My spokes are breaking
 

I've had the bike about a year now, mostly trouble free (apart from the battery which is fixed now). In the past week it felt like the rear wheel was crooked and lo and behold when I inspected it, it does have a twist in it. Plus 2 spokes were broken. A week later and 4 spokes are broken.

I've a vague recollection of hitting a pot-hole hard downhill 2-3 weeks ago, which must have initiated the damage. I didn't notice anything right away but it seem to have gotten worse. Never before have I had spokes fail on me on regular bikes. It's the rear wheel with the hub motor in it. Are wheels more prone to damage on electric bikes?

I'm going to take it to a bike shop to see if they can repair/replace it. What would you recommend? Replace the rim and spokes or try a repair? Any suggestions or advice for heavier duty equipment?

With that many spokes broken it will continue to do so as the rim has been bent. The lbs will be able to guide you if it is best to rebuild your wheel or replace it and tis is the best place to upgrade any bike as this is your largest rolling mass. Hand built wheels are stronger but you will be paying more as well.

Did you retension spokes after the first 100 miles?

I didn't see what bike you have but one poster had a LOT of trouble with his Trek breaking spokes.

When it was discovered that 2 spokes were broken, were they fixed. If not that is a good reason 2 more gave way. BTW I do think that the rear wheel on an electric bike is subject to more torque on occasion than a "normal" bike and likely more subject to problems with spokes IMO

OOps... :rolleyes: Noob here! No, not once have I retensioned the spokes in probably 3000 miles. This was my first ever bike bought brand new, electric or otherwise - so I never even knew you had to do that.

I spent a couple hours on it this afternoon. There were 7 spokes (out of 36) busted, however 3 of them had just shaken loose from the nipple. For the experience, I took the tire off and repaired those ones but I'm thinking I need to replace them all due to metal fatigue. I am embarrassed (and LUCKY) seeing how bad they had gotten! Thanks for the clue :thumb:

You'll need to retension the rebuilt wheel after a 100 miles or so. When you build a wheel there are unequal stresses that take some time to relieve themselves. There are a few people that know how to do this before you get the wheel. They are too expensive or too rare. You may have some problems finding the right spokes as I believe I've read some people having problems finding the correct spokes for Trek Ride + wheels.

If I had a Trek with spokes breaking I would take it back to the dealer for rebuild. They should be able to easily get the proper spokes. If not I would take a spoke from each side and measure them, then check with Wheelbuilder.com for replacements. They have or will cut any possible size. I would try to avoid making a wheel with hubmotor my first wheel build. There are so many considerations, and from my experience, even the manufacturers seem to short-change the wheelbuilding process. Absolutely every wheel I have ever purchased for my ebikes has been out-of-true or gone badly out-of-true very quickly. Due to the shorter distance between hub and rim, the nipples exit the rim at an extreme angle putting further stress on the spoke. For this reason I use Sapim Polyax nipples, The area of the nipple where they contact the rim is more rounded to allow the nipple to tolerate a more extreme angle out of the rim, thus less stress on the junction of spoke and nipple. I've also rebuilt my Bionx wheels with Sapim's single-butted 2.3/2.0mm (13/14g) Strong spokes. I've got one wheel I rebuilt this way and I retrued it after about 100 miles, have never broken a spoke, and in fact have not retrued it in at least a year.

Just nonsense... complete. Good wheels stand. Anyone should be able to stress relieve a wheel after reading the archives around here.

From what I've read is that the agreement Trek made with Bionx was that Bionx would handle all repairs to their hub. Last year, when they came out, many people had spoke problems. I read accounts of owners having to ship their bikes to Bionx to have the wheels rebuilt, LBS's getting the wrong spokes, cracked rims near the nipple. I would imagine these problems were sorted out by Trek and Bionx by reading the archives around here.

I have the Trek Valencia+ and after Bicycle Habitat in NYC rebuilt the wheel using upgraded spokes I have not broken a single spoke in around four months - so it's certainly looking better.

