Great Big Bags 2.0 – 138L (each) Panniers… Seriously?!

Prologue
Episode 1: 138L (each) Panniers… Seriously?! (you are here)
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar
Episode 5: Odds and Ends

When I put together my first set of Big and Cheap DIY Cargo Bike Bags, I thought two 77L panniers were huge! I fit them onto my Mongoose Envoy cargo bike project, and for several months they have been great, but not quite perfect. Not because of the capacity of the things. They were perfectly sized for that mid tail frame. But there were a few convenience issues … you’ll see below what my solutions were.

Why go bigger?

Well, I liked the Mongoose mid tail so much (it was my first dedicated cargo bike) I decided to jump all in and go for a full sized longtail with as much capacity as I could get my hands on. The Surly Big Fat Dummy was a bike I had *almost* bought before the Mongoose, and I decided with its fat tires, sheer size and very stiff frame it would offer the larger carry capacity and greater versatility I was after.

Going from a mid tail to a long tail meant I had more room for bigger bags. I could do the Rothco 77L canvas bags again, but after quite a bit of shopping around, I found Rothco’s larger, heavy-canvas 34″ long, square zipper’d duffel bag was dimensionally just about perfect to fit the BFD’s rear cargo area.

But, I am getting ahead of myself.

Parts List

$92.00 Rothco Jumbo Canvas Cargo Bag (qty 2)
  7.08 C.S. Osborne #5 5/8" hole Brass Grommets (qty 10)
 44.00 Cross Linked Polyethylene - 2lb, yellow 72"x48
 15.00 7/8" thick hardwood dowel (qty 2)
 20.00 12" soft cargo loops, 6 pak (qty 2)
  7.21 7/8" rubber chair feet 4 pak
 36.00 74" buckled 2" wide luggage strap 2 pak (qty 4)

Total Project Cost: About $221.00.
Result: 276L of pannier space. Two Hundred and Seventy Six Liters.

Notes on the Parts List

Foam
I am sure you can find something cheaper. I wanted something bright yellow so I could see the contents of the bag easily. Cross linked polyethylene is essentially a thin version of gym mat material. Extremely fine-celled. I have used Foam Factory for some esoteric jobs in business for custom cut stuff and found they had what I was after. What you want here is a big single sheet of foam that wraps entirely around the bag interior. The large foam sheet specified here is just over double what you need. Cut it in half, shave a few inches off one side and its a perfect fit. As an alternative you might try a couple of the Therma Rest mattresses that I used in my original bags, and some gorilla tape.

Grommets
You can also use #6 grommets just like I did with the original Big And Cheap Bags. It all depends on what tools you have in your garage. If you have no grommeting tools whatsoever, this #5 size midget grommet kit will give you everything you need – the tool and plenty of grommets. Cost is about $56 and you will have plenty of grommets left over so you can hammer reinforced holes into more things.

The Wooden Dowels
You can go to Home Depot and pay about half what you will at Amazon. Thats what I did, and HD has a handy manual-cut station you can use to cut the rod down if you don’t have a saw (please buy a saw instead). I only put Amazon as a source so there is an online purchase choice.

The Luggage Straps, Part 1
I specified four 2-paks for a total of 8 straps. 4 per side. Generally you only need two. But when carrying really heavy items, like the pictured load below (still in the shopping cart) that weighed about 128 lbs (58 kilos) … you want more straps to help take the burden off of your wideloaders. So, you can buy fewer straps. Or you can buy the max that will fit and toss the spares into your cavernous panniers and forget about them until they are needed. Your choice.

My first shopping trip with these bags was a Costco run. I didn’t realize I had almost 130 lbs in the cart. The duffel in the bottom goes onto the deck was at least another 20 (Just the lock is 15 lbs).

