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  Topic Name: seat pack harness prototype on: January 09, 2013, 05:45:06 AM
BRP


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« on: January 09, 2013, 05:45:06 AM »

Hey folks...
This is my first post on this forum. I just thought I'd share a quick picture of a prototype seat pack I've been working on for a while.
The one in the picture isn't quite the finished version. I decided to tweak the shape a touch more, but haven't had a chance to finish the latest prototype yet.
I know it goes against the usual bikepacking ideas of ultra light weight...especially with the Cobra buckles, but I wanted to make myself a pack that adhered to the principles of my bag company, where light weight has never been at the top of the priority list...and Cobras are my buckle of choice. ;]
It still beats the weight of racks and panniers anyway, and I like that I can really crank the straps down tight without worrying about breaking buckles...something I've done many times with plastic hardwear.

Anyway...it was more about trying out a few ideas than trying to please the majority. ;]
The one piece shell is hdpe plastic, with a high density foam backing, which gives me support and abrasion resistance, and it's built around a 13ltr Ortlieb drybag, so it's watertight too. The molle webbing strip on the bottom allows for strapping on other items or pouches.
The use of cable ties around the nose also makes it easy to fix if necessary.
I know that for most people it will be seen as overkill, but personally I'm really happy with it, but I'm always keen to get other people's opinions too...especially with so many hardcore bikepackers on here.

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  Topic Name: seat pack harness prototype Reply #1 on: January 09, 2013, 06:47:09 AM
cavscout


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« Reply #1 on: January 09, 2013, 06:47:09 AM »

My first reaction was that it looked like 10-12 oz leather and had a Harley Davidson saddle bag look to it.  I like the "stealth", "Black Ops" look of it.  Are there 3 Cobra buckles on this?  

The only issues I think there is in the design is that the bag projects up so high behind the saddle that in a down hill single track situation you would not be able to push your body weight back over the rear tire.  Not as much an issue if used on a road bike.  Repositioning the MOLLE system to the top of the "sheath" would provide protection for the items attached externally also.
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  Topic Name: seat pack harness prototype Reply #2 on: January 09, 2013, 07:17:06 AM
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« Reply #2 on: January 09, 2013, 07:17:06 AM »

I hear what you're saying, but how high it rises above the saddle is determined more by the relative positions of the saddle to seatpost, and the shape of the saddle and the position of it's rails relative to the rear of the saddle. The pack will tighten until it stops flat against the saddle/rails. If the saddle was set further back in relation to the post then the pack would sit lower due to the shallower angle.
The only other way is to radically shape the harness to curve down past the saddle, which won't work so well with a separate drybag.
Repositioning the straps to allow the pack to effectively roll back and down is also not possible as the seatpost clamp would prevent it.

With regards to the molle being on top...you are very limited for space up there unfortunately. There is one molle loop, then the buckle.
Having it underneath is to allow more space...which i assume is why most companies also place their bungee lashing down there?
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  Topic Name: seat pack harness prototype Reply #3 on: January 09, 2013, 08:27:18 AM
cavscout


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« Reply #3 on: January 09, 2013, 08:27:18 AM »

Yeah, the dimensions and angles of the seatpost and seat rails are the big variables in the equation but that just means the seat bag has to be that much more adjustable, or custom fitted.  I think if you moved the lower attachement point up towards the opening of the dry bag (maybe 4"), that would give you the flater angle.  It would probably mean the wide area it's attached at now would have to move up the same distance, but that shouldn't hurt the overall design.

I think you can see the difference in angle in this pic of my seat bag made by Hamilton Threadworks and how flat It hangs, and how I ue the bungee on top.



I'm seeing very few with the tie downs on the bottom.  I see that actually as a problem since I'm not going to carry my thin windbreaker on the side of the bag that could impact the wheel or get mud kicked up on it.  Placing it on top, even if it means a reshaping of the top would provide a much more secure and protected platform for straping things to the outside of the bag.

