20 inch BMX rims with motorcycle tires

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AussieJester
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Re: 20 inch BMX rims with motorcycle tires

Post by AussieJester » Jul 26, 2010 6:30 pm

If you fellas are after bicycle rims rather than moped rims, look in the uni cycle/trials direction they use 'solid' 20in rims
and beefy tires-->
uni_cycle_20in.JPG
uni_cycle_20in.JPG (63.14 KiB) Viewed 8891 times
KiM

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Re: 20 inch BMX rims with motorcycle tires

Post by Kingfish » Jul 26, 2010 11:05 pm

Kenkad, I see what you mean about 20-inch motorcycle tires. More below:

Aussie, thanks for the tip; I looked for Unicycle rims. It's slim pickings but I am still not yet finished with the assay. Where'd you get that pic my friend?


Addendum:
This afternoon at the end of my ride I stopped over at the local Harley-Davidson bike shop and perused their tire selection but they were too large to be of use. So I coasted on down the hill to the Bellevue Kawasaki dealership and the folks there were helpful in offering manufacturer tips: IRC, Dunlop, Shinko, and Cheng Shin.

With all this research, I have yet to settle; getting closer though, learning a lot, but not yet satisfied that I have canvassed all the possibilities. One sad note is that there does not appear to be 20-inch motorcycle tires that can mount onto a 24-inch bicycle rim in the same manner that a 16-inch motorcycle tire can be mounted on a 20-inch bicycle rim; the motorcycle sizes skip 20" altogether. Likewise, there does not appear to be a market for 22-inch bicycle rims which would seriously open up many more motorcycle tire options in the 18" range. :cry:

I fear a conspiracy! :wink:

Here's the dirt I dug up this evening:

Tire Reference:
There is a lot here, but it is difficult to find exactly the correct match. Part of the problem is that while Dunlop provides the crucial rim specifications, many of the rest do not and that has been feeling uncertain. I am pretty much drilling down on a 80/90-16 maximum spec for the tire which will still fit in my rear suspension: about 23" tall, and yet have plenty of PHAT at 3.15" :twisted: Pirelli, Deli, and Cycles U.S. are neck and neck on selection.

http://www.pirellityre.com Pirelli Tyre
http://www.irc-tire.com/mce/ IRC Motorcycle
http://www.dunlopmotorcycle.com Dunlop Tires
http://www.shinkotireusa.com Shinko Tires
http://www.delitire.com/ Deli Tire
http://www.choppersus.com/store/category/3/16/Tires/ Cycles U.S.

Rims Reference:
I focused on wide heavy duty or downhill (DH) 20-inch and 24-inch bicycle rims.

http://www.alienationbmx.com/ Alienation - lots of choices
http://www.bombshellparts.com/shop/products.php?cat=19 Bomb Shell Parts BMX Revolution 20"/24" x 1.75" wide
http://www.surlybikes.com/parts/large_marge/ Surly Large Marge 24"/26" x 65mm/2.56" wide
http://www.choppersus.com/store/categor ... Rims-Only/ Cycles U.S. - big 3" phatties here

Neat stuff:
http://www.cb450stuff.com/tires/ nifty Tire Conversion Chart
http://www.sheldonbrown.com/rim-sizing.html Measuring Bicycle Rim Sizes

After doing the touchy-feely thang at the Kawasaki dealer I was pretty impressed that should I go this route I doubt I will have many flats, and I would expect the tires to wear like iron. I wonder though what effect it will have on power consumption; start-stops would likely become slower, though cruising should be smoother.

One thing is certain with motorcycle tires: The problems I have been having with high-speed wobble due to tire (not rim) out-of-round should abate.

OK, that's me for tonight; I will hit this again tomorrow.
Thanks for the feedback and support, KF

[moderator edit to sweep corruptions = •€™]
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
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The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: 20 inch BMX rims with motorcycle tires

Post by Thud » Jul 26, 2010 11:53 pm

Here is a spot for wide formate rims:
http://www.unicycle.com/unicycle-hardwa ... nch-trials

Trials guy's have a great tire compound (I have contemplated shaving the creepycrawlers for road racing)
http://www.unicycle.com/unicycle-hardwa ... res-trials
get some......

