bud16415

I thought I would add this to the Touring forum as the bike I was dealing with was my touring bike and I would think most touring bikers are more likely to have spoke problems and when they do they are a bigger deal.

My bike a Windsor Tourist has been noted for coming with cheep spokes and or poor installation from the supplier. I was aware of that when I bought the used Windsor and asked the owner if he had any spoke issues and he said no but also never rode with a load and or any great distance. So I took a chance and did ok for a while. I had two spokes break last year (back wheel cassette side) and after the second one I took the time to check them all and found a few less tight and tried to correct the problem. This year I broke 4 more and said enough and started looking into a super wheel 48 spokes that lead to tandem bike parts that lead to wider spacing that lead to custom hubs that lead to $$$$$. and I started reading up on how all the 36 spoke touring bikes that were doing fine and thought ok lets lace what I have up with quality spokes done by hand by a pro and see what happens. and that’s what I did.
I have access to a materials testing lab and I thought I wonder how much stronger the new spokes are so I tested some and what I found was interesting and I thought I would share. (photos below)
What I found was a little surprising at first. The old spokes broke at about 730 pounds average, while the new quality spokes broke at a average of 755 pounds in the straight section. so they are a little stronger but not as much as I thought I might find. what I did find is the machine has the ability to know when a sample first starts to yield and then stops increasing the load and hold at a constant load. This is to measure different modes of fatigue etc. The spokes that came with the bike would hit failure force and then quickly break maybe 5 seconds. the new "better" spokes would start to deform in failure and then would maintain strength for several minutes. I'm not a metallurgist so I don’t know what exactly the property is that causes this but the tester said that’s a indicator of the difference between just hardness strength and strength thru a combination of hardness and alloys. I could actually feel the difference when bending the spokes by hand slightly the good spokes felt less strong or more bendy. So there is some component to the material.

I also took a couple photos of the head of the spoke as about half of them broke there. the better spokes have a much deeper chamfer to the head, the cheep ones look more like a nail head, flat on the bottom. Also the photos might not show this but there are way less tool marks in the radius area under the head, (stress risers).
The quality spoke is the one with the hallmark stamped on the head. I took my bike shops word on this spoke as being good quality. Anyone familiar with this spoke fill me in please.

Lastly is the quality of the build and only time will tell me the answer to that. Hand laced vs machine built will be a big factor I think. My guy did say to ride a couple hundred miles and bring it back it to be trued as spokes will seat sometimes at first. so I plan on doing that.
Here are a few photos:

M_S

Cool. Thanks for sharing.

Rob_E

Neat. I think in addition to strength of the metal, the design of the spoke plays a part, As you mentioned, the spoke heads had different designs and might have different results in real world use. I experianced this when building up a tire with spokes that had a rather large bend at the spoke head. I was getting breaks at the heads and, when researching the issue, I found This which described my problem pretty accurately. I did what Peter did and got some Wheelsmith spokes to relace my rim. Haven't had a problem since.
But, as you pointed out, actual strength may not vary by that much. While the design of the sproke may have an effect, the biggest effect is probably even tensioning and truing. Relacing your rim is a reasonable precaution on a touring bike (especially when spokes have already been breaking) but it's possible that a retensioning would have done the job. Once spokes start breaking, it's hard to know if the remaining spokes have been weakened or not, but I've heard that retensioning before a spoke breaks can go a long way towards fixing a poorly built wheel before it becomes a problem.

While I didn't want to cut corners on my 700c, touring bike wheel, I did make a 20 inch wheel for another bike using spokes salvaged from junked bikes at the local bike co-op. That wheel went together fine and has never broken a spoke. Of course a 20 inch wheel is a bit sturdier to start with, plus its a front wheel, so it's never seen the stress that a rear, large, touring wheel has, but it's nice to see that those old spokes still have some life in them.

rogerstg

Interesting, but when all is said and done, your problem with the spokes was like due to too low tension and not due to spoke strength. IOW, I doubt that you put over 730# of pressure on any singe spoke, yet they broke.

Many inexpensive machine built wheels (most lbs bikes in the 400 to 1200 range) don't have adequate tension for heavy loads long term. FWIW, people have toured tens of thousands of miles on those specific wheels without problems due to weak spokes.

