roadsnakes

I`ve broken 3-4 spokes on my 2 year old Trek Verve III in the past 6 months. LBS say`s they don`t seem to be overly too tight, but has recommended getting a new Rim and Spokes, or re-lacing the rim with all new spokes.
Thoughts?

Retro Grouch 

Front or rear wheel? In general, I'v e found that too loose spokes is more frequently a problem than too tight - particularly on the rear wheel non-drive side.

ClydeClydeson

Spokes don't normally break because they are too tight, but because they are too loose. As you ride the spokes have an excursion between maximum tension (at the top) and minimum tension (at the bottom), and low spoke tension around the wheel makes this excursion more extreme. Minimum tension will be as low as zero, and maximum tension could potentially be the entire load on the wheel being held by a single spoke.
Spokes that are too tight will generally cause the rim to crack and fail, not the spokes.

If the spokes are all that is failing than just replace the spokes - all of them. They work like a chain, and if some of them have experienced enough load cycles to cause failure the rest are close behind. No need to replace the rim unless it is somehow damaged, or if it takes some type of oddball spokes that are not easily available.

Also, perhaps you should find a new LBS or talk to a more experienced tech. If your account of what the tech told you is accurate, I wouldn't trust that person to build me a wheel.

pdlamb

Wut he said.

Spokes that are too loose fatigue from detensioning as you ride. Once you've got more than a couple breaking, the rest are probably fatigued as well, and a bunch of them will fail shortly. My take would be that you don't need to replace the rim (probably), but replacing the spokes is a good idea.

Drew Eckhardt 

https://www.quora.com/Why-would-back.../Drew-Eckhardt

The spoke elbows have high stress from the forming operation because parts were never taken past their elastic limit, causing them to survive too few fatigue cycles where the number is determined by average stress and magnitude of variation.

Fatigue cycles come from the spokes slackening as their rim attachment point deflects upward passing the riding surface approximately 750 times per mile. Rear wheel spokes also experience sinusoidal pedaling force variation.

Since spokes in the same group experience similar conditions, they fail about the same time like popcorn kernels bursting - one, a few, most, then stragglers.

Rear drive side spokes are the most problematic. Average stress is greater due to those spokes having the highest tension. Magnitude of their stress cycles is greatest due to higher rim deflection from the rear wheel carrying more weight (Lenard Zinn found 60–70% when he measured[1] ), pedaling force, and no hub shell torsional deflection reducing spoke length changes.

This is exacerbated by heavier riders causing the spokes to change tension more with greater rim deflection and higher peak pedaling forces.

Non-uniform tension means some spokes are tighter and fail sooner.

Such failures can be avoided by stress relieving the spokes before accumulating fatigue cycles. You can squeeze near parallel pairs, preferably wearing gloves. You can bend crossing spokes around each other or push their junction towards the axle using something softer like an old left crank arm, plastic screwdriver handle, or brass drift. Holland Mechanics makes stress relieving robots.

Most wheels are not stress relieved at the factory because it’s cheaper to deal with occasional replacements for heavier riders who ride enough to break spokes before the warranty expires.

You can also have problems with the elbows not being well formed to the hub flanges. Spokes can break at the rim when they meet it at at an angle the nipples can’t pivot to match when you have too many crosses for the small wheel diameter/large hub flange as on 32 spoke cross-3 second generation PowerTap wheels. Those issues must be corrected before the wheels are tensioned.

Do that right and you can get over 300,000 miles from a set of spokes. Replace bearings and rims as needed. Rims are easy - tape the new one on in three places, detension the spokes, move spokes one at a time taking the opportunity to properly lubricate threads and rim sockets, remove the old rim, then tension like building a new wheel.

For durability spoke count doesn’t matter. Too few just reduce lateral rigidity which can cause brake pad or frame rub when combined with a stiff rim. Zipp sells Clydestale / Max models with more spokes to limit that.

Smaller spoke diameter doesn’t cause problems. 1.8mm (15 gauge) elbows break when not properly supported in the large holes most hubs have to make lacing easy, although that’s a compatibility problem. Most small vendor boutique wheels use ovalized 2.0mm/1.5mm (14/17 gauge) double butted spokes like the Sapim CX-Ray and DT Aerolite.

Larger diameter spokes can increase life when you fail to stress relieve, although you’re better off correcting the construction. Wheels taco when a bump deforms their rim slackening spokes, the rim shifts off center while laterally unsupported, and they spring back as the bump passes. Thinner spokes stretch more at a given tension (you get about 1.0mm out of a 1.5mm spoke at 110 kgf, versus 0.5mm from a 1.8mm spoke) so it takes a bigger hit to bend rims enough for them to lose tension.

High quality spokes may last longer, although you’d get more life from a cheap set built right.

Over-shifting the chain onto spokes can notch them leading to failure. You should run a spoke protector if you’re not the sort of person to notice then immediately investigate degraded shifting.

