Anyone successfully spoke up a fatbike wheel?

[Boodyhole]

I'm planning my first build, reading everything I can, but I'm hitting roadblock after roadblock on getting info about fatbikes. Here's the plan so far;

Bike; Gravity Deadeye Monster, 21in (I'm 6'5 - 220lbs) http://www.bikesdirect.com/products/gravity/fat-bikes/fat-bikes-deadeye-monster.htm

Battery; 48V 25Ah LiFePO4 from Sun-things28 http://www.ebay.com/itm/48v-25ah-Li...598914?hash=item2118f48582:g:ticAAOSw6BdXMEcC
I was originally going to do a 20Ah, because it was the smallest they make that still pushes enough current, but for the $50 extra, I decided to go 25. They're both the same size (somehow?)

Motor; Ebay special 1000W 48V rear kit. Whatever one's cheapest at the time, or maybe one close in price with a thumb throttle. (As a side, is there a marked difference between the ones that look like the 9C RH205 and the ones with the concentric bare metal circles on them?)

My plan is to modify a Fat Rim with the hub from the Ebay kit. I'm fairly competent with tools, and mechanical things.

Now I start having lots of trouble finding information. The only article I found that was helpful at all is this one https://electricbike-blog.com/2015/03/10/pita-hub-builds-on-fat-bike-rims-101/

The process seems straight forward enough. I know It will be frustrating at times, but I know I can handle it. My problem is that I can't find any drawings or dimensions of anything. I don't know where the motor hub sits, where the bike's stock wheel's hub is, or if it's offset.

I'm looking at rims. I've basically settled on the Origin8 AT-PRO801-UL http://www.niagaracycle.com/categories/origin8-rim-26x4-0-at-pro801-ul-36-72-black

It's one of the few fat rims that uses 36H, which is on the chinese ebay special hub motors. It also seems like it can be offset laced - or- laced normally.

I'm thinking about just buying the Bike, Kit, and battery. The bike and Kit should come in first while I wait 2 months for the battery to arrive. I can assess the rim situation, and order then. Make some torque arms. Should be enough time to get everything sorted out. I have a friend with a battery to test the kit before disassembly.

Worse case scenario, I wind up buying a normal steel frame single speed, re-assembling the original hub, and riding that... Have an extra stock fatbike for fun.

Does anyone know -anything- that will help me? Thanks!

 

[Boodyhole]

Ohp... Should this be in Ebike Technical? Can someone move it?

 

[Drunkskunk]

Welcome to the forum and fat bikes in general.

The only actual problem that a fat bike wheel has over a normal ebike wheel is the width of the axle. If you plan to run a rear wheel motor setup, you have to track down one of the motors with a wider than normal axle that will fit the fatbike frame. Not something that is actualy hard, it just takes more time.

There are a lot of 36 hole rims out there. In fact I just got conformation last week that Boa-G's rims are all 36 hole.
I've used ChoppersUS rims in the past. The set I'm running now have survived my brutal punishment on my Monster bike. Singlebutted 13/14 spokes are the way to go, but straight gauge 14g spokes are perfectly suitable. You can use spoke washers if you choose. They make assembly easier for new builders, but they aren't really needed.
http://www.choppersus.com/store/category/3/71/Rims-Only/

If you are new to building wheels, then you might want to total up the costs of the spokes, rim, motor, and all the accessories you need, and what your time is worth to you, then compare them to this: http://lunacycle.com/fat-ebike-kit-1000-watt-waterproof-connectors-4-inch-rim/

As for batteries, you might want to search this forum for people's experience with that vendor. Dirt cheap batteries are often made of cheap dirt. The battery is one of the most important parts of an Ebike. A lame motor can often be compensated for by choosing a good battery, but a lame battery will make the ebike suck no matter what motor you have. Save some grief, buy a good battery. here is one option: http://lunacycle.com/batteries/packs/


As a tall guy, you'd probably love my Monster fat bike. the seat is 48" off the ground. Link to the build is in my sig line below.

