Performance Scooter Tuning

jscott - excellent write-up and pics ... do you have a pic with your bike mounted on your scoot?

Thanks for the kind words, jallen. No pics of the bike yet, but that's coming. I'm still tweaking my design. I was afraid that there would be ground clearance issues with my bike tray at the angle that it was, so I tried bending my tray last night. FYI, don't try that. It just turns it into an ugly, mangled mess.

So NOW I might have to come up with another hackjob, errrr.... FINELY TUNED ENGINED SOLUTION, to deal with my ground clearance concerns. I have a few ideas floating in my head. I'll get something going tonight and get some pictures up. Ironically, it might actually use hacksaw blades. We'll see.

Yeah, J, I totally know what it's like to mentally work on a scoot. It's one of the main reasons I haven't slept well for a few nights.

Well, here's a lesson by NON-example. It didn't work right. WAY too unstable. Actually, the way my tutorial goes, it's reasonably stable. The problem with the design of my tutorial is that the angle of the bike tray makes it so that the back tire of the bike is too low to the ground for my comfort. It was probably a couple of feet off the ground when the Stella is level, but simply putting the front tire up on a curb (such as pulling into a driveway), and the ground clearance was less than a foot. That's just too close for me.

So I had the stellar idea of bending my bike tray so that it "straightened out" level. Not just a great idea. Those trays don't want to bend at all. So my NEXT genius idea (sarcasm implied) was this:



In theory, it works pretty well. It allows the rack to fold if you didn't want to remove it. I just bolted a heavy duty hinge from Home Depot into the bottom of the tray, and used braided wire to create a bit of a suspension design. The problem with this design above is that the hinge has WAY too much play in it. The rear of the bike can sway back and forth far too much for comfort.

Here are a couple of other angles of this failed attempt:





I'm now back to the drawing board on how to do the bike tray. The FORK MOUNT is golden. Solid as a rock. I have a few ideas floating around in my head. I'll probably keep myself awake one more night thinking about it. I'll try to re-engineer the thing on Wednesday night.

Isn't this part of what StellaSpeed is all about? Learning from the mistakes of others? I should be a HUGE asset on that front.

It would require welding and it would only work with the wrap around wrack (which you have and are using) but what I would do is this:

Move the fork mount to a stub welding on the side near the seat (lower, left, and forward from where you have yours now). Then weld another 2 stubs off the left side of the rear portion of the rack. This will bring the angle of the bike higher in the rear for more clearance. Bring the weight forward reducing negative leverage on the rack, Stella, and you. And be pretty dang stable. It wouldn't take much at all for a welding shop to do it and likely wouldn't cost more than $20-$30. It would do away with the left/right/centered symmetry your design has but I think it would be the best bet. Sort of like a left side mounted vertical surfboard carrier on a bike

Just my .02

That's a good suggestion, Zac. I think what you describe would be better from both a stability and a leverage standpoint (it'd keep more weight on the front wheel). I'll probably go that route if my next couple of ideas fail. One of my main goals was to retain a stock looking Stella rack when the bike rack isn't mounted. I think welding those stubs in place would be a bit more of an eyesore than I want right now. (Granted, you could say my copper fittings are an eyesore, but I guess I see the copper as bit more subtle).

I think my next attempt will be to use a new bike tray (since I cut my first one all to hell), reinforce it, and mount it FLAT against the 4 rungs of the Stella rack. If the bike tray is bolted/screwed to each one of the 4 rungs AND the tray itself is reinforced, I think I'll get an adequately stable bike tray. The 30-second removal will be a thing of the past, but if I can find nylock wingnuts, it should still be a relatively quick attachment/removal process. I'll try this out today (I hope) and post an update.

Zac, isn't it fun to throw out a perfectly good suggestion that WORKS, then sit back and watch a fool like me try other unproven ideas?

i'm not a bike pro. but how fast are you planning to ride with this contraption?

my first thought was using just the fork mount, let it pivot on the rail, ditch the tray and allow the back wheel to roll on the ground... sort of acting like a pav trailer:



but i can see that at high speeds, or long distances you might not want to put that much wear on your tire/wheel/bike. so my second thought is could you build your self a wheel dolly that the back wheel of your bike would attach to, and roll on that rather then it's own wheel?

(did that make sense?)

I'm not at all down with letting my bike tires roll. I imaging a few 60-mile round trips, and my knobbies would all be worn off. Not to mention the wear on my freewheel! The trolling wheel is an interesting concept, BUT...

IT IS COMPLETE. It works. My latest version is good enough for me. As I said, I wanted to reinforce the standard aluminum bike tray. Since it protrudes out so far behind the bike, it's important that it be VERY stiff. I purchased some 1" aluminum "angle iron" from Home Depot (I know it's not iron, but that's what I've always called it, and "angle aluminum" doesn't sound right...). This angle aluminum drops right inside a standard bike tray. If you drill through it and the bike tray and put bolts through it, you're left with a substantially reinforced bike tray. Here's a closeup shot of the rear-most bolt that I have in my tray (camera focused on my pedal instead of the bolt, but you can still make it out)



On the front of the bike tray, I drilled/bolted through each rung of the Stella rack. Here's looking at the underneath side of the Stella rack at each of the 4 wingnuts:



And here's the top view of that same rack.