The Luggage Straps, Part 2
Notice in the pic above, and in my previous Big Bag posts, I used 2″ and then 3″ wide velcro straps (a single 3″ above). these hold fine, but in daily use, velcro is… velcro. It is constantly sticking to things it decides to stick to, and generally making my life more difficult. The straps do indeed do their job, but first and foremost just finding 3″ wide straps long enough to work with these bags is very difficult (and a process I will not describe since I abandoned them). Also these 3″ extra-long unicorns are just too damned expensive. Kydex buckled straps unbuckle in an instant, don’t stick to themselves or anything else, fit 4 to a side which is plenty and cost less to boot. Lastly, the luggage straps I am specifying adjust from 40″ to 74″ which is perfect for folding the bags up, empty, and expanding them out when full. Since the excess strap length is captured via a sewn-on sleeve, nothing is ever flopping around.

Whats With The Dowels?

My original Big Bags used hooks, and I went to a fair amount of trouble to make sure they were absolutely planted and rattle-free. And they are all that. But still, I thought there has to be a better way, and I ended up coming up with one.

Using dowels and cargo loops for hanging the bag has major benefits over hooks:

  • It doesn’t rattle
  • It is light weight (lighter still if you use an alloy tube)
  • It is cheap (less so if you go alloy)
  • It distributes the load on the bags evenly across their entire length
  • It holds them fully secure
  • There are no points of excessive wear/rubbing.

And last but not least, they make bag removal and reattachment a snap. The process described in a nutshell:

STEP 1: Loop-tie five cargo loops per side to the Dummy rails, and loop those up thru the deck itself so they drape down. If you are not making bags for a Surly or Xtracycle-compatible cargo bike, use as many loops per side as you can, as well-spaced as you can make them.

Here is one of my early fitments when I was figuring this all out.

STEP 2: Create 5 grommet holes in the top inside edge of each bag. One on each top corner, and the remaining three positioned so they are roughly equally spaced down the side of your rack. the exact positions will vary depending on your rack. I illustrated the whole grommet-creation process in the original bag creation post. But worth noting for these bags I used smaller #5 grommets and I really prefer this smaller size.

STEP 3: Line up your now-holey bag with the dangly loops and, one at a time, put each loop into each corresponding bag hole. As you do this, thread your dowel thru the loop on the inside of the bag.

Here is what this looks like with no bag in the middle


Annnnnd with the bag:

STEP 4: Remember the rubber chair feet? Put one on each end of the wooden dowel. This keeps the bag from rubbing on the edge of a relatively sharp edge of cut wood. Sooner or later it will rub enough to wear thru the canvas. But not if you have a big soft round rubber bumper on that edge.

Note the above pics show a 1.25″ wooden dowel. I downsized to 7/8″ and its much easier to fit the loops thru when putting the bag back on. You can see the smaller version in the pics below. Original concern was the dowel bending, but there are so many cargo loops to suspend it… thats not going to happen.

Spend a few minutes with some fine-grit sandpaper to make the imperfect surface of your dowel silky smooth.

Bag Removal and Re-Attachment

Here it is in a few easy steps. I photographed my first bag removal as you see, and I timed the second one with a stopwatch. It took 30 seconds to remove the bag from the bike and another 15 seconds to toss in the straps and zip the bag back up.

You can forget about making something that fast and easy with hooks.

STEP 1: Unbuckle the two bag straps. Pull the top inside corners of the bag back so each end of the wooden dowel is visible.

STEP 2: Pull off the rubber foot from one side. I removed the rear one this time.
STEP 3: Pull the dowel out from the other side. Its only halfway out in the picture. It will slide out quickly and easily.

STEP 4: DONE. The bag is now free. It is now a big duffel bag with handles you can lug into the house with all its contents. Feel free to use the shoulder strap that came with it.

Did I Mention The Kangaroo Pouch?

Yes really. Just like the original bags, Big Bags 2.0 are typically folded up when empty. The foam liner inside means the folds are fairly thick and a pouch is created in the fold. For bags this big, its pretty deep, too. And almost three feet long. Check out how I almost disappear a 2 lb sledgehammer into it, standing on its end, below.

That makes for secure storage of most daily-use items. On a typical day, a small backpack with my work clothes, pouch with my keys and alarm remote and garage door opener, and another with my wallet and phone are all snuggled in one side or the other. Road bounces and vibrations don’t disturb them, and there is enough room left over that I don’t have to open the bags up at all unless I am on a shopping trip. So as big as these things are, if anything they handle small jobs just as well as the the large ones they were designed for.

