Razor e300 ultra. Technical guide

Lightweight / Folding / Portable EVs - seats optional
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Ianhill   100 kW

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Razor e300 ultra. Technical guide

Post by Ianhill » Dec 01 2018 11:28am

In this build I will take a razor e300 and transform it s ancient design completely into the modern age with lots of hacks but no bodges. I will tackle it stage by stage and show what I'm doing and the method to my madness with some pictures and technical info and answering any questions that's thrown my way.

First up handlebars and headset .

The stock razor 31.8mm mild steel bars and threaded headset utilizing caged bearings, it does the job for a basic ride up to 30mph but we want to go well beyond that.
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So some digging around looking into stunt scooters reveals that the 1 1/8 bearing cup is still widely used but its a threadless mountain bike headset with cartridge type bearing.
IMG_20181201_152138638.jpg
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The stunt scooters use 3 main differing clamp options the one I'm interested in is a SCS clamp as shown below as it's the strongest of the lot.
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There's also two handlebar thicknesses stock there is 31.8mm and then there is an oversized 34.9mm both come in alloy, mild steel, chromium and titanuim all have various benefits but the chromium is the best bet for price, good strength and longevity.
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Then comes the SCS clamp itself these have varying levels of strength and width most are set for the oversized bars and use a sleeve reduction for the 31.8mm narrow bars some have 4 × 5mm bolts and better ones have 4× 8mm bolts.
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I can use the stock fork from the razor and cut it to length and fit a star nut inside to match the SCS image and clamp it all together with oversized chromium bars and that then is the handlebar section strong as it possibly can be.

All the parts I've shown I've ordered so this is an actual build taking place and I'll have my own photos as I go along, I'm undecided on going dual hub 7kw or single 3.5kw at the moment but I've ordered one so it's gonna happen at least so I'll finalize all that once I see one hub in hand and look around the front fork for inspiration as it will need to be 40mm or so wider, the rear is fine so I'll see how much trouble I want to make it and how well it performs with just the rear as it will be crazy light compared to it's bigger brothers of 40kg +, this will be around half their weight even less with a single hub and Lipo 20kg will be the upper limit.

cheapcookie   10 W

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Re: Razor e300 ultra. Technical guide

Post by cheapcookie » Dec 03 2018 4:48pm

Nice! I am looking forward to this thread. :bigthumb:

Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 04 2018 11:48am

cheapcookie wrote:
Dec 03 2018 4:48pm
Nice! I am looking forward to this thread. :bigthumb:
Cheers hopefully it turns out beast.
I got myself a different clamp in the end I had a change of mind the original was 6061 alloy but this one is 7075 that is more rigid and suitable as a clamp and it still has the 8mm bolts too.
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I got some camouflage grip tape for the deck and a decent set of grips but I'm still waiting for the 1600w nominal hub too clear postage on aliexpress then it's 20-40 days post so gonna be 2019 till this one sees some serious riding again.
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Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 05 2018 8:18am

I got my grip tape today so I got that fitted I don't think I needed to show a how to it's just a taredown handfile and a knife then reassemble.
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Still not heard from the motor seller less than 2 days now till it's a failed transaction.

Fastassmotors   1 W

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Re: Razor e300 ultra. Technical guide

Post by Fastassmotors » Dec 05 2018 9:07am

Nice grip tape easy little mod. Sucks about motor though good luck. And if you have any idea of controllers maybe you can give some insight as to how I fix my cheap controller and modify for more volts

Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 05 2018 10:05am

Fastassmotors wrote:
Dec 05 2018 9:07am
Nice grip tape easy little mod. Sucks about motor though good luck. And if you have any idea of controllers maybe you can give some insight as to how I fix my cheap controller and modify for more volts
Electric god is your man for a bit of controller modding what's your issue any pics ?
I'll get a motor one way or another I got money and someone in shanghi will want it.

Glued my razor grip tape on top of the cammo looks beast and hides the fold mark the seller of the cammo put on it in an envelope not a tube.
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Fastassmotors   1 W

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Re: Razor e300 ultra. Technical guide

Post by Fastassmotors » Dec 05 2018 12:51pm

Nice work that really looks good. And my thread is just posted with a bunch of pics I'll try and see if electric can help too

Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 06 2018 12:42pm

Parts slowly rolling in, got my grips and bars today i had to cut the bars for SCS use but its no big problem the manufacturer states they can be used in this way.
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I've got a set of a set of floating rotors for a mountain bike 6 bolt fitment and the hub motor im getting will use the same mount, but my other wheels and hubs don't so I'm going to make a hub simular to the one below from scratch for the wheel I've also shown below.
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I've done a bit of designing around the fork and available parts that I can get of a shelf and I've come up with the idea of using a mtb 12×142mm rear thru axle for the front wheel, with 6001zz ceramic hybrid bearings sat in a custom lathe'd out hub that ill have to get a bit of stock alu and have my local turn it out, there's a few critical dimensions I've got below now i just got to work out the lengths then get it on the computer and some time next week hopefully that will get done and I can start on the fork get the front end finished before the rear hub turns up.
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Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 07 2018 10:36am