 

[Boodyhole]

Good point on the dropouts. The bike I'm looking at actually has 135mm dropouts, but it's single speed, so you can fit a 80mm rim on it. That's where I'm getting tripped up. It's not a typical fat-bike set-up. The rear dropouts aren't offset out like a Pugsly. They just took a mountain bike frame, and stuffed a fat ass tire into it.. I think. I don't know though!!

Ahh, when I saw searching, the Origin8s were the only rims I could find for less than like $180. I'll look a bit harder, I guess... but I really don't even know what to look for. I think I want something drilled (to match the front... though I could obviously change out the front, too) and something double walled because... I dono why?

Yeah, I came across the Luna fat wheel, but I'd like to get my hands dirty. Part of the reason I'm doing a fat instead of just a wheel-swapping conversion is so that I can take on a challenge. Wouldn't feel as good to just bolt some stuff together, and wire it up. I'm looking at ~$225 for parts to build the wheel, and that comes with a controller, throttle, brakes, and other miscellaneous stuff.

As for spokes... While I've got you... If I recall correctly, all of the Ebay Chinese special conversion kits use 12G spokes. Seems like every other rim wants 14G spokes. Can I just stick some 14s in there? I have not built a wheel before.

I'm aware of the batteries. I've actually seen more positive things about sun-things28 on this forum than negative. And of course every time someone has a bad experience, they come to the forum to post about it. Fewer people come on to say "That crappy battery I bought works fine." I'm trying to keep costs low for this build to see if I'll even get much use out of the bike. If the battery dies in a year, and I love E-biking, I'll get something more reputable. Thank you for your concern, though. Everyone should weigh the risks. Hopefully it lasts me 5 years.

That is a damn sexy bike you made there! I'm gonna hit you up next time I'm in Dallas for a test drive!

 

[docw009]

Yes, I spoked a [strike]Weinmann[/strike] Origin DAT 36 hole 4" rim last winter to a 135mm hub motor. This gal was my teacher. First time spoker, I used 13G spokes. Ordered them a bit too long. Washers fixed that.

Came out OK, once I learned to do things systematically. I spoked a second wheel this summer. 700CC. Easier. Used tapered (13G-14G) spokes because that was a small hub and light wheel.

Edit: I bought the Origin off ebay. They appear to make a lot of fat bike accessories. Added their front derailleur mount. Like a fatbike needs one.

 

[waynebergman]

Hi Boodyhole
I am a hobby wheel builder over the years and my first fat tire wheel was built this year. I have a mid drive so no experience with a hub motor to the fat rim but I have never been happy building wheels with hub motors as the hub flanges are so crazy large in diameter and also narrow spacing on the flanges to boot meaning no 3 cross and crap spoke angles to your build. A hub motor will mean you can not go 3 cross for a lacing pattern so if you go one cross or radial for lacing pattern it may be an idea to lace the wheel up with your left side motor spokes going to the right side of the rim and the same idea of cross over to the other side of the rim with your motor right side spokes. You will have to do the research for getting the correct spoke length to do this but my thinking is you will be better able to true your wheel and make offset adjustments with the better angles you will get by swapping hub spokes to the opposite sides of the rim. I did this on my last build but it was because I was using old spokes that were too long for the new hub I installed on an existing wheel.

I also think thinner gauge spokes will work just fine and much easier to find at your local bike shop, go for even tension and quality spokes if you can.
Confirm from others if you take my advice as like I say I am just a hobby builder not a bike mechanic.
Details on my wheel build can be seen on my fat tire thread in the link below if crossing sides don't make any sense to you..........good luck and I also would recommend getting your stuff from Luna as was suggested in a previous post.Also that pack you were looking at seems to be close to 6" wide are you sure that is OK?

 

[icerider]

I have no real experience in building wheels at all and the only wheel I have ever built was to put a Bionx PL350 motor into the front wheel of a Mongoose Dolomite with 4” tires. There was enough room for a 1-cross lacing but I didn’t have the right length spokes for that. I looked at radial lacing but that would have left me with effectively ZERO spoke angle and I had read that was a BAD thing.

