Problems with Q100 kit - total beginner

rossw

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May 24, 2015
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2
Location
Sioux Falls, SD
Got a Q100 kit for my wife's beach cruiser.

First problem - rim on motor is much narrower than stock rim which is 1.75. Tires used on cruiser are 2.125. Is this safe on the narrow rim? (no size marking on the Q100 rim).
Also the narrow rim does not allow brake contact before the v brake arms hit the fender. I have adjusted the v brake washers as much as possible.

In addition, the motor appears to be off center in the wheel assembly. Even if I assemble without the fender, it looks like it I will not be able to get the brakes adjusted due to being off center.

Is this narrow rim typical with the Q100 kits?

Can I do anything to get the motor centered?

Thanks for helping out a newbie biker and ebiker

Ross
 
I'm guessing this is a rear motor? If so your learning curve is steep, but doable. How wide is the inside of the rim? How much offset does it have? Pictures would be helpful.
It seems that you will need to center the rim by making the spokes on the side you want to move to the center looser (use 1/4 turn to start with) and the other side of the rim tighter . This will pull the wheel towards the center. You may have about 5mm movement this way. I would go to my local bike shop and ask them to do it and true the wheel too. Money well spent. I'm sure you will hear from more members who will try to help. pictures please!
otherDoc
 
Guess OP missed the memo and multiple discussions about poor and unsuitable Chinese kit wheel builds?

Your best bet is to always buy loose motors (save a little on shipping) buy a quality comparable size rim (or teardown the bike current rim) - I prefer eyeleted Rims. Buy custom cut 13/14ga butted spokes. If USA? (please update your sig location) I buy them from Danscomp - not on website, call and ask which you must do for custom lengths anyway.

Learn to lace or take it to a shop. 1 cross is easier to learn than 3-4 cross on normal bicycle hub wheels.

This way you can solve your brake issues, dish (centering) issues and ultimately breakage issues by doing it in that manner.
 
Brutal first lesson. I made a huge first mistake, but found this place. Hopefully you won't get totally berated. These old timers just forget how dumb they once were.

That said I think you have yourself a bummer. If it can't be returned I'd try to sell it as is and start over. Hopefully your finances can absorb that. Otherwise, and I suspect you don't have the skill set or you wouldn't be here, the only route that makes sense is a redo as ykick grumped. :wink: I have a nice Sturmey Archer 3 spd drum brake hub mounted in a custom Alex DM rim that cost me $150 and is useless. I didn't listen and ask BEFORE I leapt into the bicycle abyss. It seems we think all bikes are the same, they're just bikes after all. Hruumpf.

Cut your losses, start over, or find a shop that can restring a new Alex rim using that motor. Warning, if the build is that bad then likely it will follow that the pieces and parts included are bottom rung stuff. I'm a craigslist it and start over guy.

Sadly it was mildly ugly with the Mrs. but survivable.
 
It sounds like the rim is unsuitable for use with your bike, but there may be hope.

First, measure the inside bead width. that's the area where the tire sits. That needs to be more than 23mm to fit a large tire like that. I suspect it's going to be 19mm or less, and that's just too small for that size tire.


If the brakes wont reach, try adding washers as spacers to the brake pad posts. If that isn't enough, you can remove the cup and cone looking silver washer things from the brake pad post under the nut, allowing more room for washers on the pad side. That cup and cone are semi-important to get a correct pad angle, however you should be abe to get by without them IF after getting the brake s to contact the rim, you can pull the brake handle hard enough to skid the tire. as long as the tire will still skid, you haven't lost any brake ability. it may be harder to pull the brake, and it may be noisy, but it will still be fully functional.


Of course, the easiest thing may be to replace the rim with one that fits your bike. the Q100 should be a 36 spoke motor. if your old rim was also a 36 spoke wheel, you may be able to reuse it. you will need new spokes cut to the right length. a bike shop may be able to do the work for you, but it isn't as difficult as you may think to do it your self.
 
Welcome rossw, Here's a recent thread with tips on wheel-building listed below. Some sellers use the absolute cheapest components to keep the price a few pennies cheaper, and the thin rim may be one of the results. For a fat beach cruiser tire 2.125, the narrowest rim (to save weight) that would work well would likely be somewhere around 32mm wide, but a bit wider would work, too.

DX32 rim, 26-inch X 32mm, machined rim for rim brakes, 36H for hub motors
http://www.niagaracycle.com/categories/alex-dx32-26-36h-black

"Wheel building Spoke-lacing thread"
http://endless-sphere.com/forums/viewtopic.php?f=2&t=64324

Danscomp is good for spokes. To save money get steel 14ga
https://www.danscomp.com/shop-PARTS/group/BMX+Spokes.html

For a more expensive upgrade get stainless steel "butted 13/14ga" (not listed but just ask them, fatter 13ga head near the hub, thinner 14ga on the shaft and at the nipple). gotta call them on the phone to place order, but thats a good thing.