I received my threadless headset today so I set about fitting it, the fork needed 8mm trimmed off the top for the clamping mechanism to work and the star nut is tight to fit but it does go. One thing I've noticed is most razor e300 versions vary the fork lengths aswell as the headtube but the amount that sticks out is always the same so all the razor forks would need a slight trim to go threadless and SCS clamp, the later grey models are best the headtube is longer so there is more strength in the area and no folding handle bars from stock.
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Below you can see the lip with the fork cut to size and the clamp sits at the correct height, before the fork is cut it's above the inner line so there's no bearing preload when the centre nut and cap is tightened.
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Below is a picture with the clamp fitted and holding the fork on and then the complete front, I can confirm that the setup feels rigid by manualing on the spot but the proof will be when it's riden in anger and I give her wa.
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I've also changed the design of the hub I'll go through a few versions on paper I suppose till im happy but ive decided to use a different bearing setup im going with a 3201zz they are heavy duty double row angular bearing so there's more strength to side loading when turning, high end mountain bikes use a 4 bearing setup that would put more cost into my part and complexity so this is a happy medium.
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Last edited by Ianhill on Dec 07 2018 11:57am, edited 4 times in total.

Fastassmotors   1 W

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Re: Razor e300 ultra. Technical guide

Post by Fastassmotors » Dec 07 2018 11:34am

Now thumb throttle I'm guessing definitely not a twist going on there :lol:

Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 07 2018 11:48am

Fastassmotors wrote:
Dec 07 2018 11:34am
Now thumb throttle I'm guessing definitely not a twist going on there :lol:
Thumb throttle for life, I'll have a push button on the other side to flip the throttle into a varible regen switch and ill have my brake levers ill try keep the cockpit bare and tidy as i can.

Fastassmotors   1 W

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Re: Razor e300 ultra. Technical guide

Post by Fastassmotors » Dec 07 2018 2:11pm

Ianhill wrote:
Dec 07 2018 11:48am
Fastassmotors wrote:
Dec 07 2018 11:34am
Now thumb throttle I'm guessing definitely not a twist going on there :lol:
Thumb throttle for life, I'll have a push button on the other side to flip the throttle into a varible regen switch and ill have my brake levers ill try keep the cockpit bare and tidy as i can.
Sounds badass

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tahitiboob   100 mW

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Re: Razor e300 ultra. Technical guide

Post by tahitiboob » Dec 15 2018 6:38am

hello great mounting I also have a razor e300 I also wanted to upgrade but put 2 engine keep the rear and put a front with a fork like this

https://fr.aliexpress.com/item/Haute-Vi ... 82bfi2fHC0

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spinningmagnets   100 GW

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Re: Razor e300 ultra. Technical guide

Post by spinningmagnets » Dec 15 2018 7:40am

I didn't know something like those split wheels was available, what a brilliant idea. I have changed many flat tires in my life, and having that would have been awesome.

Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 15 2018 8:29am

spinningmagnets wrote:
Dec 15 2018 7:40am
I didn't know something like those split wheels was available, what a brilliant idea. I have changed many flat tires in my life, and having that would have been awesome.
It's only by luck I found them I searched for dualtron hub after seeing the 50mph razor thread and these seem a good way of utilizing the space available so I can get more batterys in the tray and increase range.

I just got myself a 2017 kuberg freerider pro and researching it I found your electric bike review of them top work Mr magnets great help :bigthumb:

Ianhill   100 kW

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Re: Razor e300 ultra. Technical guide

Post by Ianhill » Dec 15 2018 8:41am

tahitiboob wrote:
Dec 15 2018 6:38am
hello great mounting I also have a razor e300 I also wanted to upgrade but put 2 engine keep the rear and put a front with a fork like this

https://fr.aliexpress.com/item/Haute-Vi ... 82bfi2fHC0
Good idea I've seen that front end, what concerned me is if the motors KV is the simular, if they are far apart then the rear hub at full speed on 48v may force the front motor to generate a higher voltage under regen and blow the controller but it's feesable if you find out whats what and work it out I know the hub I got is 33.3kv so have a dig see what specs you can find on the front setup by the looks it's 45kmh at 48v so it would be lower so your ok on blowing a controller but after a certain speed it will be dead weight no more torque to give.

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