Vintage GT Palomar BBS02 BMX Klunker

[Wolfeman]

So my last build, a Dyno Moto 7 cruiser that became a BBS02 powered street klunker turned out exactly the way I wanted. It is user friendly for new e-bikers, PAS only and really comfortable. My oldest daughter loved it so much, it became her bike. This of course was the perfect excuse to build yet ANOTHER ebike. Off to CL where I found a 1999 GT Palomar hardtail. I love the older bikes with rim brakes and steel frames. Basic and easy to work on.

Parts are a BBS02 from Luna with the 500c mini display and left thumb throttle for a little more control, HK Multi-stars from the battery drawer in a 14S 16aH series set-up, new Schwalbe Marathon knobbies (no flats) a Raceface 32T chainring for better climbing and trail riding.

After doing a couple of previous builds, this one went together really easily. I wanted it to be fairly stealthy and low key, so went for a rack mounted bag with battery. I'm really curious to see how the BBS02 performs with the smaller chainring and the 14S pack. With 16aH on board, I think range will be pretty respectable. Good bike for exploring trails and paths.

Finished build

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Trimming zip ties

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Series harness with anti-spark XT90

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Balancing packs

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[Wolfeman]

First impressions on a hardtail mounted BBS02....

My learning curve with ebikes has been an interesting one. My first one was a 2000W DD rear hub build that quickly went up to 3.6kW and was an absolute joy to ride. All throttle, all the time. 45+ mph,tire shredding, brake pad killing, spoke popping good times all around. The quest for, "More Power!!!!" eventually made smoke (84V @ 90A) and the venerable TREK is currently still out of service, but due to return new and improved at some point.

My second bike was almost a polar opposite with a PAS only BBS02 at 48V. Still fun, but in a laid back, enjoy the scenery kind of way. It even has a cup holder .

This third build is actually my favorite so far. With 52V and the 32T chainring, this BBS02 has more performance than I hoped. It is an absolute mountain goat on trails, climbing easily while keeping RPMs up and staying nice and cool. The throttle is a really nice addition too. It seems that this build combines my favorite features of my two previous builds. It is fast enough (26-28 mph / 41-45 kph), but really shines on trails. That being said, the rear rack battery is not my favorite, too much weight hanging too high up and too far out back. It really messes up the CG of the bike. Think I'll put together a backpack battery, but want to find a lipo charging sack to keep the pack in just in case.

[SlowCo]

Nice build!
How many teeth is your biggest rear gear?
And why not place the battery pack in the frame triangle?

[Wolfeman]

Nice build!
How many teeth is your biggest rear gear?
And why not place the battery pack in the frame triangle?

Thank you SLoCo. Biggest rear gear is 34T, and I'm still trying out different battery options for this bike. Right now I've got the 14S pack in a backpack and I'm liking it, but putting it on and plugging in every time is not convenient. I'll likely go back to a frame mounted pack, but had never tried a backpack batt so thought I'd give it a try. One of the really nice things about the backpack however is that the bike stays nice and light and the CG is low (until I get on ).

[SlowCo]

Yes, I have the same problem of the CoG going way up when I mount my bike

I'll be building up a (low budget) full suspension mountain bike with a BBS02B soon. But first I'm trying to finish a bike build with a simple brushed 1016Z motor. As soon as I start the BBS02 build I'll start looking for more builds like it on this forum to see how to do it.

[Wolfeman]

So finally got a chance to take the GT trail riding today. Did about 10 miles on nearby dirt trails and experimented with using both PAS and throttle. This inexpensive used MTB with a BBS02 is the most fun trail bike I've ever ridden. With the RaceFace chainring, it climbed everything I pointed it at. It was light, nimble, surefooted and predictable.

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Now I just have to clean it....

[Wolfeman]

Update time:

Like most of the DIYers here, I periodically really enjoy putting my bike up on the rack and tinkering with it. Tonight was one of those nights. You drink a couple good beers, listen to some good music (Stick Figure on Spotify) and tinker on your beloved ebike out in the garage. As a husband, father of teenagers, employed adult, etc., this time is precious and to be savored. You know how it is. Tonight I cleaned, adjusted cables, re-did zip ties, beefed up my wiring from the battery to the BBS02, put on a little mud fender and just really enjoyed tinkering on my bike.