All information & advice provided by Thud are "Open Source" & free for personal use & distribution under the following agreement linked below.
http://creativecommons.org/licenses/by-nc-nd/3.0/

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Re: 20 inch BMX rims with motorcycle tires

Post by Kingfish » Jul 27, 2010 1:21 pm

Thud, thanks for the link! Those Nimbus rims look awesome!

Addendum:
I found a few more interesting links that do a nice job of explaining the issues.

http://en.wikipedia.org/wiki/Motorcycle_tyre Motocycle Tyres explained
http://en.wikipedia.org/wiki/Tire_code Tire Code explained
http://en.wikipedia.org/wiki/Bicycle_wheel Bicycle Wheel (good all around reference)
http://en.wikipedia.org/wiki/Bicycle_performance Bicycle Performance
http://www.dunlopmotorcycle.com/infocenter.asp Dunlop's Info Center (a mega-FAQ!)

Interestingly the Bike Perf link suggests that wheel-to-road resistance goes higher with smaller wheels, and yet says that a smaller wheel has reduced rotational inertia thereby making it easier to accelerate. I sense dichotomy in motion. :wink: Let's not worry.

In reviewing the copious selection of motorcycle tires I decided to level the playing field a bit and create a conversion chart to make this selection process go a little faster; though imperfect - hopefully you will find it useful.

Image
Motorcycle Tire to BMX Tire Conversion Chart

Rim Width:
There is one other sticky wicket to consider and that is the width of the tire verses the width of the rim. Again I leaned on the Dunlop site having one of the more informative catalogs of data, and in the process of mining I developed a crude but effective formula that gets us in the ballpark of their specifications most of the time.
  • Rim Width / Tire Width * 0.6
Disclaimer: Always check with the manufacturer for the proper rim size. Specialty tires with peculiar sidewalls will not follow a standard. :roll:

The other factors to consider are tire pressure, durometer/tire compounds, tread, radial/bias, etc. But I shall consider these issues to be out of scope with the thread; we simply wish to pair up a BMX rim with a suitable Motorcycle tire.

Narrowing:
After looking at the Chart, I will need something like a 70-to-75mm width, with an AR of 100-120, and a nominal rim width of 1.8-inch / 46mm. (On P1, the rear suspension framework is limited to just under 3-inches wide at 26-inches diameter, however the front DH fork can accept wider).

That's all the dope I have at this point; it's a fun study 8)
~KF
Last edited by Kingfish on Mar 04, 2011 1:46 pm, edited 1 time in total.
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: 20 inch BMX rims with motorcycle tires

Post by Kingfish » Jul 27, 2010 4:01 pm

Addendum:
This is the last addendum for a while; I seriously need to sleep on this :)
I'm trying to make a list but now I have too many to choose from. The average price is running about $50.

New Links:
http://www.cameltire.com Camel Tires
http://www.mitas.cz Mitas Motorcycle Tires
http://www.veerubber.co.th Vee Rubber (a boat load of choices; awesome F/R matched sets)

Candidates:
Original Criteria is that they must be DOT-approved, however I can't say that this holds true for Camel, Mitas, and Vee.

IRC NF6 (Front) 3.00-16 4PR
IRC NR21 (Rear) 3.00-16 4PR
Shinko SR714 80/80-16
Pirelli ML75 2-3/4 – 16 M/C 46J REINF
Deli Thunder SB-108 80/80-16
Deli Venom SB-109 70/90-16 (tube and tubeless)
Deli Venom SB-109 80/90-16 (tube and tubeless)
Camel CM132 70/90-16
Camel CM2 70/90-16
Camel CM521 80/100-16 (edge case)
Mitas M-06 / 80/90-16 (23/4-16)
Vee Rubber VRM-086, VRM-097, VRM-100, VRM-355 & -356 (there's a lot here to choose from)

Corrections:
http://www.choppersus.com/store/category/3/16/Tires/ Cycles U.S.
I was confused: These are bicycle tires.

