ridethelightning
1 MW
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- Jul 21, 2013
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- 2,010
+1 iv been looking for fenders like this too.ecycler said:
is that a 17" wheel?
19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)
- Thread starter GCinDC
- Start date
is that a 17" wheel?
FluxZoom
100 W
Some folks say to use high spoke tension with thin spokes on a bicycle rim, but nothing goes along with this on motorcycle rims. Everything I read, the tools some use to tighten nipples for motorcycle wheels seems to point to much lower degrees of spoke tension than I imagined they would use. Say using 12-14 gauge spokes with a hub motor and a motorcycle rim, where to the tension limits exist? I am sure this varies wildly from rim to rim.
Powervelocity.com
100 kW
I've used 12g and 9g spokes on the MC rims. What I found is, you really need to have very good and tight threads on the nipples and spokes with thinner gauge spokes or you will have problems properly truing the wheel. Moto rims are stronger and need more tension to fix the imperfections than bicycle rims. If nipples are not tight enough on the spokes, threads will break. This is not much of an issue on thicker gauge spokes even with some play in the thread.
Chalo
100 TW
FluxZoom said:
Maybe the resulting unreliable wheels with self-unscrewing spokes have helped give rise to the prevalence of heavier, less repairable but more reliable cast aluminum wheels on street bikes.
Motorcycle spoke wrenches have much longer lever arms than bicycle spoke wrenches, which suggests higher torques and tensions. I don't know what customary practice is with motorcycles, though. When I build with MC spokes and rims, I do them up tighter than bicycle wheels based on what I've learned from bicycle wheels.
FluxZoom
100 W
Chalo said:
Awesome, thanks for the reply.
Tighter to what level of tension? I was thinking I'd just aim for whatever the maximum a spoke tensiometer would read and see how it went initially, but maybe someone here has insight. I am sure there are scooter/motorcycle rims that can handle brutal amounts of tension, enough to stretch even a 10 gauge spoke.
I've read your writing more than once that bicycle spokes need to be super tight and that using thicker than 14 gauge spokes is foolish because you can't add enough tension to something like a 12 gauge spoke (which seems typical as stock on a hub motor) with a bicycle rim. But I've never found anything that specifically says how much tension would stretch even a 13 gauge spoke. Maybe there is something like a book that really spells this out well in detail that I can't find?
Rix
100 TW
Chalo said:
No doubt Chalo you are a better wheel builder than I, hell I can't even lace 3X, but radial and 1X I am pretty darn good at. Between motorcycles and Ebikes, I have laced well over a dozen rims to various hubs. The consistent denominator I have seen is if spokes aren't tight with good tension, the wheel will go to shit. Especially true on 50+ HP motoX bikes being hammered on the pipe. On my 5 KW Fighter, I am currently running 8g spokes with an 19x1.4 rim. Needless to say in the last 2300+ miles of On road/Off road, I have only had to true the rear wheel once, and that was the first couple of rides after I laced up the rim. With tension and this big of a spoke, after the things take a set, they stay there. I know this is way over kill for a 7HP Ebike, but its sure sano. I have also found that 10G spokes perform the same way for our ebike applications.
Guys has anybody built up a cromotor with 10 gauge spokes?
What did you use to open up the holes in the hub? I have 11 gauge on my bike but Holmes don't have the 11/12gauge in stock only 10. I'm a bit nervous about this mod on my lads new cro, will it weaken the hub .. :?
What did you use to open up the holes in the hub? I have 11 gauge on my bike but Holmes don't have the 11/12gauge in stock only 10. I'm a bit nervous about this mod on my lads new cro, will it weaken the hub .. :?
Powervelocity.com
100 kW
A drill worked well in my case.
Jonboy said:
@powervelocity I'm guessing a 3.2 then ream or needle file if a bit tight.. Any probs after some abuse?
brum.. No prob "you know" how much of a fuss I'm making over the 19/17 thing...
Thinking 18 too but sorting a nice spoke is tricky for that. The excel rims are fab had them on Hondas in the passed .. Anybody fancy chiming in on spoke length and a supplier for excel, I can't find an ERD and a sensible rear width at 18" with them.. I think Rix has been down this road.. I'll have to have a dig! Unless he catches this and can comment..
keep it safe!
Jon
brum.. No prob "you know" how much of a fuss I'm making over the 19/17 thing...
Thinking 18 too but sorting a nice spoke is tricky for that. The excel rims are fab had them on Hondas in the passed .. Anybody fancy chiming in on spoke length and a supplier for excel, I can't find an ERD and a sensible rear width at 18" with them.. I think Rix has been down this road.. I'll have to have a dig! Unless he catches this and can comment..
keep it safe!
Jon
macribs
10 MW
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- Jul 22, 2014
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Excel are great rims. A little pricey but great rims. Holmes hubbies got spokes for you in correct length. If you contact him he will figure out what spokes you need, and fix correct length too. I think he also has those concave washers to make things easier.
Rix
100 TW
Jonboy said:
I have drilled every one of my spoke flange holes bigger to accommodate bigger than the 2.9mm 11g standard. No problems at all.
