Any suggestions greatly appreciated.

[Teaker68]

Finally had fat tire bike wheel built for 170mm dropouts. Was able to remove spacer line up disc brake that still needs some fine tuning.

I know I was going to have to customize a few things but I don't know now if this set up is even going to work. As you can see from picture bike is upside down with 1/2" clearance from gear sided stay and 1 1/4" from disc brake sided stay. Haven't tested derailleur or chain yet for the fact being know once tire is mounted its going to rub. I can put jamb nut and spacers to increase current dropouts 170mm but this wheel was supposed to be specked out for 170mm.

Appreciate any feedback.

 

[Todd]

The picture's look "text book" as if the wheel is not dished to fit drop outs. have you considered that?

 

[Drunkskunk]

Pictures may be worth a thousand words, but its really hard to tell from those pics what the problem is. Is the wheel just way off center?

If so, what size rim (width) is that, and who made it? And who laced it?

 

[Teaker68]

Still have to file out dropouts a little for axle to sit into deeper but do you think it's going to make up 3/4" to center wheel. I'm talking maybe 2-3mm. Old axle was 8mm this axle is 9mm.

 

[Todd]

So you changed the axle in the motor and laced motor to a different hoop?

 

[Teaker68]

Yes, it is 3/4" off center. Wheel is 3 1/4" wide same as the old one that came off. Bike was set up with 9 speed cassete and new wheel to 7 speed free wheel. Bought 1000W motor from China -Ebay and had somebody in NJ build. But spinning wheel it's true to the same dimensions. 1/2" from gear sided stay and 1 1/4" from disc side.

 

[Teaker68]

No Todd, the original axle was from a Framed Fat Tire bike that specs at 8mm. The electric motor was built with 9mm.

 

[Todd]

Is axle machined for a 135 mm drop out or 170 mm drop out. Can you check the dishing of the wheel?

 

[Todd]

It do not look like you axle diameter is the issue here it's that the axle length and dishing are both off

 

[Drunkskunk]

Now I see what you mean. Some side shots of the spokes may help, but it looks like the wheel needs some serious dishing to be centered. that may not be possible with just spoke re-tensioning. it may take some rim re-drilling to work, but that can be done on a fat tire rim without too much trouble.

Do you own a drill, and have you ever laced a wheel before?

 

[Teaker68]

Axle is machined for 170mm dropouts. I'm sorry but don't know how to check for dishing. To be honest don't even know what dishing is. I will take some pictures of side of wheel.

 

[Todd]

Drunkshunk... I'm new to hub motors but not to wheel building or cycle building. Can the 135mm axle be replaced with a 170mm axle?

 

[Todd]

Correction... The 9mm axle looks to be machined for 135mm drop out then placed in to 170mm drop out giving you all that extra space. If you place spacers in to take up that space it looks as if you will need to dish the wheel for your set up. That compensation may place more stress on the drive side spokes than is needed. Also it will put more stress on the bearing in the hub, the farther away for the bearing the stay is the greater the stress.

 

[Todd]

http://sheldonbrown.com/gloss_da-o.html#dish

Dish
A bicycle wheel should have the rim centered directly in line with the frame. The forkends are symmetrical with respect to the frame, and the hub axle locknuts (or equivalent surfaces) press against the insides of the dropouts.
Wheels should be built so that the rim is centered exactly between the axle ends on the hub. In rear wheels, the spokes attach to flanges which are not symmetrical about the centerline...the right flange is usually closer to the centerline than the left flange, to make room for the sprocket(s).

When rear wheels are built properly, the spokes on the right side are made tighter than those on the left side, pulling the rim to the right, so that it is centered with respect to the axle (and to the frame.) Viewed edgewise, a rear wheel built this way resembles a dish, or bowl, since the left spokes form a broad cone, while the right spokes are more nearly flat.

By extension, the term "dish" is used as a general synonym for accurate centering, even in the case of symmetrical wheels.

See also my Wheelbuilding article

Dish Stick

A tool for checking the dish of a wheel. It has the form of a curved stick with an adjustable feeler near the middle. The two ends of the stick rest on the side of the rim, 180 degrees apart, and the feeler is adjusted to just touch the locknut or other locating surface at the axle end. The wheel is then inverted, and, if it is correctly "dished" the three points will all contact the corresponding points on the second side of the wheel.

 

[Drunkskunk]

That axle looks fine.

You have 3/4" difference between the sides, but that means you only need to move the wheel half that distance to get it centered. Converting to all 8ths measurement. 1-1/4" = 10/8ths. 1/2"= 4/8ths. So you're 10/8ths on one side, 4/8ths on the other, and you only need to move it 3/8ths to make them both equal 7/8ths". That isn't much, less than half an inch, but it may be asking too much of those spokes by the way it is laced.

"Dishing" is a term used when the spokes are tightened in such a way that the wheel doesn't sit centered on the hub, but is centered in the bike's frame. The Asymmetrical form kind of looks like a dish It can be done by tightening one side's spokes and loosening the other side until the wheel is pulled closer to the center, but often the tightest side needs shorter spokes. the end result looks like this pic.

