Broken Spoke

[RunForTheHills]

The problem with heavier gauge spokes on a bicycle rim is that most bicycle rims are not strong enough to allow you to get the proper tension on a heavy gauge spoke. They will be too loose or if you do tension them properly, they may crack the rim. You need a moped or motorcycle rim to get the right tension and, of course, that adds weight. This is a good write up from Peter White, a well known custom wheel builder.

https://www.peterwhitecycles.com/tandemparts.php

 

[fooferdoggie]

The problem with heavier gauge spokes on a bicycle rim is that most bicycle rims are not strong enough to allow you to get the proper tension on a heavy gauge spoke. They will be too loose or if you do tension them properly, they may crack the rim. You need a moped or motorcycle rim to get the right tension and, of course, that adds weight. This is a good write up from Peter White, a well known custom wheel builder.

https://www.peterwhitecycles.com/tandemparts.php

yep my rim cracked with 13 gauge spokes and this was a decent bike. time for new parts and triple butted 14g spokes.

 

[Bitmugger]

We're set up with a set of 13g Sapim spokes and a 36 hole rim with stainless gommets reinforcing each spoke hole, so we're good to go from that perspective. I did ask several builders (none local unfortunately) about the heavier spokes available. The ones that are 13g with 12g ends. ALL said they were overkill. Could I get away with a lighter 14g setup? Maybe, but I have no intention of ever finding out. The wheel came from the manf. with 13g spokes, and I'll be staying with them.

You are wasting your time with grommets on the nipple ends, the spokes break at the hub side for me 100% of the time without exception. The nipple end is rock solid, it's something about the hub or lacing or whatever but they always break at the hub.

 

[AHicks]

yep and they broke.

At this point, I'm assuming they broke because the factory wheel did not use Sapim spokes -AND- they were not properly tensioned. Or maybe closer to the real story, they were not tensioned for somebody my size. That remains to be seen. I'll circle back and add some info there as I get some time/miles on the now quiet rim. Honestly, it would not surprise me if the rim cracked due to the extra tension I've placed on the spokes. We'll see.

The 2 spokes that I managed to break already did break at the hub.

There's so many opinions regarding lacing patterns. I was going to go with a 3 cross lacing pattern, mostly because it LOOKS stronger! Grin says nope, you don't need to do that. They do a LOT of wheel building with hub motors (not just conventional bicycles), including the wheel on my 1000w MAC 12t which has stood the test of time - in 2 respects. It's been under this 300lb butt since new, AND, it's handled 1000w for several years now, using a 1 cross pattern without a single issue. Point here is I have a tendency to listen when they say something based on that experience. They are a 13g believer (no 14g coming from them), but it would appear they use a couple of different lacing methods. One suggests the spoke heads face in, and the other, which I'm probably going to use, alternates the head position. Thought being on the alternating head plan, it adds side support, AND, it spaces the spokes so they don't touch where they cross..... not sure if that makes any difference, but I like that idea.

So that's where I'm at, but as always, I have an open mind. -AL

 

[AHicks]

So, I had a question for Grin, regarding the spoke hole size in the rims they sell (by Alex). I was pleasantly surprised by their response, from Robert (the Wheel Builder) himself. Clearly I had misunderstood/confused an earlier conversation, possibly from somebody else (it's been a while). Anyway, here's the response, that I found pretty informative-

"Those rims (the reinforced Alex rims) will NOT fit the 5mm nipples, nor will any of the rims we sell. We build all of our wheels with the 13/14g Sapim spokes found on our website. Here's why: 1. We tested the reduction nipple with the 13g spoke and found it to be weaker. Sapim is, in fact, going to stop making them. 2. The 13g straight spokes are actually only about 10% stronger, but when used with reduc nipple, even that small advantage is reduced.
3. Most rims sold have the 4mm hole for a 14g/2mm spoke nipple. 4. We've been making wheels for over a decade with the 13/14g spoke with great success. 3,000 ish in the past 4 years. 5. The tension and flexibility characteristics are excellent using the Sapim Strong 13/14g spoke.
Drilling out the holes on an eyeleted rim can make a mess.
Let me know what you think.
Cheers,
Robert the Wheel Builder "

Apologies to Foofer. His advice turned out to be pointed in the right direction.....

