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Discussion Starter · #1 ·
I am concerned about strength of my current wheel set, which is a set of 2008 Mavic Crossride wheels. Each of these wheels are laced to a heavy rim (that has a large cross section) with 24 straight bladed stainless steel spokes. That means 12 drive side spokes in the rear wheel are carrying the majority of my 200 pound weight. My old wheel set had Shimano M756 hubs and Mavic 223 rims laced together with 32 DT Swiss Champion spokes in each wheel. I temporarily retired these wheels because the rear hub’s drive side cone and lock nut constantly worked its way loose and last summer finally pitted the free-hub cup. Replacing the cone, free-hub, the ball bearings and axle for $50.00 is not the issues that is preventing me from using these wheels--it is the narrow rims and the hassle of constantly retightening the cone and lock-nut on the rear M756 hub. Up until this year I have been riding on 26 x 2.0 tires, which fit in the 223 rims, however this year I bought 26 x 2.2 tires and really like the extra cushion and traction they provide over the 2.0 tires. 2.2 tires are too wide for the 223 rims so that is why I am riding on my Crossride wheels because the rims are wide enough to accommodate 2.3 wide tires. How much stronger are the 223 wheels with 32 spokes (16 effective spokes supporting the rear dished wheel) than the Crossrides with 24 spokes in each wheel?
 

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A wheelist
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bwalton said:
That means 12 drive side spokes in the rear wheel are carrying the majority of my 200 pound weight.
It's a lot worse than that. Your weight is standing on about three to four spokes. The less spokes the wheel has, the less spokes are supporting the weight, the more each one is doing and the more the wheel goes out of true if one breaks.

How much stronger are.......wheels with 32 spokes than the Crossrides with 24 spokes in each wheel?
We have no way of measuring that but the answer has got to be "lots".
 

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I rode a set for 3 years until the paws in the hub and the bearings gave out. The 1st year I was at 220 and the next two years around 200. I checked the rims peridically in a truing stand, but never once made an adjustment. Aside from dings, the rims are as true as the day I bought them.

Good luck
 

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I had Crossrides a few years back when I weighed 195. Never had any problems and only switched because I crashed and ended up putting my foot through the front wheel which tore 3 spokes out of the hub. Being that it was a proprietary spoke and hub, I just got different wheels since it didn't make financial sense to repair.
 

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Discussion Starter · #5 ·
Mike T, I took some spoke tension measurements this morning while sitting on three different bikes to get a feel if the Mavic Crossride rear wheel (559 x 19C—unknown ERD) is strong enough and durable enough to support my weight. My wife measured the tension of the three bottom spokes using a Park Tool TM-1 while I was sitting on the bike holding myself up on a door jamb. I weigh about 205 pounds with clothes and was sitting in a more upright position than I normally do when riding.
2009 Mavic Crossride rear wheel with (24) two-cross 2.2-1.3mm S.S. bladed spokes. Unknown if the spokes are at a uniform tension on each side of the rear wheel:
Rider’s Weight (pounds) Drive-side (Kgf) Left side (Kgf)
0 137 76
205 95-BDC 51
205 107 76
205 107 76

Conclusion: Two spokes support the riders weight whereby (one) drive-side spoke is carrying the majority of the weight.

Conventional 622 x17 wheel with (32) three-cross 2.0 straight gauge S.S. Wheelsmith spokes laced to a Specialized CT/Alex ACE17 or ACE18 (with an ERD of 602mm+) double walled (boxed) rim, which I re-laced after the OEM spokes started to fatigue:
Rider’s Weight (pounds) Drive-side (Kgf) Left side (Kgf)
0 121 to 137 56 to 62
205 107 BDC 56
205 137 62
205 137 68
Conclusion: Two spokes support the riders weight whereby (one) drive-side spoke is carrying the majority of the weight.
Conventional 700 (622 x 14 with an ERD of 598mm) OEM road wheel with (32) 2.0mm generic S.S. straight gauged spokes laced to an Alex R500 double walled semi-aero rims in a three-cross pattern. I replaced one drive side spoke with a 14 Ga. DT Swiss Champion because the OEM one fractured at the threads. I adjusted all the spokes to have uniform tension on each side of the wheel, trued it radially and laterally within 0.5mm, dished it and stress relieved the spokes after I replaced the broken spoke:
Rider’s Weight (pounds) Drive-side (Kgf) Left side (Kgf)
0 121 to 137 56 to 62
205 107 BDC 56
205 137 68
205 137 62
Conclusion: Two spokes support the riders weight whereby (one) drive-side spoke is carrying the majority of the weight.
BWW Commuting wheels with an Alex DH19 doubled walled rear rim (622 x18 with an ERD of 599.7) laced to a Deore hub with (36) 2.0mm straight gauged S.S. spokes in a three-cross pattern. Needless to say these wheels are bullet proof but heavy. I re-trued the rear wheel last year but never checked the tension of the spokes, which from the readings below are way too high and may not be uniform:
Rider’s Weight (pounds) Drive-side (Kgf) Left side (Kgf)
0 156 95
205 179 76 BDC
205 179 85
205 179 95
Conclusion: One spoke is carrying the majority of the rider’s weight or more likely the deep sectioned DH19 rim deflects so little under my 205 pound load that the tension meter and or my wife could not read the difference in spoke tension. (36) Over-tensioned spokes and a deep sectioned rim, which bridges the rider’s weight across many spokes is what makes this wheel so strong.