I broke a few spokes on Crystalyte wheel. If they are breaking at the spoke "elbows", it may be advisable to rebuild the wheel with some 13/14 quality double butted stainless spokes, with some brass spoke washers, as the seating of the spoke in the spoke holes may be a bit loose, leading to increased likelihood of broken spokes at that location. And do tighten up the loose spokes if you here "pinging" at any time. Some spokes can get loose over time. My Crystalyte spokes, although 12 gauge, were not high quality spokes.

heres my setup....

my bike is a hybrid 700c " giant" brand bike...

front wheel is 700 c - with 14 gauges spokes

back wheel is 700 c with {36** 12 gauge spokes....I sent this wheel off and had it spoked up and trued by a proffessional. I told the guy to put loctite on the spoke threads....he got this wheel perfectly trued up and all 36 spokes are tight...I have my rear hub motor on the rear wheel.

when I got it back I tied the spokes where they crossed, with stainless steel wire , and then I applied a dab of silicone over the wire ties and put a dab of silicon on each spoke nipple/rim to keep the spoke nipples from turning...

hopefully these precautions will ensure none of my spokes/spoke nipples come loose and none of my spokes break.

Sunnyday: you're probably wise to do this. I'm running a rear 26" setup. In the 300 estimated miles I've put on this I've had to true the wheel 3 times and tension the spokes twice. I don't know what guage they are but the biggest spoke wrench I have won't fit it. With a 700c wheel I would imagine this becomes even more critical.

I agree...I would think putting loctite on the spoke nipple threads and then adding a dab of silicon to the outside of each spoke nipple and rim area, would keep the spoke nipples secure, so they never loosen up out of the rim.....

then as added measure, tying the spokes at each cross section , should help keep the spokes from bending/ breaking...and going with 12 gauge spokes on back hub, instead of 14 gauge.

I spent about 3 months setting up this electric bike , to try and make it dependable for the long haul...as far as the tires, spokes/rims are concerned...

when you think about it, most problems people have with bikes, is tire/wheel /spoke related. I wanted to try and take those problems out of the equation.

the guy who laced up my rear wheel, told me that once he got the spokes tightened and the rim trued, it should stay that way as long as spoke nipples dont turn and spokes dont break. Of course if I hit a deep pothole at 25 mph, I expect the possibility of rim damage to happen, but as far as problems related to spoke nipples losening up and spokes getting loose, I hope that isnt a problem I face.

You don't need to do that and don't want to because it will make road side truing due to a bent rim harder if not impossible (the spokes may not have the torsional stiffness needed to resist bending with the lock tite).

Lubricate the spoke threads and nipple/rim interface with anti-seize - I like an acid brush with half the bristle length cut-off. Tension the wheel to uniform high tension appropriate for rim stiffness and dish. Enjoy until you bend the wheel with a road obstacle/crash or wear out the brake tracks.

Bend the out-bound elbows with your thumbs so they seat against the hub flanges before you tension the wheel, where the spoke angle at the rim is too excessive for the nipple to swivel to match bend the spoke so that it leaves the nipple at an angle instead of with a curve before you have a lot of tension in the wheel, achieve high uniform tension (110kgf front and rear drive side is a nice number for many rims), stress relieve (this requires an overload - I like to twist spokes where they cross with a brass drift, although squeezing parallel spokes with heavy gloves works too), and do a good job compensating for wind-up or at least position the wheel with each axle-end down and press around its perimeter (riding it will do the same thing, but then you'll have a tire mounted and you'd at least need to move the lateral truing probes on your stand).

It should stay true until you bend the rim and not break spokes unless you get something caught in them for at least a few hundred thousand miles.

Tied spokes may keep a broken spoke from damaging your paint job but aren't going to prevent breakage.

12 gauge spokes will make things worse if you're not getting them tight enough to avoid loosening nipples.

Read The Bicycle Wheel. The iterative approach to finding a rim's elastic limit isn't applicable for deep/stiff rims (use a $50 Park tension meter and do a better job lubricating if you're getting squeaking problems) although everything else in the book is.

My Park Tool Tension Guage can't measure the spoke tension on my drive hub. The hub is too big and the cross too extreme. I've been somewhat cautious in tightening the spokes, making 1/4 turn adjustments. I hope I've finally got them where they need to be as next week the 35amp controller goes on.:eek:

One thing we must remember is that we are really pushing bicycle design limits. My bike probably weighs 60# + my considerable bulk + high speeds means a watchfull eye on the low grade componets a necessity.

appreciate the info...im quite naive when it comes to bicycle truing /spokes...but a few counter points :

1. I doubt I would ever try to do a " roadside" truing adjustment to try and repair or temporarily fix a bent rim....I dont personally have enough knowledge/practice in truing spokes to expect I could fix a bent rim, out on the road.

