Lacing Pattern for Q128 Hub Motor on 700c?

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addicted2climbing   100 W

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Lacing Pattern for Q128 Hub Motor on 700c?

Post by addicted2climbing » Mar 05 2017 10:35pm

Hello All,

I am about to have a wheel laced up and I am about to order my rim and spokes. I will be using the DT Swiss 545DB 700c on a Q128 CST. I did the calc on both Grin and the DTswis site and got fairly close numbers. However, I am unsure if I shoudl buy 2 different sized spokes, split the difference or buy the shortest version. Also lacing pattern will dictate the spoke length. I had planne don a 3 cross, but after reading the suggestions on the Grin calculator it mentions that due to Hub Motors having a larger flange diameter than a standiard bike hub that its best to just do 1 cross. Can someone verify that. The Q128 is a bit on the small side and perhaps I shoudl go to 2 cross. Any advice would be helpful. Also can people check my math to make sure I did this correctly.
Spke Calc - Grin.PNG
Grin Spoke Calc
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Spke Calc - DTSwiss.PNG
DTswiss Spoke Calc
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Q128C-135 Outline (7).pdf
Q128 Drawing
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As for spokes I will liely buy the Sapim black spokes fromn Luna or a set of DTswiss Champion spokes when I order the wheel.

I am open to any help and advice.

Marc

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Ykick » Mar 05 2017 11:11pm

Only 1 cross allows for acceptable nipple angle, IMO. Avoid nipple-to-rim angles much beyond 10 degrees.

I’ve laced Q128 and Q100 motors into 700C rims and originally wanted to do 2 cross but when I realized the steep angle of the nipple in relation to the rim, I elected to do 1 cross.

I used to fret about exact length spokes but in practical application 1-2mm short is often better than too long. If you need to dish more than a couple mm offset a shorter/longer spoke relationship may help?
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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by FluxZoom » Mar 05 2017 11:18pm

Spoke angle is usually an issue for hub motor wheel builds. The large rim diameter and smaller hub motor make it much less of an issue here. I've asked about spoke/nipple angle maximums, never really get a solid answer as it's often supremely circumstantial, some rims might be better suited for high spoke angle. The important element to understand is that if the spoke angle is bad, the spoke will take a somewhat sharp bend right where the spoke and nipple meet, often premature spoke failure forms there.

http://www.sapim.be/nipples/brass/polyax Sapim makes a nipple that is claimed to be better for spoke angle. You can see the picture illustrates the otherwise sharp angle as the spoke leaves the nipple. If you use sapim polyax brass nipples you probably could get away with 3 cross here as the spoke angle comes out to be 78.2.

I am no wheel building expert, but that dishing seems pretty intense in my mind. I don't know if that is going to be a severe issue though.

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Chalo » Mar 05 2017 11:36pm

Ykick is right-- cross-one lacing is pretty much the way to go with any hub motor unless you have to use radial lacing. I don't use cross-two anymore for a hub over 100mm in flange diameter.

I use leonard.io/edd for spoke calculations (it's Damon Rinard's Spocalc spreadsheet behind a web form). I round up to the next longer size.

The limit of nipple angle at the rim is a function of the nipple diameter, hole diameter, and rim thickness. Spherical nipple heads are nice, but they don't Increase the angular range of the spoke.
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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by docw009 » Mar 06 2017 9:17am

Better to be 1 mm too short than 2mm too long. With double wall rims, the spokes won't protrude into the tube, but you can run out of threads. If the calculator gives you two different numbers, don't try to average them unless you don't care about dishing. First wheel I ever did, I had disk brakes, so the wheel didn't have to be centered. The next two were rim brakes, Wheel wanted to be centered.

I did a Bafang with a 120 mm flange into a 700cc wheel. Single cross worked. Spokes a little long. I needed washers.

Last wheel was a 109mm Q100H into a 20" wheel. I tried to alternate the spoke heads on the flange, in/out, like they show on youtube. Got bad angles where the inside spokes had a big bend and wouldn't touch at the cross. Flipped them all to outside spokes, and it was much better, but they sure were hard to re-insert.

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by addicted2climbing » Mar 06 2017 1:19pm

docw009 wrote:Better to be 1 mm too short than 2mm too long. With double wall rims, the spokes won't protrude into the tube, but you can run out of threads. If the calculator gives you two different numbers, don't try to average them unless you don't care about dishing. First wheel I ever did, I had disk brakes, so the wheel didn't have to be centered. The next two were rim brakes, Wheel wanted to be centered.

