19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)

[GCinDC]

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.

TIRE AVAILABILITY:
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.

TUBE
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

RIM STRIP:
I got an 18" rim strip:

WEIGHT PENALTY:
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.

SPOKES/NIPPLES/WASHERS
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 width:

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):

LACING
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..

 

[Rix]

GCinDC, you are off to an awesome start. Dlogic suggested I start up a thread like this earlier this year. Initially, I didn't think there was enough of an interest. Based on the amount of PMs I get, I was wrong. I am glad you go this going. I will start posting my wheel builds on here. My next wheel build will be an 18MC tire on a 5405 for the Bomber, I will post a bunch of pics comparing 17 to 18, 19 to 24MTB in the near future.

Rick

 

[bzhwindtalker]

Will take some mesurements on my 17", all I can say for now is that it is a bit smaller in diameter than a 24" with a fat tire.Great guide BTW, I really need thos shinkos 241 in 17"!

 

[Rix]

Will take some mesurements on my 17", all I can say for now is that it is a bit smaller in diameter than a 24" with a fat tire.Great guide BTW, I really need thos shinkos 241 in 17"!

Not sure how wide your swingarm is, but the 3.00x17 SR241 is the best I have ran in this size. I also have a 2.75x17, I can run the 3.00x17 at slightly lower air pressure because its a little bigger and wider.

 

[Hyena]

Good info Greg.
It's probably worth mentioning that most 19" moto tyres are actually closer in rolling diameter to a 24" bicycle tyre with the difference being only around 5mm.

The below picture shows the 2 shinko 19" moto tyres of choice against a relatively skinny 24x2.35 bicycle tyre. The next picture is a worn out 24x3" bicycle knobbie vs the 19x2.75 shinko.

 

[GCinDC]

i think the motors have gotten a bit heavy for bmx wheels, but this thread should also be referenced for the bike to mc wheel compatibility/comparisons:
20 inch BMX rims with motorcycle tires

with this helpful table from KF:

the thread looks to have gotten corrupted when it got to 18" MC wheels tho..

 

[dan974]

much appreciated :wink: for info the Knobies HALO contra 24"x3 are 25.6"x2.7 outside with a 34mm rim
does anyone tried trial bike rims in 19"x1.5 or 1.6 with motorcycle tyres ?
http://www.trialprod.com/fr/372-jante-ar-echo-tr-19.html

 

[crezzy2k1]

Awesome write up Greg. I have been looking for this information for quite some time.

 

[GCinDC]

Going to include links to other member's 19" MC wheel builds. Feel free to add more. Here are a couple now:

ZombieSS's Official Greyborg Warp build thread

Electric Jeepster - New(ish)member new build

 

[zombiess]

Just another warning to watch your rim width when going to MC rims/tires. I purchased some 19x2.14" wide Warp9 wheels but did not fully understand the width until I received them already built from VoltRiders. They were WAY wider than I anticipated. With the tires mounted the 19x2.75" Shinko SR244 tires ended up being 3.3x" wide at the cross section! Luckily for me this was not an issue and everything fit my Greyborg Warp frame and DNM USD180 forks. The forks have the tightest fit with less than 1/4" clearance to the narrowest part of the down tubes.

I did not set out to build a fat tire bike but it is now what I have and it looks and rides AWESOME!

Be aware you will pay a weight penalty of around 5-10lbs per wheel when going to a MC setup, but the benefits are super long tire life, low chance of a flat tire (my main reason I went MC/Moped in the first place), a more cushioned ride (lower air pressure required), stronger spokes since it is now OK to build with spokes as thick as 8-10 gauge and far superior traction. Another upside I noticed is they loose air a lot slower so they require less frequent pumping. Yet another upside is that building a moped/MC setup costs about the same as a bicycle setup! Most rims/tires/tubes for moped/MC are the same or even cheaper than the same bicycle parts.

For reference in the last 3 years of bicycle riding i have experienced at least 10 flats between all my bikes when running bicycle tires. On bicycles with moped/mc tires I have had ZERO flats. Total miles on each type of setup is ~500.

For most bicycle setups I suggest not going larger than 19" as it is very hard to find a tire that will fit in 21". For 19" there are narrow (2.5") street tires available for old school dirt bikes and mopeds. Check out treatland.tv for some 19" street suggestions.