2. went with 12 Ga spokes on back because IMHO, it only makes logical sense that thicker spokes would be stronger then thinner spokes. My bike weighs 70 lbs and I weigh 280 lbs...so IMHO, thicker stronger spokes, that are properly laced , should provide more strength then thinner weaker spokes that are properly laced.

3. I seriously doubt my back spoke nipples will come loose...they have loctite on the threads, and each spoke nipple has a dab of clear silicone on the nipple and rim to act as a secondary backup to hold the spoke nipple in its position, just in case the loctitie alone wasnt enough. I think its safe to assume that many broken or loose spokes, are the result of spoke nipples that do not stay in a fixed position. My spoke nipples should stay in a fixed position with normal riding , because of the loctiite , clear silicone and tying of the spokes...Now, if I hit a huge pothole at 30 mph, then I expect the possibility that my precautions to hold the spoke nipples in place, may not be as effective.

4. I had a proffesional lace up my rear wheel , with 12 Ga spokes...I checked the spokes after he laced them up,. and all of them felt tight .

5. Most of my riding will be 30 miles or less on the shoulder areas of hiway roads/ flat roads/surfaces...so I shouldnt have to worry to much about big potholes, curbs , rocks, etc damaging my rim/spokes. The precuations I took on my rear wheel { loctite, 12 gauge spokes, tying , silicone** are mainly to keep the spokes/nipples in a fixed position from normal riding , with my 280 lb bodyweight. In other words, I tryed to make it so I never have to worry about readjusting spokes/ nipples again, from just normal riding on flat surfaces. If I accidently hit a huge pothole at 28 mph, then I dont expect my precautions to stop rim damage.

6 . Many riders experience spoke nipples that come loose, and loose/broken spokes , from just normal riding , without hitting a pothole or curb.....this is what im trying to avoid....spoke and nipple issues, from normal riding.

Drew's advice is sound. FYI; I use a very old, tried and true practice of using boiled linseed oil as my threadlock. When I replace a spoke or build a wheel I use a trimmed up small acid brush and dab a tiny bit of linseed oil on the threads of the spoke, then assemble the spoke and nipple and tighten up. After the wheel is built or the spoke work is done the linseed oil will set up (dry) acting as a wonderful threadlock that will still allow roadside truing and later maintenance. Super clean. Anti seizing. Thread locking yet adjustable.

An additional point... (I don't see this mentioned in this thread) With the deep V rims on some new ebike kits the spoke nipples will seat themselves deeper in to the V over time as the the wheel is used. So re-tensioning the spokes is necessary as a result of this effect and not always due to any loosening of the threads of the nipples. In this particular situation threadlock isn't going to save you from having to re-tension the spokes.
-DS

spasmus ,
since you started this thread,
Can you give us more detail, on what bike, on what brand wheel/rim it had happened?
Well built wheel on QUALITY rim like ALEXRIM with quality spokes will last very long time.
Instead of blaming motor weight, rider weight, tensions just go on Google and compare prices of good rim like Mavic or Alex with prices of cheapChina brand trash and you will have an answer why.
Proof?
On my TForce ebike Alex rim 26 wheel lasted with no retensioning for over 21,000km right now!!
That's with rather heavy TF 1000W motor laced into it.
On my another ebike E+ Alex rim wheel still doesn't need any job after over 1000 km.
You all forget that quality of rim/spokes plays major role here and lot's ofwhat you describe has to do with quality of metal.

Hubs that are wider (IGH or electric bike hubs) require a rim that aims the nipple and spoke out more than they would for a narrow hub, otherwise the spoke will be under a lot of stress right where the spoke exits the nipple. I had this issue with a wheel built around an IGH, kept breaking spokes right where they came out of the nipple. My LBS figured out the problem and reemed the holes in the rim so that the nipple could angle out more to accommodate the wider rim. Problem solved, no more broken spokes.

I had the same problem with breaking spokes and changed over to a wheel with 64 spokes. About avery 3-5 months, I check spoke tightness. It's now been about 2 years and haven't had it happen since.

It might be the 64 or it might just be better spokes. Once they rebuilt the wheel with better spokes I had no trouble. Well, until the axle broke, then I got a new wheel. No spokes have broken with the new wheel but I have had a problem with nipples becoming loose and falling inside. So I do check the spoke tension every other week or so, which isn't a bad idea anyway. This thread was originally about the Trek EBike spokes, and that's what my problem was.