No offset

[Kirill]

Hi everyone!

One guy laced up the motor wheel without offset. The offset is 6 mm. The frame is a 2010 Specialized Demo II.
Can I put few spacers about 6 mm thick without some problem with the frame and dropouts?

Or is it necessary to adhere to the 135 mm size?

 

[gromike]

Are you talking about going from 135 to 141mm?
Me thinks you can spread the dropouts a few mm's, but 6mm is probably too much. Aluminum can be fragile that way, and the dropouts are no longer parallel. Maybe someone who has spread them that far can chime in.

 

[Chalo]

The answer is to fix the wheel spacing so it centers in the frame it goes into, at the spacing of that frame. There isn't another correct answer.

 

[Kirill]

Are you talking about going from 135 to 141mm?
Me thinks you can spread the dropouts a few mm's, but 6mm is probably too much. Aluminum can be fragile that way, and the dropouts are no longer parallel. Maybe someone who has spread them that far can chime in.

Yes. I’m worry about too.

 

[Kirill]

The master assembled a motor wheel "as it will be stronger" without offset.
And he suggests using washers to achieve the correct positioning of the wheel in the frame. But I don't have any motor washers to replace.

In his opinion, it is impossible to do offset on a DD motor. Because the offset weakens one side and there is a chance that my too strong 12G spokes will rip the nipples out of the weak aluminium MTX rim.

 

[Kirill]

But without offset there won't be any problems.
He is ready to do it with offset 6 mm but doesn’t give any guarantees for the work and is ready to show the same rims as mine with torn nipples.

 

[99t4]

...there is a chance that my too strong 12G spokes will rip the nipples out of the weak aluminium MTX rim.

That right there is the core of the problem. The rim type and spoke gauge must be matched. 12g spokes need a moped or motorcycle type rim. Bicycle rim needs thinner spokes, 14-13g single-butted spokes have been proven to be a reliable solution for offset lacing hubmotor to bicycle rim.

Sapim Strong Single Butted J-Bend Spoke

A butted spoke is drawn to its specific profile, which defines its high strength. The strongest spoke in Sapim’s product range, the Strong is developed for specific and heavy usage such as tandem, e-bikes or heavy load use. In case of large hub holes, the Strong is the recommended choice...

wheelbuildingparts.com

Crack developing on ebikeling rim sidewall-- need to repair | Endless Sphere DIY EV Forum

 

[Chalo]

In his opinion, it is impossible to do offset on a DD motor. Because the offset weakens one side and there is a chance that my too strong 12G spokes will rip the nipples out of the weak aluminium MTX rim.

I use cross-1 lacing so I can place all the spokes on the same side of the flange. If the hub has a lot of offset between one side and the other, I put all the spokes, both sides, on the same side of their respective flanges, to help cancel out some of the hub offset. For instance on a rear hub where the flanges are both offset to the left, I lace all the spokes on the right sides of the flanges.

If I'm using a rim that has offset between the holes, I lace to the opposite side of the rim if the spoke departure angle is feasible.

Also, I use 14-15ga (2.0/1.8mm) double butted spokes when possible, with washers at the spoke heads and nipple heads if necessary to prevent pull-through.

 

[Kirill]

with washers at the spoke heads and nipple heads if necessary to prevent pull-through.

Yes! That's what I suggested to him. As many others decide to do so.
But his decision is not! No washers.

The master claims that he did it as best as possible.
Any other way the rim will break very quickly.

 

[Chalo]

Any other way the rim will break very quickly.

Spokes that are too thick are the quickest way to break rims without overloading them. 12ga (2.7mm) is much too thick for bicycle rims.

 

[99t4]

Sure sounds like your wheelbuilder is not that experienced with hubmotor wheelbuilds. And/or not open to learning new methods. Time to find another wheelbuilder? Or DIY?

 

[Kirill]

Spokes that are too thick are the quickest way to break rims without overloading them. 12ga (2.7mm) is much too thick for bicycle rims.

What should I do now? I can't find a motorcycle rim that fits my bike tire.

For 26” bike tire fits 22” motorcycle tire.

Of course, for the summer I can find a tire for some motorcycle rim. Any kind. But I can't find a studded tire. Because I ride in winter too. In my area there can be snow and ice in winter

 

[Kirill]

Sure sounds like your wheelbuilder is not that experienced with hubmotor wheelbuilds. And/or not open to learning new methods. Time to find another wheelbuilder? Or DIY?

Yes. But if he is right? Some share his point of view. He has been assembling the wheel motor for several years. I’m forced to listen to his opinion.

I can look for another wheel builder, but he himself is ready to do as I say.

I'm just trying to understand how true his statements are or it's just over-cautiousness.

 

[99t4]

What is your planned use? What is the tire size (width)? How much do you weigh? How much cargo are you planning to carry? Will it require the added strength of a moped or motorcycle rim? If not, suggest you lace up one-cross with a high quality appropriate width bicycle rim and the 14-13g single-butted spokes listed above, dished to center the rim to the frame.

This post has several good links and tutorials: that should answer most of your questions:

Accidental ebike newbie with controller and battery questions

Hello hello. I got my first cargo, disc and ebike all in one package the other day. I was aware of the first two specs but not anticiapting having a MXUS 250w 36v front hub motor involved. According to the previous owner, hub works but he gave up trying to sort out a new battery/controller. So...

endless-sphere.com

 

[DogDipstick]

This thing takes 4500w contin, 12kW peak, on 12g Sapim stainless in a Sur Ron rim.. and is offset 8mm to keep the rim on center.

What Chalo says is usually true.


My personal wheel build .... I use a 19" DOT Sur Ron rim and Sur Ron hub, 20mm axle front... ,.. Very common to find.... and I custom laced the rear wheel into the Ron rim. Yes it needed offset.

