The Unofficial 'CroMotor' Owners Tech-Tips Thread

zombiess said:
John in CR said:
You guys and your wheels that need truing all the time crack me up. This motor needs motorcycle spokes, and no, 14ga isn't going to cut it.

It's probably a lot easier for you to get stuff done in Costa Rica due to less litigation problems, some shops here just simple won't touch some things because they are terrified of being sued.

This shop also has as sign on the door that states they absolutely will do no work on any motorized vehicle... guess I'm the exception since the head guy there likes nutty stuff :)

Motorcycle spokes would be nice but I haven't found a shop in town to build one yet and no bike shop will touch a motorcycle spoke that I've talked to. I'll post up if I break any spokes or have any issues, but I trust the guy doing my build. He said there is more that goes into a wheel build than just the gauge of the spokes. My other 20" wheel with the 2806 is doing fine for about 200 miles so far, haven't even had to tighten the spokes up yet. Unfortunately my cheap ass when with a crap rim at the time without thinking and I regret it. The wheel is perfectly round but has a small high spot (I noticed due to using linear pulls on it) and the shop that built it said they did the best they could (not the current shop I'm using). I bet the guy who is doing my current build could fix it but I'm not gonna fix what isn't broken since it's a non issue for me.

How many people on here have posted about breaking crappy Chinese spokes? Hell, my first wheel I ordered from ebikes.ca came with a freaking flat spot and out of round and the package was in perfect condition. I have several of those Chinese spokes that came out of it and they are crap, no where near the 14 gauge spokes I'm using now which are much stronger.

How many others here are putting one of these motors in a 20" bicycle wheel or 16" moped wheel besides me?

He did mention that if I go to a larger wheel than a 20" I should probably go to at least an 8 gauge, the problem with this motor is the spoke holes are so large.

****EDIT****
Just found a shop, for 36 custom length 8 gauge spokes, wheel and building it would cost me $250-300 depending on the wheel. If I put another one of these motors in a larger wheel I'll probably go this route.
Do they have a website?
 
Keep in mind, if you run bigger spokes than your rim is capable of stretching/yielding, then you're going to always have a basket case wheel that needs regular attention and tuning etc.


So, if you've got a motorcycle rim that can handle a thousand pounds for each spoke without ripping the nipples out or taco'ing itself, then by all means run big fat spokes.

If you have a bicycle rim, and you run spokes that need a thousand pounds of tension each, but your rim can only support 100lbs of tension before the nipple rips out of it, then you're asking for a basket-case wheel to run any spokes larger than what your rim can allow to be properly tensioned.
 
I think I will lace it with 12 gauge and a DX32 from jrh. Maybe not as solid as a motorcycle wheel, but for my needs it should be good.
 
liveforphysics said:
Keep in mind, if you run bigger spokes than your rim is capable of stretching/yielding, then you're going to always have a basket case wheel that needs regular attention and tuning etc.


So, if you've got a motorcycle rim that can handle a thousand pounds for each spoke without ripping the nipples out or taco'ing itself, then by all means run big fat spokes.

If you have a bicycle rim, and you run spokes that need a thousand pounds of tension each, but your rim can only support 100lbs of tension before the nipple rips out of it, then you're asking for a basket-case wheel to run any spokes larger than what your rim can allow to be properly tensioned.

Now that is something I didn't think about. I saw some 16" motorcycle wheels and I really didn't want to go to something that heavy. Makes me feel even better going the route I am. Probably best to not go much over a 12 gauge for a bicycle wheel unless it's a killer super duty wheel.
 
If weight's such a great concern, then run a road bike spokes, rim, and tire. :mrgreen: You have a motor now, a high power one at that. I'm sure it's an emoto/emoped rotor, so install a proper wheel. The difference between a heavy duty bike wheel and a roadie wheel is the same as the difference between a moto wheel and a heavy duty bike wheel. Would you run a lawn tractor tire on your car if it would fit?
 