I did a Bafang with a 120 mm flange into a 700cc wheel. Single cross worked. Spokes a little long. I needed washers.

Last wheel was a 109mm Q100H into a 20" wheel. I tried to alternate the spoke heads on the flange, in/out, like they show on youtube. Got bad angles where the inside spokes had a big bend and wouldn't touch at the cross. Flipped them all to outside spokes, and it was much better, but they sure were hard to re-insert.
Hello Doc,

Thanks for the reply. So based on what your saying should I buy the spokes at 241mm? I will be just under by .8mm for the 241.8mm spoke and 2.2mm too short on the 243.2mm spoke.

Or is it best to split the difference and order 242mm as 241.8mm is pretty much 242mm and I will then just be 1.2mm too short on the other spoke. However perhaps the 241mm spoke helps with having a bit more adjustment on the 241.8mm side.

This hub seems to need a fair amount of dishing to make room for the cassette. Or is this a normal amount of dishing for a typical hub motor.

I have never built a wheel, but my dad is pretty good at ruing wheels and he does have a wheel stand. Or I can just pay to have it done, but the quote i was given was $120 which seems pretty high. I can have it done for $70 but will need to drive a bit farther. What is a fair price? All other bike shops in my area said due to their insurance they could not build an electric wheel. Should I give it a shot myself? If so any good hub motor specific youtube videos I should watch.

Marc

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by molybdenum » Mar 06 2017 2:53pm

I did my Q128c, 700c alex DX18 in a 2 cross. The spoke angle was 81 degrees, whereas a single cross would have afforded a spoke angle of 85 degrees - not that much difference imo. I put the non-drive side elbows facing in and the drive side elbows facing out to help with the dishing and reduce spoke tension differences. It has worked for me for over 4k km.
2012 Kona Dew Deluxe, Q128C and 9spd cassette, S12S sinewave controller, 48V Panasonic battery

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by motomech » Mar 06 2017 2:56pm

The amount of dishing depends not only on the motor, motor type(Cassette requires more than free whl.), but also the bike. Using a Q100C, one of my bikes required extreem(enough I went with a free whl motor), while then other required very little.
You should DIY.
Start w/ the "inner" spokes and install them all loosely, then install the "outers".
I don't have a stand, just use the bike upside down.
No dial gauge either. My technique is to use a felt marker pen, rest my hand on part of the bike, get it real close to the rim and spin the wheel and it will mark the high spots. I do this both for up & down and in & out. Work a bit on the high spots, then clean w/ brk. cleaner and mark it again.
If you get to a point where you just can't get a bad spot out, loosen ALL the spokes somewhat and start over.
Personaly, I would lace that whl w/ a 2-cross. W/ the sm. diameter motor and big rim the distance would be such that there would be very little deflection @ the nipple. I've laced wheel/motor combos w/ less distance that had some deflection and it really isn't a problem.
100_0108.JPG
100_0108.JPG (65.91 KiB) Viewed 2513 times
Q100C in a 26" whl. w/ bicycle size spokes(14 ga.?) If you look closely, you can see a slight bend the nipple.
The wheel has been solid and I weigh a lot. After 2 "re-tightens", it has stayed tight.
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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by addicted2climbing » Mar 06 2017 6:49pm

motomech wrote:The amount of dishing depends not only on the motor, motor type(Cassette requires more than free whl.), but also the bike. Using a Q100C, one of my bikes required extreem(enough I went with a free whl motor), while then other required very little.
You should DIY.
Start w/ the "inner" spokes and install them all loosely, then install the "outers".
I don't have a stand, just use the bike upside down.
No dial gauge either. My technique is to use a felt marker pen, rest my hand on part of the bike, get it real close to the rim and spin the wheel and it will mark the high spots. I do this both for up & down and in & out. Work a bit on the high spots, then clean w/ brk. cleaner and mark it again.
If you get to a point where you just can't get a bad spot out, loosen ALL the spokes somewhat and start over.
Personaly, I would lace that whl w/ a 2-cross. W/ the sm. diameter motor and big rim the distance would be such that there would be very little deflection @ the nipple. I've laced wheel/motor combos w/ less distance that had some deflection and it really isn't a problem.
100_0108.JPG
Q100C in a 26" whl. w/ bicycle size spokes(14 ga.?) If you look closely, you can see a slight bend the nipple.
The wheel has been solid and I weigh a lot. After 2 "re-tightens", it has stayed tight.
Thanks for the advice. What are the pros and cons of single, double triple cross. Does the addition of crossing spokes give more lateral support? I ordered my rim, but have not ordered my battery or spokes so can still switch to a different cross pattern.