 

[BigNerd]

So what's the verdict here? Order 14g Sapim spokes?

 

[AHicks]

Oh man, I'm still in the thick of this. There is a LOT to this for a first time wheel builder like me. I wouldn't do or suggest you do anything unless you are forced to at this moment. I'll circle back with more info, the info that worked for me, when I get this all worked out. There's too many opinions being offered by a lot of guys that are considered experts. You cannot possibly use all of it on one wheel. Impossible! So you have to decide on how YOU want to do it with their advice in mind.

I'm currently rebuilding my rear wheel with Sapim Strong 13/14g (single butted) spokes. Robert (the wheel builder) advises putting the elbows for the drive side spokes on the outside of the hub to reduce necessary dishing. This offers 2 advantages that I can see. It spreads out the base of the triangle supporting the rim (helping with side loads), AND helps reduce the load on the drive side spokes (the ones that always break) by spreading out/equalizing the spoke load between both side of the hub. Or maybe better put, the percentage of the load placed on the spokes for the drive side and the brake side spokes is closer to 50/50 (which would be perfect if you can achieve it). This will likely make much more sense if you refer to Grin's spoke wheel building data sheet. Here the link to the worksheet loaded with the data I'm using (currently, subject to change!).

https://ebikes.ca/tools/spoke-calc....e&rim=cust_dia584_e555_lo2_ro2_w31.5&relb=out

-Al

 

[BigNerd]

So on the spokes I've broken, I do notice they are always on the chain/drive side... which actually is easier for me to replace because if it were on the disc brake (left) side, I can't thread the spoke.

 

[AHicks]

So on the spokes I've broken, I do notice they are always on the chain/drive side... which actually is easier for me to replace because if it were on the disc brake (left) side, I can't thread the spoke.

Would you mind sharing your weight? Wondering if you are having a weight related issue as I assume I am, or if there isn't something else going on.

FWIW, the drive side spokes are the most highly loaded because the rim is offset from the center of the hub. The spokes leading to the brake side are at more of an angle so they don't carry as much of the load/weight.

It's a warranty issue for sure. Espin will pay for the repair(s) IF you can find a shop that will work on it.

 

[BigNerd]

Oh yeah... I'm a big boy too... ~275 so right at the limit for the Espin.

This is actually the only bike I've had broken spoke issues with... none of my regular non e-bikes have this problem.

And I'm just riding regular paved paths... no curb jumping or off-roading.

 

[AHicks]

Oh yeah... I'm a big boy too... ~275 so right at the limit for the Espin.

This is actually the only bike I've had broken spoke issues with... none of my regular non e-bikes have this problem.

And I'm just riding regular paved paths... no curb jumping or off-roading.

Yup, me too. Riding it like you think an old man might ride. You have an Espin too, right?

I'm finally finishing up my new spoke install that I started the first of the week. First set of spokes way too long due to a miscommunication. Second set the right length but 11 of the 40 spokes were not usable because the threads had not been cut (rolled) correctly. So today everything all bolted up, rim has been trued, just want to confirm uniform tension and go over everything prior to a test ride.

Biggest changes would be the use of the single butted spokes that are reinforced where they always break, and installing the drive side spokes with the spoke elbow mounted "out", rather than "in" the way they come.

To see what I'm talking about, check out the diagram here. These are all the specs I'm using-

Online Spoke Calculator for Hubmotors and Ebikes

Our handy spoke length calculator allows for easy calculation of spoke length for custom builds - and is the only one of its kind to include paired spoke holes in the flange as is common with many large diameter hub motors. It also creates an automatic side view drawing of the laced wheel and...

ebikes.ca

 

[AHicks]

Test ride went well for a few minutes, then it was back to the familiar spoke pinging. Came back and checked, all were uniformly tight with the gear side just slightly higher (to be expected). This using a tension gauge. So a lesson earlier had me trying the ping test, plucking the spokes. Not bad. Then I tried the ping test on another couple bikes - way higher pitch. Then it dawned on me that the calibration of my tension meter was NOT the same as the Park Tool tension meter (the one costing twice as much as the 40. I paid for this one). Using the Park Tool, you're looking for a reading of about 28. On the one I bought, it turns out I should be looking for readings closer to 35. That explains a ton.... Will post back after re-tensioning and test riding. Probably tomorrow. Feel better knowing I've likely solved the last hurdle on this job.... -Al

Update: second test ride, with the spoke tension set properly, went perfectly. 6 miles without a peep from the spokes. I'll start really trusting it in a month or so.....