A few spokes were made with bad stainless steel, leading to chloride stress corrosion cracking at their rust stains. Cheap galvanized spokes can also fail due to rust.

Once you have multiple failures you’ve ruled out a single defective spoke. All cut spokes must be replaced from an overshift (8 in a 32 spoke wheel). Otherwise all spokes in the failing side of a multi-cog wheel or all spokes in a nearly symmetric wheel must be changed.

Building wheels including respoking them correctly is not difficult. Jobst Brandt tested the instructions in his book The Bicycle Wheel by having his grade school sons each build a set with no additional help.

Unfortunately, building wheels fast enough for the hourly profit to compete with other work takes a lot of experience which few mechanics have. The market moving to proprietary factory built wheels reduced the number with that experience. Most compromise by doing a bad job fast.

Your options for reliable wheels are building them yourself or outsourcing to a competent one-person operation like Peter White where the hands that earned its reputation build your wheels.

For less effort you can buy a new factory wheel, stress relieve it, and hope the elbows match the hub flanges well enough. Insuring sufficient uniform tension is also prudent so the wheels stay true until bent. For inexpensive bicycles you can buy new aluminum rimmed wheels from Amazon starting at $25.

You can true wheels mounted in your bicycle frame or fork, but will be more comfortable sitting at a table using a truing stand. Use rim brake blocks for lateral true. Attach a stick with rubber bands to observe radial runout.

You can set dish by flipping the wheel in the frame or truing stand to check for even lateral spacing, although a dish stick is more convenient.

Replace spokes one at a time so they have the same orientation (inbound/outbound, leading/trailing) for good support and no additional stress risers in the hub flanges.

Lubricate spoke threads and rim sockets. Zinc anti-seize is ideal because it oxidizes preferentially over aluminum rims and nipples. Plain grease usually keeps water out well enough to prevent corrosion, even with alloy nipples and road salt. With adequate tension you don’t need any sort of thread locking compound like boiled linseed oil to prevent losing true due to loose nipples. Wheelsmith developed Spoke Prep so they could avoid warranty returns from under tensioned wheels produced by machines running at high production rates.

You can check relative tension by plucking spokes and listening for the same tone. When very non-uniform it’s easier to start from scratch and you definitely want to detension the wheel. Screw nipples on to the same engagement depth. I put my thumbnail in the last spoke thread as a stop. Then tension.

When bringing all spokes up to tension, put a tape flag on the first two after the valve stem hole to see how much windup you’re getting and compensate.

Set absolute tension with a $5 cellular app if you don’t want to buy a meter. 110 kgf rear drive side is good absent instructions from the rim maker. The non drive side ends up with whatever is needed to center the wheel left to right.

Undo any windup by putting the axle on a block of wood and unloading the bottom side spokes by pushing on the wheel with your hands at 3 and 9 o’clock as you move around it. Flip and take care of the other side.

Have fun.

FiftySix

My low end single speed Schwinn has broken two separate rear drive side spokes this summer. Both at the spoke elbows.

In my case, I think its the cheap steel hub that can't seat the spokes into the hub holes properly. The hub's spoke holes are a bit oversized for the 15 gauge spokes going through it.

I also figure that riding on trails and over curbs aren't really helping matters either, considering the cheap build of the wheels.

roadsnakes

Thanks for all the replies.
I`ve learned a lot!
I know will be able to discuss my options with my LBS more intelligently.

All the spokes have been on the rear tire, and I think all on the drive side.

(I am a heavy guy)

Today`s spoke popped while going slowly up a steep grade.

A few weeks ago one popped hitting a pothole.

trailangel

Popping spokes? What exactly is popping? and Where? Where are the spokes breaking??

roadsnakes

'


By popping, I meant breaking.

Rear Tire

At Hub, Not at Rim.

veganbikes

If you are a heavy rider the wheels probably aren't going to be put together well enough to last. A good wheel should be built by hand but not machine or at least hand tensioned at the end.

When you break more than one spoke it is a good sign the wheel is going to keep failing and replacing spokes is not going to solve the problem, You can probably re-use the hub and potentially rim if not in bad shape but I would certainly get new spokes and nipples and have a professional wheel builder put the wheels together. You might also just talk with them and ask them what they recommend for you, your riding style, weight and needs.

cjenrick

what brand spokes? what gauge? what kind of hub? how much wheel dish?
14 ga DT stainless are hard to break..

race freaks use to trade spoke breakage for speed, Robergel double butted 15 ga.

they break like a dry twig in a stiff desert breeze.

something that very few people know about, but Phill Wood does know about is that some hubs do not have the holes drilled in the right place, that is, they are not equidistant from the center of the axle, nor are they equidistant from each other. this can cause problems.