I chose a radial pattern crossed from left to right which gave me some spoke angle and gave me a spoke length for which I had the right length good-quality 13g spokes lying around.
When I unbuilt the wheel to remove the original Chinese hub, I laid the rim flat on the concrete floor of my garage and it lay nice and flat so I think I had a good rim to start from.

I built the wheel by the simple-minded expedient of counting the turns on each spoke and keeping them equal all the way around. When they got nearly tight, I tightened only ¼ turn on each spoke for each trip around the rim. I tightened until they “felt” tight and “plucked” to about the same noise as my other 26 inch 13g Bionx rim.

I don’t have a truing stand so I cobbled up an arrangement that let me spin the wheel in the bike’s fork and use simple pointer to check runout. The wheel was very round and had less wobble than it had before I took it apart to add the Bionx motor. I tried to correct the largest wobble and reduced it pretty easily to < 2mm. I called that good enough. I checked the tightness every couple of days for the first couple of weeks and didn’t notice any real changes. The wheel has been working fine for several months and I still don’t see any changes in tightness or in the wobble.

I tell the story only to suggest that the 4 inch rim was pretty stiff and probably contributed to what was clearly beginner’s luck in my case. I think that might hold true more generally, that the wider rims are stiff enough that a good round flat wide rim is a good candidate for a first attempt at wheel building.

If someone knows that this isn’t true, I would appreciate being corrected before I get myself hurt by a bad wheel build.

 

[Chalo]

I recommend a rim without holes in it, because a hub motor makes a weaker wheel than a normal hub, but a hub motor bike demands more of the wheel. My first choice would be the Origin 8 DAT-PRO 65, which is double walled without vanity holes. When I've tried to build up DAT-PRO 80, the seam wasn't square and the wheel couldn't be finished satisfactorily.

One issue you'll run into with a centered 135mm rear end on a fatbike is chainline. If you choose too wide a rim or tire, the chain will rub on the side of the tire. Both the front and rear sprockets must be moved to a more outboard than normal position so that the chain will clear the tire but still run straight from front to rear. It's a lot easier to get it right with a 3.5-4.0" tire on a 65mm rim than with wider rim and rubber.

Another advantage to a 65mm rim is that you can use tires in the 2.3-2.8" range if you want to.

 

[icerider]

... because a hub motor makes a weaker wheel than a normal hub ...

Is that simply because the motor is a larger radius than a hub and the choice of lacing pattern is more constrained ??

 

[Chalo]

... because a hub motor makes a weaker wheel than a normal hub ...

Is that simply because the motor is a larger radius than a hub and the choice of lacing pattern is more constrained ??

It's because the flanges are narrower across and the bracing angle is less than you get with a normal hub.

 

[teslanv]

We lace MXUS Hub motors in the Origin8 DAT-PRO 101 Rims (100mm), and as Chalo mentioned, you will need to dish the wheel to the brake side to get a good chain line without the chain rubbing the tire.
You will only be able to do a single cross lacing pattern, most likely. The 100mm wide rim we use will probably be too wide for your frame, but I think the DAT-Pro 65 rim might be a good fit.
Get a low-Kv motor (Lower RPM per volt) if you want decent torque with those big tires, and without the need for a monster controller. A 6Kv DD Hub with a 48V- 30A Controller would probably do quite well, I'd say.

 

[DRMousseau]

... because a hub motor makes a weaker wheel than a normal hub ...

Is that simply because the motor is a larger radius than a hub and the choice of lacing pattern is more constrained ??