With a moto wheel and moto tire, What are the different options or combinations in terms of diameter, width, ...etc. to achieve about 24 inch total??? I know nothing about moto rims.
 
fractal said:
With a moto wheel and moto tire, What are the different options or combinations in terms of diameter, width, ...etc. to achieve about 24 inch total??? I know nothing about moto rims.

I'm pretty sure that a 19" moto rim comes out at about the same size as a 24" bicycle rim. That what i'm going to use, moto rim, big spokes.

Gow.
 
fractal said:
With a moto wheel and moto tire, What are the different options or combinations in terms of diameter, width, ...etc. to achieve about 24 inch total??? I know nothing about moto rims.

I was really suprised by the 9.5kv rating, I expected 13-14kv based on the italian guy's posted 84mph. I just talked with JRH, and bumped my rim on this build up from 17" (@22" OD) to 19" (24" OD), which only gives me about 8% more speed. The actual diameter of the wheel depends on the height, which depends on the Aspect and Series for that tire, but 24" is a good rough estimate. I hope my last-minute change doesn't delay my build too much, JRH has been really good about it.

I'm probably going to start with my Methods controller before moving up to the Kelly, here is the workup I used to compare 17"/19" performance at 100v:

24" 22" Diameter
75.36 69.08 Circumferance, inches
6.28 5.76 Circumferance, feet
840.76 917.20 revolutions/mile
9.50 9.50 KV of CroMotor
100.00 100.00 Voltage
950.00 950.00 RPM Unloaded
67.80 62.15 MPH unloaded
760.00 760.00 RPM Loaded (80%)
54.24 49.72 MPH loaded

John sent me a link with some 19" tires http://www.treatland.tv/SearchResults.asp?Search=19+tire and I went with the DeeStone 2.5". Once I have the build stabilized, and I can examine the tires first hand, I may go up to a bigger diameter - I have about 3.5" where I expect the sidewalls to land, too bad the aspect is not the widest part of the tire. OTOH, a lot of these tires are HEAVY. I had a poke about on Amazon looking at 19" tires, below is what I came up with, sorted by Aspect then series. When I moved onto Motorcycle Superstore, I didn't find any new options. I like the bridgestone spitfire and TW39 a lot...

