tube is a beam simply supported at the headtube and elastomer) the neutral axis carries neither compression nor tension.

 

[BentBierz]

Thanks John,
My intent is to

Thanks John,

My intent is to drill two holes on the left side, one on the opposite side of each of the cable stops, so that I can run dyno wiring through the frame. I tried widening the existing stops and took out about as much metal as I am comfortable doing and can now get a coaxial wire and a cable housing through but it is still a tight fit.

 

[keithkling]

Hi Super Slim. I have used those nuts you are talking about and they are very handy in the right situation, but drilling a hole in the side of your bike frame to hang a rack on is asking for trouble. The area the John suggested might be stress free won't be stress free when you hang some weight on it, you will already have a place for a crack to begin. I would find a different way to hang that rack. Do whatever you can to NOT DRILL A HOLE in your beautiful bike. On the S 1 there are holes in the seat pan that something could be mounted to. Maybe you can come up with some kind of bracket that would allow the rack to be mounted that way. I have made a rear rack for my S1 and mounted it completely on the seat back and seat bottom using only the existing holes. I have seen an aluminum bike frame crack and tear from stresses. The only way to fix that properly would be to replace the frame.