BMX-90cc-four speed-trail bike

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mojomoto

New Member
Apr 2, 2010
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Minnesota
Please take a look at my ongoing prototype project.

I plan on adding a Sturmey Archer drum on the front, stronger rims and spokes.

For those that know, since weight isnt an issue.... what are the strongest 20 inch rims for a bike? Steel? Aluminum? AND anybody have a good resource for heavy duty spokes? Electric bike spokes?

I was thinking of giving it a good shakedown this summer and possibly making a batch of frames if there is an interest.
Opinions welcome.


.wee.http://i1125.photobucket.com/albums/l588/mojomoto/Bugoutbike.jpg
 
timboellner

timboellner

Member
Apr 1, 2009
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Towson Maryland
That's a wild looking creation you've built

Can you give more details about what you've got going on there?
What kind of drive is that?
Does that rear wheel only get support from one side?
How about that frame? Did you build it from scratch?
It's cool but not gonna be street legal without pedals.

Can you put up some more detailed pics?

If you've got 20 inch wheels go to Dan's Comp. They have a lot of
sturdy BMX wheels. My son is into BMX and his old Haro is built like a brick $hit house.

TiM
 
M

mojomoto

New Member
Apr 2, 2010
28
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Minnesota
The engine is 90cc 4 speed auto clutch honda copy.
The swing arm is single sided.
Built from scratch except the forks.
Its street legal. Registered as a custom made motorcycle.
Cost...out of pocket? hard to say. Lot more time than money. So far.
Will go to Dans Comp.
 
K

Kahlas

New Member
Nov 27, 2011
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Illinois
Well not sure about elsewhere but in Illinois you'd have to register/plate it as a class L motorcycle and also get the class L endorsement on your drivers license. It would definitely have to be cheaper than a 100cc equivalent dirt bike to make it worth getting.

How sturdy is the frame? Have you put it through any torture testing yet?
 
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mojomoto

New Member
Apr 2, 2010
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Minnesota
Way strong for a 50cc. For a 90.... Time will tell. Im upgading the front brake, rims and spokes. Then...out for abeatin'.
 
bairdco

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
Worksman has 20" wheels with their clincher rims, drum brakes, and 11g spokes.

back in the 70's/80's you could get dimpled Femco rims with HD spokes, before ultra-lightness was important on BMX bikes. i don't think you can get anything like that anymore.

but you could always look into getting moped rims and tires.
 
wayne z

wayne z

Active Member
Dec 5, 2010
1,743
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louisiana
That is one awesome design! Kudos to you for thinking outside the box. It could be done with a 49cc and pedals and be a legal motorbike.
 
happycheapskate

happycheapskate

New Member
Nov 26, 2009
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Rockwall TX
Looks great, but it's going to beat you to death off-road with a rigid fork and 20" wheels.

If getting there is more important than getting somewhere fast, looks like you've got it made.

I had a pair of Alex 48 hole 20" wheels, that had press-fit bearings, flatted axles, and rims that were aluminum alloy and about 1" deep, double wall. They were noticeably much heavier than standard wheels, but were very strong, and so tight you could ring them like a bell.

Something like this Primo BMX 3/8" 48 Spoke Front Wheel Hoffman S&M Standard Profile Federal GT DK | eBay

http://www.ebay.com/itm/Primo-BMX-H..._Accessories&hash=item5646c3ca2c#ht_766wt_952
 
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Gator Wrestler

New Member
Jan 22, 2009
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Springfield LA
A 16" moped wheel is the same diameter as a 20" bicycle wheel. The tires will interchange as well, but DOT moped tires are better on a MB. Ebay usually has a few in the $65 to $100 range. They can be found with drum brakes too, another plus.
 
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Gator Wrestler

New Member
Jan 22, 2009
124
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Springfield LA
Mopeds can be found with several different size wheels. The 16" and 17" are common, others use 14" (not real mopeds but some 50cc Honda and Suzuki bikes) The sizes can be confusing since Motorcycles measure the rim diameter and for bicycles measure the height of the wheel with tire. I'm not alone on this forum brnotin my use of the 16" moped wheels.
 
Ibedayank

Ibedayank

New Member
Oct 29, 2011
1,171
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Columbia Tennessee
the 50 cc suk uses a much smaller than 16
and there is a BSA moped trike that uses 12 2
the 17 moped is 20inches rim seat to rimseat so are the rims on the 80cc honda dirtbikes
 
M

mojomoto

New Member
Apr 2, 2010
28
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0
Minnesota
Bairdco Thanks. I will be getting 11 spokes.

Happycheapskate My plan is mostly trails and the street. I do have a set of shocked forks on the way (cheap set). There arent a lot of options for suspended forks that are semi affordable.
I just bought the Archer 36h brakes so 36h are the rims. I ordered a set of 2" wide tripple walled rims and some 2.25 wide tires.

Ibedayank 1" axle for now. The hub is only 2.5" wide so the side flexing will be minimal. (I had a Triumph 955i and an RSVT. Both had single sided. I like the simplicity and look) Im guessing the bike should be around 85 lbs. I have some engineer friends that will do the # crunching for strength. Im more of the creative type.
 
Ibedayank

Ibedayank

New Member
Oct 29, 2011
1,171
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Columbia Tennessee
mojo

cool my trike uses 3/4 for the rear wheels and mounted only one side.
was just hoping you didnt use a regular bike axle. Nice job so far will be watching as you finish the build
 
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