E-bike rims...

DMLPDX

Member
Greetings. I have completed an E-bike conversion of a Trek 8.6 DS with a Bafang BBS01 with a 52V 11.5 amp SharkPack - both from LunaCycle. Overall I am very happy with the conversion and I am continuously in process with tweaking the build.

However, I continue to be made aware that the conversion process has many side effects. Last week, after I changed the stock hybrid tires to a pair of Schwalbe Energizer Plus, ironically, I had my first flat tire in distant memory on the rear tire. I changed the inner tube only to find the puncture was on the inner diameter, not the outer. I thought that was odd. But today, on my way home I heard a pop, then the rear tire rubbing producing a pulsation in movement. I quickly determined I popped a spoke.

Obviously, moving at higher speeds, hitting object etc, produced stresses on the rim that resulted in the spoke breaking and the rim deforming. The rims on this bike are Bontrager AT 650 (700x38c) which by all accounts are low end rims. I've begun the process of looking for a new rim and I'm amazed at how expensive they can be. I'm wondering if anybody has had a similar experience or if any particular wheel offers a better strength vs weight offset, but without spending more $ than what is really necessary.

Comments are appreciated.

David
 

Ann M.

Well-Known Member
Alex Rims has a line of bike rims designed to better handle the extra stress of a motor; they're all double wall and super strong. Proper spoke length and spoke tension is also critical, particularly in the rear to keep the stress balanced going over rough terrain or during hard turns. Consider working with an experience LBS to help you build new wheels if needed. Since you have a mid mounted motor, they won't need to worry about lacing in a hub motor.
 

Ann M.

Well-Known Member
Alex Rims has 5 different rims specifically designed for electric motor set ups; however, if you're riding with a wider profile set of tires, choose one of the wider width rims, perhaps the DM 18 which is designed for MTB style wheels. Make sure your rim tape or rim strip is properly covering the spoke holes and consider adding some tire liners, like Mr. Tuffies, or another tire liner brand, to keep the road garbage away from the tube if it does pierce the tire and adding to the problem.
 

DMLPDX

Member
Thanks Ann. Any suggestions on where to purchase?

NB The Schwalbe Energizer Plus tires come with their own embedded liner. As I state, I was surprised to find the inner tube puncture to be on the inner diameter - I think this somehow means that perhaps the rogue spoke possibly punctured the tire before it gave way.

This is all new to me. Ebikes.ca has a selection of spokes also. Any recommendations on this?

David
 

JoePah

Well-Known Member
Are you going to build the wheel yourself? If you are there is a steep learning curve on spoking and truing.. Lots of good vids on YouTube.

If you're not going to build the wheel, bring it to your LBS and tell them you don't want another crappy Bontrager rim. Tell them you want 13 gage SS spokes to match the color of your original wheel, and you want a heavy duty Alexrim double wall rim.

Building the wheel should cost no more than $50 in labor, $30 in spokes and $50 for the rim. They should reuse the disc and the hub. If the hub is serviceable have them regrease it.

If it were me, I would rebuild it, and call Niagra cycles.. They are very helpful folks and their prices are great.. Even if you don't they are good for advice....http://www.niagaracycle.com/categor...ack-road-rim?gclid=CKPWp7eR3soCFQsnHwodhNkENw
 

DMLPDX

Member
Thanks JoePah. Yes, I am thinking about doing it myself. Do you have any recommendations out a specific Alexrim?
 

Ravi Kempaiah

Well-Known Member
Thanks JoePah. Yes, I am thinking about doing it myself. Do you have any recommendations out a specific Alexrim?

Alexrims FR30. I had this on my previous eMTB and never went out of true.
Also, it can take larger tires compared to DM18.

The best option would be to get DT Swiss wheels.
 

DMLPDX

Member
Alexrims FR30. I had this on my previous eMTB and never went out of true.
Also, it can take larger tires compared to DM18.

The best option would be to get DT Swiss wheels.


Thanks Ravi. What I've been able to determine is that I need something along the line of 20-622 to 28-622 in terms of size. I was looking the FR30 and am having trouble finding the size anywhere. Also would like black color. The Supra rim also looks like an option. However, what I seem to notice is that the sizing on Alexrims website is not consistent with what is available.

I may have to look at DT Swiss, though I do note they are premium wheels.
 

JoePah

Well-Known Member
David I looked at your bike and it's a 32 spoke rear wheel?

I think you need a 36 spoke hub and rim sets for your BBS motor. I think most ebikes have 36 spoke wheelsets. Check reviews of mid drive bikes with 700c wheels.

Again give a good bike shop a call for sizing... tell them your tire size.

