Hub successfully rebuilt! need advice for cutting and welding larger seat and chain stays on rear triangle

[kenshippo]

Hello all

I am a first time builder of a hub as I purchased a 26 inch hub motor instead of a 24 inch one. Its hard to find hub motors that size that would ship in a decent time so I decided to purchase spokes from Grin Technologies and a 24 inch rim from either there or somewhere else. I have used their spoke calculator as well.

They have several rim types and I am not sure which one to get. I was looking at the crystalyte one but the infamous Chalo was saying its rubbish.

Rim24J31

24

ebikes.ca

Rim24_DM30

24

ebikes.ca

I also heard weinmann isn't that bad.

I then heard the Halo rim is the bees knees. While I respect the price of 69$, that combined with the lack of a rim profile on grin is going to make it more expensive and more of a headache. While the ERD and rim width is provided, I haven't been able to find any information on the left and right offsets for it. If anyone has one and can provide them that would be great.

NEW Halo SAS 24" Disc Rim 36h - Black | eBay

Halo SAS 24" Disc Rim 36h - Black. The anodized rims can be used with rim brakes. The anodized finish will wear and reveal the silver colored aluminum. As the braking surface is not CNC finished, there is a bedding in period.

tinyurl.com

The rim will be used on a front loading cargo bike. The rear hub motor is 2000w 72v.
So my first question is how much should I be stressing over the rim, and which one should I get.


This is my old rim, 26 inch. Also its worth nothing that the axle doesn't fit in the dropouts, so I tried bending the frame with some but not enough success.
I am worried that the torque of the hub might be too much for the dropouts as well. Would like some opinions on this.



I've purchased the 24 inch halo rim, and I suppose brought the thing into dish.

Right now I am concerned that the wire exiting the hub motor is too close to disc brake mounts. Any suggestions?




UPdate@
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We have been running, I've limited the power to 48v, up to pas 4 max out of 5. At pas 5 we get around 36-38mph top speed.
We have done 280miles on the odomoter with no signs of wear to the dropouts.

Now we have another issue. No suspension on a bike like this is brutal. I increased the size of the tires but its too wide for the seat stay. I have been playing around with the idea of unwelding and welding to the bike but I am not a welder. I don't know if I should try to pay someone to do the weld or of I should buy a welder, learn how to weld and do it myself.
If I were to do the welding myself, any reccommendations on a mig welder? Tutorials, etc?
If I were to outsource the work, would it simply be better to entrust this to someone who knows what they are doing?
My bike is certainly steel. The length of the seat stay bars are 13 1/2 - 14 inches.

Theoretically I would love for this bike to support 4.0's in the back, which would require me replacing both the seat stay and the chain stays, but that would be more complicated to do I assume, but would it be worth it to just do that now instead of just expanding the seat stay?

1) I want to expand the seat stay bars so it can support a wider tire
-This involves cutting the current seat stay bars off, then welding wider bars.

2)What type of steel should I use for something like this? I know there is mild steel, stainless steel, stronger steel with various numbers. I assume that I don't have to match the type of steel exactly? I don't know the specific type of steel my bike is made from.

3)Where should I source the steel from?
(I've been trying to do a lot of research on this, and have found various websites, some of which want you to ask them for a quote) Columbus Zona fatbike seat stays - 19 OD - .6 wall - length = 560 I was looking at this one but honestly I have no idea what I should buy. I want it to be heavy duty asf, weight is not an issue. I know that the tube is hollow so you obviously need to taper the end to fit the dropout.




And finally my new paranoia are these two tubes. Especially after the babboe situation...The vertical one goes to the handlebar, but unlike other bikes of this type, it doesn't have a supporting upper tube, I wanted to weld a bar going from the vertical tube to the seat post tube but I realized its threaded on that lip there, so some other options would be ideal. Also if anyone has a solution or a size recommendation to attach a spring to the kickstand so I don't have to use the bungee cable that would be great.

