Under seat bags

[JonB]

I found a $5 cheap bag for the handlebar using straps to attach it self to the handlebar, aka a more or less permanent attachment. I put mine under the seat. It is a isolated bag, and it is just big enough for a 6-pack and 2 cheese burgers :mrgreen:

 

[Mark B]

JonB wrote: I found a $5 cheap bag for the handlebar using straps to attach it self to the handlebar, aka a more or less permanent attachment. I put mine under the seat. It is a isolated bag, and it is just big enough for a 6-pack and 2 cheese burgers :mrgreen:

Jon,

You've been around here long enough to know the rules; this thread is useless without pictures! :lol:

Mark

 

[JonB]

Mark B wrote:

JonB wrote: I found a $5 cheap bag for the handlebar using straps to attach it self to the handlebar, aka a more or less permanent attachment. I put mine under the seat. It is a isolated bag, and it is just big enough for a 6-pack and 2 cheese burgers :mrgreen:

Jon,

You've been around here long enough to know the rules; this thread is useless without pictures! :lol:

Yes i know, but my stupid windows mobile phone would not sync with my mac yesterday. Let me try now. Nope, still wont work right.

 

[JonB]

I finally got the pictures.

The bag is still there on the bike even after i have had it parked various places in Copenhagen. I guess the bag is not so attractive?

 

[JonB]

the bags didnt last long. One strap fell off, and the straps continuesly slipped from the locks. So they are gone now. To replace them, I have considered making what I have been drawing below.

The thin red lines are the minimum tubing i have to make to get a pannier hanger.
The blue outline is my 17" laptop pannier from Altura. The blue ontop is the handlebar.
The yellow outline is the mounting plate. The green squarres in the yellow outline are the tubehooks.
The larger orangegoldish squarre is the release button. It is pushed down towards the bottom of the picture.
The yellow line at an angle is a support hook that can slide along the yellow line.
The green dashed angled line is an idea of how to use the support hook. Unfortunately it can move a little as the spring suppension is absorbing bumbs and such.
The white dashed line is a suggestion to make more tubbing to make sure the pannier isnt moving.
The black dashed line is the same idea, just a different route.

I think the horizontal red line, the tube to hang the panniers at, is, or can be made just long enough to support 2 front panniers next to each other.

 

[Gromit]

Jon
I guess that the objective of the under-seat pannier rack is to isolate your laptop pannier from road vibration as the rack is on a suspended part of your Freerider? The experimental handlebar bag was exactly the opposite as it was attached to the swing arm and hence subject to full road vibration. Returning to the subject of the under-seat pannier rack. Wouldn't it be better to extend the base of the rack downwards to support the lower part of the pannier bags rather than using the extension of the rear pannier rack stays? The rear pannier rack stays move with the swing arm as you of course know.

 

[JonB]

Gromit wrote: Jon
I guess that the objective of the under-seat pannier rack is to isolate your laptop pannier from road vibration as the rack is on a suspended part of your Freerider? The experimental handlebar bag was exactly the opposite as it was attached to the swing arm and hence subject to full road vibration. Returning to the subject of the under-seat pannier rack. Wouldn't it be better to extend the base of the rack downwards to support the lower part of the pannier bags rather than using the extension of the rear pannier rack stays? The rear pannier rack stays move with the swing arm as you of course know.

I'm not worried about vibrations, since the laptop is cusioned inside the pannier bag. The reason is primarely to be able to have a basket ontop of the rear rack, and with in time, probably a child seat. Besides, the lower the weight is the better.

The handlebar bags was just to get something quick. I couldnt have a laptop in them, but i did have food that needed to be kept cold.

I do not fully understand what base of the rack it is you want to extend downwards. Do you mean the white and/or black dashed line at the drawing on the picture?

I know the extensions will move. I mentioned them as a reason because i was not sure about how i could securely attach the dashed white/black lines to the red ones. I saw that an extension would be much more solid and load able. I completely forgot that this part does not handle any load, it just keeps the pannier in place.

 

[Gromit]

JonB wrote:
I do not fully understand what base of the rack it is you want to extend downwards. Do you mean the white and/or black dashed line at the drawing on the picture?

Yes. The white and/or black dashed lines.
I was puzzled by why you were thinking about using the extensions (dashed green) to secure the pannier lower mounts. The extensions move with the swinging arm as you go over bumps in the road whereas the tube hooks are fixed to the suspended part of the frame. Just seems wrong to me. I'll bow out and leave you to it.

 

[JonB]

Gromit wrote:

JonB wrote:
I do not fully understand what base of the rack it is you want to extend downwards. Do you mean the white and/or black dashed line at the drawing on the picture?

Yes. The white and/or black dashed lines.
I was puzzled by why you were thinking about using the extensions (dashed green) to secure the pannier lower mounts. The extensions move with the swinging arm as you go over bumps in the road whereas the tube hooks are fixed to the suspended part of the frame. Just seems wrong to me. I'll bow out and leave you to it.

Dont worry, i like questions, suggestions and such. I seeked the advice of people showing up tonight at the club meeting at Leitra/Pedalkraft. I got suggestions for material, construction and mounting. I will make some drawings and post them.

 

[Gromit]

Jon. Here is a suggestion.
I found an interesting laptop bag for sale on a website here in the UK (scroll down to the bottom of the web page). It doesn't say who makes the bag.

