20 inch full suspension street build (now with twin motors)

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Gab   100 W

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Re: 20 inch full suspension street build (now with twin moto

Post by Gab » Apr 11 2015 5:04am

awesome build !

Being sensorless and mid drive do you have any motor stutter issues if you chose the wrong gear and go very high load and low rpm at starts ?

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Re: 20 inch full suspension street build (now with twin moto

Post by macribs » Apr 11 2015 5:39am

He runs a left chain drive to a single rear sprocket. As he runs dual motor he got insane amount of power a relatively low gearing so I doubt he would ever be in a stall situation.

Image

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 11 2015 9:32am

Gab wrote:awesome build !

Being sensorless and mid drive do you have any motor stutter issues if you chose the wrong gear and go very high load and low rpm at starts ?
High load low RPM is always an issue. But, with twin motors it is not a problem.
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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 11 2015 10:58am

I've been riding the bike quite a bit and I think I will gear it down for 45mph top speed. 54 is just too fast. Also, I want to reduce the amp draw a touch. So, dropping the gearing will reduce my top speed, reduce the amp draw a bit, and give better snap for wheelies. :-)

Matt
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Warren   100 kW

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Re: 20 inch full suspension street build (now with twin moto

Post by Warren » Apr 11 2015 11:47am

45 mph is the speed I like to drive my car at. So yeah, I think it should be plenty for a bicycle.

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spinningmagnets   100 GW

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Re: 20 inch full suspension street build (now with twin moto

Post by spinningmagnets » Apr 11 2015 11:55am

If I had ordered a custom build and could choose either a higher top-speed, or...better acceleration that tops out at 45-MPH? For me, 45-MPH is the most I'd recommend.

I'm not a big wheelie fan, but brutal 0-45 acceleration is an extreme roller-coaster with no lines to wait in...and that's something that enthusiasts will pay big money for. Its addictive fun to embarrass gasser cars and motorcycles from stoplight to stoplight...

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 11 2015 5:03pm

Ok, I'm lovin this thing. 45 mph gearing is awesome. The controllers are far happier, the bike is more fun to ride, and everything is running cooler.

I did some range testing. Under race conditions (super hard throttle at every corner exit, riding as hard as I can) the bike is good for 18 to 20 miles of range. At 45mph the range is 32 miles. In wye at 25mph, it is good for over 60 miles. That is 23wh per mile. Pretty darn good for a twin. :-)

Matt
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Re: 20 inch full suspension street build (now with twin moto

Post by John Bozi » Apr 14 2015 4:59pm

just saying.jpg
just saying.jpg (246.65 KiB) Viewed 2994 times
We all love seeing the inner workings of a vehicle and how it was made even, but at the end of the day when everything is set to how it will be. You don't drive cars without a bonnet for example right?

2 cents of subjective taste, less is more. Just a couple of light side covers might funnel air through too?

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 14 2015 5:25pm

Yuck....

There is a reason "Naked" motorcycles are so popular.

I agree, taste is an individual thing. That look would be far too boring. The point to this bike is to be hard edged, not soft and compliant. It is a top fueler, not a Camry. :wink:

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Re: 20 inch full suspension street build (now with twin moto

Post by Stielz » Apr 14 2015 5:43pm

I'm really impressed with how much current those little ESCs can take! you mentioned it was pulling 600A during acceleration, how many seconds would it be pulling that much current for?

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 14 2015 6:00pm

Stielz wrote:I'm really impressed with how much current those little ESCs can take! you mentioned it was pulling 600A during acceleration, how many seconds would it be pulling that much current for?
331 per controller for 1 second and 280 amps per controller for 1 second.

Remember, that is so much power the front wheel is of the ground much of the time. So, it is short bursts.

Matt
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Re: 20 inch full suspension street build (now with twin moto

Post by Grinhill » Apr 14 2015 6:16pm

Awesome work as usual!

Sorry if you already mentioned it, but what did your wheelbase measurement end up at?
1995 Giant Hybrid - Zeta2 with 12V 7AH SLA - removed after one year.
2006 Converted Giant to Geared Brushless Rear Hub with 24V 17AH SLA - bike stolen 2007.
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Grinhill's Medium-power RC-Motor Hardtail build
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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 14 2015 6:42pm

Grinhill wrote:Awesome work as usual!