Lurkin
100 kW
FluxZoom said:
I started with the maximum tension stipulated by the rim manufacturer, took a little off it to be on the safe side and did the drive side up to that. This may or may not be the maximum per your tensiometer - it should be based on the maximum tolerance of your parts, not your tools. You may require different tools for moto stuff as its likely to withstand higher tensions. I don't know, because I dont use it.
Need to maximise tension to build the strongest wheel possible for any given spoke, rim, hub combination - this isn't different based on moto/bike, its exactly the same physics/engineer principles applied to both.
Also maximise the other side but undo non drive side for dish.
Tension maximised, wheel strength maximised. Win.
Jonboy said:
I use 9/10 gauge spokes on my cromotor.
It is simple to enlarge the holes.
Get one of those numbered drill bit sets, like the ones from #1 to #64.
Then find the drill bit that just fits in the hole. Then go to the next # larger and enlarge all the holes. If it doesn't fit, go to the next # again. I did it this way to play it safe to keep the hole perfectly centered by enlarging it in very small increments.
10 gauge spokoes should just about fit without drilling. 9 gauge took just a small amount of enlarging the hole, I had to use 3 drill bits in the # set.
With 9 gauge the rim held up perfectly fine with lots of off roading. Drilling it larger won't harm the strength.
macribs said:
Any of these dirt bike / motorcycle rims are way too strong for our electric bikes. Excel rims are totally overkill and not necessary as you are paying for higher grade aluminum. Get the cheapest rim like prowheels.
I am still considering drilling my prowheel / holmes hobbies rims to lighten them.
ridethelightning
1 MW
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- Jul 21, 2013
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Offroader said:
you might be right there, but i have found hitting a lump in the road at speed with a hubmotor is like taking a sledge hammer to the rim...never ends well, usually with a large bent section or flatspot, and im talking about steel or aluminuim moto rims. id hate to think what a pushbike rim would look like after that.
Rix
100 TW
http://www.buchananspokes.com/categories/custom_spoke_sets.asp 9/10G swaggedJonboy said:
ccmdr
100 W
Hit a pothole on the first build ebike, it had front/rear EXAL EX-19 700c rims with 38c schwalbe marathon tyres. 30mph and a small pothole, bent the lip of the rim in 2 places allowing the tyre to move a small amount and tear a slight hole in the valve. Doesn't matter if you have wired tyres with greenguard if they slip and tear the tube 
.
Now using moto rims with 2.75 k46 moto tyres. No flats so far, even with higher speeds, glass, potholes , heavier motor and frame. Apart from the power upgrade the mental security of moto rims is by far the best upgrade imho. Using unicycle 12G spokes on CroV3, cut/threaded them due to moto rim manufacture not understanding the ERTD standard used for bicycles.
.Now using moto rims with 2.75 k46 moto tyres. No flats so far, even with higher speeds, glass, potholes , heavier motor and frame. Apart from the power upgrade the mental security of moto rims is by far the best upgrade imho. Using unicycle 12G spokes on CroV3, cut/threaded them due to moto rim manufacture not understanding the ERTD standard used for bicycles.
Jonboy said:
I personally got my spokes from buchananspokes. http://www.buchananspokes.com/categories/custom_spoke_sets.asp
About $ 95.00 for a set of 36, check the link. You will have to tell them the custom size.
These are very high quality USA made steel spokes, and the nipples are high quality brass. You will easily see the quality difference compared to cheap china spokes and for almost the same price. Highly recommended if you want quality spokes. Brass nipples are the way to go because they don't seize up like steel nipples. Their brass nipples are also small enough to fit our prowheel and holmes hobbies rims.
My 9/10 gauge stainless spokes, I have yet to ever break 1 single spoke or damage a nipple. I decided to get these after having trouble with other spokes that broke and cheap steel nipples that pulled right out of the spokes when climbing stairs. I broke well over 30 spokes before I got these 9 / 10 gauge and also damaged a good amount of steel nipples which pulled right out of the threads of the spoke.
I would recommend 10 gauge spokes for ebikes, as 9 / 10 gauge is overkill. Since these are high quality steel, they are much stronger than that china crap pre-cut spokes so you can go with a thinner spoke.
I see you are in South Wales. I assume you may try this company, only I can recommend it because it is one of the few companies that seem to do custom motorcycle spokes.
http://www.central-wheel.co.uk/spokes/spokes.html
Both of these companies roll there own spokes and use high quality stainless steel.
Also, I highly recommend you get a spoke torque wrench when building your own wheels. You can't do this by feel very well, trust me and don't think you can unless you have built 100's of wheels. The Torque wrench will guarantee you get the proper torque spec for each spoke which is around 30 inch lbs if I remember correctly. The wheel won't come untrue.
There is simply now way of knowing how tight you have the spokes unless you use this. You will most likely not tension high enough and the wheel will come untrue.
I personally use the Buchanan spoke torque wrench, but I guess you can use what ever motorcycle one will work with your spokes. I like the buchanan design because it allows me to bring up the torque spec slowly, like to 10 inch pounds, then to 15, 20, 22, 25, 28, 30. This makes sure all spokes are equally tensioned.