 

[amberwolf]

Hello all

I am a first time builder of a hub as I purchased a 26 inch hub motor instead of a 24 inch one. Its hard to find hub motors that size that would ship in a decent time so I decided to purchase spokes from Grin Technologies and a 24 inch rim from either there or somewhere else.
<snip>
This is my old rim, 26 inch.

It's not clear if you mean the original rim on the bike is 26" or you mean the new motor's rim.

If your bike came with 26" rear wheel, you will change the handling and ground clearance of the bike by going to a smaller rear wheel. Whether those affect things negatively or not you'll have to verify by experiment.

They have several rim types and I am not sure which one to get. I was looking at the crystalyte one but the infamous Chalo was saying its rubbish.
I also heard weinmann isn't that bad.
I then heard the Halo rim is the bees knees.

I don't know Halo from experience, but it seems to have been used on some tough bikes from a quick google.

I have not had a Crystalyte rim that was any better than the average to worst rims on the junk bikes I've gotten from people and thrift stores over the years to use as parts for my projects.

Weinmann has been good enough so far for the ones I've come across in wheel builds; I don't think I've had one in my own wheels; most of mine were unbranded, except for pretty old stuff by Araya and SunRims. And more recently, a couple by AlexRims (which seem like the cheap side of better based on results so far).

But: If you match teh spokes and nipples you use to the rim's capabilities (especially don't use too-thick spokes), and correctly tension things, and stress-relieve the wheel and retension as needed, you will probably end up with a good-enough wheel build even with average parts.

Also its worth nothing that the axle doesn't fit in the dropouts, so I tried bending the frame with some but not enough success.

If you mean spreading the stays laterally to get more distance between them, that works ok for steel frames. For aluminum ones it can crack the metal and cause problems later on.

I am worried that the torque of the hub might be too much for the dropouts as well. Would like some opinions on this.

See The Torque Arm Picture Thread for many options, DIY and commercial, to deal with that. Ebikes.ca has probably the best commercially available ones, in the new v7 clamping arms. One on each axle end, secured to your frame, would probably take care of the issue.

 

[99t4]

They have several rim types and I am not sure which one to get. I was looking at the crystalyte one but the infamous Chalo was saying its rubbish.

Yes Chalo for sure can give you valuable suggestions. Not sure what you mean by "infamous"?

I then heard the Halo rim is the bees knees. While I respect the price of 69$, that combined with the lack of a rim profile on grin is going to make it more expensive and more of a headache.

Not sure what you mean by this?

While the ERD and rim width is provided, I haven't been able to find any information on the left and right offsets for it. If anyone has one and can provide them that would be great.

Vendor should be able to provide that information. Have you inquired with them? OTOH, I recently built a 26" on a 1500W DD hubmotor and the staggered rim spoke hole offsets did not make much difference as far as spoke fitment.

I am worried that the torque of the hub might be too much for the dropouts as well. Would like some opinions on this.

As AW recommended above, go with the Grin Tech TAs. Most all of the other Amazon/eBay/Ali* TAs are not sufficient (poor fit/poor materials/poor design, usually all three).

 

[kenshippo]

Yes Chalo for sure can give you valuable suggestions. Not sure what you mean by "infamous"?

By infamous I mean that I've seen Chalo engage in many a heated debate.

Not sure what you mean by this?

Chalo himself recommended the halo SAS rim, which I eventually purchased. That said I've seen it get one or two bad reviews...
There are already profiles on grin for the rims that they sell. This makes it so much easier to plug them into the spoke calculator. If I ordered from grin my spokes and rim would already be on the way. Now I most likely have to wait for the rim to get here, measure it properly, then order the spokes, and hope that the measurements are correct. This process is going to make everything several times longer. Especially because now I am in desperate need of reliable transportation and have been working on getting my bike up and running for months now.