Or is it because of the narrow 35mm-40mm spoke flange width of hub motors??? And jus what effect does this narrowness have on wide rim wheel builds??? I'm watching this topic with GREAT interest, since, as noted, there just isn't much info out there about these kind of builds, and I'm about to begin an unusual and unique winter build project myself. While I've laced a few wheels of various nature in my life (including motorcycles and even early 30's automotive wheels), I've never wandered far from OEM standards and setups. And this time,... I'm venturing far beyond those and anything similar. The 4" wheel will be custom drilled, and will likely be offset to the brake side as necessary. Since this is a radical full custom build, the entire bike will be designed around the rear wheel/hub motor assembly.

With such narrow hub flanges, jus what is likely the best drill pattern and position on these wide rims???

 

[DRMousseau]

Sorry,... hadn't noticed Chalo's reply when I made my previous post,...

It's because the flanges are narrower across and the bracing angle is less than you get with a normal hub.

But I still find it important to know where this weakness lies and if it can be somewhat accommodated by considerations of special custom hole locations in the rim. While I understand that that this bracing angle can be improved by swapping spokes across the rim, if the spoke holes have some offset in the rim,... is there any reasonable minimum that bracing angle should be??? Does this weakness induce worrisome stresses somewhere, that are increased with a wide rim??? While others have to consider rim construction and maintaining shape and trueness, I'm most concerned with stresses on the spoke holes of the hub flange and other parts of the motor assembly (axle and bearings).

 

[teslanv]

Fat rims generally have spoke holes staggered (offset from the centerline) around the rim. Other "normal" bicycle rims have spoke holes that stay in line. This fact contributes to a very low bracing angle between the hub motor and rim. With a narrow hub, the problem is even worse. You might end up with a hub flange width that is almost exactly the same as the spoke hole offset distance of the rim, in which case there is zero bracing angle to provide lateral stability to the wheel assembly.
As such, you will have more success choosing fat rims with narrow hole offsets, and hub motors with wide spoke flanges.

 

[Chalo]

If the holes aren't tilted too much, sometimes you can lace across to the opposite side of the rim to increase bracing angle. There are limits to this because it twists the rim more than normal lacing and sometimes destabilizes the joint.

 

[DRMousseau]

AH!!! I understand now! And I'm sure others will too. Thanks!!!

But "I" still have personal concerns of my motors spoke flange,... and spokes to a degree. My rim isn't any different than a solid machined casting,... no seams, and completely unyielding to any deformation in any way by the WORST forces a "heavy" bicycle would subject. While I understand the physics of "normal" spoke bicycle wheel construction, and the important relationship of "give" in rim and spokes (standard hubs and motor hubs have no give or flex), you might see I have some unusual circumstances to consider. The only "give" is in the spokes,... or the hub flange!!! ugh!

I think I'm best to consider my finished assembly, to actually be more of a solid wheel construction,... with spokes. The spokes serving the only function of centering and truing the hub motor to the solid rim instead of what is "normal". I'm actually considering additional spoke holes to double the number in my hub, to distribute forces more evenly about the hub flange. Since the typical hub such as mine, has holes for 12ga spokes, I'm sorta assuming this is the largest the flange construction can reasonably accommodate,... although 12ga are not the best choice for "typical" bicycle wheels ( I still don't understand "why" these have 12's for the intended use on bicycles!). I also believe the hub design CAN accommodate the added holes without weakening adjacent holes (my hub motor does NOT have paired holes as found in some). AND, I will stick with the 12ga with hopes that the unique manner of construction will not have the inherent problems of standard bicycle wheels. I'm thinkin' mine will be similar to wheels of the Ford Model A,... although they were subject to great lateral forces on a suspended spindle, AND the cast hub had to accommodate an internal brake!!! The seemingly simple spoke work is actually an incredible work of engineering! Thank goodness I'll have none of these concerns!!!!

Now,... I had some thoughts of a straight laced assembly, but my front is a standard and typical 24" wheel, and I'd rather NOT reconsider that to match the rear in appearance! Since I'm drilling my rim as necessary, the additional spoke holes in the hub will also allow a single-cross with an acceptable angle. This will match the front close enough,... even with double the number of spokes.