Name-----------cost---------Aspect-------------series-------------weight-----------url
Dunlop K70 Front Tire - 3.50-19/-- 72.99 80 100 x http://www.amazon.com/Dunlop-K70-Front-Tire-3-50-19/dp/B0043YB7MY/ref=sr_1_6?s=automotive&ie=UTF8&qid=1321987680&sr=1-6
Bridgestone Spitfire S11 Sport Touring Front Tire - 90/90-19 146897 58.88 90 90 9.8 http://www.amazon.com/Bridgestone-Spitfire-Sport-Touring-Front/dp/B0012TUT5E/ref=sr_1_192?s=automotive&ie=UTF8&qid=1321988733&sr=1-192
Bridgestone TW39 Trail Wing Dual Sport Front Tire - 90/100-19/-- 61.99 90 100 x http://www.amazon.com/Bridgestone-TW39-Trail-Sport-Front/dp/B000I5ETC2/ref=sr_1_256?s=automotive&ie=UTF8&qid=1321988975&sr=1-256
Shinko 244 Dual Sport Front - Rear Tire - 2.75-19/-- 25.99 100 60 x http://www.amazon.com/Shinko-244-Dual-Sport-Front/dp/B0043YF4G4/ref=sr_1_42?s=automotive&ie=UTF8&qid=1321988120&sr=1-42
Shinko SR241 Front/Rear Dual Sport Tire - 2.75-19/-- 30.99 100 60 8.9 http://www.amazon.com/Shinko-SR241-Front-Rear-Sport/dp/B001PS2QQC/ref=sr_1_68?s=automotive&ie=UTF8&qid=1321988202&sr=1-68
IRC GP-1 Dual Sport Rear Tire - 2.75-19/-- 47.99 100 60 x http://www.amazon.com/gp/product/B001CD8ZCO/ref=noref?ie=UTF8&s=automotive&psc=1
Dunlop MX71 Geomax Hard Terrain Front Tire - 70/100-19/-- 38.99 100 70 x http://www.amazon.com/Dunlop-MX71-Geomax-Terrain-Front/dp/B0052QVOLQ/ref=sr_1_109?s=automotive&ie=UTF8&qid=1321988340&sr=1-109
Shinko SR241 Front/Rear Dual Sport Tire - 3.50-19/-- 47.99 100 80 2.1 http://www.amazon.com/Shinko-SR241-Front-Rear-Sport/dp/B0032W1ZNO/ref=sr_1_147?s=automotive&ie=UTF8&qid=1321988583&sr=1-147
Shinko 712 Front Tire - 100/90H-19/-- 44.99 100 90 13.6 http://www.amazon.com/Shinko-712-Front-Tire-90H-19/dp/B001CD5E8M/ref=sr_1_126?s=automotive&ie=UTF8&qid=1321988391&sr=1-126
Shinko SR733F Front Cruiser Tire - 100/90-19 57H/-- 53.99 100 90 13.6 http://www.amazon.com/Shinko-SR733F-Front-Cruiser-Tire/dp/B001PS0P38/ref=sr_1_191?s=automotive&ie=UTF8&qid=1321988733&sr=1-191
Kenda K671 Cruiser ST Front Tire - 100/90-19 046711905C1 57.76 100 90 x
Shinko SR241 Series Dual Sport Motorcycle Tires w/ Free B&F Heart Sticker - 3.50-19 / Front/Rear 60.93 100 100 x http://www.amazon.com/Shinko-SR241-Sport-Motorcycle-Sticker/dp/B00524ULF8/ref=sr_1_239?s=automotive&ie=UTF8&qid=1321988897&sr=1-239
Shinko 705 Series Dual Sport Rear Tire - 110/80-19/-- 48.99 110 80 15.1 http://www.amazon.com/Shinko-Dual-Sport-Rear-Tire/dp/B0020DY1NC/ref=sr_1_152?s=automotive&ie=UTF8&qid=1321988583&sr=1-152
Kenda K657 Challenger Cruiser Motorcycle Tires - 110/90-19, Load/Speed: 68H - Front 64.36 110 90 36 http://www.amazon.com/Kenda-Challenger-Cruiser-Motorcycle-Tires/dp/B0056E3EL2
 
excellent info!!! what gauge spokes will you have?
 
fractal said:
excellent info!!! what gauge spokes will you have?

He said he needed to back it down to 12ga for that diameter, but with my suspension it should be OK - 200mm travel forks and 229mm rear.

-JD
 
oatnet said:
fractal said:
excellent info!!! what gauge spokes will you have?

He said he needed to back it down to 12ga for that diameter, but with my suspension it should be OK - 200mm travel forks and 229mm rear.

-JD

the width of your rims would something like 1.85 (47mm)?
 
Gow864 said:
fractal said:
With a moto wheel and moto tire, What are the different options or combinations in terms of diameter, width, ...etc. to achieve about 24 inch total??? I know nothing about moto rims.

I'm pretty sure that a 19" moto rim comes out at about the same size as a 24" bicycle rim. That what i'm going to use, moto rim, big spokes.

Gow.

Too much depends on the tire to make broad generalizations. eg Two of my hubbies have 14" moto rims, and one has a tire giving it a 19" diameter, with the other 20.5". I've got a 16" rim + tire that also ends up a 20.5" diameter. I have both 17" and 18" rims with tires that each end up as 24" diameter wheels.
 
John in CR said:
Gow864 said:
fractal said:
With a moto wheel and moto tire, What are the different options or combinations in terms of diameter, width, ...etc. to achieve about 24 inch total??? I know nothing about moto rims.

I'm pretty sure that a 19" moto rim comes out at about the same size as a 24" bicycle rim. That what i'm going to use, moto rim, big spokes.