Thanks,

Marc

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by docw009 » Mar 06 2017 8:58pm

Your calculator appears to have already shortened the spoke lengths for you. And you need the assymetical length if you are going to put the rim in the middle of the axle.

This is dogman's page on spoking and you get to see his feet, I think. Dogman Dan likes to put all the spokes in facing out. He also says single cross.

This is a link on youtube that was pretty simple to follow. This gal uses the traditional alternate in/out spoke.

So which is better? I don't know. Some wheel builders feel the crossed spokes are stronger if they cross when they touch. On the larger e-bike hub, they won't touch if you alternate the spokes. I have two hub motors wheels that were done by the manufacturer. One is a 26" with in/out. The other is 700CC with all out. I did my own 700cc in/out. Only the all out lacing have the spokes touching, but I've not had any problems with any of these wheels. The spokes are straight.

With in/out single cross on a 20" rim, the spokes that faced inside were so badly curved. Not straight at all. I had to to change it. So your call on a 700cc wheel. Either will work, but not on a 20".

For truing, I had an old fork I clamped to my desk. Taped a piece of paper to make a guide. Work methodically and carefully, and the process really works. Took about 1-2 hours.

If those vendors didn't charge $120 to ship a wheel, I'd just pay the $30 and have it done in China when I bought the motor. As it was, it cost me about $50-60 for spokes/rims. I get the Saphim Strong, which are 13G elbow and 14G end.

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Andrew Cooke » Nov 04 2017 5:09am

What did you do in the end? How did it turn out? Would you do the same again?

I have a cannondale Bad Boy with 700c rims and 9 speed cassette, looking to fit the same rim and motor as you. I'm thinking that it would suit 2 cross, but need to decide on suitable 13g(?) black spokes.

cheers, Andy

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by d8veh » Nov 05 2017 7:18am

Andrew Cooke wrote:What did you do in the end? How did it turn out? Would you do the same again?

I have a cannondale Bad Boy with 700c rims and 9 speed cassette, looking to fit the same rim and motor as you. I'm thinking that it would suit 2 cross, but need to decide on suitable 13g(?) black spokes.

cheers, Andy
Use 14g spokes. They're lighter and will give you less problems. I did my 26" Q128c 1-cross to get a better angle at the nipple. Some deep rims don't allow the nipple to tilt much, which is another readon touse 14g ones.

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by addicted2climbing » Nov 05 2017 11:23pm

Andrew Cooke wrote:What did you do in the end? How did it turn out? Would you do the same again?

I have a cannondale Bad Boy with 700c rims and 9 speed cassette, looking to fit the same rim and motor as you. I'm thinking that it would suit 2 cross, but need to decide on suitable 13g(?) black spokes.

cheers, Andy
I cant remember what gauge spokes I bought but do remember buying them from an ebay seller who only sells spokes. They were Sapim Brand, butted and specifically for ebikes. If your bike has a Sram crank you may need to make an adapter as a spacing tool to get the PAS ring in place. I almost bought a Badboy for this conversion, but it was a tripple chainring and I wanted a 1X setup. I was able to get a 1x11 to fit on the Q128 using a MTB 11 speed cassette. I love the bike and it worked so well I am about to convert a bike for my wife. I had the rim laced 2 cross.

Marc

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Andrew Cooke » Nov 06 2017 5:45pm

Thanks Dave and Marc,

I've ordered 14 gauge spokes, hopefully the right length for 1 cross lacing.

My bike is already converted to 1x9 (11-32), I suspect it'll need a bigger chain wheel as it's only a 36, but I'll try it first. There isn't much space for the PAS ring, so I'll probably mount it on the chain side using the now spare mounting holes.

Andy

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by addicted2climbing » Nov 07 2017 2:37am

Andrew Cooke wrote:Thanks Dave and Marc,

I've ordered 14 gauge spokes, hopefully the right length for 1 cross lacing.

My bike is already converted to 1x9 (11-32), I suspect it'll need a bigger chain wheel as it's only a 36, but I'll try it first. There isn't much space for the PAS ring, so I'll probably mount it on the chain side using the now spare mounting holes.

Andy
Andy my bike had a 40t Chainring and 11T was my smallest on the cassette and I would run out of resistance pretty quickly. I changed my chainring to a 46T and its much better now. If you have a 36T you may as well buy as large a chainring that your frame will accommodate.