SweetLou

Those are DT Swiss spokes. DT is not my favorite, but they should be good.
That is a common saying of people who don't build wheels properly.

paul2432

If your library has it, check out "The Bicycle Wheel" by Jobst Brandt. Your testing, while interesting, has little to do with the strength of a properly built bicycle wheel. Assuming the wheel is properly constructed with uniform high tension (per side on the rear wheel), the ability of a spoke to yield elastically will have the largest influence on spoke durability. It turns out that because of this, perhaps counter-intuitively, double butted spokes (thinner in the middle) are stronger than straight gage spokes in bicycle wheel service.

Paul

Booger1

If you look closely at a good spoke,you will see it has rolled threads and a rolled radius under the head.Same holds true for bolts and fasteners.This will help spread out stress loads.Butted spokes work better because the middle parts (thinner) absorb more of the tension differences when being loaded/unloaded.As opposed to the heads and threads having to do it.It spreads the tension loads over a greater area,thus less fatigue failures.

Thanks!....Now if you'll check some graded and ungrades bolts for us.....

bud16415

Thanks all for the input.

I have learned a lot already. My spokes are DT made by the Swiss and not no names made in China. They are not favored by some but should be good enough. That good wheel builders wouldn’t need to offer an inspection after a break in period. I kind of knew that a wheel is a space frame of sorts and there are all kinds of internal strains contained in the wheel and forces being transferred around in the wheel when motion is achieved. I will for sure look into the book suggested I have read some excerpts from it on line on other forums. Thanks also for the Peter White link as that was very interesting read.

There are a collection of forces in spokes I would assume other than tension and like anything pre-tensioned I would assume the idea to be let the pre-tension exceed the working tension and thus reduce any movement. When I first saw disc brakes on spoke wheels I thought wow all that torque is going up thru those spokes to the tire and into the road. Fishing poles are tapered for a similar reason chasing the bending moment down the rod as the force is increased.

I didn’t want to try and answer any question in particular about what makes a good spoke a good spoke. That science is way beyond me at this point. It is true in bicycles as in most machines that a chain is only as strong as its weakest link. Be it the spoke itself or the assembly process you would think cost cutting at the humble spoke wouldn’t be the best place to start. Being a machine designer by trade it's interesting that machines haven't been invented to better assemble a wheel than they have by now.

on edit:
Booger1 Thanks for the input and what bolts did u have in mind?

fietsbob

Bikes Direct is about lowering cost , bypassing the LBS and the shop workers
doing a full checkover and wheel prep, as they assemble the bikes to put on the sales floor..

generic low ball spoke supplier is part of the math in the bottom line..

bud16415

That’s probably a very true statement, and most business models wouldn’t survive under that situation in the past. But with the internet there is a ever expanding customer base of first time buyers. Even if most of them do their job as best they can and run down the spec sheet and see fairly good quality components across the board they will overlook the simple spoke, maybe the quality of the paint finish, bar tape, etc. and throw in a rear rack. not to mention an ill suited gear range for the type of bike it is.

I do wonder then a bike like the Fuji Tour that for all practical purposes is the same bike retailed in the same manner but for a few hundred more dollars more. Would they be paying more attention to things like spokes?

pdlamb

+1. Or maybe +100.

Note, too, that the "old" spokes have been stress cycled many hundreds of times; that's probably one of the factors that leads to them breaking quickly. Also, since you're testing yield strength, that's a function of the material (iron, as the principal constituent of steel), so there's not going to be any difference in yield between old and new other than perhaps a difference in diameters and stress fractures that reduce effective cross section.

Back to the main topic, any spoke will probably work if it's properly tensioned and stress relieved when new. Do that with your new spokes, and you should have many trouble-free miles in front of you!

wahoonc

I have a set of wheels that were handbuilt by me about 35 years ago for a transcontinental tour, I rode from Spokane, WA to Virginia Beach, VA and continued to ride those wheels for another several years. The bike was loaned out for a few more years and came back home and was partially dismantled and hung in the shed. I pulled the wheels out a couple of weeks ago. Just out of curiosity I tossed the front on in the truing stand, it has a bit of a wobble, but nothing serious. Checked the spoke tension, they were +/- about 4%. These wheels are nothing fancy. Wolber Super Champion 58 rims, Suntour LePree hubs, spokes are quality (don't remember the manufacturer) 14ga stainless. The key was the proper hand build and reasonable quality parts. I don't use the wheels anymore because they are old 630 (27") and the rear is a 5 speed freewheel. However I would not hesitate to put them on a bike load up and start touring on them again.

Some of the stuff that comes on bikes nowadays surpasses even the cheapest stuff in lack of quality that was available 30 years ago. I saw a double chain ring the other day that had been stamped out of a single piece of steel...

Aaron

fietsbob

you mean the people that work for the retail dealer?

