A-Lines Abound: Electric drive implosion

[recumpence]

Looks good.

There are a number of us working on downhill bikes with 20 inch wheels right now. I have two full suspension freeride frames (not quite as beefy as a downhill frame, but with longer suspension than a cross country FS bike) that I am looking at. As for bottom bracket hight, yes, you will want to do something about that. I am making a custom rear suspension linkage on my Diamondback X6 frame to accomplish this. One thing about raising the rear end is that the headtube angle increases as you raise the rear. However, a downhill frame already has a relaxed headtube angle. So, increasing it slightly may not make that much difference. I do like the longer wheelbase that a 26 inch bike with 20 inch wheels appears to have. It looks more like a motorcycle. 26 (or even worse, 29) inch bikes have a distinct bicycle look to them, while a 26 inch frame/20 inch wheel setup definately looks more motorcycle.

Matt

[zombiess]

ZombieSS like 20" wheels on A-Line Check's bank account... nope, not happening for a while, too many other projects.

[MattyCiii]

Here are some pictures of the tires/wheels. I took them to cross/post with this post http://endless-sphere.com/forums/viewtopic.php?f=28&t=29888&start=60#p542254, but also to show the wheel in relation to a close cousin: 406mm bike tires on a more standard bike rim.

Both front and rear are 406mm x 47mm rims (from the Recumpense group buy) with Pirelli moped tires:


Here's the whole thing, laced into a NuVinci N360. Mmmmmmm, beefy!


Here it is next to another 406mm wheel from my "daily driver" Dahon folding bike.


The Schwalbe is a 20x1.6 inch tire. Here it is alone:


And here they are stacked.

[rojitor]

So those are the rims of the group buy, those wheels make most motorcycles feel jealous

[etard]

That's the perfect setup for high powered ebike for the streets, I can't wait to get my spokes in to lace this up! Those dropouts are sick too man. About the BB clearance on 20's, just put some 150mm crank arms on and you'll have a nice low bike and still have pedal clearance on turns.

Hey can you put your calipers around those tires? I'm wondering if the wider rim profile flattens out the tire face at all.

[MattyCiii]

Hey can you put your calipers around those tires? I'm wondering if the wider rim profile flattens out the tire face at all.

67mm.

I have about 4mm clearance between the Lefty and the tire up front!

[Byte]

Nice! Will follow this one!

[zombiess]

Hey can you put your calipers around those tires? I'm wondering if the wider rim profile flattens out the tire face at all.

It looks like it does flatten it out a little compared to my front on a 20x1.75 BMX wheel, here are some pics I have a 16"x 2.75" ML75 on a standard 20x1.75 BMX wheel on the rear, sorry I don't have pics of the front. The 2.75" and 2.5" are pretty close in profile, not much difference. I wanted a more rounded sidewall for cornering grip. The 2.75" wide might be a better match for the wheel. I really like the way that rim looks, especially if you can fit a 3.0" tire on it.

[MattyCiii]

Damn! That's one helluva rear swing arm extension!

[MattyCiii]

Suspension:
I'm going to replace the rear shock's bushings with a needle bearing kit from Real World Cycling. First I have to press out the bushing:


Don't need special tools to complete the task. Just some appropriately sized sockets, and a vice. The smaller socket presses against the bushing and bushing collar/spacer, and the large socket will be on the other side against the shock's shoulder.


I'll swing by a friend's place this weekend and use his vice.



Here's what will be installed in its place:



Not a lot of work, but without a vice I can't move forward and install the shock.

[zombiess]

Damn! That's one helluva rear swing arm extension!

If you mean mine, it's 8" longer, but the stock one was pretty short. It's still a wheelie monster if I feed it any power at low speeds or even up to 20mph if you hit the throttle fast on the 75% or 105% setting and accidentally weight shift back a little from the jolt the front will start to come up. On my ride home from work yesterday I must have had the front end off the ground at least 6 times unintentionally. Only 1-2 inches at lower speeds, but enough that it worries me. I think my throttle control project just moved up the list on priorities.

[MattyCiii]

Pressin' out the old bushing, replacing it with a bearing.

On top of the shock: The old bushing sticks out the side. On the bottom, the socket driver is larger than the bushing but small enough to brace the shock mount point evenly on all sides:


A couple quick turns and things are going fine. The bushing is near flush with the shock body:


To press the bushing and its collar out of the shock, I use a smaller socket driver. This 10mm driver has an outside diameter smaller than the hole in th shock, but larger than the parts I want to press out. I just need to ensure everything is centered and ease on the pressure...


All is well... The driver has broken the plane of the shock's mount hole without me destroying the shock. Huzzah!


Quick check - Take it out of the vice to check all is going well...