Vendor should be able to provide that information. Have you inquired with them? OTOH, I recently built a 26" on a 1500W DD hubmotor and the staggered rim spoke hole offsets did not make much difference as far as spoke fitment.

I inquired about the offset of the holes and I haven't received a response, it would be great if someone who has it would happen by this thread and post the offsets though. I'm glad you mentioned that because I do tend to get paranoid about measurements. That said there is an option for that in the spoke calculator so I don't know, but it also depends on the specific rim and how staggered they are I imagine.

 

[Chalo]

Weinmann DM30 isn't bad. That and SE Bikes J24SG are the next best thing to the late great Alex DM24.

Halo SAS is a phenomenally strong rim for its weight, and it's not light. The lateral offset on the spoke holes is small enough as to make no practical difference in spoke length versus no offset.

 

[kenshippo]

Weinmann DM30 isn't bad. That and SE Bikes J24SG are the next best thing to the late great Alex DM24.

Halo SAS is a phenomenally strong rim for its weight, and it's not light. The lateral offset on the spoke holes is small enough as to make no practical difference in spoke length versus no offset.

Its the legendary Chalo!

I ended up purchasing the halo due to your recommendation, and I've built the rim on the 24 inch hub and tightened the spokes to the threads but am waiting for my bike to finish the cold setting process so I can fit in in to begin tighting/ truing it further.

Fun fact, I asked a guy at a bike shop what he would charge to finish up the rim. he said that it wasn't that bad and mostly true but he would charge 40$ for it. I decided it was do it myself kind of money.

Thanks for the tips

 

[kenshippo]

Bumping this thread due to update. Any suggestions on getting the wire further away from the hub motor so it doesn't brush up against it while spinning?

 

[amberwolf]

If you're still using this mounting method in the image below, you could grind or file a channel in the washer stack to let the cable be further from the rotor screws. Then you can ziptie or otherwise secure the cable to the frame to ensure it stays out of the way. If you use zipties or other plastics, use ones with UV protection so they last longer in any sun the bike sees.

 

[offGridDownUnder]

I am worried that the torque of the hub might be too much for the dropouts as well.

That seems almost certain.
A related problem is that you must attach the add-on torque arms somewhere in there, and decide how the motor cable fits with that.

If I interpret your picture correctly, I see the motor casing, then the 6 bolts to fasten a brake rotor, but with no brake rotor - rather the bolts are holding a spacer where the brake rotor would go.

If I'm correct so far, you must decide whether or not to have a disk brake rotor in there, and you should mount it before you try to work anything else out so you can take it into account.

If you don't intend to use a disk brake rotor on that motor, then you can remove the 6 bolts and the spacer to have a better idea of what space you have to work with.

The motor is supposed to be oriented so that the cable lies in the drop out slot, which permits it some relief so it bends away from the motor/rotor. Your choice to orient the motor cable so it does not lie in the drop out slot, and also to clamp it with those washers takes away your options. Grin and other do sell C-washers of varying thickness so that you can space with the washers and also permit the cable to bend away from the motor and fall into the drop out slot. You can also make some with a hack saw by cutting out the slot yourself in some washers that are sturdy enough.

If you align the cable exit with the drop out slot, and don't clamp it with your washers, you may find you don't have a problem with the cable - particularly if you aren't using a brake rotor and remove those unused bolts and the spacer.

HOWEVER - you really need to work out the torque arm before celebrating. I am using a v7 Grin torque arm to mount my SX2, and the block is 8 or 11 mm thick (I forget which, but it's THICK). Remove the 6 brake rotor bolts if you can along with that dummy spacer, fit the rotor if you are using a brake there, and then work out where that torque arm block fits in with some eye to how it interacts with the motor cable.