Gow.

Too much depends on the tire to make broad generalizations. eg Two of my hubbies have 14" moto rims, and one has a tire giving it a 19" diameter, with the other 20.5". I've got a 16" rim + tire that also ends up a 20.5" diameter. I have both 17" and 18" rims with tires that each end up as 24" diameter wheels.

I wasn't being general. The 19" moto rims I have measure within 1mm of the 24" bicycle rims I have. Clearly tires will change the overall diameter.
 
Sorry, not paying close enough attention and missed that you were talking about just the rim. Some guys are using moto tires on bike rims, but I don't know about vice versa. I'd be leary of mixing and matching, since bike tires and moto tires lock in the rim very differently. You don't want to do something in an effort to make a stronger safer wheel only to have the tire roll right off the side of the rim in a turn.
 
John in CR said:
Sorry, not paying close enough attention and missed that you were talking about just the rim. Some guys are using moto tires on bike rims, but I don't know about vice versa. I'd be leary of mixing and matching, since bike tires and moto tires lock in the rim very differently. You don't want to do something in an effort to make a stronger safer wheel only to have the tire roll right off the side of the rim in a turn.

Another good caution point. I'm using Perelli ML75 16" scooter tires on 20" BMX wheels. The motorcycle gear shop I bought them from said they didn't see it being any issue since a 20" BMX wheel is actually 16" and has a bead to seat. I'm also running the thick scooter tubes and others on here have run the same tire with good results. Should end up with an OD of 21 inches.
 
John in CR said:
Sorry, not paying close enough attention and missed that you were talking about just the rim. Some guys are using moto tires on bike rims, but I don't know about vice versa. I'd be leary of mixing and matching, since bike tires and moto tires lock in the rim very differently. You don't want to do something in an effort to make a stronger safer wheel only to have the tire roll right off the side of the rim in a turn.


Yeah I'm not sure about tyres yet. I've still got some research to do, but it will be moto tyres not bicycle. It seems crazy to me to trust bicycle parts for a motor of this power. I've got a 5305 in a 26" with maxxis crossmark tyres, I don't like how it feels in fast turns, really it does feel like the tyres are going to roll right off the rim.

Gow.
 
Gow i dont think a tire ll roll out a rim if it has a good fit.

Have you tried something like this?
http://www.choppersus.com/store/product/690/Rim-Only-26-x-2.5-Black/
 
A choppersUS rim would fold at 20mph. They aren't good for anything structural, other than slow pedal bikes and snow bikes.
 
I had the impression that they would hold some load... i mean who would want to pedal a chopperbike with 4" tires if you can use a hub motor. hehe
 
They will hold a load if you aren't hitting bumps. First bump to hit the seam at 20mph will turn it into pacman though. The old ones were bad enough you could see light through the seam!
 
A lot of talk about rims and spokes. At the power some of you are planning, don't forget bike tires could be a one time use item.

Or you could ride em till they shred on ya, at 50 mph.
 
dogman said:
A lot of talk about rims and spokes. At the power some of you are planning, don't forget bike tires could be a one time use item.

Or you could ride em till they shred on ya, at 50 mph.

Good point! I was going to lace mine on a DX32 12 guauge spokes with a Hookworm tire. I'm starting to think that its not such a good idea. I will probably end up lacing with moped wheels and tires. I'm researching a lot on different combinations trying to find out what would fit. Ideally, I would like an overall diameter of 24 inches. I like the Pirelli ML 75 although I cant find the overall diameter of these tires, they come in 16 and 17 inches with a width of 2.5 wich is perfect. http://www.pirelli.com/tyre/ww/en/motorcycle/sheet/ml_75.html?url=?subtype=scooter&use=1
 
johnrobholmes said:
The ML75 is about at 22" high when 17" and 2.5 width. One of my favorite tires!

How would this look on a DH bike (front and rear)? Is the diameter too small? I guess it would bring a lot of stability to the bike bcause of the lower COG.
 
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