Current state of affairs

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Figured while all the really commonly used items were out on the bench it was a good time for a pic. We probably all have a similar assortment. DIYers, pay attention you'll need this stuff. Heat gun, heat shrink assortment, good adjustable soldering iron, a good sized bag of male/female XT90 connectors, decent beer, bluetooth speaker, good lighting, extra wire, etc.....

Get yo'self the tools

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Discovered a cool trick this evening while tinkering. Need to solder wires while the drive is still on the bike and don't want to make a soupy mess of it? Use your hobby grade helping hand device and a good strong magnet. The helping hand is secured to your steel frame with a good magnet, and voila, stable soldering for clean connections.....

Hit the easy button.....

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That's about all for now, just wanted to update the thread. The GT has about 500 miles on it now and is a fantastic general purpose ebike. If anyone reading this is contemplating a first conversion, do it. Ebikes are the most fun hobby I've ever been involved in. The are so enjoyable to ride, build and maintain. I use mine for fun daily and to commute to work regularly. I started with a well used CL find ($175), added a Luna BBS02 and am slowly adding parts until it's just right. Hope everyone is well and enjoying their awesome ebikes during this challenging time.

[Wolfeman]

The ever trusty Palomar's BBS02 hit 600 miles just the other day and I was getting the itch to make the next improvement.

Fat tire bike?

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Ordered 26" x 2.4" Schwalbe Super Moto-X tires from Bike 24 in Dresden, Germany. Shipping was fast, communication fast and clear and the tires were delivered well packed and in perfect condition. I LOVE these tires.

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[soaresdacosta]

Nice. Very nice.
I feel the same with the time on my garage. Im building another ebike, and still waiting for 90% of the parts, and I kill some time, just looking at it.
Take care,
Luís.

[Wolfeman]

Update to the post/blog for this super fun bike. My old clunky 7 speed rear deraileur ate a stick on the way home from work the other day and was beyond saving. My LBS has a nice new Acera on the shelf for $10 cheaper than Amazon and I think it suits the bike really well.

The Schwalbe Super Moto-X tires are my favorite ebike tire so far for general purpose commuting/fun use. They are really grippy at deep lean angles and I got a goat head thorn through the sidewall the other night. They are smooth, fast, quiet and cool looking. Most of the time I ride this thing like an oversized BMX bike, swoopy, fast, curb hopping fun.

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It still needs a Lekkie 36T for better chain alignment and I think some polished silver 170mm Lekkie Buzz Bars would be pretty sweet. There's always gotta be something to look forward to right?

[Wolfeman]

The GT just hit 1100 miles the opther day and I figured it was time for an update. Since the last post I've added a Lekkie 36T bling ring and 170 mm buzzbars to the BBS02. These 2 improvements are probably my favorites yet. The Lekkie parts are beautifully designed and machined and really seem to up the quality of this humble hardworking little mid-drive.

Lekkie bling....

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The Lekkie 36T ring works perfectly with the new Acera derailer, and I get full use of my 7 speed cassette with no skipping or shifting problems. A new KMC chain rides the teeth, transferring all 1.3 kW of goodness to the back wheel.

Chain and derailer

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Overall, this old steel frame hardtail really shines with this setup. The 52V 16aH lipo battery is still going strong after approx 3000 miles on different bikes. Voltage sag is minimal and range with PAS in 2 or 3 is easily 45 miles. The BMX handlebars are still my favorite for a more upright riding position, frankly I'm surprised more folks don't run them.

GT klunker goodness

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One thing I still want to change is the brakes. I put on Kool Stop MTB pads which work excellent, but the brakes themselves are cheap and wonky. Lots of good options out there, especially the Paul Components Moto-Lites.

[methods]

ripping hard

Thanks for your contribution.

-methods

[Wolfeman]

ripping hard

Thanks for your contribution.

-methods

Thanks dude

[motomech]

Take care of those MultiStars, they are no longer available.
Of course the smaller bricks can be replaced with high-value 25C Turnigys, but the big bricks, like your 10 Ah are hard to find and cost an arm and a leg.

[Wolfeman]

Take care of those MultiStars, they are no longer available.
Of course the smaller bricks can be replaced with high-value 25C Turnigys, but the big bricks, like your 10 Ah are hard to find and cost an arm and a leg.

Hey Moto, yeah I noticed. I still have 3 16aH 6S packs and 2 16aH 4S packs. Gonna have to eventually switch to the Turnigy Graphene packs.