All heads in, 8mm offset, different length spokes right to left... *( not much like 1.5-2mm)... 10-12kW peaks.. going on the fourth year with this motor right there... and the motor before this one burnt at a 10kW peak after three years... and never a single rim/spoke trouble issue. I originally tried with cheap(est) " 10g" galvanized spokes.. but they didnt tension right or uniform... so I went to a custom cut 12g Sapim with long nipple. I bought mine form a place called "Yojimbos garage " ( bike shop) in Chicogo.

Bike tracks great front to rear.

 

[Kirill]

What is your planned use? What is the tire size (width)? How much do you weigh? How much cargo are you planning to carry? Will it require the added strength of a moped or motorcycle rim? If not, suggest you lace up one-cross with a high quality appropriate width bicycle rim and the 14-13g single-butted spokes listed above, dished to center the rim to the frame.

Of course, using 14-13g single-butted spokes is the best solution.
But I can't find such short butted spokes.

 

[Kirill]

What is your planned use? What is the tire size (width)? How much do you weigh? How much cargo are you planning to carry? Will it require the added strength of a moped or motorcycle rim? If not, suggest you lace up one-cross with a high quality appropriate width bicycle rim and the 14-13g single-butted spokes listed above, dished to center the rim to the frame.

As I said, the tire size is 26 inches.

I weigh 80 kg.

On the bike frame there is a Lifepo4 16S 50 Ah battery weighing 22 kg.

And yes, I carry a lot of things with me. I have three Givi motorcycle cases.

With the MАС motor and 14g spokes there were no problem with this rim.

 

[99t4]

But I can't find such short butted spokes.

Where have you looked? How short is short?

As I said, the tire size is 26 inches.

Width?

With the MАС motor and 14g spokes there were no problem with this rim.

Ok good, well you hadn't mentioned this before. Guessing that was offset? No problems with that, right?

Still looking like your "problem" is the wheelbuilder's lack of experience with ddhubmotor wheelbuild and insistence on inappropriately using 12G spokes, covering this up with further insisting on no dish to compensate.

Were you able to look at the tutorial and video links?

 

[Kirill]

Where have you looked? How short is short?

On the official sites of the producers. Sapim. DT.
165mm.

Width?

2,35 - 2,5 inches.
I would like it wider, but I can't find one wider.

Ok good, well you hadn't mentioned this before. Guessing that was offset? No problems with that, right?

There was no need to mention it.
The frame is the same. Yes, it was laced with the offset.

Still looking like your "problem" is the wheelbuilder's lack of experience with ddhubmotor wheelbuild and insistence on inappropriately using 12G spokes, covering this up with further insisting on no dish to compensate.

Of course I’m not happy with the decisions of the assembler. He contradicts himself.

Were you able to look at the tutorial and video links?

Yes. The website ebikes.ca is my main reference.

 

[99t4]

On the official sites of the producers. Sapim. DT.
165mm.

Look more closely at the link I provided in post #7. The dropdown lists sizes ranging from 135mm - 310mm.

I personally obtained a set of 168mm last year no problem.

 

[Kirill]

Look more closely at the link I provided in post #7. The dropdown lists sizes ranging from 135mm - 310mm.

I personally obtained a set of 168mm last year no problem.

I found Pillar PSB spokes(Analig Sapim Strong) Single butted. There are short ones.

 

[wturber]

Yes. But if he is right? Some share his point of view. He has been assembling the wheel motor for several years. I’m forced to listen to his opinion.

I can look for another wheel builder, but he himself is ready to do as I say.

I'm just trying to understand how true his statements are or it's just over-cautiousness.

My experience is limited, but it corroborates what Chalo is telling you. I ran a 1000 watt DD hub motor on an 80-90 lb mountain bike (carried a lot of battery, a direct drive motor, and a MeanWell potted "charger". This was a hardtail. So the wheel takes a fair bit of abuse. The original wheel was built with 12ga spokes. It lasted 5000 miles and then started breaking spokes. This was caused by the rim beginning to fail. You could see where cracks were forming at some of the spoke holes.

I had the wheel re-built by Dave's Custom wheels (a very reputable wheel builder) using 14 gauge spokes and the standard offset needed for this typical mountain bike. I've ridden the bike another 10,000 to 15,000 miles (I stopped tracking after the 10,000 mark) and have had no problems. The wheel is still true. No spokes have ever broken.

My experience can't be proof, but it does line up with the "what makes a good strong wheel" explanation that Chalo gave (and still seems to be giving) back the. I think the 12ga scheme actually will work fine for many people because they will never put the 5000 miles on the bike that I did. So I'd add that to the list of questions. How much will you ride this bike?

 

[Kirill]

How much will you ride this bike?

I've driven at least 2500 miles on the Mac.
And I would have continued driving if it weren’t for a breakdown that forced me to change the engine.
My mileage is in the thousands.

 

[Papa]

Of course, using 14-13g single-butted spokes is the best solution.
But I can't find such short butted spokes.

I laced a GMac/406 DM24 rim that required 117.3mm and 117.8mm. Purchased here....

Sapim Strong 13-14g Butted Spoke, Silver

Custom Cut Silver Sapim Strong Spoke, Butted 13-14 Gauge, Includes Nipple

ebikes.ca

 

[wturber]

I've driven at least 2500 miles on the Mac.
And I would have continued driving if it weren’t for a breakdown that forced me to change the engine.
My mileage is in the thousands.

OK. Then longevity matters. Matching the spokes to the rim (meaning no thick gauge spokes for bicycle rims) is necessary for longevity. BTW, that bike got dragged on asphalt for about a mile. It ground the axle on the left side down by about 3/4" and ground the nut on that side about in half. The five year old wheel with 14 gauge spokes is still intact and true.