I used to think the 77L bags were crazy big. I spent a lot of time agonizing over whether I was wasting time and money even attempting to go bigger with these duffel bags. Now, having had some time to live with them and on more than one occasion to stuff them full, I can’t imagine why I would want to go smaller.

The Surly Big Fat Dummy Project

Prologue (you are here)
Episode 1: 138L (each) Panniers… Seriously?!
Episode 2: Big Fat Dumb Wideloaders
Episode 3: Kickstand Kaos
Episode 4: Add a Flight Deck. And a Hangar
Episode 5: Odds and Ends

Less than a year ago, I started the Mongoose Envoy Project. I loved the bike and – after dabbling with fast-carry-stuff ebikes for a few years (that ended up looking more like zombie-apocalypse bikes), it was my first actual purpose-built cargo bike.

The Mongoose Envoy, in its final form with the 44″ skateboard deck, indestructo wheels and big poofy tires

With respect to the cargo platform, I. Freaking. Loved. It. I am not a recreational rider. I never have been since I started riding in the 1970’s. I put in long commute rides, and I try and do as much as I can of my daily errands on a bike vs. uh… one of my automobiles. Yes I have to admit that while I am doing the whole save-the-planet schtick and trying not to drive, its because I love riding bikes and I always have.

I bought a station wagon because i hate bike racks and could put a bike in the back. Things got out of hand.

Anyway, where was I? Right. Cargo bikes. So… I built the Mongoose out until it was truly as perfect as it can be for its intended purpose. Its even a good value and componentwise I would put it up with just about any high end cargo bike. With that said, it has some problems.

  1. It doesn’t fit me quite right. Mostly in the upper body. I have done pretty much what I can to deal with this. A LOT of the problem has absolutely nothing to do with the bicycle and has everything to do with lingering injuries from when I was T-boned by an inattentive driver in a SMIDSY type collision. I did a passable Superman impression on the arc upwards… and a decent impression of Vinko Bokataj for the landing.
  2. It hurts to ride the damn thing. Again, this is all about residual pain from the above-referenced accident and has nothing to do with the bike. My wrists remain in bad shape, probably permanently, and while the Jones bars help by putting my hands at a better angle, I need both a higher upright riding position to take weight off my wrists, and a suspension fork to reduce the impacts that are part of normal street riding.
  3. As the cargo bike platform expanded my idea of what a bike could accomplish, I wanted more than the Envoy, with its mid-tail size and only plus-sized (after upgrading) tires could deliver. Go big or go home as the saying goes, and the Big Fat Dummy is arguably, physically the largest production 2-wheel bike on the planet.
  4. The addition of the larger 2.8″ plus sized tires on the Envoy worked so well, and I have done so much work with the fat tire platform, I wanted to go fat on a cargo bike and take advantage of the added capacity the fat tires give (and since my very first serious Costco run weighed in at a total of over 500 lbs counting me and the bike… good decision!)

So, this section of the blog, of which this page is only a teaser that will eventually house the episode menu, will document the custom work I have done on this bike. What is worth mentioning that is. This is not going to be a rivet-scraping pass over the bike. We’ll just hit the high points.

Planned (so far) Project Episodes

One bike to rule them all? So far yeah. Its all that.

The BBSHD: Musical Chainrings

It seems inevitable.  When I build a bike, I go through front chainrings trying to get the gearing just to my liking.  My Mongoose Envoy build has pretty much set the world record for tweaks in this regard.  But gearing wasn’t the problem so much as chain alignment.  Alignment is one of the most talked about issues with mid drives and up to this point I have not had to work too hard to get it right.  This build, not so much but I think I finally got it (like $350 later).

While dealing with this I have fooled around with three different sets of crankarms (160’s, 170’s and 175’s).  Not the subject here so if you notice the different crankarms in the pics, I am ignoring them on purpose.

Sidebar:  When building the Surly Big Fat Dummy, I found exactly the same thing as I did here insofar as chain alignment is concerned.  And used the same solution – the USAMade adapter listed as an Honorable Mention below got pulled out of the parts pile and put to use.