Gosh, you know if someone were bright enough to make a wide 21" rim they could sure swoop up a lot of business, but I'm not tellin' :wink: <hint, nudge>

Enjoy, KF
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: 20 inch BMX rims with motorcycle tires

Post by Kingfish » Jul 28, 2010 2:32 pm

Yet another Addendum:

New Tire Link:
http://www.conti-online.com Continental Tires

Expanding Search to Motorcycle Rims:
As an alternative, decided to open myself up to more options as I began to have some serious concerns about having enough choice between rims and tires. The gating factors being: Diameter, Width, Aspect Ratio, Hole Count, Product Type/Usage, Quality of Workmanship, Reputation, Price, and Availability. Failure to meet criteria of any one of these attributes could sink a potential match. Here are some motorcycle rim manufacturers/suppliers that I reviewed:

http://www.mooseracing.com Moose Racing Rims (this official site is lame, so Google a supplier)
http://www.rkexcelamerica.com/mx_excel_rims.html Excel Rims (so is this one; other retailers do a better job)
http://www.prowheelracing.com/products/mx/rims Pro Wheel Racing Rims
http://www.buchananspokes.net/categorie ... l_rims.asp Buchanan's Rims; supplier of several types - including bare, unpunched rims for custom orders. Spendy!

Suppliers:
There are a lot of sites out there to help us find the proper tires and rims. The problem that I had with many of them is that they want us to provide the make, model, and year of the motorcycle/scooter before offering a selection which in my mind is ass-backwards if I already know the diameter, width, hole-count, etc. Google, TheFind, Amazon, eBay, and their ilk were of limited value, and often frustrating as a utility when attempting to craft a proper search string. One gem though stood out:

:idea: http://www.tyres-pneus-online.co.uk Pneus-Online finds the tyres we need in the UK! This gets the Most-Useful Website award: Big time saver, a great tool for comparison, with up to date reports, and best price listing. I found this site at like 9PM last night and I am still on it this morning. *** :D

Picking a Favorite:
I have decided upon the Continental Conti-Go! 2.75-18 M/C 48P TT (70-457) tyre mounted on an Excel Takasago 18x1.85 (457-47) 36h Rim. I will leave the front and rear to be the same since I am crafting a 2WD bike.

I cannot begin to explain the challenge here in attempting to match a tyre and rim, it was a struggle until I found the very last link Pneus-Online***. :? However by then I had pretty much figured out the math and formulas for converting the sizes on the fly and I was in the final stages of sorting out the suppliers.

Why Continental:
I have close to 9 months experience running the Continental Contact Reflex both F and R on my current e-build; they are adequate and give me little trouble. That ended up weighing in during in the process of removing unknowns from the calculus. There are some great manufacturers out there, but most of what they offer is difficult to source, and if it is found, pray it doesn't cost your next-born child. The Continental Conti-Go appears to be a decent modern all-weather road tire, though I will need to pick something else for snow or off-road.

Image
Continental Conti-Go! New City tyre for light motor bikes.

Why the 18-inch Wheel Size:
The Excel 18-inch/457mm rim when combined with the 2.75-inch/70mm wide tire (and similar aspect ratio) should not exceed a total diameter of 24-inch/610mm - thus meeting the criteria to drop the overall bike height by at least an inch/25mm. Presently I have the Mavic EX 729 Disc Rim with the Hookworms pegged for install - effectively setting the wheel diameter to 27.5-inch/700mm and exacerbating the already tall-for-a-medium-sized frame (it's a Felt-Compulsion 1). Then I added Marzocchi 888 RC3 EVO DH forks which will raise the height even more.

As for why I picked 18-inch over 17-inch or 16-inch, I just thought that it might look a little odd if the tires were too small. The other problem is that the rear suspension framework is too narrow to load a 3-inch-wide tire; even if the diameter was smaller there's just not enough room. Once I gave up on the 3-inch-wide tire idea, another struggle ensued to find any tire narrow-enough to fit.

