are you intrigued by the fat tires and beefy rims of motorcycle wheels like this? (image borrowed from http://voltriders.com/
until i get my own done):
there's been a lot of interest lately in 19" motorcycle wheels for ebikes, but a lot of confusion because measurements are different for each wheel type.
i've not seen a thread that explains the differences so i'm going to hope to do that here.
this is not for academic purposes, but to help the dude who's trying to figure out whether or not and then how to get an MC wheel on his ebike.
So, 26" BICYCLE RIM AND TIRE MEASUREMENTS:
26" Bicycle wheels have tires that are nominally 26" in diameter, but vary between 25" and 28", depending on the size of the tire:
here's a commonly used hookworm which fully inflated is about 27", but sagging a bit here is 26.5"
here's a flat studded tire which looks closer to 25" in diameter.
the rim diameter for a 26" wheel is around 22.5" at the edge.
the inside diameter of the hookworm bicycle tire is under 22".
19" MOTORCYCLE RIM AND TIRE
19" Motorcycle rims have an outside diameter of roughly 20"
But the inside diameter of the tire (and hence the inside of the rim) is 19":
fully inflated, the outside diameter of the tire is around 25":
So, the outer diameter of a 19" motorcycle tire is just smaller than a small 26" bicycle tire.
So before you quench your lust for a 19" MC tire, you should also know that it's a very difficult size to buy tires for!
There are rare old tires that pop up, but (who wants an old tire?) and most people that I know buy either of the Shinko Dual Sport tires, which are also incredibly cheap:SHINKO 244: 19 X 2.75
(2.95" ACTUAL - so measure the width of your frame)SHINKO 241: 19 X 2.75
(2.95" ACTUAL - so measure the width of your frame)
If anyone knows of other tires, particularly street tires for 19" wheels, please include pics and specs!
19 x 1.85" RIMS
Most aluminum 19 x 1.85 wheels seem to retail for around $200, but on ebay, the colored ones go for as little as $35 + $15 shipping w/in the US
i have heard you can use rims as narrow as 1.4", but the shinko site recommends 1.85, so that's enough for me.
If 1.85" sounds kinda narrow, that's cause it's the measurement inside the rim where the tire bead sits:
the actual width of this 19 x 1.85 rim is 2.5":
I think I read that Rix knows the guy behind Pro Wheel
, and that even he'd consider putting smaller holes for spokes so they don't need washers. See below for spokes/washers.
If you can figure out how to run a tubless MC tire, good on you. But when if you find other tires than the shinko's above, make sure to see if it's a TT type, needing a tube. Here's the one I got
, but I'm honestly not sure if I should have gotten the 2.75-3.00-19. We'll see... get it? Wheel see? haha
I got an 18" rim strip
To never have flats again, you do have to compromise somewhere, and the weight of these rims and tires (and tubes) is substantially more than bicycle wheels!
I'll update this later with weights.
12g spokes don't stretch as well as 13/14's but JRH/volt riders sells custom oversized nipples and washers that fit motorcycle wheel spoke holes.
standard 12 spoke/nipples (silver) and standard 12 black with moped/MC rim nipple/washer set:
standard 12 nipple width for rim hole:
special moped/MC nipple width for rim hole:
prowheel mc rim hole:
spoke washer contour:
nipple with washer on:
washer inside diameter:
washer outside diameter:
the washers before they were shaped seem like about 1.1mm but this is the best measurement i could take of the edge:
If you decide to get a PRO WHEEL and JRH custom spokes and washers, you can figure on an ERD of 460mm. and i know you want a cromotor but i don't know the spoke sizes for those, but you can use the ebikes.ca spoke calculator
for other motor types (showing here the xlyte hs series):
for bigger hub motors 9C, xlyte hs3540's, h40xx's, and maybe cromotors, i think single cross is the way. maybe others can help in this department. i've just copied what i've seen around.
and i just noticed that this volt rider's cromo wheel has all the spoke on the inside of the hub:
whereas the spoke directions on this volt rider's one alternate:
i hope this helps, and others can add useful info.
i know there are many more smaller MC wheels, and while those are great for non-pedaled bikes, i always feared getting the pedals too low w/ 17 and 18" wheels. but i've never tried one so don't really know, and that's why i made this about 19" MC wheels..