Booger1

A good mil spec grade 8 against a Chinese grade 8 might be interesting..... But to make it fair,you have to use a nut and the typical Chinese "class" fit....lets see how they work as a team..

Just kiddin.....

Will that strain gauge make salt water taffy too.......

SweetLou

If it's a good bike shop, they will. The first thing I do when building a bike is to put the wheels in the truing stand. Most bike's wheels are under tensioned and not true or round. After the wheel is trued, I will adjust the hubs if they are adjustable.

Building a bike is more than just slapping the parts on the frame. Everything needs to be adjusted and lubed.

MassiveD

"Assuming the wheel is properly constructed with uniform high tension (per side on the rear wheel), the ability of a spoke to yield elastically will have the largest influence on spoke durability. It turns out that because of this, perhaps counter-intuitively, double butted spokes (thinner in the middle) are stronger than straight gage spokes in bicycle wheel service."

That is only a true statement because the all things equal part of the sentence rules out the real reasons spokes break. The remaining percent added by having butted spokes is minimal. We know this for several reasons. One is becaus most wheels do not use butted spokes and when properly built are very durable. I only recently upgraded to butted, and have never broken a straight spoke even when I weighed 270+gear+bike. two is because people are always talking about butted spokes dealing better with sudden impacts, but riding the tar, I rarely have those, and anyway, I don't break straight spokes, or even have wheels built with them that need truing.

The big picture stuff if you read Jobsts book is to reach max tension, have enough spokes (he is a big believer in 36 minimum for all light wheels), and stress relieve. Other major factors are the fit of parts and the competent build of the wheel in maters other than max tension and stress relieving. Stress relieving is pretty easy. Max tension is probably the most difficult because it can be difficult to determine, and a lot of rims, are not up to it.

"Note, too, that the "old" spokes have been stress cycled many hundreds of times; that's probably one of the factors that leads to them breaking quickly."

I guess it would be true that if something is going to fail, then it is probably nearer to failure when old. But Jobst's real message is that spokes are very long lived, he had one set that had like 300 000 miles on it. If you build a wheel properly and a spoke fails, the ping you hear is the sound of weakness leaving the wheel. The likelyhood is that the rest of the spokes are real keepers, and if you drop the one or two bad ones you are in for the long haul. Of course if the wheel sucks you will have lots more trouble in due course. Jobst recomends keeping your spokes and just building on new rims, but for a variety of reasons, shops want to switch out everything, and will not use old spokes. For one thing, they don't know the quality of the stuff that is there, or the condition. Which is why some of us prefer to do it ourselves.

By the way for the Op:

- 36 is enough for most touring. If you can get 40 that is better still. There are options out there for 40 and 48 that do not require tandem width wheels. Buying quality components does not guarantee good results, there can be compatibility problems, so in that regard, be sure to source a proven package, not just proven individual components. If you don't know a formula, one answer is to find a local shop that does a lot of courrier or touring business. Another option is to copy the formula on Peter White's pages. There are dozens of tricks in assembling quality wheels, in some cases you can combine almost all of them in one wheel. So keep searching on the net and read books, and read specs.

wahoonc

Re: 40/48 spoke wheels. I only would consider them if sherpa loaded or running a tandem. However many quality 40 and 48 spoke rims are still on the market, hubs are bit harder to find. Only bikes I currently own with 40 spoke wheels are my old Raleigh 3 speeds. I typically run 36 spoke wheels on everything else, have not broken any spokes in years, and I am no lightweight my current city bike (with redone handbuilt wheels) fully loaded with me and groceries tops out over 300#.

Aaron

BigBlueToe

I had a mail order bike - a Nashbar tourer, bought in 1992 - that had real spoke-breakage issues. I suspect the wheels weren't laced carefully, and weren't built with the highest quality parts. Also I carried too much weight and I weighed 215 at the time.

Since then I've had two rear wheels - one built by a local pro, and one built by me based on the instructions on Sheldon Brown's website. Neither has broken a spoke after several fully loaded tours. I still carry a lot of weight, though not as much as on that first big tour because I've replaced some of my gear with lighter weight stuff, and I don't carry as much stuff. I'm down to 195 lbs, which is also significant. 20 lbs. is 20 lbs.

I think the difference is that I now have wheels with really good parts - good hubs, good rims, and good double-butted spokes. I also put a lot of time into tensioning the spokes. I use a tension meter and go over the wheel carefully.