Marc

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Andrew Cooke » Nov 07 2017 3:18am

addicted2climbing wrote: Andy my bike had a 40t Chainring and 11T was my smallest on the cassette and I would run out of resistance pretty quickly. I changed my chainring to a 46T and its much better now. If you have a 36T you may as well buy as large a chainring that your frame will accommodate.

Marc
Would you have gone larger than 46? My bike originally had a 48, and I think I can get as large as 50 in a 104 BCD. I'll check how the std 48 looks before ordering a new narrow - wide ring.

Andy

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by addicted2climbing » Nov 07 2017 1:18pm

Andrew Cooke wrote:
addicted2climbing wrote: Andy my bike had a 40t Chainring and 11T was my smallest on the cassette and I would run out of resistance pretty quickly. I changed my chainring to a 46T and its much better now. If you have a 36T you may as well buy as large a chainring that your frame will accommodate.

Marc
Would you have gone larger than 46? My bike originally had a 48, and I think I can get as large as 50 in a 104 BCD. I'll check how the std 48 looks before ordering a new narrow - wide ring.

Andy
My bike pretty much maxed out at 46T so that is what I bought. Its a huge improvement and I think its perfect on my end. 48T might be better, but at 46T and 11T with motor and pedaling im moving pretty fast and unless the pavement is smooth it can get sketchy. When I had the 40T I would spin out in anything more than casual pedaling. Now I can actually use the gears more and now probably use the rear 4 cogs when cruising. Rarely go into the big rings on the back unless I am climbing a big hill and want to keep pedaling to help. My bike has no throttle.

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Tony01 » Nov 09 2017 11:20pm

2 cross should be fine for you. I just laced a 26" rim with a 105mm pitch circle hub 3 cross. The more crossings the stronger the wheel is to hub forces. I like to always do 3 cross or even 4 cross if there is enough space.

Lacing a wheel is easy. If you have a stand its REALLY easy. I used to just use a junk frame I had with a stand under it, and zip ties for truing.

Just two things to remember (two starting points)

Starting point 1: Around the valve stem hole, make sure the spokes are parallel, so that filling the tire will not be difficult

Starting point 2: The parallel spoke on the other side of the valve stem hole, which is facing the opposite direction (leading or trailing), needs to come out the hub flange the same side as the spoke in front of it. ie: trailing spoke forward of stem hole, left flange, outside of hub (left of flange); leading spoke backward of stem hole, right flange, inside of hub (left of flange).
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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by d8veh » Nov 10 2017 5:37am

A large offset (dish) in the rim means that the spokes on the brake side won't have enough tension. A small offset doesn't make much difference, but as you go further, the difference in tension rises exponentially until you reach the limit where the spokes on the drive side are perpendicular to the axle and the spokes on the brake side have no tension at all.

You can minimise the amount of offset by adding a spacer to the axle on the brake side, but this brings the brake disc out of line with the caliper. That's not a problem for rim brakes. If you have a disc brake, you can add a proprietary disc spacer behind the disc to bring it back to the caliper or put some washers/spacers behind the caliper adaptor to bring it to the disc. Even a little spacer, say 3mm, can make a big difference to the difference in spoke tension.

I found that spacers help a lot on wide motors like the Xiongda and Q100C that need big offsets or when using 8-speed freewheel gears, but I didn't need them on my Q128c.

Obviously, if you already have a wide motor, adding spacers will make it wider, so you have to stretch the frame a bit.

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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Chalo » Nov 11 2017 10:46am

beginner01 wrote:2 cross should be fine for you. I just laced a 26" rim with a 105mm pitch circle hub 3 cross. The more crossings the stronger the wheel is to hub forces. I like to always do 3 cross or even 4 cross if there is enough space.
I used to maximize the tangency of spokes when I built high flange hubs, but I don't anymore. It breaks spokes and you just don't need it. If your spoke line passes more than 3/4" from the axle center at its closest point, you'll have all the torsional strength you need. Remember that torque is shared among all spokes, so each one only transmits 1/36th of the force at that radius.

I have not built any Q100 hubs yet, but I've built Rohloff gearhubs that are about the same size. Even when built into 700c wheels, those tend to break spokes at the threaded end when laced cross-2. When laced cross-1, they don't. I have observed the same thing when lacing smaller gearhubs with cross-3 or cross-4 patterns.
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Re: Lacing Pattern for Q128 Hub Motor on 700c?

Post by Ypedal » Nov 11 2017 10:55am

+1 for single cross
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