Looking for robust 24'' rim

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wturber   1 MW

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Re: Looking for robust 24'' rim

Post by wturber » Sep 23 2018 4:07pm

hias9 wrote:
Sep 23 2018 2:16pm
The top speed shown in the simulator is without any field weakening. It will be around 55mph for a 17'' mxus 3k 3T with a fully charged 22S battery.
It would be cool if the simulator would also support calculations with field weakening.
It may be hard to model but would be kinda cool since it would show us not only the increase in speed, but also the decrease in motor efficiency.
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Re: Looking for robust 24'' rim

Post by hias9 » Sep 29 2018 9:36pm

Yes, it would be very interesing to see the efficiency with field weakening.
I thought that the most efficient point would be the max speed with field weakening disabled.

In most cases rpms are still below the point of maximum efficiency.

Not sure if it would be possible to archive a higher effeciency with only a bit of field weakening.
Any way to calculate this?

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Re: Looking for robust 24'' rim

Post by hias9 » Feb 22 2019 3:26pm

I am planning to lace a MXUS 3k into a 24'' SAS rim. I have never built a wheel before. My friend in the local bike shop is on holidays at the moment.

Would 13ga DT Swiss Champion spokes in a one cross pattern be a good idea?
Is it possible to get the spokes in the correct length somewhere or do I have to cut them and then cut a thread?

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Chalo   100 GW

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Re: Looking for robust 24'' rim

Post by Chalo » Feb 22 2019 11:19pm

hias9 wrote:
Feb 22 2019 3:26pm
Would 13ga DT Swiss Champion spokes in a one cross pattern be a good idea?
Is it possible to get the spokes in the correct length somewhere or do I have to cut them and then cut a thread?
14ga is better than 13ga, and 14-15ga double butted is better yet, if you can get them in the length you need (which is doubtful).

If you're dealing with monster hub holes, you may need washers even for 13ga spokes.

Danscomp.com will cut spokes to order, but they don't sell DT Swiss. They do sell equally good Belgian-made Sapim spokes, including 13-14ga single butted.

I build quite a few Halo SAS, and that's a really good rim.

Rear hub motor wheel builds are in some regards the most challenging I've ever done, out of hundreds of custom wheels. If the insertion angle is extreme, you're best off lacing them radially. And even if you use cross-1 lacing, lace the spokes all on the same side of the flange, using that small lateral offset to help equalize the bracing angle and spoke tension between one side of the wheel and the other as much as you can.
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Re: Looking for robust 24'' rim

Post by amberwolf » Feb 23 2019 1:34am

Chalo wrote:
Feb 22 2019 11:19pm
If you're dealing with monster hub holes, you may need washers even for 13ga spokes.
I had problems with the last hub I used wshers on (probably had too big a hole in them, so likely my own fault). So now I just drill new holes between the existing ones. With even a crappy drill press and a vise, it's easy; I did this on two MXUS 3k's so far.

Last time I didnt' even use a vise, I just used the axle nut and some washers and directly bolted the wheel to the drill press's movable plate in it's bolt-slots (meant for bolting a vise to).

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Re: Looking for robust 24'' rim

Post by Peterfr12 » Feb 23 2019 12:57pm

Hi

I have a Halo SAS 24-inch rim and on front wheel of my recumbent and it does a great job. It is very sturdy and solid and I can go at 40 mph on road with no issue. I went several through potholes at 30 mph and the rim is still perfect. I also have a SAS 26-inch rim for the back wheel laced to a Mac hub motor. SAS seems to build very solid rim, much stronger than the Alex rim which I bent at 35 mph through a pothole. However, bike tyres even from a good brand as Schwalbe Marathon plus get worn too quickly: after less than 2000 miles they are good for recycling which is expensive and pain in the arse to change. I am also not sure bike tyres are safe at 45 mph downhill. Therefore, I have ordered motorbike rims and will use motorbike tires in my next setup. I will save money.

Best regards,

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Re: Looking for robust 24'' rim

Post by Chalo » Feb 23 2019 1:53pm

Peterfr12 wrote:
Feb 23 2019 12:57pm
Therefore, I have ordered motorbike rims and will use motorbike tires in my next setup. I will save money.
Save money while making your bike heavy, ugly, and slow. That's more of an American tradition, isn't it?

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markz   100 GW

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Re: Looking for robust 24'' rim

Post by markz » Feb 23 2019 6:45pm

Halo SAS rims are stout

Motorcycle rim + motorcycle tube + motorcycle tire (2 ply or 4 ply) 5-10lb difference overall per wheel
vs
Bicycle rim (450g)+ bicycle tube (120-200g) + bicycle tire (ene fat tire is 1400g)

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Re: Looking for robust 24'' rim

Post by hias9 » Mar 15 2019 2:56pm

I am going to drill smaller holes for 13ga spokes tomorrow.

I have 13ga Sapim spokes and 4mm nipples here (cannot use 5mm nipples with this rim).
According to ebikes.ca it would be better to use 13/14ga butted spokes instead of the 13ga spokes.
What do you think?

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Re: Looking for robust 24'' rim

Post by amberwolf » Mar 16 2019 2:26am

The thinner section allows more stretch during tensioning, so ti holds tension better, without having to have as much actual tension on them, thus placing less stress on the rim itself.