Try the old spokes on the new rim (two different 26-inch rims may have a few mm difference between them on spoke lengths), then order new spokes if needed.
 
Danscomp prices 14ga spokes save $9 for 36qty since shipping is the same. Trouble is, 14ga spoke head doesn't fit Q100/Q128 spoke holes as well as 13ga head. I've built 5 wheels with Q100/128 mini motors (could be differences of course) but the only one I've needed to rework was the 1st attempt using 14ga spokes. Didn't really save any money doing it that way.

My frames/wheels normally need so much dish that I run all spokes facing one direction to gain rim offset in the motor flange. A good fitting 13ga spoke head seems to survive this lacing variation better than the looser fitting 14ga head.
 
It's not nearly as bad as what they'rd all saying. The rim is ideal for tyres up to 1.95, but I have 2.1" tyres on one of mine. It's not ideal, but it works.

The brakes are easy to desl with. When you buy brake pads, they come with spacers (cups and cones) on the bolt. The short pair are normally on the inside and the long ones on the outside. There's nothing to stop you putting an extra pair on the inside so that the lever arms are further away. I've done that before and it works.

If you have rim brakes, you need to get the rim central. That means dishing yhe wheel. For that, you need to know a little bit about wheel-building and truing. If you want to sort it yourself, have a look at Sheldon Brown's guides and some of the Youtube videos. It's not as difficult as it looks. You don't need a truing stand. You can put a zip-tie on the chainstay to use as a guide. On the other hand, you can take it to a bike shop for them to do. $30 to $50 is probably what they'll charge.

When you buy a rear motor kit, they have no idea what gears you're going to use or how much off-set in your frame, so you will neatly always need to make a bit of adjustment if you want your rim central.
 
What Dave said.
I have used a half a dozen "Cute" wheel builds and they are just fine for 20 mph ebike builds.
Yes, the require "adjustments" ranging from simply tightening the spokes for the frt., to severe dishing for the CST rear.
It's not rocket science. If the OP cannot spend an hour or two researching and another hour or two putting what he learned to work, then he should have spent the extra $150 and bought from a "reputable" vendor.
 
rossw said:
Got a Q100 kit for my wife's beach cruiser.

First problem - rim on motor is much narrower than stock rim which is 1.75. Tires used on cruiser are 2.125. Is this safe on the narrow rim? (no size marking on the Q100 rim).
Also the narrow rim does not allow brake contact before the v brake arms hit the fender. I have adjusted the v brake washers as much as possible.

In addition, the motor appears to be off center in the wheel assembly. Even if I assemble without the fender, it looks like it I will not be able to get the brakes adjusted due to being off center.

Is this narrow rim typical with the Q100 kits?

Can I do anything to get the motor centered?

Thanks for helping out a newbie biker and ebiker

Ross

First on the question of the rim width. A rim with the internal bead to bead width of 19mm (outside width of about 24mm) is commonly used by many E-bike wheel builders. The reason for this is it is suitable for a wide range of tires from 28mm to 47mm. The high end of that range however is often exceeded by many riders; I have personally gone up to 2.15" (55mm) on the same size rim.

rim width.gif

See what Schwalbe has to say about the matter here: http://www.schwalbetires.com/tech_info/tire_dimensions

Second, you really should be able to adjust your brake pads to reach the rim even if it is narrower than the original. Did you swap the interchangeable spacers so that the wider one is inside as shown below?

V-brake.jpg

Third, as the others have stated Chinese wheel builds are notoriously poorly done. A Q100 wheel I previously owned (new but bought second hand) required some time on my truing stand to get it round, centered and uniformly tightened. If you don't have a truing stand you can do it with some patience on the bike using the V, canti or caliper brake pads as a guide. The pads should be temporarily adjusted very close to the rim to do this. I often touched up my wheels this way with very good results in the days before I owned a proper truing stand. If you don't want to do the work yourself then find a bike shop that will work on an electric bike (some won't) and pay them to true the wheel for you or re-spoke it in a wider rim.

-R
 
Ok - first - thank you everyone for the great responses - took me a little by surprise. I have been through this before and ended up building two of my own boats. I also build my own golf clubs (easy).

The motor is a front wheel installation, I should have mentioned this. I checked the link for the tire wheel width combinations and I should be fine with my setup - the rim width is 19mm. The rim is still off center. I elected to take it to a bike shop because I want to get this on the road quickly as my wife is recovering from surgery and wants to ride. For future builds I will be looking at building my own.

I have adjusted the cone washers on the brakes, but the problem is the combination of a wide fender with the narrower rim. I will break out the dremel tool to cut slots to give clearance for the v brake arms.

This is a low powered and low speed bike set up on a beach cruiser and I think it should be fine with this setup.

Sorry no pics right now but I will post some when finished.

Thanks again to all!!

Ross
 
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