You might be wondering why I have the short ~12" piece of bike tray still attached to the fork mount. Do you see where the bike fork actually mounts to the fork mount? It's BEHIND it. Without some sort of rear support for the fork mount, I was afraid that it would try to rotate itself downward. I've used 1/4" grade 8 bolts to connect the tray to the Stella rack.

This picture shows a bit better view of how the fork of the bike mounts behind the actual fork mount. It also shows where I transport my bike helmet:



My mountain bike shoes just fit in the glove box. Here's a right-hand view of the whole thing, with my front bike tire bungee corded on (I'll be picking up some Velcro straps to replace the bungee):



And the left-hand view:



As for riding? Well, I only went about 8 miles on it tonight. It's clearly a different experience. Felt downright nervous for the first couple of block. Straightline stability is just fine. It's the turning that's weird. At first, I though the bike was acting like a bit of a rudder, working against any turning motion. However, since it happens at very low speed as well, I've concluded that it's simply the high center of gravity. When you try to turn the scoot, the high center of gravity tries to oppose it. It feels a bit like it's trying to lean you in the opposite direction that you'd like to lean. To be clear, I'm exaggerating the description. It's NOT a bad riding contraption. Just different. Much like riding with a passenger is a very different experience. I never got out on the open road, so my top speed was only 45 mph. For now, that's as fast as I want to go. I still want to feel what it's like with gusty crosswinds before I take it any faster than that. Tomorrow is supposed to be a very windy day here in the plains of Kansas, so maybe I'll take it out then.

But again, driving in a straight line was a breeze. Even hitting bumps, the scoot didn't seem to behave much differently. The bike does bounce up and down slightly, but this is just from the very slight flexing of the Stella rack and the bike tray. Nothing big. All in all, a great finish to this project! Now it's time to start reaping the gas mileage benefits so that I can start paying off the bike tray I ruined.

sir, that's some brillant engineering. nice job!

Nice work! I can't wait to see you on the road!

Heh, yeah, I thought that just a regular old Stella got stares. Man, people nearly go of the road rubbernecking at this contraption! I'll be taking her to Lawrence on Friday, so wish me luck.

Where are you at? Do you give tours of this thing? I wanna see it!

I live just a few blocks from Scooter World, and actually work in the building right next to them. I'd be happy to show the thing! Where do you live?

So I know this threads a tad old, but I don't think I've ever been more impressed with anything. Just wow. You're amazing..

Thanks so much, Casey. That really does mean a lot to me. I figured there HAD to be other mountain bikers/cyclists out there who could find this to be useful. Or maybe for the non-riders, it's just pure entertainment!

Just found this thread myself since it was towards the top. Good job. Goes to show that just about anything can be done with a Stella!!

How's this thing holding up? I've got a big 29'er steel frame that I want to carry. I think I'm going to fab up something to let it roll behind me though. I don't see how that can be too damaging to the tires. Anyone got an idea on how to make the hinge mount work?

We were brainstorming on it last night and thought about small bearings inside a low-profile thule front fork mount.

Looks great. Very impressive. Uh, can you get some kind of a ticket for that contraption? Is it legal??

Yeah, so probably time to update this thread. Don't try it at home, folks. It's hella dangerous. I mean SERIOUSLY so. It lulled me into a false sense of confidence on straight roads with little wind. But I'm telling you, as soon as a wind gust hits you, it takes a miracle from God to keep you from crashing. I was granted one such miracle, and the bike rack has never again been used.

There's a better design on this forum that mounts the bike BESIDE the Stella. It looks quite a bit more stable to me.

Wow!! Good thing you didn't learn the hard "road" way. Glad to hear you're in one piece and you realized you can only ride one bike at a time.

I am sorry to sound like an ass, but this is a bad idea for many reasons.

Your bicycle may be lightweight if you pick it up at its center of mass, but if you put it on a torque arm (a rack hanging off the back) it is not so lightweight. Also compare the tubing and fasteners and welds of any bicycle rack for cars with the luggage rack on your scooter. I'd also bet against anyone at LML in quality control x-raying the welds on the luggage rack. I wouldn't put more than 15 lbs on one.

Copper fittings and silver solder aren't meant to take any structural loads. Silver solder doesn't bond well with chrome, to my knowledge. Sheet metal screws, small bolts, and metal epoxy are also no substitute for welded angle iron. Then there is the fact that a minor low-side is now a two-vehicle crash, and possibly a very gory one if you're in the middle of a bicycle-scooter-road sandwich.

People with 500 lb motorcycles have gotten bad wobbles just by putting too much stuff in tail bags or saddlebags.