Mongoose Envoy Update – Cargo Deck 3.0

When I originally used a double-kick longboard deck to make an XL cargo carrying top for my Mongoose Envoy project, its 33″ (84cm) length and 10″ (25cm) width seemed really big.  Considering I was coming from a world of ordinary bike racks on normal-wheelbase bikes, it was quite large.

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Deck 1.0, shortly after installation. I try to avoid the word “festoon” to describe a bike build so those two little bags in back went away soon afterwards.

The XL deck worked *splendidly*.  I had no complaints whatsoever, and I could have left it like that forever.  However…

The board, by virtue of its 33″ length, only used 4 of the 5 available rows of M5 mounting bosses.  So I had definitely left some available space on the table.   In a perfect world, I would have found a longer version of the same board:  Say a 40″ double-kick.  But alas, at the time, I couldn’t find one.  I also could not find another board that had this same 10″ width.  Everything else was more narrow.  But I could get close with what became Deck 2.0: a 40″ x 9.75″ kicktail longboard.

It installed easy enough.  I painted it with Rustoleum truck bedliner to pebble the surface just right so it held onto gear a bit.  I used the same inverted grub-screws for drill guides like I describe in the Deck 1.0 post.   And the rack was now long enough so it used all 10 mounting points on the frame.  It couldn’t be more solid – the board is 8 layers of Canadian maple – and makes a sturdy handle I can use to pick the bike up and move it around from the rear.

And… its 40″ long.  With that solid center mount kickstand, its handy to have a coffee table with you wherever you go.  From a cargo standpoint I could easily net down a 3-foot duffel bag on top and still have room to spare.

Still, It didn’t work out quite the way I planned.  I thought I wanted to move the rack further forward so I could mount gear under the seat.  So I did that and the idea was to take up the otherwise wasted space just behind the seat.  But once I had it set up, I found the space effectively unusable.  I needed to keep some room back there for the Thudbuster to flex as part of its normal duty cycle, and my legs hit whatever was jacked up all the way to the front.

I also missed the front kick on Deck 1.0, which provided a natural slope to keep gear from sliding forward under hard braking.  As a substitute threaded a couple of M6 bolts directly into the M5 holes (no fixing nuts needed) that existed for the nonexistent trucks. These held down a simple 50-cent L bracket wrapped in my favorite padded rubber mastik tape.  It worked but in the end I removed it for aesthetic reasons. 

Lastly, I mounted the board just a hair too far forward, and occasionally I brushed it with my legs during the pedal stroke.  Not a big deal unless you are a perfectionist. I didn’t want to redrill the holes so I could move it back. It was a minor imperfection. So I left the board on for several months and it worked great.

But I did acquire a 44″x9″ kicktail longboard from Magneto, with the intention of using it on the back of a planned Surly Big Fat Dummy build.  That plan went away, and the 44″ board had no home… so what the hell lets put it on the Envoy.

While I was at it, I decided to make a couple of changes.  First of all, the Magneto board comes with an aggressive, highly abrasive grip coating on it.  I took an orbital sander and smoothed it down some so it would not potentially wear thru duffel bags and bits I’ll have netted down on top of it.

Next, I painted it with the same Rustoleum truck bed coating spray.  This took a little more of the harshness off the grip coating and gave the deck a tough finish.  I also decided to two-tone it with some medium gray paint on the underside.  It turns out this is totally invisible unless you are laying on the ground looking up at it.

Also, instead of re-using the 25mm post spacers, I bought new ones 40mm tall. These required longer 75mm bolts.  Having used the rack already for several months with 25mm between deck and frame, I wanted more room to move my hands in and out attaching/detaching net hooks, passing cinch straps thru etc.

It came out great.  This Magneto board is a sandwich of bamboo and maple so it has a touch of flex to it. This made  bolting to the somewhat uneven frame easier.  Its still rock solid despite the now 4″ longer tail out the back, which I do not notice from a convenience standpoint (its not too long, which I worried about).  The 40mm spacers are an absolutely perfect height to let me get my hands in there without being so long they compromise the solidity of the mount.

The board has a front kick, but it turns out it can’t easily be used, for the same reason I couldn’t use the front few inches on the 40″ deck. However it is slightly narrower than the shorter board so even though it is just as far forward, I no longer hit it with my legs.

As a gear-stop/bumper, I wanted something a bit more substantial than the half-assed L bracket I used on the shorter board, so I used a couple of the leftover 25x13mm M5 spacers, plus some 10x10mm spacers I had in my parts bin, to create some ‘electrode’ stanchions fore and aft.  With the large area washers at top, they either provide a bumper for gear stowed on the deck, solid purchase for a hook, or a place for my net to grab onto in the very back. Silicone grip scraps fit right over them to ensure the edges of the top washer don’t bite into my gear.

The two forward stanchions are extended from the deck mounting holes and go all the way thru to the frame.  They use 110mm M5 bolts.  The two in the rear use the rearmost holes drilled for the trucks. These use matching countersunk bolts and finishing washers like those used with all the other mounting hardware.

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A bit of scrap silicone handlebar grip tucks under the rear stanchions to provide a smooth, grippy place for my net to glom onto. You can stretch the net all the way back and over the kicktail, too.

Compare this pic above to the 40″ board and its clearly longer, but functionally, the increased length is no bother.  If I had to fit the bike on a train or bus then this is not the best solution.  At some point, if I need some extra carrying space out back, its available.  At present, I have an extended amount of space for my round 40″ duffel.

… and a bigger coffee table.

Author: m@Robertson

I'm responsible for the day-to-day operations at my place of business: Leland-West Insurance Brokers, Inc. We do classic and exotic car insurance all across these United States. I'm also an avid auto enthusiast, a born again cyclist (i.e. an ebiker) and participate in medium and long range CMP and NRA sanctioned rifle competitions.

4 thoughts on “Mongoose Envoy Update – Cargo Deck 3.0”

  1. Thanks very much for this Envoy write-up – I fiddle with (too many) ebike builds myself, and have had thoughts of building on yet another, this time, cargo bike. Envoy starting point, with a Crust Clydesdale fork, with a 5 or 6 grocery bag max space capacity. Would you happen to know if Mongoose did anything out of the ordinary with the headset?

    1. Its funny… the frame, fork … and headset… are the only things I did not replace on the Envoy. I am sure the headset is just an ordinary zero-stack, and I doubt the fork is tapered. I had it loose once but honestly its been so long since I replaced the handlebars I can’t remember what I saw. I have never experienced any sort of speed wobble, but the Cane Creek Viscoset is such a nice addition to the upper half of the headset I would go that route to make sure it never becomes an issue as it does with a lot of cargo bikes. My choice for the bottom would be a Cane Creek 40 and a steel crown race.

      If it weren’t for the fact that standover is already at my comfort limit on the medium/large frame, I would have put on a Wren Inverted suspension fork, which is a marvel of stability on my Big Fat Dummy.

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