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Discussion Starter #1 (Edited)
Grom Chapman - the no-Gromsense grommuter build. Grom!

Hey all, first time poster, frequent lurker. After my Vespa GTS got totaled in a minor fender-bender, I went ahead and replaced it with a brand new 2018 Grom ABS which I am super stoked about!
Inked20190426_165822_LI.jpg 20190426_165748.jpg

This is my only bike, so I use it for everything. I'm a year-round commuter, plus I usually go for fun rides on the weekends. Don't do any stunting or off-roading, and I don't need to do any highway riding so stock performance is adequate (for now :biggrin:). That makes my priorities look something like:
  1. Safety
  2. Comfort
  3. Cost
  4. Cargo space
This forum has provided invaluable insights into Grom life and identifying parts and modifications. I'd like to contribute back by putting together what, for me, is a good blending of the disparate threads I've read.

I'll put in links to the parts I'm using. Most of them will be Grom-specific, though I'll also be adapting some of the gear I had for my Vespa to use it on the Grom.

Phase 0 - Stock Grom, as delivered
Phase 1 - Get the Grom set up to bare minimum for me to do my work commute.
Phase 2 - Simple bolt-on upgrades to improve the bike (ergonomoics, protection, aux. electrical, etc.)
Phase 2.5 - Smoother shifting
Phase 3 - Ready for winter commuting, maybe some performance enhancement?
Phase 4 - ???
 

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Discussion Starter #2 (Edited)
Phase 1

In this phase of the build, I did the following:

  1. Install Vagabond fender eliminator and cargo rack.
  2. Install milk crate, using a Vagabond clamp plate.
  3. Install AF1 Sport Mirrors (Vespa GTS)
  4. Install RAM Zinc-coated U-bolt mounting base.
  5. Install a badge holder.
After:
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1_12.jpg

Before:
20190426_165748.jpg 20190426_165730.jpg
20190426_165741.jpg


Notes:
  1. The bolts on the Vagabond fender eliminator DETACHED during installation! I was using a torque wrench, and both bolts pulled out at maybe half of the specified torque. I've emailed Vagabond about this issue and will update when I receive a response. In the meantime, I used two 20mm M8 bolts in their place (fed up through the plate, secured by the Vagabond-supplied flange nuts under the seat). **UPDATE** Vagabond quickly sent me a replacement fender eliminator, they stand by their products with a lifetime warranty.
  2. To steady the milk crate, I cut a piece of 1/2" PVC panel, left over from when I replaced the shelf under my sink, to fit the base of the crate. It sits underneath - the clamp plate goes through the crate, the panel, and then into the cargo rack using the supplied screws.
  3. The sport mirrors just happen to be a perfect size for the Grom; the stock mirrors are too narrow that I couldn't see behind me while riding. Just remember to remove the thread adaptors from the Grom, those things were cranked on TIGHT!
  4. N/A
  5. I used some strips of Scotch Extreme Fasteners - this stuff is perfect for affixing things like the badge holder, an E-Z pass, etc. I need this because my workplace has a security checkpoint for vehicles and need to be able to readily whip out my ID for inspection. The back of the speedometer seemed like the best place. I can also stick my E-Z pass here if I'm going through tolls.

Next steps (parts on hand or en route):
  • Corbin seat
  • OTB chain adjusters and spools
  • Axle, handlebar, and frame sliders
  • A relay-switched fuse block for powering accessories
  • Heated grips
  • USB charger
  • Tire Inflator
  • Under-seat toolkit
  • Windscreen
 

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Groms are great for cheap efficient utility transportation! :)
And while I don't use my Grom for commuting as I need a work truck in my job, I do use it for everything else.
If you can get by, a smaller crate works well without any extra support.

IMG_1028.JPG

I also did other mods with a goal of reducing weight and simplifying the bike. Rear fender delete, exhaust, rear sets, front fender, LED signals. So far I lightened the bike by 13 pounds. Less weight makes the bike handle easier and perform better.
 

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Discussion Starter #4
Nice; I like what you've done there! The milk crate and support panel were both from my Vespa; I was using it because I had it mounted directly to the seat and wanted to protect the leather.