The last factor was based on selection and availability: There simply is not enough choice, and that can be easily proven by using the Pneus-Online*** website. U.S Domestic supplies are limited: I had to go look across the pond to Europe before I finally found the tyre.

The 1.85-inch/70mm-wide x 18-inch/457mm diameter Excel motorcross competition rim, being machined from lightweight 7-series aluminum, is stronger than any bicycle rim, and as a 22-inch equivalent-bike size - it falls neatly between the 20-inch and 24-inch inch gap. Trivia: This size also called an ISO 457mm standard, 22x2.125, and 22x1.75, and impossible to reliably find in bike-size.

Image
Excel Takasago Signature Series Rims, available in several colors.

Caveats:
  • There is lots of poop about the Excel rims needing their own spoke kits; another work item.
  • Need to source a tube and rim-liner as well.
  • Then figure out how to get the tires balanced.
No doubt it will be a burly-strong setup though when complete! 8)

<pause to graze, looking for something to nibble on

Conclusions:
Q: Rhetorically, can we find and mount a 16-inch/406mm motorbike/scooter tire onto a 20-inch BMX wheel?
A: Yes, certainly. For example, mounting the Continental Conti-Go! 2.75-16 on say a Bombshell BMX Revolution Pro 1.75-inch Rim would create a wheel that drops a standard MTB frame by more than 2 inches; a viable solution, it's lighter, less expensive, more bike-like, and exceedingly meets the criteria.

My choices however are constrained by many factors, beginning with the narrowness of the frame. Picking a slightly larger rim expands the selection, raises the load characteristics and the top speed, and I end up getting a more durable pairing.

In the end, I guess one could say if you look hard enough, you will likely find what you're seeking, or...maybe it will find you. :)

Trouble always finds me; no need to look that.

Thoughts? KF
Last edited by Kingfish on Mar 04, 2011 1:48 pm, edited 1 time in total.
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: 20 inch BMX rims with motorcycle tires

Post by johnrobholmes » Jul 28, 2010 5:26 pm

It is going to be a heavy setup with the 18s. I choose 16s or 17s for my "hybrid" wheels. Even then, they are much heavier than bicycle parts. You will likely add about 8 pounds of rotating mass, depending on the tire you choose at 18". Have you added up the penalty yet?
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Re: 20 inch BMX rims with motorcycle tires

Post by Kingfish » Jul 29, 2010 12:16 pm

johnrobholmes wrote:It is going to be a heavy setup with the 18s. I choose 16s or 17s for my "hybrid" wheels. Even then, they are much heavier than bicycle parts. You will likely add about 8 pounds of rotating mass, depending on the tire you choose at 18". Have you added up the penalty yet?
That is a good question. Let's take a look.

Mass of Tires:
Unfortunately I haven't found a single motorcycle tire manufacturer that posts the weight of their products. However, if we calculate the difference between 18-inch tire and 16-inch tire:
  • 18/16 = 1.125, or 1/8th more mass than a 16-inch tire
Certainly not very welcoming for city/commuting with lots of starts and stops, however if used in touring we would see more efficiency.

Motorcycle/Scooter Tires:
  • Continental ContiGo Tyre: TBD. I may make a run down to the Kawasaki dealership and throw a tire on the scale just to see what we are dealing with.
Heavy Bike Tires:
For point of conversation... :)
  • 26” Hookworm tire: 26x2.50 = 1125g
    26” Fat Frank tire: 26x2.50 = 940g
Motorcycle Rims - Excel:
I placed a call to the U.S. Distributor; curious, the sales rep went out to the warehouse weighed the items on the UPS shipping scale; I have no idea if this includes packaging.
  • Rim Weight of Excel 18x1.85 (32h): 3.8 lbs / 1724g
    Spoke Kit Weight: 1.2 lbs / 544g
Compared to Bicycle, 8-9 gauge spokes are about 1.5 times the weight of 12 gauge spokes. However, the length of spoke for an 18-inch rim is less than the length for a 22-inch (26-inch bicycle) rim by 2/3s (with a 9C hub) because the spoke is now effectively 2-inches shorter. Doing the math on a 12-gauge spoke for a 26-inch bike rim verses a 9-gauge spoke for a motorcycle 18-inch rim, the calculation is:
  • (1.5) * (2/3) = 1, or in other words ~ it's a wash.
I can confirm this with my shipment of Sapim spokes used on the Mavic-9C mating which weighted just over 2 pounds for 80 spokes & alloy nipples. Worst case; we pick up 0.3 pounds between two rims. Alloy nipples will be lighter than Stainless and Carbon Steel. Going to a 16-inch motorcycle rim would naturally reduce the spoke weight further.