Its not hard to do, but your spoke nipples are staggered, so you're limited in how much dishing you can do with that rim unmodified. You can try it without drilling first, even getting closer to center may be enough. But if it doesn't work, the rim will need to be re drilled, and new spokes might be needed.

The good news is Fat bike rims are huge, and there is a whole lot of room to drill new holes. In fact outside of Ebikes, it's pretty common to drill out the rims to make them as light as possible, and get the spoke placement where it's best needed for that bike. Its not a high percussion job, either. it's the kind of thing an average person can do with a cordless drill and a measuring tape.

There are a few ways to do this, each depending on your skill. Moving every spoke hole 3/8ths closer to the gear side would allow you to keep the original spokes but move the rim 3/8ths inch closer to the brake side. that will do no harm for the bike. off center spokes are fine.

Here's a pic of a rim with off centered spokes.

 

[Teaker68]

If I shimmed the dropout on gear side chain stay it probably would have little impact on seat stay correct? Like Todd was saying would it put too much pressure on hub and frame in general? That is an American tape measure in pics.

 

[Todd]

Teaker68,
If your placing a 135mm hub in 170mm drop out you may a few issues to look at.
1st.. The approx. 35mm space
2nd.. Dishing that offset, as mentioned Drunshunk above
3rd.. Your chain line
Is this frame "symmetrical”? It looks to be. Meaning that the rear triangle is symmetrical, like most traditional bikes, with equal spacing of the right and left dropouts from the centerline of the frame.
Is the bottom bracket 100mm?
An offset frame may solve most of your issues (you would still need to do some dishing approx 17.5mm), this is a common Fat Bike solution for the use of a 135mm rear hub.

 

[Teaker68]

Todd, the 35mm you mention is very close to the distance I have on disc side and a little less then a 1/2" on geared side throwing the wheel off center. Did check all my measurements from bottom bracket which is 100mm and they were all symmetrical. I'm under impression that wheel wasn't dished properly like you both had stated. The wheel over the hub is not properly placed. Waited forever with hopes of bringing bike to Cape but now will probably get the no return email or phone call from guy who built it.

Just wondering if I shimmed out gear sided dropout with washer/spacers if it would work without putting too much pressure on frame.

 

[Todd]

??? It's a considerable space. I would not think it would work on a standard bicycle axle due to the fact it's hollow. This is what people that try and put an 8 or 9 speed free wheel in an older 10 speed frame find out. The axle bends due to the length, free hubs help this issue greatly with the bearings being farther apart. Free wheel axles bend when used as designed all the time. Now your axle is beefier, how much in proportion to the weight and torque...?? I would tend to think that welding an adapter to the frame extending it to the hub might be a way to go.

 

[Teaker68]

Todd, just found this picture in regards to what you were stating about 135mm.

 

[TSAR]

Looking at the very first pic, is there a giant spacer on the brake side? Can it be removed?
If it can be, that should take care of it, but you may have to dish the rim the other way after centering and shimming. My LBS is usually good for that, they can center the rim without taking the wheel out of the dropouts

 

[Drunkskunk]

If I shimmed the dropout on gear side chain stay it probably would have little impact on seat stay correct? Like Todd was saying would it put too much pressure on hub and frame in general? That is an American tape measure in pics.

You could shim the motor over if you removed the spacer used for the brake disk. but then you would need a way to mount the brake disk and get it aligned for the brake caliper. You'll have as many problems getting the brake aligned as you are now having getting the wheel aligned by going that route. Though it may be an easier problem to solve for you. Just depends on your skills. If it was me, I'd stick with moving the rim, since the brake is already aligned and looks like it will work. no point breaking that to fix a rim issue.

The other issue I saw but hadn't mentioned was your chain line. It looks like you won't be able to use the bottom gears on that as the chain will hit the rim and tire. It's hard to tell from the pic just how bad it will be, but would be partially solved by moving the rim over on the spokes.

Good basic reading you're going to need is Sheldon Brown's guides to wheel building and wheel truing. http://sheldonbrown.com/wheelbuild.html

 

[TSAR]

On second look, if the motor axle is machined out to 170mm, removing the brake spacer will not solve it.
Like the others have said, just dish the wheel left by a few mm, it's not that much, and it will free up the low gears on the right too

 

[Drunkskunk]

Doh!!

I should have thought of this sooner. Which motor is that? Do the spoke flanges sit perfectly in the middle of the motor like that drawing, or are they off set to the drive side like this one?

If they are offset, which is normal for most motors now, that can totally be reversed, which will offset the rim to the brake side, and give you a good bit of clearance. It does involve taking the motor apart, but nothing more complicated than taking the side cover off, pulling outer ring off, and slapping it back on in reverse.

With that done, you probably can make the rest of the adjustments with just a spoke truing. no re-drilling or new spokes should be needed.

 

[Teaker68]

Motor is a 1000W direct drive, Drunkskunk you are right never thought about removing and reversing. You guys are right regarding losing first and second gears. Just put it together again and Todd was right regarding axle being too long, had to remove derailleur to get wheel in. Don't have a chain for free wheel have to stop by LBS to pick one up tomorrow. I truly appreciate everything hope you all know that.