From these quick imprecise readings of the 6 bottom spokes in the four sets of wheels, the two spokes on the bottom of the Mavic Crossride rear wheel compresses just like the two other rear wheels with 32 spokes. The Mavic’s combination of a deep section rim and pre-tensioned bladed spokes with reduced mid-sections can stretch more than a standard round straight gauged 2.0mm spoke without taking a permanent set (i.e. the cold formed stainless steel wire’s load cycle stays within its elastic zone) keeps the wheel strong enough to carry my 205 pound weight. Without the additional spokes to collectively add to the Mavic’s overall pre-tensioned structure, I do not believe this wheel has a lot of extra capacity if I were to hit a large bump at a fast speed or land from a bunny hop. I will put my old rear Mavic 223 wheel with 32 spokes on mountain my bike tomorrow and measure the tension on the six bottom spokes and see how they compare with these results.
 

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nice work. :thumbsup:

what stuck out to me is that, predictably, the Mavic wheel spokes lose more tension than the conventional wheel spokes.

however, it's pretty hard to discern anything if you don't know that spoke tension is uniform (which means you also don't know the starting tension of at least two of the three spokes you're measuring). are your wife's measurements repeatable?

tension going up in the last wheel makes zero sense (as in, it didn't happen that way) and tells you there's a problem with the methodology.
 

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Discussion Starter · #7 ·
I measured the static tension of a few random spokes in each wheel before I sat on the bike and let my wife take over the measuring when I sat on the bike. The (36) spoked commuter rear wheel by the BWW is over tensioned because the DH19 rim is so strong that it has the extra capacity to support the extra tension of the spokes without yielding (i.e. buckling or turning into a taco). So I believe the spokes that my wife measured did compress either very little or by a good 30 Kgf, which means they are tensioned to approximately 200+ Kgf. I will back the tension off to about 130 Kgf on the drive side this weekend so the nipples do not pull out of the rim holes.
 

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A wheelist
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Great stuff. When you're done can you please sum up your findings. I'm sure at that point, our learned friend meltingfeather will have interesting comments.
 

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Save Jesus
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A couple of comments:
You don't need the wheel to be true, nor evenly tensioned for your measurement to be meaningful. However, you do need to measure the before and after tension of these bottom few spokes.
The total tension change should be a reasonable fraction of your weight.
I hope you are doing this with tires mounted and inflated.
 

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Discussion Starter · #12 ·
February 1, 2011
Listed below are the results of the second tension measurements that my wife and I took this morning of the 5 bottom spokes in five separate rear wheels. The methodology we followed for the tabulated measurements below is a lot more precise than the ones I listed yesterday in this post, which need to be discarded. First off, my wife measured the same five spokes using a Park Tool TM-1 spoke tension meter with and without my 205 pound body sitting on the bike seat in a riding position. The TM-1 was lubed, position as close to the center of each spoke as possible and the instrument’s spring calibrated push rod was slowly released against the spoke to get the most accurate measurement possible. Again the purpose of this exercise is to compare the strength and durability of a 2009 Mavic Crossride (559 x 19) two-cross rear wheel laced with (24) 2.2-1.4 S.S. bladed spokes in a 2X pattern with several conventional rear wheels with (32) or (36) 14 Ga. (2.0mm) spokes laced in a 3X pattern.
The spokes are labeled 1 through 5 and are orientated with respect to a person viewing the rear wheel from the left side of the bike (i.e. the non-drive side).
Spoke No. 1 a drive-side spoke positioned two rim holes in front of spoke No. 3.
Spoke No. 2 is a left flange spoke positioned one rim hole in front of spoke No. 3
Spoke No. 3 is a drive-side spoke at bottom dead center (BDC).
Spoke No. 4 is a left flange spoke positioned one rim hole behind spoke No. 3
Spoke No. 5 is a drive-side spoke positioned two rim holes behind spoke No. 3

I. 622 x 18 Alex DH19 rim laced to a Shimano Deore non-disc hub with (36) 2.0mm generic straight gauged spokes in a 3X pattern. This wheel was built be the BWW a few years ago.
Weight (lbs) Spoke 1 (Kgf) Spoke 2 (Kgf) Spoke 3 (Kgf) Spoke 4 (Kgf) Spoke 5 (Kgf)
Bike >179 85 156 95 179
205 168 76 121 76 179
Difference unknown 12% 29% 25% 0

II. 622 x 17 Specialized CT/Alex Ace17 or Ace18 rim laced to a Shimano Alivio disc hub with (32) 2.0mm S.S. straight gauged Wheelsmith spokes in a 3 X pattern. I re-laced this OEM wheel last year after three OEM non-drive side spokes fatigued/fractured at the elbow.