And I thought I'd add the photo below, because I found this unique construction "inspiring". This is the rear of a full custom motorcycle build I saw this summer. Of course motorcycle wheels ARE NOT anything close to bicycle wheels!!! I was jus surprised to see a straight laced rim on a Motorcycle of such HUGE engine power. While it looks "showy",... it jus seems unnerving to me. And others might notice the unusual "disk" brake/sprocket! The craftsmanship and uniqueness of the entire bike was exceptional among all I've seen in my life.

This week sees the beginning of my frame jig construction AND the beginning of my rear wheel assembly and construction. My entire build is centered and constructed around this rear wheel/hub motor matter and it's limitations. I'll start a separate build topic with pics as this progresses, but I'd like to welcome any comments or considerations here that might also be of concern to other "fatbike" wheel builds.

 

[Boodyhole]

for lacing pattern it may be an idea to lace the wheel up with your left side motor spokes going to the right side of the rim and the same idea of cross over to the other side of the rim with your motor right side spokes.

I also think thinner gauge spokes will work just fine and much easier to find at your local bike shop, go for even tension and quality spokes if you can.

Also that pack you were looking at seems to be close to 6" wide are you sure that is OK?

Thanks for the reply, waynebergman

I came across crossing the spokes on another build, and they gave the same reasoning. I will assume that I'll have to do that and start off with that plan.

My question about the spokes is whether they'll fit in the hub. Will the balled end of the smaller spoke be too small, and slip through the hole? Looks like they're rather oversized, and it shouldn't be a problem.

Yep, 6" monster strapped between my legs. Hope it doesn't blow. I'll definitely be referencing your build. thanks for the link!



Thanks for the anecdote, icerider. I plan to do basically the same thing.

I recommend a rim without holes in it, because a hub motor makes a weaker wheel than a normal hub, but a hub motor bike demands more of the wheel. My first choice would be the Origin 8 DAT-PRO 65, which is double walled without vanity holes. When I've tried to build up DAT-PRO 80, the seam wasn't square and the wheel couldn't be finished satisfactorily.

That was my initial thought. I think I will go with the undrilled version of the 80mm rim. I'm thinking 80, because the bike comes stock with 80. I guess I could use a 65mm rim, and a 4" tire, and the tires would still match, but a 80mm rim with a 4" tire should have the same clearance issues as a 80mm rim with 4" tire, no? Could you go into more detail about what you mean about the DAT-PRO-80 you tried using, and why it didn't work out? The rim that you got was bent? Thanks for the reply!

We lace MXUS Hub motors in the Origin8 DAT-PRO 101 Rims (100mm), and as Chalo mentioned, you will need to dish the wheel to the brake side to get a good chain line without the chain rubbing the tire.

Hi, teslanv. Would you mind looking at the pictures of the bike with more experienced eyes than mine? It seems to me that the rim isn't dished, but they just managed to squeak the chain by because it's single speed. I'll find out when I get the bike, but I just can't tell from pictures online. For this build, I'm just going to grab a -whatever- motor. I can re-use the chinese parts to build my girlfriend a traditional mountain ebike later if I want to upgrade. Just looking for some experience now. I'll keep that info about the motor in mind, though. Thanks!


Looking forward to your build, DRMousseau. Sorry I don't have any good advice for you!

 

[panurge]

Everything has been yet reported, I'll just add this link to another cheap china 80mm rim that has narrow 36H (7.5mm offset) and are proven to be acceptable quality....http://www.stars-rim.com/english/product1.asp?id=742 I've laced many fat tires here for PedegoItaly and various customers, even 20" Fat wheels. those stars-rims are better than many others, at least they are pretty round and offer narrower holes than the standard.
A fat wheel is typically easier to be laced than regular ones if the rim is round. that's because you don't need to really true it. However, when a Fat wheel needs to be really trued, once properly laced and progressively tightened, that means easily It can not be trued at all. That's because, due to the wide rim holes offset and narrow hub flanges, as yet stated, a high increase in tension, correspond to only little truing effects....resulting in not trued wheels and/or wheels with crazy exaggerated tension somewhere or everywhere.
That's why the rim play a more important rule in a fat wheel than in a standard bicycle one.
Another question is that lacing 1 cross, with a hubmotor, will result in excessive bend in the spokes intersection, so that, many, choose to not overcross the spokes each other. From my bicycle perspective, this is crazy, but in motorcycles that was not uncommon, so I would use butted sapim spokes in a regularly crossed wheel but beefed spokes if a 1 cross without intersection is the choice.