Putting a v7 torque arm (and some other versions as well) on the OUTSIDE of the frame is possible if there is enough motor bolt protruding, but it's a problem. The clamp in that block must be torqued down hard on the axle, and that means the regular motor axle bolt won't move the block - you really want to find a way to put the v7 torque arm between the frame and the motor so the motor axle bolt can do it's job clamping the frame to the motor. Have a look at Grin's torque arm to clear up what you are working with.

 

[offGridDownUnder]

Oh, and if you're going to use an external torque arm, discard those washers with the tab that goes in the drop out slot - replace them with 'just washers' or with C-washers as useful. The washers with the tab aren't of use if you have adequate external torque arm(s) and they will close off the relief of the motor cable routing through the drop out slot. Discard them.

 

[kenshippo]

HOWEVER - you really need to work out the torque arm before celebrating. I am using a v7 Grin torque arm to mount my SX2, and the block is 8 or 11 mm thick (I forget which, but it's THICK). Remove the 6 brake rotor bolts if you can along with that dummy spacer, fit the rotor if you are using a brake there, and then work out where that torque arm block fits in with some eye to how it interacts with the motor cable.

I do have a torque arm, I tried to put it on the other side but it gets in the way of chain. Currently its looking impossible to put it on this side, on the inside. I have the grin v6 torque arm. Some other torque arms came with it but what if I used only one torque arm?
That's a good idea, removing the bolts and spacer could solve my issue by itself. But considering the power of my motor, 2000w 72v, which might not have been a good idea to go with that much power- Is it really a good idea to only rely on front brakes? Maybe it works I don't know. At the same time with my old ebike (stealth bomber frame and 34mph top speed)I found it was cheaper to not have brakes and use my feet to stop.

The motor is supposed to be oriented so that the cable lies in the drop out slot, which permits it some relief so it bends away from the motor/rotor. Your choice to orient the motor cable so it does not lie in the drop out slot, and also to clamp it with those washers takes away your options. Grin and other do sell C-washers of varying thickness so that you can space with the washers and also permit the cable to bend away from the motor and fall into the drop out slot. You can also make some with a hack saw by cutting out the slot yourself in some washers that are sturdy enough.

The orientation of the dropouts don't allow for that. I have some c washers but they would have to go over the wire and the axle





Thanks for the information though. I'll definitely consider not having a rear disc brake, but any new ideas are definitely welcome and appreciated.

 

[calab]

I would make my own torque arm out of flat bar and place it on the axle nut on the outside, hose clamps keep the ta tight to the bicycle tubes chain or seat stay, however sometimes you have enough axle length to place another bolt overtop the steel bar, other times you wont have enough axle length at all. Make notches for the hose clamps so they shimmy loose. Bushes, branches, grass all get caught up down there unless you never go off the asphalt.

 

[nicobie]

You can probably do without the rear brakes.

 

[kenshippo]

Bump for update(read bottom of top) Rear tire is too fat, but I prefer it even fatter. Now venturing into replacing the entire rear triangle or the seat stay. Whenever I research welding I get mixed answers. I was looking at something like this

Columbus Zona fatbike seat stays - 19 OD - .6 wall - length = 560

Columbus Zona fatbike seat stays. 19 OD - .6 wall - length = 560

framebuildersupply.com

But I am struggling with a way to go about choosing a seat stay. But if I want to go big, maybe I should replace the entire thing,
The chainstay is significantly wider than the seatstay.
-If I do replace the entire thing, I'd prefer to have a reccomendation on the seat stay and chain stay, plus dropouts and how to weld them together.
-It would be simpler to just replace the seat stay.
-Regardless, is it simple enough that I can buy a welder online , do a couple of practice welds and weld it myself, or..
-If I should purchase a welder, there were a bunch on amazon of various prices, not sure what I should be looking for. From my research it seems like mig welding is in order.
-Is it too complicated that its easy to mess up, and I would be better off hiring a welder to do it for me?

Its rubbing, and I don't know how the rub feels.

 

[nicobie]

I'd hire a experienced welder. It's your ass that's on the line.