My so-far-trouble-free wheels have 36 spokes. If I weighed more than 250 lbs. I might consider 40 spokes or more. Right now 36 spokes are working for me.

fietsbob

do bring a few spare spokes of the proper length..,
and Know how to replace them anywhere,
and you should get where you need to go.

MassiveD

"hubs are bit harder to find."

Myself I find the reverse. There are many sources for 40 spoke, and 48 spoke hubs, but rims are a problem. Of course your point is probably true if you want cheap sources, they are a lot further appart for hubs. While 40-48 rims while getting rarer, are usually the same price as other drillings or little different. Periodically actual cheap sources for hubs come up, but they tend to be old stock situations. My favorite cheapish source are PW freehubs, but I realize that for many that is a non-starter. Possibly another cheap hub would be the Rohloff tandem, though I have only heard of those, if you want Rohloff I suppose the drilling part would not add much cost!

robow

I personally would like to thank all that contributed to this thread concerning failed spokes and failed rims (note my sarcasm) because today while going over my rear 26" wheel on my LHT, I found a stress fracture on both sides of an eyelet on the Mavic XC 717 rim and will have to rebuild. This would never have happened if we would keep our thoughts to ourselves

hybridbkrdr

If you have access to a machine like that, it would be cool if you tested Wheelsmith, Sapim and DT Swiss spokes, straight-gauge and double-butted to see which ones are best. Of course, finding single spokes to save money might be a chore.

bud16415

Thanks to all that have posted. I have learned a great deal. My initial thoughts in testing the spokes China against Swiss as it be, (and for the record the two China spokes I tested were from the spare spoke carrier and were virgins) I did just the simplest of simple strain tests on the ultimate tensile strength of the material they were made from. Accounting for slightly different wire sizes between the two samples they both pulled at right around 150,000 pounds/sq inch. That is a pretty respectable number and not at all what I expected between two vastly different products. If I were to set up a test as some mentioned to compare several of the major brands, the test would look completely different. sure we could do just a tension test but a real world life test would be much more interesting to see. Something where the spoke was fixed just as it is in a bike and under preload as tensioned in a bike. then a load similar to real life could be cycled into it for millions of cycles and watch for failure. maybe even a better test would be to lace a wheel to specs and then build a test rig that holds the wheel on something like a treadmill with a load pushing it down and see what happens after a simulated run. Testing like this would take months 24-7 to do but would be interesting to see. I don’t know if any of the bike manufactures do these things of not.

Even though I didn’t buy my Windsor on line (second hand) I can see the logic in going thru a LBS for set up and things like checking and redoing the spokes at least before setting out. In all honesty mine being second hand the first owner could have messed up the factory spokes before I got it but I don’t think that to be the case. I have also found that not all LBS are able to do this and at the rates charged most people are not willing to pay that much for a casual rider. One shop told me we can sell you a new wheel assembly for less. I didn’t stick around there too long.

Where I live the selection of true touring bikes is quite limited. I haven't found any resentment to working on my Windsor when I bring it in with such issues but I would suggest finding out ahead of time with them if you don’t want to tackle your own spoke setting, or for that matter all the bike adjustments required after shipping. I read enough negative reviews dealing with spokes on this bike to have me assuming it most likely was quality of materials and as it well could be is quality of assembly more so. I also have read of people doing the TA on my exact same bike pretty much out of the box and having no issues. What I'm not sure of did they have the bike gone over with a fine tooth comb first.

We have never made saltwater taffy on the tension machine that I know of but it has been suggested we press grapes many times with it.

wahoonc

In reference to the BD wheels...

They may have switched suppliers along the way? Companies like that are constantly churning vendors in an attempt to improve the bottom line. If company "A" was selling them a basic quality wheel for $35 (completely random number) and they purchase 10,000 wheels a year, then they get a bid from company "B" for $32 a wheel and they are the built using the same or very similar components they are going to jump at the chance to add a quick $30k to the bottom line. So what if a few wheels go bad, replacing a few wheels is still pretty cheap, even if the customer does complain.

Aaron

bud16415

I would say that’s correct. When you read their specs some items are very clear, others say you may get this or that and others are kind of non descript. Hubs, rims, spokes, bars, bottom bracket, chain, stem, etc. are all items it would seem go to the lowest bidder.

As a side note I was watching a TV show last night called How's it made and they did bike wheels. Was quite interesting showed how the rims are rolled and welded and drilled and turned and how the spokes were installed and the robot that did the final tension and true. These were some fancy race wheels and the spokes didn’t have the bend at the hub but had a dovetail fit and a plate that held them in. but the tightening was the same method.