Back in the vice - line everything up - gentle pressure - check again:


I got close to bottoming the 10mm socket before the bushing came out. So, Plan B: A small clamp that just happens to fit...


But after a bank-shot off the face, I notice the clamp is not up to the job...


Bushing collar - whatever it's called - is almost out


OK, off camera there was some twisting with channel lock pliers, and some hammering...

Bushing parts gone!

Here's the replacement. Looks identical doesn't it? But it's a needle roller bearing, not a bushing. So there!


Pressing it in is about the same process as pressing the bushing out. Here's the final assembly: Bearing is pressed into the shock. Inside that is a hardened surface for the bearing rollers to mate with. Inside that is a 6mm ID to 8mm OD spacer (I won't be using this as my mount holes/bolts are 8mm OD).



Not much effort, and only $40 invested I have what purports to be a very nice suspension upgrade.

When I get back home I'll install it into the A-line and post some pic-porn.

[MattyCiii]

<sound of crickets chirping in the background... chirp! chirp! chirp! ... suddenly interrupted>
<cough!>

Progress update - or more correctly, update on the lack of progress!
Since I do plan to pedal this beast, I decided to fit it with enough gearing range to drag it up hills and plow it through the air on padal power alone. I went and purchased a Schlumpf Speed Drive (errr - the Taiwanese version) http://endless-sphere.com/forums/viewtopic.php?f=2&t=37269. I keep making that "first build" mistake of not using my time wisely. I should have spent some of the time I waited for the drive (which was delightfully short by the way for something coming over from Europe) to look around for an installer. I'll hopefully have an installer lined up in the next few days and the drive installed by next week.

[MattyCiii]

Latest update:
ATS drive installation progresses slowly http://endless-sphere.com/forums/viewtopic.php?f=2&t=37269.

I've chamfered the bottom bracket - got a pile of aluminum shavings on the back patio. Once I receive my order of 4mm spacers from Utah Trikes, I'll be able to do the install, and have the next step complete... the bottom bracket.

[MattyCiii]

Some limited forward progress to report.

I bought the A-Line frame when I was bitten by the "replaceable dropouts" craze that hit several ES members this past winter. But from the start it was always a stretch whether other efforts would suit my needs: Most people were creating dropout replacements for hub motors. From the start, my plan has been to build the bike with a left-side RC drive and NuVinci hub. So my notional dropout replacements would be something like the two pictures below. My thought being, I can simplify my dropout design by using off-the-shelf modular components that give me dropout, derailleur (== chain tensioner) hanger, and disc brake mounts. These are pics pulled off the web that I used as a design guide:



So drawing on inspiration/ideas from Oatnet, Magudaman, Andje, Sn0wychild, and help from Adam333 and especially Fractal, my path led to a custom design of my own and fabrication by emachineshop.com (I plan to create a "review" thread of emachineshop.com in the near future - but the bottom line up front is it's a great service, thumb's up).

My custom dropouts give me about 3" more length and 1" more height than the originals. The right side replacements showed up Friday and the left sides should arrive early next week. Here's the thing mounted, with of course the original in the background:


Why the extra holes? Well they only added a couple of bucks to the order, so why not? The smaller holes on the upper edge (tapped for M5 bolts) are for possibly mounting a mudguard in the future. Anyone know a good 22" diameter, 3" wide mudguard? The larger hole is tapped for M8 and is there for whatever - I was thinking possibly a mount for a trailer hitch. I suppose if I was smarter I would have made the diameter and thread pitch the same as the original A-Line holes, making my A-Line dropouts literally able to accommodate a downhill hub as was original. Live and learn.

More pics:
The mount holes on the new and old are vertically aligned. Big difference!


Comparing the insides: I had some material cut out but not nearly as deep as the original. Strength over lightness. When in doubt, over design. Note the custom parts, when mounted, are 150mm between the inside faces. The bolt-on modular parts by (from Paragon Machine Works) are 7mm thick, taking me close enough to the 135mm spacing the NuVinci needs.


Comparing the outside faces:


One more pic of the dropout, mounted. It's a really tight fit! I had to do a light sanding in a couple of places, no big deal. These will be a bugger to take off- but I won't ever need to take them off, so I don't mind.


So I'm waiting eagerly for the UPS man early next week. Once I get the left side dropout assembly installed, I'll be able to mount the rear wheel and at least have a bike I can ride rolling down hill (electric and human power propulsion still awaiting some parts...)

[MattyCiii]

One more angle on that replacement dropout assembly:


After looking at all the pix I notice I don't have any shots of the back side and how closely that mates to the original. Where did I leave that camera...

[adam333]

The piece look great!

I am curious about the price from this supplier. I didn't know they exist. Pretty cool to get a quote online.

[fractal]

hey matt!!! great work!!! im very happy for you!!! they look great. mine will be ready next week. its been a challenge but seeing the results sure feels good.