As you can see, the bag hooks over the top of the seat. Would that save you a lot of work making up a pannier rack?
Edit
I think that it may be a Radical Design Solo Laptopbag.

 

[JonB]

Gromit wrote: Jon. Here is a suggestion.
I found an interesting laptop bag for sale on a website here in the UK (scroll down to the bottom of the web page). It doesn't say who makes the bag.
[attachment]rapto_lt_bags.jpg[/IMG]
As you can see, the bag hooks over the top of the seat. Would that save you a lot of work making up a pannier rack?

nice idea. But i already have my laptop pannier, and on the seat rest means higher up, which means the center of gravity moves up.

 

[Gromit]

Jon. You must have a really heavy laptop that you are so worried about keeping your centre of gravity low.

 

[JonB]

Gromit wrote: Jon. You must have a really heavy laptop that you are so worried about keeping your centre of gravity low.

Yeah thats right, very heavy. All the data weighs alot.

 

[Gromit]

JonB wrote:

Gromit wrote: Jon. You must have a really heavy laptop that you are so worried about keeping your centre of gravity low.

Yeah thats right, very heavy. All the data weighs alot.

Oh right! Secure data, locked in concrete! :lol:

 

[JonB]

So, this picture shows the mounting suggestions i got.
The blue bag outline is the old position, the magenta is the new position.

The yellow rectangle is a new support suggestion which would work for other bags than mine. But because my the way my laptop pannier mount is created, it would be hit by the yellow support. If i move the pannier to the magenta position, the yellow support will work, but then the bag would hit the front wheel.

I also heard a suggestion about the cyan support, but i cant have something between the arms that prevents movement. Think of looking at an A with the horizontal seat tube going through the A. So the cyan support doesnt work, and neither does the yellow for me. This leaves me with the old red outlined support and the green outline.

 

[JonB]

This is probably how i will make it.

In the right side of the drawing there is a red circle filled with black, and a cyan line arround it. What i will do is take a thin 2 mm flat 2 cm wide profile and wrap arround the round tube or solid stick and then a bolt through the wrap arround.
Something like this will make the red front support and the red rear support. The dashed white line is made the same way.

The magenta lines are supposed to be the round tube/solid stick that i will hang my pannier at. I dont know yet if i will get a solid stick or a hollow tube. But it will be round. The material will decide the shape. Iron can be a tube, aluminium will have to be solid and carbon fiber will probably have to be a solid as well.

Because the magenta line is on the side of the bike, and the top mountpoint of the red rear support is in the middle, then i will have to make something that goes out to the sides. I was thinking of something like a A when viewed from behind/front. A upside down T is an option too, but i think the A has more stability. The top mountpoint of the red rear support is a tubeclamp. Maybe i should just use the existing tubeclamp. I will probably try it first. The red supports will probably be made so the magentalines are not horizontal to prevent the pannier from moving back and forth.

The white dashed line does not carry any weight so it can be a hollow tube. And when i need to wrap arround, i can just squeeze it flat. For stability i will probably have something similar to the dashed white line between the right and the left side of the bicycle, since i plan to make pannier hangers on both sides. I think it will be hard to make some carbon fiber as the white dashed line.

Since i plan to make it on both sides, i have been thinking of bending the magenta lines in the front and make something like a U or V. This bending will probably prevent the usage of carbon fiber.

If i use iron tubing i could weld it together, technically you can weld aluminium too, but noone at leitra/pedalkraft can weld aluminium and i dont even think they have the needed gear for welding in aluminium which i have heard should be quite toxic. Because i cant weld, i will probably make it in aluminium only. But maybe i will make one in iron and learn how to weld If i weld, the support mounts could be done differently.

 

[JonB]

I think i found the final solution and material. I will soon make some drawings, but the actual work has to wait until Leitra is back from Spezi, because i plan to use his workshop and tools + materials.

 

[JonB]

JonB wrote: I think i found the final solution and material. I will soon make some drawings, but the actual work has to wait until Leitra is back from Spezi, because i plan to use his workshop and tools + materials.

Here is one drawing of one of the parts i need to make. For strength it is triangle shaped and is made of uses 10 mm hollow tube, probably aluminium.

The top of the triangle connects to a tubeclamp arround the outer seat tube below the existing tube clamp. The idea is to make the triangle as small as possible, therefore the tubeclamp is as low as possible. If seen from the side, this triangle is entirely vertical.

This piece is made from a single 10 mm hollow tube which is squeezed in both ends to attach to the seat tube clamp using bolts. 2 other sections of the hollow tube is also squeezed flat. These flat sections and then wrapped arround the horizontal bar (which is also round but solid, not hollow.) A bolt will further secure the wraparround so it doesnt move.

The intention of using a hollow tube is that the 2 tube sections will add stiffness to the triangle so it doesnt move from side to side when loaded (very) uneven.


The horizontal solid round bar will be made of 10mm aluminium bend in a U shape so both sides will also be a single piece.


It was suggested that i combined the triangle and the horizontal bar into the same single piece, but that means the horizontal bar will not be so long.

 

[MailSeanBell]

This might be a helpful link to create an underside bag:

http://www.faculty.virginia.edu/guilford/pannier.htm

Just need to use bigger hooks off the bag to reach under the seat.