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MadRhino   100 GW

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Re: Looking for robust 24'' rim

Post by MadRhino » Mar 16 2019 10:12am

[quote=hias9 post_id=1451893 time=1552679796 user_id=60030]
I am going to drill smaller holes for 13ga spokes tomorrow.
...
I have 13ga Sapim spokes and 4mm nipples here (cannot use 5mm nipples with this rim)

What do you think?
[/quote]

Use nipple washers. No need to drill, and washers are making a better job.
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Re: Looking for robust 24'' rim

Post by markz » Mar 16 2019 12:49pm

DM24's are a robust rim
Stay away from Crystalyte
Stay away from using thicker spokes, thinner spokes are what you want for bicycle rims as stretch is good otherwise a 12g can break the nipple hole. I need look no further then this website, https://www.ebikes.ca/shop/electric-bic ... pokes.html and ask myself, why don't they sell 12g spokes. They got the Clyte Crown (LINK) a powerful direct drive motor. Another Link giving you a range of power, which is a better way of specifying a motor. Clyte Crown is 9.2 kg and Typ. Power 1000-3000 W. No need to look any further as far as "how to build" a wheel. Meaning, 13/14 butted spokes are good, thats what I bought this go around.

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Re: Looking for robust 24'' rim

Post by hias9 » Mar 16 2019 9:19pm

I am using 13ga Sapim spokes for this motor, and maybe 13/14 butted spokes for the next one.

Would you lace it with the spoke elbow to the outside for all spokes or alternating?

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Re: Looking for robust 24'' rim

Post by Chalo » Mar 17 2019 3:27am

hias9 wrote:
Mar 16 2019 9:19pm
I am using 13ga Sapim spokes for this motor, and maybe 13/14 butted spokes for the next one.

Would you lace it with the spoke elbow to the outside for all spokes or alternating?
Not alternating, and not all elbows-out or elbows-in for a rear hub. Rear hub motors and most disc brake compatible front hub motors have asymmetrical flange spacing, which makes for unequal tension-- sometimes ridiculously unequal-- and a weak wheel. Lace the spokes all outside the flange that's closer to the midpoint of the axle, and all inside the flange that's farther out. That helps compensate for the asymmetrical flange spacing.

Alternating spokes inside/outside the flange is necessary for multi-cross patterns that would cross too near to the flange, but for radial and cross-1 lacing, you might as well take advantage of the bracing angle options afforded by putting the spokes all on one side of the flange.

If the hub has symmetrically spaced flanges, then it's usually best to lace all the spokes elbows-out. But when the hub diameter is close to the rim diameter, it becomes necessary to lace all the spokes elbows-in to moderate the angle at which they enter the rim holes.
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Re: Looking for robust 24'' rim

Post by hias9 » Mar 17 2019 12:36pm

Thanks a lot for the info.

I will do it the way you say for this motor because I require some dishing.
I have another 45H motor here which has an asymmetric motor case, but a centered flange, so that one would not require dishing.

What is the way to go if no dishing is required? Alternating or all elbows out?

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Re: Looking for robust 24'' rim

Post by Chalo » Mar 17 2019 7:18pm

hias9 wrote:
Mar 17 2019 12:36pm
What is the way to go if no dishing is required? Alternating or all elbows out?
All elbows-out, unless the spokes are very short. In that case, all elbows-in.
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Re: Looking for robust 24'' rim

Post by MadRhino » Mar 18 2019 9:25am

You need to avoid spokes rubbing/bending on the edge of the flange, because that is forcing stress on the J-bend and eventually breaking them. That has to be considered when deciding if you lace them in or out.

Some spokes have a longer J-bend, letting you use flange washers. This is making the spoke safe off damage from the flange edge.
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Re: Looking for robust 24'' rim

Post by hias9 » Mar 18 2019 10:13am

My motor had 4mm spoke holes and I was not happy also with using 2 washers, so I drilled 2.7mm holes (very tight, maybe 2.8mm would be better) for 13ga spokes.

Lacing with elbow in on the left and elbow out on the right gave the right amount of dishing that I needed for this motor.

Unfortunately the knobs of my 24x3.00 Duro Razorback have contact with the chainstays.
Is there any alternative to this tire which is a bit more narrow?

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Re: Looking for robust 24'' rim

Post by Chalo » Mar 18 2019 6:39pm

hias9 wrote:
Mar 18 2019 10:13am
Unfortunately the knobs of my 24x3.00 Duro Razorback have contact with the chainstays.
Is there any alternative to this tire which is a bit more narrow?
You could use an angle grinder while the wheel is turning to trim the problem knobs a bit.
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Re: Looking for robust 24'' rim

Post by hias9 » Mar 18 2019 7:02pm

I already trimmed them, but I think that will make cornering grip worse. I did not find a comparable 24x2.5-2.8 tire so far.

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Re: Looking for robust 24'' rim

Post by Chalo » Mar 18 2019 9:06pm

Hookworm 24x2.5", unless you need to ride in mud, sand, or other squishy stuff.
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Re: Looking for robust 24'' rim

Post by hias9 » Mar 18 2019 9:59pm

What about tires for offroad? Maybe Minion or Holyroller?

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Re: Looking for robust 24'' rim

Post by hias9 » Mar 26 2019 10:23am

I will try Maxxis Minion DHF 24x2.4 DH.

When lacing a motor with centered flange, what exactly speaks against lacing alternating elbows in and out?

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Re: Looking for robust 24'' rim

Post by Chalo » Mar 26 2019 1:30pm

hias9 wrote:
Mar 26 2019 10:23am
When lacing a motor with centered flange, what exactly speaks against lacing alternating elbows in and out?
An inside spoke has less bracing angle than an outside spoke. So you give up some lateral stiffness and strength when you lace spokes inside the flange.

With a large hub motor and a small rim, sometimes it's advisable to lace inside the flange, to moderate what might be an unfavorable insertion angle to the rim. But when that's not a factor, outside the flange is better.
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Re: Looking for robust 24'' rim

Post by hias9 » Mar 26 2019 6:47pm

So the way to go for a mxus 3k size hubmotor with centered flange in a 24'' rim is to lace it with all elbows out, correct?

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