A new rear set is definitely on my wish-list, but I'm going to start with a new seat and then adjust the handlebars before I do the rear set. Haven't decided if I'll buy a new bar or use some kind of riser, though. Once the seat gets installed (arrives on Wednesday :D) I'll figure out what adjustments are needed for my arms and then the feet. Some kind of highway-peg like setup would be nice, too, to really stretch out on longer rides.
 

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Looking good and welcome to the forum.

I originally picked my Grom up just commuting to and from work. Be careful, modifying the Grom can get out of control pretty quick and you won't know what hit you until it's too late :crazy:
 

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Nice; I like what you've done there! The milk crate and support panel were both from my Vespa; I was using it because I had it mounted directly to the seat and wanted to protect the leather.

A new rear set is definitely on my wish-list, but I'm going to start with a new seat and then adjust the handlebars before I do the rear set. Haven't decided if I'll buy a new bar or use some kind of riser, though. Once the seat gets installed (arrives on Wednesday :D) I'll figure out what adjustments are needed for my arms and then the feet. Some kind of highway-peg like setup would be nice, too, to really stretch out on longer rides.
You have the right order... user interfaces for more comfort. Seat, bars, pegs. The Monkey rear sets don't alter the position of the pegs. I did them just to reduce bike weight.

htVdv4f.jpg
 

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Discussion Starter #7
[...] Be careful, modifying the Grom can get out of control pretty quick and you won't know what hit you until it's too late :crazy:
Hah! I can see that for sure. Once I get this last set of parts on, I'm cutting myself off. Don't even have 100 miles on the bike yet! And I'm already pouring over what I can do next...
 

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Hah! I can see that for sure. Once I get this last set of parts on, I'm cutting myself off. Don't even have 100 miles on the bike yet! And I'm already pouring over what I can do next...
Good luck with that. I've tried it, more than a few times, lol. I just placed another damn order for another damn part, smh.
 

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Hah! I can see that for sure. Once I get this last set of parts on, I'm cutting myself off. Don't even have 100 miles on the bike yet! And I'm already pouring over what I can do next...
The very first day I had my Grom I ordered $600+ worth of tail tidy, led taillight, led blinkers, and exhaust.:wink:
 

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hang on a minute, whose build thread is this!?



looking good furiousD, the grom is a really solid utility bike for zipping around town.
 

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Discussion Starter #11
Yeah, self control in this case (i.e., pacing myself in getting more parts) is going to be tough!

On the plus side, even a stock Grom is loads of fun, and it has so much potential.
 

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Yeah, self control in this case (i.e., pacing myself in getting more parts) is going to be tough!

On the plus side, even a stock Grom is loads of fun, and it has so much potential.
lol, "self control" and "Grom" in the same post :crazy:
 

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Discussion Starter #15
Underseat Storage Prototype

So I was inspired today to try something different (and, thus, spending additional, unplanned funds :big smile:). Luckily it only cost a few bucks in hardware plus a dry box that I already own. With it, I should be able to store a modest tool kit for the road or various other goodies.

On my Vespa, the underseat storage (the "pet carrier" we would call it), I could fit an extensive toolkit, spare clothes, ropes/bungees, tire repair kit & inflator, bike chain, etc. It was dry and lockable and perfect to just carry your stuff and forget about it. The Grom has precious little space that can do that short of adding a lockable top case (which, to be fully honest, I'll probably do at some point). In the meantime, my experience doing the fender eliminator and cargo rack suggested another possibility.

Enter the Pelican 1120 case that I had lying around. It holds just under 2L, is waterproof dustproof, and crushproof, and is right-sized for mounting under the Grom's tail. After drilling three holes in the lid, these will be used to mount the case to the underside of the tail section using longer bolts for two of the cargo rack mounts and one for the battery clamp.