The Right Tool For The Job

The Mongoose build is a first for me in many ways.  One thing in particular:  the BBSHD fits the frame really well.  Its a 68mm bottom bracket with absolutely zero chainstay obstruction for the secondary housing.  So I can butt the motor right up against the bottom bracket.  Further, its a lonnnng way back there so chain alignment and misalignment – an inevitable concern with an HD build – is a lot more forgiving since the angles are gentler thanks to the longer reach.  On this bike, if I want I can even forego the offset non-drive side crankarm and the pedals are still easily centered under me.  So the HD is a great fit here.

About That Job…

The Mongoose is a cargo bike.  So it hauls heavy stuff (usually groceries).  It has a secondary job as an unladen backup commuter, but primarily it needs to be optimized to start from a stop while the entire system – with me – weighs 400-450 lbs (180-204kg).  I have really loaded it that heavily so this is not a theoretical exercise.  So I want a big-ish chainring for when I am pedaling fast and light, and still need to be able to get to the big cogs in the back for when I am loaded up and chugging along like a two-wheeled freight train.

Plan A:  Luna Eclipse (42T)

The Luna Eclipse is one of the best BBSHD chainring setups on the market, with a unique ‘wicked’ tooth profile meant to eliminate the possibility of a chain drop under extreme use.  It also has the most extreme internal offset of any chainring option.  This will do the most to overcome the grief visited upon the BBSHD builder by that drive’s secondary housing sending the chainring way out to right field.

Its also gorgeous.  The gunmetal finish I chose matched beautifully with the dark grey frame.  Unfortunately 42T (which is the standard for full-offset chainrings as any smaller and you can’t clear the secondary housing) was not large enough to keep me from clown-pedaling when riding the bike as a commuter.  There was another problem:  Chain alignment.  Running that smaller 42T ring with the smallest rear cog resulted in, after only a few weeks, a whole lot of wear on the inside.  This is why mid drive builds demand the most out of the builder in terms of thinking things thru.  Time for Plan B.

IMG_20200503_123800
Its not ruined yet, but its lifespan sure has been shortened.  this was only a couple hundred miles of wear.

The Eclipse is a proprietary chainring platform, but fortunately other sizes are available.  the largest of which is what I tried next.

Plan B:  Luna Eclipse (48T)

So Plan B was to swap in a Luna 48T ring onto the Eclipse center section to fix the clown pedaling, and to stay the hell off the 12T small rear cog to deal with the alignment issue (I am using a welded together steel cluster for durability and the 12T is alloy and not a part of the welded cluster, so its better to stay off it for the sake of longevity anyway).  I thought that 48T/14T on this bike was the perfect sweet spot.  A small front ring is best when its on cargo duty, and a large one is best when its a commuter.  48T, when used in conjunction with upshifts, gave me pretty much everything I needed.

Pretty much but not everything.  First of all, remember the deep offset of the Luna ring?  It moves the chain inboard 24.8mm which *usually* eliminates the damage the BBSHD does to chain alignment.  Not on the Mongoose, whose narrow bottom bracket effectively papers over all of the sins committed by the motor (at this time I had not yet fully figured this out).  So, as I found with the 42T ring, it was inset too far, even when I stayed off the smallest cog.

So Plan B helped, but it didn’t solve the problem.  After only a couple weeks (I am now checking carefully and frequently) I saw the beginnings of the same wear on the inside of the chainring.  Like the 42T, I had to retire this thing fast so I could use it on some future project.

IMG_20200503_123820
Not as bad as the 42T, but still bad.  Both this one and the 42T looked perfect on the other side.

Sidebar: A mid drive chain powered by a 1500w motor is a chain saw when it comes to components rubbing against it.  That is just a reality of a mid drive and you have to deal with it as part of your design/build process.  When you get it right, you are golden for thousands of happy miles.  Get it wrong and you are sawing thru chainrings and cogs like nobody’s business.

