Light dirt bike, QS 120 70h motor, custom steel frame

bht said:
if you use by rated power my motor give to you zero problem ;) my new motor builded in unitemotor factory and cant say is bad quality


nothing to do w/ rated power. the yellow phase wire wasn't properly tied in so it ended up touching the rotor. a quality control issue

anyway i just got back from an event...

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Congrats on the complete build, the first place and the paint job. Really fun to see the bike completed.

Great job and cool bike.
 
Awesome!

Even if you race alone, please use some protection (if you are low on cash buy the first items).
I've purchased the cheapest stuff on amazon and I really like the products.
Gloves: https://www.amazon.com/gp/product/B07B4SZBP1/ref=oh_aui_search_asin_title?ie=UTF8&psc=1
Boots: https://www.amazon.com/gp/product/B00SX59UNC/ref=oh_aui_search_asin_title?ie=UTF8&psc=1
Knee/shin guard: https://www.amazon.com/gp/product/B008YAVIOK/ref=oh_aui_search_asin_title?ie=UTF8&psc=1
Body armor: https://www.amazon.com/gp/product/B002TJZRQM/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

Using those changed my riding style from "hehe this is going to hurt" to "who cares, i'm god." I think this is usual, because the jacket comes with a sleeve that says something like 'WARNING even if you use this jacket you can die from an accident" :lol:
 
Overclocker said:
anyway i just got back from an event...

Congrates! :thumb:

Did you won a race? or a building contest?
 
trazor and madin888,

it was a race but nothing serious, was just for fun. slow twisty track so i didn't even put on all my gear, coz i'm not an all-the-gear all-the-time person :lol:

but thanks for the links trazor! when out trail riding i put on elbow, knee/shin, gloves, and hiking boots.

PS here's the all-electric lineup:

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That's awesome! Looks like that red scooter was likely your toughest competition :)

great job on the build and 1st place well deserved
 
thanks skeetab!

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just got a budget quad piston for the front only. the rear tire is already easy to lockup

working great so far. i also got these 203mm rotors. thicker and heavier than shimano RT-66 that i replaced. 250g each. seems to be more powerful too, probably due to having more contact area i.e. less drilled out
 
i just got 4 boxes of #41 chain (10ft/bx). interestingly #41 uses the exact same size sprockets as #420. much lighter weight. slightly smaller pins. we'll see how fast it wears out...

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i'm also posting these side-by-side pics of these various size chains because i couldn't find any proper pics on the web. top to bottom:

- #25H
- 1/2" x 3/32" (for 6 7 8-speed bicycle)
- 1/2" x 1/8" (also known as #410, for single-speed bicycle)
- #41
- #420
 
Overclocker said:
just got a budget quad piston for the front only. the rear tire is already easy to lockup

working great so far. i also got these 203mm rotors. thicker and heavier than shimano RT-66 that i replaced. 250g each. seems to be more powerful too, probably due to having more contact area i.e. less drilled out

I've found the same conclusion. I use 180mm on rear wheel since is enough to lock up, 203 in front.
Up to now my prefered brakes are the Shimano Zee. https://www.chainreactioncycles.com/shimano-zee-m640-disc-brake/rp-prod82434 , quad piston designed for downhill, amazing modulation.
Those 203 rotors you have look thick. Are the usual 1.8mm width? Magura makes 2.0 rotors by default. Talking Magura, I purchased one MT5E, these come with brake cut switch and are flip flop (you can use left or right). https://www.amazon.com/Magura-MT5E-Carbotecture-Bicycle-Brake/dp/B01EQS1Z6O . Last years I've been using other Magura device to make the brake switch ( https://www.amazon.com/gp/product/B015DJWWM6 ) but I can't find any dealer that carry these anymore. That makes me ask... do you have a brake switch on the brike?
 
Tektro makes 2.3mm
These are coupled with brake supports designed for up to 45km/h as they advertise it.

Usually brake rotors are ~1.8mm

Ps. Chinese brakes comes with thin regular brake rotors and are advertised as brakes up to 45km/h.

Never tried but I think before mentioned magura brakes are good brakes. In the same price range as alternative comes tektro hd71x, hd72x.
 
trazor said:
I've found the same conclusion. I use 180mm on rear wheel since is enough to lock up, 203 in front.
Up to now my prefered brakes are the Shimano Zee. https://www.chainreactioncycles.com/shimano-zee-m640-disc-brake/rp-prod82434 , quad piston designed for downhill, amazing modulation.
Those 203 rotors you have look thick. Are the usual 1.8mm width? Magura makes 2.0 rotors by default. Talking Magura, I purchased one MT5E, these come with brake cut switch and are flip flop (you can use left or right). https://www.amazon.com/Magura-MT5E-Carbotecture-Bicycle-Brake/dp/B01EQS1Z6O . Last years I've been using other Magura device to make the brake switch ( https://www.amazon.com/gp/product/B015DJWWM6 ) but I can't find any dealer that carry these anymore. That makes me ask... do you have a brake switch on the brike?



https://www.aliexpress.com/item/new-arrival-bicycle-brake-rotor-bicycle-rotors-MTB-rotor-203mm-with-bolts-SH-rotor-7b/32540715682.html

1.9mm

no brake switch. yes i know, dangerous :lol:
 
Really like this bike looks a nice well positioned ride, how do you find the rear wheel bearing hold up? I only ask I got a kuberg it's uses 219 chain and a simular looking hub with either a 12 or 15mm axle if I remember correct and after 100 miles or so the wheel needs a rebuild bearings shot with the torque loading how you getting on in this regard, Thanks again Ian.
 
Ianhill said:
Really like this bike looks a nice well positioned ride, how do you find the rear wheel bearing hold up? I only ask I got a kuberg it's uses 219 chain and a simular looking hub with either a 12 or 15mm axle if I remember correct and after 100 miles or so the wheel needs a rebuild bearings shot with the torque loading how you getting on in this regard, Thanks again Ian.


i'm using a rear hub for a 150cc motorcycle that weighs over twice. uses sealed cartridge bearings but no signs that they need replacement despite repeated river crossings...
 
Couldn't be a pain and ask you the dropout width of your rear ?
Sounds like I need a better hub ideally it's tapped out.
 
Top man for replying, my hub is 145mm so that's not gonna work, I've got the most heavy duty hub available for the size but 12kw geared low just smashes the rear end to bits, new swing arm time I think.
 
Grantmac said:
Have you looked at the OSET hub?

Yes I'm gonna ring them in the morning and see what axle they use, I've got a 15mm axle after checking.

It's for a kuberg freerider pro i gor second hand the original wheel was a 14,3.00 trials rim with a wierd sprocket that matches a disc brake hub but with 7 bolt pattern, I only noticed after I bought a oset sprocket carrier and then noticed 7 not 6 so I need to build a new wheel from scratch or a swing arm and upgrade.

I got a 36 spoke dh32 rim 20 inch and sapin spokes spare so I could take a punt at the hub get a sprocket for my carrier and see if it solves the issues, I will say though the torque seems alot for what's a push bike setup really to cope with and that's factory.

I can't find much info on the surron hubs but I bet that route would be more expensive than just making a new swinger and getting a decent mx rim on there.

Thanks guys for the input.
 
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