i will let you in on a little secret if you promise not to tell anybody, the best wheel builder on the planet used Locktite Blue on the spoke nipples. and why not. why would you grease up something that you do not want to slip? better off with no grease at all. But Locktite? People would buy wheels from this guy and they would never go out of true. Nobody could figure out how he did it, the secret came out after he dies. He used rims that were measured to ensure that they were circular, and he used Phill Wood hubs, spokes were tied and soldered, and also a tricky tensioning technique that involves tightening one spoke, then rotating the wheel 180 degrees and tightening the next spoke. This is a painstaking process but results in a better wheel.

me? Robergel spokes, Mavic SSC 180 gram rims, Mavic hubs with titanium quick release with Corsa CX. Pulling spokes on the rear wheel are 14 ga, trailing spokes 15 ga,, tied and soldered,
Watch my blinking red light disappear.

jpescatore

I'm pretty sure the Verve 3 has 32 spokes rims/wheels - that is a good thing for a heavy rider, better than 28 spokes.

When I weighed 250 I would break spokes frequently on a low end hybrid. The detailed advice above listed the key things - what worked for me was going to a 32 spoke wheel, with a triple cross lacing pattern, hand built by the LBS I trusted. You already have a 32 hole rim,

If that doesn't solve the problem, the 32 hole rim I ended up with was built for tandem bikes. Never broke a spoke again on that wheel in 10 years. It was a factory built wheel, but the bike shop had me come back after a month of riding and they retensioned everything like a rebuild.

Phil_gretz

Definitely find a new shop. This fellow gave you (from what I can understand in your post) poor advice. The correct answer is to re-build the wheel in a 3x pattern with quality spokes and nipples. By calling around and asking for recommendations, you'll be able to find a master wheel builder in your locale, and take it to him. Get the job done right.

Thomas15

Great thread. Lots of good information.

mack_turtle

pay attention to which spokes are breaking. if they are are in the same place on the rim, it's likely that the rim is bent. getting the wheel true means making a few spokes much tighter than the other. the over-tight spokes are under more stress and break again and again.

but a stronger wheel. something with a burly rim and maybe a higher spoke count would be wise.

most of the time, buying a complete wheel is much cheaper than having someone build a custom wheel for you.

pdlamb

I agree with everything in the quoted post except "drive" in the paragraph above. Until I bought a tensiometer (on sale) and started using it, I probably broke 2-3 non-drive side spokes for every drive side spoke. As Drew notes lower (and I hereby paraphrase but fail to quote), properly tensioned spokes don't unscrew. Lower tension on the NDS let the nipple unscrew until it would detension completely while riding, and that stress cycling through zero is what fatigues and breaks the spoke.

With a little more effort, you can detension such a new wheel completely, bend the spoke at the nipple to correct the line, and then true and tension. Jobst Brandt suggested correcting the spoke line while building a new wheel, but it works as well on pre-built wheels if you relax the tension to the point you can bend the spokes. I don't know about $25 wheels (at some price point I expect cheap cheese materials), but a set I bought for $100 years ago had no problems after such treatment.

BlazingPedals

Long story short: Breaking a spoke caused the nearby spokes to be over-stressed, causing them to break soon thereafter. Yes, they are generally caused by being too loose and then being allowed to bend. Once the second spoke breaks, your best bet is usually to have the wheel rebuilt with all new spokes; otherwise you'll be replacing them in ones and twos forever.

Drew Eckhardt 

14 gauge spokes break under heavy riders when not stress relieved.

I've ridden 14/17 gauge spokes for decades without issue, and in flattened form like the Sapim CX-Ray and DT Aerolite they're now standard on boutique wheels.

That's the sign of an incompetent wheel builder or one cutting corners to maximize profit. Wheelsmith invented Spoke Prep so they could run their wheel building robots at a high speed yielding under tensioned wheels without warranty returns from heavy riders due to losing true.

Properly built wheels with sufficient tension never go out of true unless you bend their rim or stretch a spoke in a freak accident - e.g. I had a battery pack fall off my handlebar while still tethered to its light head then squeeze between a spoke and my fork on its way to the back side.

Drew Eckhardt 

The stress barely changes.

The other spokes fail because they've undergone the same number of fatigue cycles under nearly identical conditions.

Pop N Wood

Who is Spokes and why you be popping him?

Cougrrcj

I personally built a set of wheels in 1977 that lasted for more that 30,000 miles. My FIRST set of 'custom' wheels. IIRC, they were considered 'narrow' clincher rims (at the time), with stainless 15/16ga butted spokes. I barely even had to 'true' them in all that time/miles... until I inadvertently (lack of attention on my part) dropped off the edge of the pavement (4-5" drop) and my 'correction' tacoed my rear wheel... Even the best wheels just aren't made for that sort of side-load!

A properly-tensioned wheelset should last thousands of miles!!! Let those spokes get a little slack, and not only does your ride feel 'dead' and unejoyable, but also it signals the downward spiral death of your wheelset!