Plan C: Lekkie Bling Ring (46T)

So now what?  42T was too small.  48T was more or less just right.  And the chainring offset that lets me use the inner cogs at great alignment still needs to be reduced or I can’t use anything but the lower gears.  Lekkie has a Bling Ring available in 46T.  It has the same internal offset their 42T ring has and, since I use them on two other bikes I know they are top quality.  At 18.3 mm its offset is quite a bit less than the Luna.  So I got a 46T.  I also added a 2mm spacer underneath it, further reducing the chainring offset to 16.3mm.  That is a whopping 8.5mm less than before so I hoped I would be good on the smaller outer cogs and still let me use the big inners.

And, pretty much, it was.  Chain alignment didn’t seem to be much of an issue, although it still wore down a bit more on the inside.   I was also able to shift up to the biggest cogs in the rear for very low gearing options.  Those are important on a full cargo load and if I am dealing with hills.

But… I flat out missed that 48T high gear for commuting.  And I was still seeing – very slight but noticeable – wear on  the inside of the chainring teeth from the chain, which was still visibly angling outboard a fair distance.

IMG_20200503_123847
This one was on for a few months and had 8.5mm less offset.  But it still shows signs of premature aging.  This was undesirable but livable.

I decided to try an extreme option I had not previously considered.  But on this bike, where all of the normal chainring offset stuff doesn’t seem necessary, it might actually work.

Plan D: Luna 130 BCD Adapter and Wolf Tooth 48T Ring

BBSHD chainrings are generally all proprietary to the platform.  Not so in the cycling world, where chainrings are universal, needing only to match the proper Bolt Circle Diameter for the chainring bolts.  Match the BCD between crankset and chainring and you are good to go.  There are adapters out there in the world that allow a Bafang motor to use standard 104mm and 130mm BCD chainrings.  The problem is they don’t give you anywhere near as much inward offset.  But given my experience so far, maybe I can live with that.  They should fix my alignment on my ‘commuter’ cogs, but will I still be able to use my ‘cargo’ cogs?

In addition to the LunaCycle 130 BCD adapter, I also chose the Wolf Tooth Drop Stop chainring as those rings are best-in-show for this sort of thing on a mid drive.  Attachment to the adapter was a little different than the usual chainring-to-crank operation in that its backwards.  The chainring bolts onto the inside.  I was able to play some games to good effect:  I reversed the chainring so it is logo-side-inward.  Not as pretty, but doing that lets me take advantage of the countersunk bolt holes on what is normally the outboard side.  The countersinking let me mount a bolt so it is almost flush with the ring, which in turn is butted up almost on top of the secondary motor housing.  With the countersinking it now has plenty of clearance.

Plan D Results

FINALLY.  Everything is working right.  The reduced chainring offset means my 14T cog (still not using the 12T for the reliability issues mentioned above) lines up straight back.  This outboard shift did affect my inner cog alignments but I can still get to all of them but the biggest 32T.  I’m comfortable with the angles on all but the second-largest 30T for long term use, and in a pinch, that 30T will work fine.  I just don’t want to stay on it for a week.  So this 9-speed is now a 7-speed and as DIY mid drives go thats still better than a lot of builds can manage.

And worth mentioning, like a lot of what they do, the CNC-machined Luna adapter is freaking gorgeous, and very precisely manufactured.  So much so it really stands head and shoulders above another adapter I got my hands on and was able to compare it directly to.

Honorable Mention: USAMade 130 BCD Adapter

I was surprised at how well this worked and how nicely it was made.  The part only cost me $29.99 on Amazon.  Still, it was Made in USA, well machined and rock solid.  The only things I didn’t like about it was the fact it was machined a bit too heavily, which meant it placed the chainring a millimeter or two further outboard than was necessary, and in this game millimeters count.  Further, as you can see above I was able to reverse the WolfTooth ring and take advantage of the bolt head countersinks.  That didn’t work with this part as USAMade countersunk the outside edge of their part, which made the bolts too long to allow my trying the same trick on the inside, where I needed it.  For a different build it might work fine so I am keeping it for my parts pile.

As for the Stone chainring seen on the USAMade adapter (scroll up to the title image at the top of the page), thats a Chinese Special that ran less than the godawfully expensive Wolf Tooth.  Its noticeably lighter in construction than the WT and I’m not sure I am sold on the tooth profile.  This ring will sit in my parts pile waiting in the wings as an emergency replacement.