 

[Boodyhole]

Everything has been yet reported, I'll just add this link to another cheap china 80mm rim that has narrow 36H (7.5mm offset) and are proven to be acceptable quality....http://www.stars-rim.com/english/product1.asp?id=742 I've laced many fat tires here for PedegoItaly and various customers, even 20" Fat wheels. those stars-rims are better than many others, at least they are pretty round and offer narrower holes than the standard.

Thanks for the reply, Panurge. I'm not having any luck finding a place to actually buy those rims, though.

Maybe I'm not explaining my concern correctly. The bike that I'm looking at is a fatbike with a 135mm rear dropout. I can't tell for sure, but it seems to me that it uses a standard single speed hub, and it just has an extra fat rim on it.

My concern is that the hub will be off center, because it seems like the hub motors usually are.

Do I just cross the spokes to the other side, and use longer spokes on one side than the other? Will that work for this frame?

 

[Toorbough ULL-Zeveigh]

I recommend a rim without holes in it, because a hub motor makes a weaker wheel than a normal hub, but a hub motor bike demands more of the wheel.

to be absolutely clear;
you're saying Justin is selling weaker wheels.
do i have this straight?

Have any of our unlaced hub motors built up into a rim size of your choosing

 

[Drunkskunk]

...
Maybe I'm not explaining my concern correctly. The bike that I'm looking at is a fatbike with a 135mm rear dropout. I can't tell for sure, but it seems to me that it uses a standard single speed hub, and it just has an extra fat rim on it.

My concern is that the hub will be off center, because it seems like the hub motors usually are.

Do I just cross the spokes to the other side, and use longer spokes on one side than the other? Will that work for this frame?

Yes, offset, or "dishing" a wheel is going to be weaker than a normal wheel build without dish. But unless you plan to ride down a black diamond slope all year long, it's not going to make much difference.
Still, there are things you can do to make the situation better. One is to drill new holes in the rim that are as offset from center as the hub motor's flanges. Your spokes do not need to be at the center of the rim. Most cars' spokes aren't. While having the spokes near the center makes the wheel easier to true, the key word there is "near". On an 80mm wide fatbike rim, there is a whole lot of space in the middle of the rim that is "near" the center.
The other thing you can do is to cross lace the wheel. that means the spokes from the left hand flange go to the right side of the rim, and vise versa. It aids in wheel stability, but is often overkill.

 

[Boodyhole]

Alright, perfect. I'll just go ahead and get a solid rim with 2 sets of offset holes. When the motor comes, in, I'll take my measurements, do my calculations, and decide whether or not I want to drill new holes for the spokes, or just use longer spokes on one side.

I think I'll cross lace it just for peace of mind.

Thanks everyone! I'll be a few months saving money for parts, and I'll put up a build thread when I'm done... or... more likely, I'll come with more questions when I'm half-way done.

 

[Chalo]

Alright, perfect. I'll just go ahead and get a solid rim with 2 sets of offset holes.

The Un-holey Rolling Darryl is the only rim I know of like that, and it's only available in 32h.

 

[Ozzzz]

I think the Alex rims, my mac's laced to, are available online? Solid/offset/36h?
Personally (though far from being an expert, just getting better at cost/time/benefit) i'd just by one laced, and probably into a hub with some rep.

 

[Chalo]

On their website, it looks like Alex's fatbike rims are all shot through with windows and thus radically weakened versus a continuous surface rim.