Weight (lbs) Spoke 1 (Kgf) Spoke 2 (Kgf) Spoke 3 (Kgf) Spoke 4 (Kgf) Spoke 5 (Kgf)

Bike 137 65 107 65 101

205 137 56 85 51 95

Difference 0 16% 26% 27% 6%

III. 622 x 14 Alex R500 rim laced to a Joy-Tech or Formula hub with (32) 2.0mm generic straight gauged S.S. spokes in a 3 X pattern. I replaced one drive-side spoke last year that had a stress fracture at the top end of the thread.
Weight (lbs) Spoke 1 (Kgf) Spoke 2 (Kgf) Spoke 3 (Kgf) Spoke 4 (Kgf) Spoke 5 (Kgf)
Bike 137 <51 137 56 137
205 121 <51 107 <<51 121
Difference 13% unknown 28% unknown 13%

IV. 559 x 17 Mavic 223 rim laced to a Shimano RH-M756 XT disc hub with (32) 2.0mm DT Swiss Champion straight gauged S.S. spokes in a 3 X pattern. This wheel was built two years ago by the BWW.
Weight (lbs) Spoke 1 (Kgf) Spoke 2 (Kgf) Spoke 3 (Kgf) Spoke 4 (Kgf) Spoke 5 (Kgf)
Bike 156 51 156 90 125
205 137 <51 137 76 121
Difference 14% unknown 14% 18% 3%

V. 559 x 19 2009 Mavic Crossride (19.5 x 24.8 rim) with a Mavic ISO disc hub and (24) straight-pull bladed 2.2-1.4mm S.S. spokes laced in a 2 X pattern. This rear wheel has maybe 200 miles of wear on it.
Weight (lbs) Spoke 1 (Kgf) Spoke 2 (Kgf) Spoke 3 (Kgf) Spoke 4 (Kgf) Spoke 5 (Kgf)
Bike 131 55 125 67 121
205 131 54 107 54 118
Difference 0 2% 17% 24% 3%

Notes;
1. Any measurements that are preceded with a greater than or less than sign are off the Park Tool conversion chart for the TM-1.
2. Difference is simply dividing the smaller number into the larger number and recording the numbers that follow the decimal as a percent. For example 100/80=1.25 or 25% change. This simplified calculation of percent change is not to be mistaken for percent difference. The percent change is used only as a rough indicator of the change in tension for each spoke.
Unexpected results and questions:
It is interesting that spoke number 4 in the wheels listed in I, II, IV and V compressed more than the spoke number 3, which is located at the bottom dead center (BDC) of all the wheels. Somehow these non-drive side spokes are carrying over 35% of the rider’s weight (or in my case over 72+/- pounds). So no wonder left spokes fail so often. I was under the impression that drive side spokes carried the majority of the rider’s weight because they need to be tensioned at twice the force as a left side spokes to center or dish the rim about center of the axle. Well these test results dispels this myth except for the Alex R500 road wheel, which must be dish more than the other wheels in this test.
The next surprise is that the shallow 18mm tall by 23mm wide double walled Mavic 223 rim (an ERD of 538.5) laced with (32) 14 Ga. DT Swiss spokes deflected less than the three deeper rims under my 205 pound weight. The Alex DH19 (19mm deep x 24.6 with an ERD of 599.7mm), the Alex R500 (approximately 21 mm tall with and ERD of 598mm) and the Crossride rim (19.5mm tall x 24.8mm wide) all have slightly deeper sections than the Mavic 223 rim and therefore should be more rigid when loaded like a beam across the supporting spokes. The Crossride rim has the longest span between its spokes but did not deflect as much as the deepest rim out of the bunch—the Alex R500. The shallowest rim, the Specialized/Alex CT or Ace17, has the most rectangular section out of the five rims but also deflected the most out of the bunch. So how does a consumer pick a rim if section depth does not equate to beam or bridge strength?
Lastly, is a strong wheel a combination of many over tensioned thin spokes laced to a shallow heavy rim, which loads up more than three spokes at a time? Or a wheel with a deep rigid rim supported by many over tensioned thick spokes? These five rear wheels did not answer this question. According to the book, The Bicycle Wheel by Jobst Bradt, (36) or “many” thin or swaged spokes tensioned to about 10% of the rims yield and laced to a deep rigid boxed doubled walled rim in a 3 X pattern makes a strong wheel.
Summary of results translated into pounds support by each spoke:
The Mavic Crossride is the weakest wheel out of the five rear wheels because my 205 pound weight is carried by two spokes somewhat equally or 102 ½ pounds per spoke.
The Alex DH19 rear wheel in test sample I, distributes my 205 pounds across four spokes where the majority of the load is carried by the two bottom spokes or about 70 pounds/spoke. And Spokes 1 and 2 carry about 30 pounds each.
The Alex R500 road wheel carries my body weight on the three drive-side spokes only in the following proportion: Spoke 1=58 ½ lbs, BDC Spoke 3=88 lbs and Spoke 5 58 ½ pounds.
The Alex Ace17 wheel spreads its load across the three bottom spokes: Spoke 2=53 lbs, BDC Spoke 3=74 lbs and Spoke 4=78 lbs.
The strongest rear wheel out of the bunch is the Mavic 223’s that predominately distribute my weight over three spokes somewhat evenly: Spoke 1=66 lbs, BDC Spoke 3=66 lbs and Spoke 4=73 lbs.

