The Crown vs 24 inch Rim grrrr

Spacey

100 kW
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May 15, 2010
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Trying desperately hard to lace up this huge motor with the 125mm spokes that came with the motor that are for a 24 inch rim.

The rim size is 507mm x 30mm if the sticker on the side of it is to be believed .... But the rim feels to big, I just can't get the thing to lace up. Any ideas?
 
Ithink so .... :?

Rim Specs: Diameter: 507 (24). Drilling: 28, 32, 36. Valve: AV. Sidewall: N/A. ERD: 489

Same as in this pic:

http://www.crystalyte.com/TC with 24 inch wheel s.jpg

TC_V4%20wheel%20freewheel%20side.jpg
 
This is how far I had got, but the spokes are too small it would seem. Have only laced one side partial and no more thread to go on the nipples.

24inch rim TC65.JPG
 
Your rim isn't as deep cross section as the stock rim, so the stock spokes will be too short. Looks like you need another 5mm or so.
 
Starting to think that also, but all the 24" rims I can see have the same erd.....or does erd not mean what I thought it did? Confusing question I know :?
 
looks to me like you could try zero cross - there will still be a decent torque angle spoke to rim from the look of your pictures....
 
bobc said:
looks to me like you could try zero cross - there will still be a decent torque angle spoke to rim from the look of your pictures....

I woke up and read this and though....doh...I'll give it a go. Sure enough it seems to be working out so far, I was told to copy the motor on the Crystalyte website so figured it had to be 1 cross, the bend in the bottom of the spokes imply this as well...but 0 cross is working so far.

Just hope the spokes can take the 6kw that's going to be rammed through it.

Cheers for putting my head straight.

0 cross 1.JPG

0 cross 2.JPG
 
spoke tension is now trying to pull the spokes out of the hub - I couldn't see that in the earlier pictures & assumed they were more like standard - you'll have to be confident they'll stay put...... ;^)
 
I did try looking for deeper rims but could not find any that would have made enough difference for the spokes to have seated in a 1 cross lacing.

However I have put the motor in my old Cannondale Gemini, just have to build the A123 green cell pack (72v 12Ah) to test it.

TC65 Cannondale Gemini.JPG
 
Spacey said:
Starting to think that also, but all the 24" rims I can see have the same erd.....or does erd not mean what I thought it did? Confusing question I know :?

ERD = "effective rim diameter", or the diameter of the rim at the nipple seats plus any desired protrusion into the nipple heads. The deeper the rim section, the smaller the ERD. ERD only exists as a concept because rims in the same size have different sectional depths.
 
Hey Spacey,

i would not ride the bike the way you laced TC in this rim...it is not correct...and for sure it is dangerous if you want to go high speed.

The way you laced the spoke they will pop out the holes very easy...you laced it wrong.

Check out the original Crystalyte picture again...you must do the cross the right way...than the spoke can not pop out.

If you want your bones to stay in one piece...you better lace the motor right... :D
 
Good luck with your radial lacing. If I were you, I would just order some custom length spokes and do a 1 cross.

Radial length spokes are good for front wheels. If radial lacing is going to be used on a rear bicycle tire then it would only be used on the "non-drive side" (the side opposite the cassette or freewheel) and a cross pattern of some sort should be used on the cassette side. Here is the rub. On an ebike, BOTH sides of the rear wheel are the drive side so a radial pattern should not be used on either side of the drive wheel of an ebike.

The radial lacing is super strong side to side and a bit weak torsionaly. If you are looking for a super strong lacing pattern then use a crow's foot pattern. It has the torsional rigidity of a cross pattern and the lateral rigidity of a radial lacing pattern. That is what I am using on my new wheels when they arrive (fingers crossed). The down side is that you need two vastly different spoke lengths.
 
@Spacey

all you have to do, is just to flip the spokes bei 180°, they will have 1x cross and the lenght should be OK, too.


Is it possible to upload a picture directly to the forum?
 
I built the wheel for the hell of it, certainly wont be using it. The spokes supplied with the wheel were so damn short for 24inch rim it was a joke.

I will get longer spokes, it's just a bugger trying to get the right length, will try to get the rim erd etc.... cheers for help.
 
Radial lacing has been used on many many bike wheels for many years. I have seen many examples on this forum of big hub motors laced radially. Some road bike hubs don't recommend it, but anyone can see that as far as the rim is concerned, it's an improvement over any number of crosses.
For torque transmission, just do the sums if you're worried - all that matters is the angle at which the spoke meets the rim tangent. Your hub leaves you with about 5degrees from right angles from the look of your pictures.
Let's say you have 36 spokes & the thrust at the rim is 360Newton - that's 10N per spoke. the spoke tension change will be 10/cos(95) = 114N
Your "resting" spoke tension will be 500 to 1000N - the 114N will be added or subtracted from that
360N thrust at 22mph (10m/s) is 3.6kW....
 
i used radial lacing for Crystalyte 3540 in 20'' wheel with Sapim spokes and quality BMX rim. No issues.
 
The OP is getting new longer spokes. The issue is not that it's radial laced wheel- Yes there are plenty of hubs with radial laced rims, but with the way the spokes fit in the crown motor. They MUST be laced in a cross pattern to get angle on the spokes to hold them into the slots on the hub. The way it is right now, it's probable that the spokes will pop out of the hub. But as I said the OP is getting new spokes and said he's not going to use it like this so it's all good. ..
 
perfect!
would moto spokes fit this motor?
EDIT: also it may be little challenging for 20inch rim to lace 1x cross.
 
unique spokes afaik- they are straight on the hub end, not bent at 90 degrees like normal spokes. Not even sure who would supply the spokes other than clyte.

I've seen straight ones on the BMW R1200GS but I think they might be a little bit heavy duty for an ebike...
 
Spicerack said:
unique spokes afaik- they are straight on the hub end, not bent at 90 degrees like normal spokes. Not even sure who would supply the spokes other than clyte.

I've seen straight ones on the BMW R1200GS but I think they might be a little bit heavy duty for an ebike...

Sapim offers straight pull spokes, Holmes has them in stock but they are 14ga.. Will check with Sapim Belgium directly for other straight spokes.
 
Consider me told! :D Thanks for enlightening me...I shall stop trolling this thread now... and good luck to the OP- it'll be interesting to see how the Crown goes.
 
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