For those interested in the Shinko offerings, the SR241 is a 60% dirt / 40% street tire and the SR244 is a 60% street / 40% dirt tire from the many reviews I have seen.

 

[LSBW]

Just for reference, 18" rear moto tire vs. 24" front bicycle tire:

http://electrotransport.ru/ussr/index.php?topic=19081.216

According to the owner, it's about 3/4" smaller OD than front.

 

[GCinDC]

awesome input.

another thing that's nice about the shinko dual sport tires is that the width is measured in inches, like 2.75".

because if you're looking for other sizes, it's more common they're measured like this, which can be totally confusing:

by this code, the shinkos would be 70/100-19 (where 70mm=2.75" and 100 (%) means the tire's as tall as it is wide... so don't even consider larger tires like the trials 110/80-R19's, unless your rear triangle is 5" wide down there... and if it is, chances are you don't have pedals!

ps. while checking the measurements on the shinko site, i noticed the have another 70/100-19 tire, the 540 series:

speaking of MC tires, at some point you might find out that they're a bit more difficult to put on and take off than bike tires! lol.

but with the right tools and some determination, it's not too bad...

 

[Dauntless]

Hmmm, I haven't found motorcycle tires so difficult. But then when I first got out on my own and was desperate I. Pried car tires onto rims after I cut the bad one off.

What a great thread thoough. With the 20" bike wheel taking a 16" tire, i'd never have expected the 19" to fit the 26" wheel. Do you suppose the 29" inch wheel (WalMart has such a bike around $100) might take a 21" tire?

 

[GCinDC]

i'd never have expected the 19" to fit the 26" wheel.

Woah, a 26" bike wheel definitely doesn't fit on a 19" MC rim! did it sound like i was suggesting that? i totally have to clear that up!

the point of the thread was to compare the tire sizes/dimensions, explaining how they're measured differently.

and just for fun, here's my 2012 highlights vid, in which i beat up a 26" rim and spokes and install a 19" MC wheel:
[youtube]UZZQhX1mlXU[/youtube]

maybe it's the weight, but the MC wheel adds a much higher feeling a stability for me, esp at high speeds.

ps: i would love to see a vid of this:

Pried car tires onto rims after I cut the bad one off.

what did you use to cut the tire off? a chain saw?

that's living up to your username!

 

[Rix]

With the 20" bike wheel taking a 16" tire, i'd never have expected the 19" to fit the 26" wheel. Do you suppose the 29" inch wheel (WalMart has such a bike around $100) might take a 21" tire?

That's impossible. A 26MTB and 19MC will never cross fit on each others application. The only MC and Bicycle tires I know of that can cross fit are 20" BMX wheels and some 16" MC tires. BMX rims known as 20 inch wheels can except certain 16MC tires. Reason being is that the bicycle industry measures their wheels by outside diameter of a bicycle rim mounted with a proportionately height and width 1.75" tire which was the original standards popularized by the inventors of MTBs. I am talking Joe Breeze, Tom Ritchey, Gary Fisher before Fisher and Ross days from the late 70s. Yes bicycle wheels had been measured in this fashion decades before, but this was the time the 26MTB came into its own and was purpose built for non paved roads and climbing with multiple gears. So here is a break down of bike rims and true sizes. 20' BMX has 16" rim, even seen a 15.5" rim once, 24MTB has a 20.5" rim, 26MTB has about 22.5" rim , 29"MTB is 25.5" (seen slight variations in this size though) Not sure what the 650B would be but its rated at 27.5" so I am thinking it would be right around a 24" rim. MC wheels/tires are measured by rim size and not total external tire OD. This is why some 16"MC tires can fit on BMX rims, and this is why a 24MTB and 19MC are really close in same size inflated diameter when mounted on their respective rims. The only other MC to MTB compatible equipment option is that 21MC tubes that are designed for full size dirt bikes front wheels will fit 24TMB tires. I am currently running a super heavy duty Maxxis 80/90x21 tube on my 24x3.00 Duro Razorback on the front of my Bomber.

Rick

 

[GCinDC]

So here is a break down of bike rims and true sizes. 20' BMX has 16" rim, even seen a 15.5" rim once, 24MTB has a 20.5" rim, 26MTB has about 22.5" rim , 29"MTB is 25.5"

And just to be totally clear, those measurement are for the outer diameter of the rim, not the inner rim diameter (as in 19) used for MC rims...

