Project: Adding passenger seat to FS bike

[cwah]

Hello,

I've finally decided to add a seat to my bike:

I've already prepared anchor for the side of the bikes that would allow to put M6 bolts:

The principe would be similar to Thebikeseat, but with working for 20" wheel, with bigger box capability and working for full suspension bike:

Here's what I'd like to achieve:

Key requirement:
Able to support 75kg passenger at 30mph and small potholes vibrations


So there are 4 things I need to make sure are right:
- The pillar tube that needs to hold on passenger weight + box weight. I'm thinking to get 6mm thick * 20mm width bar for each side:
http://www.ebay.co.uk/itm/304-Stainless-Steel-Flat-Bar-Strip-10-15-20-25-30-35-40mm-x-3-4-5-6mm-thick-/252123870089?var=550966013650&hash=item3ab3c0f389:m:mKmAXQgsaPVW-Hva8fNkPig
It will be fixed by 1 stainless steel M6 bolt:
http://www.ebay.co.uk/itm/M4-M5-M6-M8-M10-A2-STAINLESS-STEEL-COUNTERSUNK-BOLT-CSK-ALLEN-SOCKET-SCREW-/181276846436?var=480302297717&hash=item2a34f12964:m:mgpaglHKBfZXoxcL7wueiFw

- The top of the box will use the same 6mm thick * 20mm width bar. The rest will use 2mm thick 20mm width bar.

- The hinge... I don't know what to get. Any idea?


What do you think about this plan?

 

[jpgey]

Hello, the pillar will bend, you should use round tube.

 

[greg176]

You could use a moped seat with an additional brace to the main frame.

 

[cwah]

Hello, the pillar will bend, you should use round tube.

Would buying an already made rack be stronger? Such as these ones?
https://www.sjscycles.co.uk/carriers-racks/thorn-expedition-steel-rear-cycle-pannier-rack-seconds/

http://www.tredz.co.uk/.Axiom-Journey-Rear-Rack_54655.htm

Then I'd just have to add the hinge.

 

[cwah]

You could use a moped seat with an additional brace to the main frame.

It would look too much like a moped and illegal I think..