[MattyCiii]

I am curious about the price from this supplier. I didn't know they exist. Pretty cool to get a quote online.

Adam, the price was in the same ball park as the prices you researched for David and I. I would have paid $236 for one copy of each side, but decided I'd "buy in volume and save". I got 3 of each side for $295 each side, total cost $590. So now I have some small aluminum sculpture pieces More details here: Machining service: eMachineShop.com (A user review)

hey matt!!! great work!!! im very happy for you!!! they look great. mine will be ready next week. its been a challenge but seeing the results sure feels good.

Thanks! One of the reasons I "branched off" from our previous combined effort was the hassle of re-doing all those STL files. I know my best bet was to re-draw from scratch, and so went with the eMachineShop CAD tool. I can't wait to see how yours turn out. I'm also quite pleases with the whole experience of eMachineShop.

[MattyCiii]

Side 2 arrived today. About a half hour later I got it installed.



Glamor shot - both custom dropout pieces installed...


Here's the rest of the assembly - modular dropouts from Paragon Machine Works.


I added 0.1mm all around to my measurements to ensure a snug - not loose fit. Man, that was just about perfect. It had to be pressed in, but with hand strength only:


The washer:


The first bolt:


When fully tight, the bolts are totally inset:


A shot of the inside. That gap is so small you can't slide a sheet of paper in that gap.

[MattyCiii]

Here's the whole thing, also posted n the first page.



In my rush to mount the rear wheel to go for a test roll, I put it on backwards! Also note the rear brake mounted to the front. Don't ask, that'll be righted soon.

The huge space in the triangle in front of the rear wheel is where the Shumaker drive and Astro 3220 will go...

[MattyCiii]

The bike is too squat for cranks!

I can't say I wasn't warned, but the bike is too short when I put 180lbs of me on the seat. 172.5mm cranks will touch the ground. Matters will get worse when I add batteries, etc.

Strategies for "heightening"

• I have 155mm cranks on order, but that only buys me 1/3 of an inch. Enough that I won't scrape earth when sitting still, but too close for comfort if I'm pedaling when the suspension compresses.
• My rear shock is currently 9.5". I can make this longer:
  • I can gain an some height by getting the longest Fox DHX at 10.5" (Do bicycle shocks come in any greater length?). But an inch in the shock translates to (far) less than an inch in height, right?
  • I can maybe go for a scooter shock, like this one. It's 12" long and $100 - two great reasons to at least consider it. Down sides are uncertainty in my ability to mate it with the bicycle mount points, and the fact that every inch I add to the shock changes the suspension geometry, with possible bad side effects. What else should I consider?
• Larger wheels. I think this is a no-brainer, upgrading to 18" moped wheels should gain me about 2" in height, right?

I'd love to hear from the community on this one!

[sn0wchyld]

hehe... 'i told you so' sorry couldnt resist!

yea i'm not really happy with mine, and thats with a 26 front and 17mx rim rear (22 inch effective). I cant pedal on corners or through any bumps, and the loss of rollover height is a bit of a pain too.

How hard would it be to make some new 'dropout' sections to those dropouts? ie remake the black smaller part of those dropouts to add an inch or so of height?

Also, is your front shock at its max height? I've added about 2cm to mine just by moving the clamps up the shock.

You can also add an inch to your travel (so maybe .5 inches to your ride height) by choosing the lower of the two mounting holes for the rear shock.

Finally, check your sag %. since this is primarily a onroad bike you might be able to go with say 25 or 30% sag rather than the usual 40ish. should be able to gain a inch or two there too!

good luck mate.

ps

are you sure the shock is supposed to be in that way? or doesnt it matter? on my norko its got the resovware on the top. being round that way opens up some more space in the triangle...

[Timma2500]

MattyCiii,

Awsome build mate! Those dropouts are fantastic, so clean and an elegant solution!

Going with a longer rear shock will more than likely need a longer fork to balance the height gain to keep your head angle where it should be.
It'd be worth looking into exactly how much extra length you would gain by going to normal DH forks, it may be less than you think as those Leftys look fairly long already.

Where as going to larger rims and tyres stands to gain you anywhere from 2" to 3" in height depending on your diameter choice.
I'd go with the bigger rims for sure. Someone on the site would surely buy your current wheels to help get back some valuable ca$h.

Just my 2c, hope it helps

Paul

[etard]

Did I hear somebody say they were gonna sell their rims??

That sucks man, personally I would go with bigger wheels for aesthetic reasons alone, it looks kinda funky in current guise. Those dropouts are real nice, I'm jealous! One option might be to put a bigger wheel on front and then use those two front shock mount holes to build an extension tower that would jack the rear triangle down an equivalent amount so that your head angle stays the same. Another option is pegs instead of pedals.