Spoke tension max depends on the wheel, but my reading would indicate about 130 is max, with many running 100-110 to avoid the potential for rim cracking. I set mine at 100. -Al

 

[BigNerd]

Broke another today and I was careful. The ones I broke in the past used to be when I go over bumps so I'm now trying to shift weight off the rear whenever there are bumps and that seems to work... but this one just popped on a regular flat surface... at the elbow like the others.

This is strange... and this one was a non-drive side spoke.

Gah.

 

[fooferdoggie]

Time for a professional rebuild so it does not keep happening.

 

[BigNerd]

Time for a professional rebuild so it does not keep happening.

How much does that usually cost?

 

[fooferdoggie]

How much does that usually cost?

not too much new spokes and labor usually under 150. good spokes are about 2.00 each

 

[AHicks]

I'm circling back to complete my story, after getting pretty confident now that I have a few miles on the new spokes. Short story is installing the new spokes (single butted Sapim) seems to have straightened out my issue - which I believe was due to a spoke tension issue as much as anything. When I bought a spoke tension meter to check them, I was told (by Espin) to use the "28" setting on the tension meter for proper tension. This proved inaccurate, as the tension meter I used was calibrated differently. The plan is to tension the spokes to about 100-110 kg. To do that with the meter I purchased, the correct reading on the scale was 35-36, NOT the "28" figure I had been given.

When I retensioned my original spokes to the 28 number, I loosened them badly. My next trip out managed to break 3 spokes within about 5 miles. In hindsight I SHOULD have know something was wrong at that point.

Bottom line, spoke tension is important, and with a heavy butt in play, they're critical. After being through all this, my advice for BigNerd would be to get the spoke tensions checked and set properly. If that doesn't do it, if still breaking spokes, then go with a fresh set of single butted Sapim spokes. Mine were less than 2 bucks cut to the exact length they need to be, purchased through wheelbuilder.com, an outfit I would highly recommend if not buying locally.

 

[BigNerd]

Already got my Sapim spokes from Wheelbuilder... bought 40 (just in case I needed extras) and will have my wheel rebuilt. According to Espin, need to put them all drive side to be stronger... I think @AHicks said the same thing... is that how you put them on?

They also told me to use Park Tool's 27-28 setting with the wheel totally deflated but you are saying that's wrong?

 

[AHicks]

I used 20 (18) 210mm spokes, and 20 (18) 212mm spokes. The short ones go on the power (sprocket) side, the long go on the brake side. Power side spokes are installed with the "elbows" on the OUTSIDE of the hub flange (toward the sprockets). Brakes side spokes are reinstalled the way they were originally, with the elbows located towards the center.

Andy (Espin) and I have exchanged a (quite a) few emails. He's been VERY patient and helpful! I pointed out the wild goose chase I had been on due to the Park Tools setting he gave me (28) , and he's changed the copy and paste advice he supplies to reflect that the 28 setting is for Park Tool users only (as of yesterday). Others should look up the setting their tool requires to tension the 13g/2.3mm spokes to 100-110kgf with the tire deflated. He mentions that's the proper setting for the power side, without mentioning a tension setting for the brake side. I found them to be the same on my install. YMMV.

Holler if I can help any further. Happy to pay Andy's patience forward..... -Al

 

[john peck]

If they are straight gauge or single butted, the quickest source is going to be a local bike shop with a spoke machine that can cut them to length and thread them. Other than that, you can buy spokes on eBay or Amazon.

That´s fine if your LBS is equipped to do it. None of the shops near me carry spokes let alone the means to
make them. Larger shops in large urban areas may have the means. I just order a full 36 spokes to use as
needed.