I built a BMC geared hub wheel with 36h SunRims rhyno lite.. very stout, and cheap!..I think I used 12 or 13 gage spokes

http://www.niagaracycle.com/categor...r-black-nmsw?gclid=COqfjeuK38oCFcMRHwodqTQJFA

My Stromer has a AlexRims but I can't figure out the size.. Also 36h very stout rims.
 

Ann M.

Well-Known Member
Definitely agree with the above comments about 36 hole rims vs. standard 32 hole simply because the stress on the wheels coming from the added weight and torque of the motor are hard on the wheels. Sapim is another good brand of spokes, get butted or double butted. Better quality spokes do cost more, up to $150 or so but you won't see them break as much. If you are really set on building these wheels you need a good truing stand; I recommend Park Tools brand and a spoke tension measuring tool. Too little tension and the wheel collapses, too much tension, the rim cracks where the spoke nipples thread in and you can get broken spokes.

ParkTools Spoke Tension Meter.jpg Spoke Tension Meter, Park Tools
 

DMLPDX

Member
Thanks Ravi, JoePah, & Ann. Amazing how a broken spoke changes everything.

So, here's what I'm contemplating:


As far as I can tell, these Shimano hubs are similar in length to the existing Shimano RM-66 hubs, which are manufactured in 32/36h configuration but as far as I can tell, the 36h option cannot be found anywhere.

Nothing is ever as simple as it appears, is it? Thoughts?

David

NB I called a LBS - they said they don't work on ebikes as a policy, telling me they would charge me $80 per wheel to lace, true, etc. I haven't shopped that fee, but at that cost and given the fact I probably will be lacing more in the future, I may as well learn the craft.
 

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JoePah

Well-Known Member
Good luck with your winter job! Have a couple suggestion on building a wheel.. let me know when you start.

Personally, would only build the rear wheel at this time, since the front one is not going to be loaded with motor torque or additional weight. If the front one goes, then replace it.. There's no savings buying both. Just inspect the front wheel and see what shape the rim holes are in and maybe tighten and true the spokes.

I'd pick a rear rim and spokes that matches your front rim and spoke color..

I'd go with single cross or double cross spike pattern.. that's plenty for 36h.
 

DMLPDX

Member
Personally, would only build the rear wheel at this time, since the front one is not going to be loaded with motor torque or additional weight. If the front one goes, then replace it.. There's no savings buying both. Just inspect the front wheel and see what shape the rim holes are in and maybe tighten and true the spokes.

I'd go with single cross or double cross spike pattern.. that's plenty for 36h.

I know I don't have to but I'm kinda a nut about uniformity for some reason - it's probably my ADD talking there.

I'll look at the cross pattern issue.

...and will do...

David
 

DMLPDX

Member
So I visited a couple of LBS here in Portland over the past 2 days. I went to a Trek store and they wanted $80 per wheel for the build; went to another and they tried to sell me a pair of SunRingle 32 hole that were gathering dust that had the Shimano Deore 525A hubs. Luckily my phone had some connectivity issues and I couldn't transfer any $ to my debit card and so I walked away. Went to one more (Universal Cycles) who could provide everything I wanted...without a build fee. So here's what I'm getting:

  • SunRingle Rhyno Lite 29/700 (ISO 22-622) Black
  • Shimano MH525A Black 135 mm Rear
  • DT Swiss Competition Double Butted Spokes 2.0-1.8 Black
  • DT Swiss Black Brass Nipples 12 mm
I paid 143.00 for this. Not too shabby I think.

The build will be complete on Thursday. I'm going to have them add a Shimano 9-speed 11-34t cassette also.

In the meantime, I'm integrating an Avid BB7 mechanical disk brake into my harness off the front wheel for shifting/safety purposes while also giving the bike a good general frame and chain cleaning. With all the rain we've had here over the past 2 months, she's pretty dirty.

Can't wait to get back to breaking the speed limit on my ebike on Terwilliger here in PDX. Will post pics upon completion of the rear rebuild

David
 

DMLPDX

Member
Yeah I get that... Post a pic when you're done!

Also, the stock Bontrager rims (AT 650 Disk) are on the lower end of the low end, so I think for safety purposes, it's smart to just swap them out. I'm going with just the rear for now, but will have Universal Cycles build the front in a week or two also.

As a side note, I definitely have found it difficult to find the the 36h rim at least in the 29er size. The LBS here in PDX seemed to think that a stronger rim would justify a 32h. That notwithstanding, I am told the trend in bicycle rims is for fewer holes. It will be interesting to see if the 36h dogma will persist into the future.

Will post the rear when she's done.

Cheers!

David
 
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