Bike Rims:
  • Weight of Bombshell: TBD. Distributor won't answer phones; email sent.
    Weight of 26-inch Mavic EX 729 Disc Rim: 1.49 lbs/675g ~ 40% of the Excel mass.
Accessories:
  • Weight of the Rim-Strips: Negligible.
    Weight of the Tube: TBD.
I run the Specialized Desert Protection Tube with my bike tires; they are more than twice the weight of a conventional tube but well worth the money: On my last long trek (to California) I picked up a nasty piece of road-wire-trash on the side of a very busy highway. I removed the wire, rolled the bike backward to cover the hole, and in less than 30 seconds the leak had stopped almost entirely (the tube was replaced at the next destination). This heavy tube though should not be required with a motorcycle tire.

Other weight comments:
Last week when I picked up my newly mated Mavic EX 729 Disc Rim & 9C hub the repair guy at REI, they thought they weighed 30 lbs and suggested that I make “two trips" to carry the wheels out. I told him that he was mistaken, that those hubs don't weigh more than 14 pounds each, so...he weighed them and was completely floored: I guess the weight is all concentrated that's what threw me off. No worries man. I carried the lot out in one load

BTW, one other reason for not selecting 17-inch rims is that the only size I could source in aluminum with 36h were 1.4-inch or 2.15-inch wide; both a little too far out of spec. However there are steel rims available in the 17x1.6 size (17 X 1.6 aluminum 36H rims are now available in 2014).

John, what did you use for a 17-inch rim?

Accepting the Load:
Generally speaking, we are already living with a weight penalty with an EV over that of a pure human-powered transport. My ebikes in particular run heavier because I am interested on long-range which translate into larger battery capacity, the weight of which is countered by using LiPo. For commuting, the batts weigh 12 lbs/5.4kg, and for long-distance they were 46 lbs/21kg. I also broke 5 spokes on that trip with the non-hub tire (the same one with the received the flat)
  • When we are talking about mounting motorcycle or scooter tires onto a bike, regardless of which rim is chosen, we are blurring the distinction even more between bike, moped, and light-motorcycle.
I accept that weight burden because I seriously desire a more rugged tire system that is able to withstand the trash we are forced to drive through on the margins of these city streets and highways. I am also slowly migrating to more stout platforms for testing, and I can easily imagine my next frame (P2?) will be closer to motorcycle than bike; might as well start planning now to have burly wheels :wink:

~KF
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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Re: 20 inch BMX rims with motorcycle tires

Post by Kingfish » Jul 31, 2010 6:06 pm

Small note:
I am having trouble sourcing my dream tire. The Michelin Sporty appears as a good alternative in some interesting sizes and looks quite Motard, though it too is difficult to find in the USA. Through this hunt I kept a record of interesting sites as I was looking for that great tire or buy... and this list became very lengthy :idea:

With permission I constructed a new thread and posted it here:
Rims and Tires Reference

Hopefully it will find value for others as well :)
Cheers, KF
* My 2WD Garden Wall
* Kinaye MotorSports
* Primary ride: 2WD Disc 9C 2806-equiv / Dual Lyen 12FET / 20S7P LiPo.
* Epics: Going to California: 2011 8)
* 50-mph, 101, 10k-Club. 12,527 miles-to-date, 7037 as 2WD.

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed.
The hands acquire shakes, the shakes become a warning.
It is by caffeine alone I set my mind in motion.

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