I'm by all means a novice to the bikepacking scene so hopefully others will chime in to privde you some better views.  All in all a very cool project.
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  Topic Name: seat pack harness prototype Reply #4 on: January 09, 2013, 04:22:02 PM
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« Reply #4 on: January 09, 2013, 04:22:02 PM »

The saddlebag in your picture is at a lower angle because the saddle is further back and the angle of the underside of the saddle is different.. The top of both saddlebags is effectively a flat surface which runs parallel to the rear section of the saddle and then continues on past the saddle at that same angle. So if for example I was to put your saddlebag on my bike and pull the saddle rail mounting strap tight, it would follow the same angle as my own, because the tops of both are flat....except the seatpost collar would probably be at the wrong angle to mount properly.
If you were to move your saddle two inches further forward or use a saddle with a different angle under the shell, then your saddlebag would also rise up higher behind your saddle because the angle between the post and saddle would be steeper.
If you look at the angle between the seatpost collar of your bag, and the top section, it's pretty much exactly the same as on mine.
The different rise of the bags is down to the different saddle positions between the two bikes...in my opinion at least.
If you look at this picture you can see what I mean a little better...once the saddlebag is pulled tight against the saddle, it follows the same angle as the saddle.

Also, the bungee can be mounted on top because you don't have an end compression strap and buckle in the way. It also means though that anything you strap on top will then be in the way when you move back over the wheel, so it kind of cancels out the lower bag angle.
Carousel, porcelain rocket, bikepacking.eu all have their bungee lashing on the underside.

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  Topic Name: seat pack harness prototype Reply #5 on: January 09, 2013, 04:37:45 PM
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« Reply #5 on: January 09, 2013, 04:37:45 PM »

As you can also see from my second picture, the seatpost clamp design also plays a part in that this particular one stops the nose of the bag being able to move any higher up the seatpost.
A less bulky clamp would technically allow the whole bag to rotate up at the front and down at the back.
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  Topic Name: seat pack harness prototype Reply #6 on: January 21, 2013, 10:13:31 PM
ascar_larkinyar


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« Reply #6 on: January 21, 2013, 10:13:31 PM »

i like the look.  smooth and polished.

the only thing i see is that the side buckles and top/back buckle could maybe rub on the rider?  maybe not.  moving them lower or to the other side is an easy fix.  good job!!!!!
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  Topic Name: seat pack harness prototype Reply #7 on: January 22, 2013, 02:39:26 AM
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« Reply #7 on: January 22, 2013, 02:39:26 AM »

Although it doesn't look that way on the picture, the side buckles are actually out of the way of the riders legs, but on the final version I've switched to cobra frame buckles instead, and moved them lower. These are smaller and lighter, and non quick release, as I don't really think they need to be in that application, as once the harness is on, it stays on until the ride/tour is done.
The top/back buckle doesn't seem to cause any contact problems either... Unless you were to slide a long way back while still seated.
The bike its actually going on though  has a different seat post and the saddle is a bit further back... Both of which move the bag down a bit at the rear and get it further out of the way.
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  Topic Name: seat pack harness prototype Reply #8 on: January 30, 2013, 11:56:36 PM
wunnspeed

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« Reply #8 on: January 30, 2013, 11:56:36 PM »

Things can look a lot heavier in photos than in real life. Strangely, it does look really Harley biker to me too.

I would avoid the underneath attachment points. I have them on my on my Carousel seatbag and have always wondered why they were there. The elastic cable continually rubs the tire as would anything that would be attached under the pack (in my case). There's, at most, 1.5" between the bag and the saddle.

Your comment is true about the relationship of the seatpost/saddle/bag. If the saddle wasn't so far forward the bag might lay a little more horizontally.

As a fellow bag maker, I have found that padding on most things is overkill and weighs things down.. .a lot. I also think that lining everything is going a bit too far as well. That's me though. I don't see bags lasting long enough (even though I make mine to last a long time) to warrant it. My one run on the TDR with X-Pac 21 did a lot of damage to the bags. Of course, that's pretty lightweight material. The Ortlieb bag (I live close to where they're based) will last a lifetime though.

Congrats on setting yourself apart and doing your own thing. That's quite cool.
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  Topic Name: seat pack harness prototype Reply #9 on: February 07, 2013, 07:47:01 AM
VABikePacker


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« Reply #9 on: February 07, 2013, 07:47:01 AM »

that looks cool...

Is the drybag removable or stationary?
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