The "26" MTB rim has roughly and outer dimension of 22.5" (but more like 22" inner dimension)...

But few really need to know that.. since the 26" rims/tires are more or less standard sizes, unless you're measuring for spokes....

 

[Rix]

Yes, I should have clarified I was referring to outside OD on the rims since the bicycle industry uses sizing on tires outside OD.

Rick

 

[grindz145]

Greg, this is freaking awesome. I've never done this succinct of a comparison before. I had never realized how close the dimensions of a 19 Inch motorcycle whee ultimately are to a 26 Inch bicycle wheel!

 

[SkyknightJohn]

Great guide.

 

[sigimem]

speaking of MC tires, at some point you might find out that they're a bit more difficult to put on and take off than bike tires! lol.

but with the right tools and some determination, it's not too bad...

I got the advice to never put the mc tyres on aluminium rims without proper tools.

That advice was from a guy who is building wheels for over 20 years. So I would be careful or just go to a shop.

(Also GCinDC said it before, guess I just wanted to stress it )

 

[GCinDC]

i don't live anywhere close to a motorcycle shop, and was pretty savage changing my first tire. so yes, like all things, having the right tools makes a huge difference.

and youtube is our friend. i learned something just now:
[youtube]spYCtr3yEeg[/youtube]

 

[Rix]

Good video, but one detail was incorrect, if anyone is running a rim lock, don't tighten it until the tire is full inflated and the tire rises up on the bead and sets. In my experience when rim locks are tightened before inflation, the tire doesn't rise up on the bead at the lock and seat correctly. Having said that, bead locks are not necessary if you keep your PSI at or above 22 pounds. Probably get away with less on Ebikes but I wouldn't chance it. For those that don't know, the danger of low PSI and no bead lock are if you ride in conditions with a lot of creek crossings or rainy weather, and your tire PSI is low, from brake loads, the tire can slip on the rim and tear the valve stem away from the tube causing a flat. This has only happened to me on my gasser when I ran less than 16PSI on the front with no bead lock. I have never had it happen on the rear but unlike the front, I have always used a bead lock and never ran less than 11 PSI. Like I said, on ebikes, MC tire slippage is not a big concern, Comparing the 19 MC rim and tire to any size MTB tire is no comparison, the bead/rim/surface/tire contact on the 19 MC rims/tires we are running are more than double contact area at the bead over the MTBs. The other thing the guy in the video didn't mention was each time he levered the tire on to the rim with the spoon, you can see his fingers on his other hand up and inside of the tire a little. What he is doing is ensuring that the tube is away from the rim bead so he doesn't grab a piece of that with the tire spoon and pinch when prying the tire on to the bead. Looks like he is using window cleaner spray to assist with prying the time on the rim. I use a sponge and some dish soap. I don't have the rim saver and bead blocker. The rim saver would definitely protect the rim from pry mark scratches.

Rick

 

[bzhwindtalker]

I had a flat on my 17" rear wheel caused by the issue you described Rix, I don't know the exact pressure but it happened when digging in wet grass with the bike. I will get one of those tire locks next time !

 

[Rix]

I had a flat on my 17" rear wheel caused by the issue you described Rix, I don't know the exact pressure but it happened when digging in wet grass with the bike. I will get one of those tire locks next time !

Yah, if you want to run low pressures, bead lock is a must. Having ran the 19 and now 17 MC tires on the rear of my Bomber, I haven't had any issues with slippage, and that includes some very aggressive mud and fairly deep creek crossings cuortesy of when I met Hyena in Yosemite. I attribute the success I had with non slippage to the fact that I run 25-28 PSI in my rear tires at all times. I like keeping the PSI at 25 and up. On my 19 MC rim, I bent it center punching a rock. Of course the tire didn't flat nor did I pinch the tube, but now I got a flat spot on an otherwise round rim. That was cause I was running at 20 PSI. Still, the tire didn't slip on the rim that time either.

Rick

 

[johnrobholmes]

Great thread Greg! I've got a lot of info on building of the wheels and little time to share it unfortunately. Subscribed for later fullfillment :wink:


19s seem to be the popular choice at the moment, especially for front wheels. A lot of guys seem to like 17 rear 19 front as well, keeps the pedals up and torque high.