Sorry if you already mentioned it, but what did your wheelbase measurement end up at?
43.5 inches

It looks like an even 40 miles of range in mixed riding. This bike is crazy how the range differs depending on riding style. With this much power, the range can really change if I get on it a lot.

Matt
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Re: 20 inch full suspension street build (now with twin moto

Post by giblet » Apr 15 2015 2:13am

John Bozi wrote:
just saying.jpg
We all love seeing the inner workings of a vehicle and how it was made even, but at the end of the day when everything is set to how it will be. You don't drive cars without a bonnet for example right?

2 cents of subjective taste, less is more. Just a couple of light side covers might funnel air through too?
Yuck agreed!

Don't give up your day job, unless your day job is designing fairing for e-bikes :)

Looks way better raw.

Also - recumbence - do you do builds for people?

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 15 2015 12:20pm

giblet wrote:
John Bozi wrote:
just saying.jpg
We all love seeing the inner workings of a vehicle and how it was made even, but at the end of the day when everything is set to how it will be. You don't drive cars without a bonnet for example right?

2 cents of subjective taste, less is more. Just a couple of light side covers might funnel air through too?

Also - recumbence - do you do builds for people?
On occasion. I have done 7 or 8 builds if I remember correctly. My builds are costly, though, due to the high performance nature of them.

Matt
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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 17 2015 8:28pm

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Re: 20 inch full suspension street build (now with twin moto

Post by Warren » Apr 17 2015 9:09pm

Not "deathbike" but just watching scared the hell out of me. :-)

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Byte   1 kW

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Re: 20 inch full suspension street build (now with twin moto

Post by Byte » Apr 18 2015 6:22am

Nice! More, more, more please :mrgreen: :mrgreen:

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Re: 20 inch full suspension street build (now with twin moto

Post by litespeed » Apr 18 2015 7:07am

Wow, that looked fast.

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Re: 20 inch full suspension street build (now with twin moto

Post by macribs » Apr 18 2015 7:15am

Wow I will start saving right away cos I need that much power too :twisted:

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Re: 20 inch full suspension street build (now with twin moto

Post by MitchJi » Apr 19 2015 10:13am

Best Wishes!

Mitch


Buying a new Tesla? Please consider using our referral code https://ts.la/lynnem96959 to get one thousand miles of free Supercharging.

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Re: 20 inch full suspension street build (now with twin moto

Post by MitchJi » Apr 19 2015 10:21am

Hi,
I cannot believe how well all of my projects have worked out lately. Everything just works right the first time.


"experience"...it makes all the difference.
"talent"...it makes all the difference.
Best Wishes!

Mitch


Buying a new Tesla? Please consider using our referral code https://ts.la/lynnem96959 to get one thousand miles of free Supercharging.

The best quality batteries and lowest priced batteries for DIY EV's are tier 1 OEM Quality Cells from salvaged (wrecked) EV packs. Three examples are Chevy Volt and Nissan Leaf and Tesla Model 3 packs.

Nissan Leaf Module specs are here
Chevy Volt Pack Info - Salvage 16kwh Packs Under $2k here

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » Apr 19 2015 12:58pm

I'm finally getting really used to the power. It feels good not being startled every time I hit the throttle.

So far so good. The only issue I have had so far is a loose flange on one of the motor pulleys.

Matt
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Re: 20 inch full suspension street build (now with twin moto

Post by StinkyGoalieGuy » May 11 2015 5:25am

Matt, when you originally cut the tubes on this frame and welded on the plates to build the battery box, how did you square off the ends of the tube? I assume it never left the frame jig. How critical is this "squareness"?

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Re: 20 inch full suspension street build (now with twin moto

Post by recumpence » May 11 2015 7:12am

StinkyGoalieGuy wrote:Matt, when you originally cut the tubes on this frame and welded on the plates to build the battery box, how did you square off the ends of the tube? I assume it never left the frame jig. How critical is this "squareness"?
I used a grinder with a flap disc. I tried to make all tubes and plates as tight as possible. I would say 2mm gap is the largest gap I had to fill.

Tight gaps and clean material makes TIG welding so much easier and stronger.

Matt
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