For this project, I needed the following:
  • One Pelican 1120 dry box
  • 2x M8-1.25 35mm flange bolts
  • 2x M8-1.25 lock nuts
  • 2x M8 (or compatible) washers. I used two flange washers I had lying around
  • 1x M6-1.0 70-75mm hex bolt
  • 1x M6-1.0 flange or lock nut, whatever
  • 1x M6 (or compatible) washer. As above, I had a random flange washer which worked.
  • 1x weather-resistant/rust-proof padlock or other locking mechanism that works with the drybox lid
  • Silicon caulk (or substitute, used to seal the holes drilled in the drybox).
First, remove the three bolts marked below. These are the lower two M8 bolts used in the rack, and the M6 bolt used to secure the battery.
Inked20190502_180657_LI.jpg

Next, I aligned the case to the underside of the frame. There are two "slots" on the lid, not sure what they're for, but they fit perfectly on the edges of the Vagabond fender eliminator. Holding it securely in place, I used a pencil to mark the locations of the three holes on the lid of my case, shown here:
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Note that it probably helps to bias the holes slightly, as the bolts themselves are roughly vertical but the box will be at a shallow angle. I didn't do this, and just manually widened the holes as needed while fitting it to the bike.

Like before, the two M8 bolts will be installed from the top, pointing down. The longer bolt is able to reach through the Vagabond cargo rack and is just long enough to get through the lid of this case. Conversely, the M6 bolt will start from inside the case and point up. At my local big-box hardware store I was only able to find a sufficiently long M6 that was partially threaded - with a fully threaded bolt you could probably go top-down like the others if you prefer.
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Notice in the picture above that I've pre-installed the padlock to the lid BEFORE I started fitting the drybox to the bike. There wasn't enough clearance to get the padlock through the hole after driving the bolts through the top. I ended up having to widen the hole slightly to fit the shackle in this case. (This isn't meant to be theft-proof, but to just deter someone from walking up and opening the case without any slowing down.)

Between driving the two M8 bolts down and the one M6 bolt up, I ended up with this:
20190502_184021.jpg
Before tightening the bolts down, I used silicone caulk to plug up the holes and help prevent water incursion.

Make sure to tighten the M8 bolts to whatever torque spec should be used; I think 28 ft-lbs is what Vagabond's instructions said. Once those bolts are properly tightened, begin securing the case using the M8 and M6 nuts. The case itself should not be super tight - too tight and I found the lid clasps were difficult to open/close and the lid started to bow. Since the lid is not perpendicular to the bolts, the washers will also be at an angle and you're not going to get a flush fit. I used trial and error here. Didn't check what the battery's M6 "should" be tightened down to, so when tightening that nut on the top I just went by feel.

In the end, here's how the box ended up looking on my bike. It feels very sturdy and secure! Also, I love that it's basically invisible from behind and not particularly noticeable from the sides unless you're crouched down and looking at it.
Inked20190502_185006_LI.jpg
Inked20190502_185017_LI.jpg 20190502_185028.jpg

The padlock key I've put on a ring and set that on the helmet hook underneath the seat so that it's easy to get to. So I just lift the seat, unlock the padlock, pull the clasps and the box opens! It actually sits quite nicely on the top of the mudguard.

So, the two things I can see as potential problem points are the suspension travel causing the box to hit the mudguard/tire, and the lid/clasps failing and the box opens unintentionally. I dropped down hard on my seat multiple times and it didn't feel like the box was hitting anything above the wheel so I think that should be fine. Likewise, the padlock should stop the box from flinging wide open but it will lose waterproofness if this happens. I thought about using a thumbscrew or a wingnut on the right side of the box (where there is a hole identical to the one I used on the left for the padlock) but didn't immediately find anything that would fit the clearances.

I've loaded the drybox with a nice, large rock. I'll drive around like this for a week or so, regularly checking the case and the mounting bolts, before I commit to putting anything useful in here. Given the location, I wouldn't want to store anything valuable or irreplaceable but some cheap tools for use on the road should be just fine if this shakedown test works out!
 

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Discussion Starter #16
Oh, and you can see from those pics that my new Corbin seat finally arrived! Oh my gawd that thing is sweet, I love the new position. The seat is definitely firmer than stock, I'm really looking forward to breaking it in and getting a perfectly-molded buttcrack. Now I need to figure out how far back I want to sit and what changes I'll need to make to the pegs and handlebar to make this an ergonomic masterpiece.
 

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Fricken awesome, I've got some small pelicans laying around, hmmm. That seat looks great, good luck finding that sweet spot to for your rearend mold.
 
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