Possible Errors:
1. The TM-1 is two years old and may be out of calibration.
2. The precision and accuracy of the TM-1 as well as its scale limits skewed the data. However; as an indicator instrument the TM-1 is more than adequate to measure general trends and relative tension differences between spokes.
3. TM-1 operator error.
4. Uneven left side and ride side spoke tension in the five test wheels.
5. Taking one measurement of each spoke. A minimum of three measurements of each spoke should have been taken with two closely matching results to be statistically significant.
6. More rear test wheels with deep sectioned rims and swaged spokes would have helped to prove Jobst Bradt’s theory that strong wheels are formed from these components.
7. Rounding errors when calculating percent change and weight in pounds per spoke.
 

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Without getting into the numbers, I rode the crap out of a set of Mavic Crossroc wheels (24 spokes, 2X, UST rim) and the rim and spokes were bomber. Can't say as much for the rear hub, but the spokes and rims did just fine.

For the record I weighed between 205lbs and 225lbs during the years I rode them.
 

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I have really enjoyed reading your findings, from a comparative analysis perspective. I can't comment on the other wheels, but regarding the DH19 36 hole wheel set, the referenced spoke tension measurements still seem extremely high. I may be a little confused though, are you converting Kgf to pounds of force, by any chance? That would produce higher #'s, but then your referenced tension readings (converted back to Kgf) would mean that the spoke tension would seem a little low.

If the tension readings haven't been converted, that would mean that somehow spoke tensions have increased over time. Most rims/wheels aren't too happy past 130-140 Kgf, meaning calculable variances in spoke tension start creating lateral deviation when the wheel is stressed. IMO, most wheel builders are probably happy with consistent tension readings that are below 130, (or even much less).

I don't use the Park tensiometer, so my practical knowledge with its usage is nil.
 

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bwalton said:
It is interesting that spoke number 4 in the wheels listed in I, II, IV and V compressed more than the spoke number 3, which is located at the bottom dead center (BDC) of all the wheels.
This is wrong. Spoke 3 had the largest absolute change, as expected. The fractional change doesn't mean anything. Compression is proportionately related to change in lbs.

Your results fail a basic sanity check, as I pointed out in a previous post: The sum of the tension changes has to be a reasonable fraction of the applied load.

Looking at two examples:
Crossride:
unloaded 131 055 125 067 121
loaded 131 054 107 054 118
difference 0 1 18 13 3
sum: 35

DH19:
loaded >179 085 156 095 179
loaded 168 076 121 076 179
difference>11 9 35 19 0
sum >74

So where did this extra weight go?

The tension change distribution is peaked near the bottom spoke and tapers off as you go further (See the Bicycle Wheel for the more exact distribution). The sum of this lump is approximately the load applied. Any measurement that doesn't follow this pattern is suspect in both the individual measurement error as well as overall scale. This pattern doesn't depend on the initial tension of the spokes because that is only a preload and the elasticity of the spokes and rim determine the tension changes.

You also didn't mention what tires you had mounted on the rims.

I would fix your measurement technique before drawing conclusions about rims.
 

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very nice work, mr. walton! :thumbsup:
bwalton said:
Unexpected results and questions:
It is interesting that spoke number 4 in the wheels listed in I, II, IV and V compressed more than the spoke number 3, which is located at the bottom dead center (BDC) of all the wheels.
beanbag is right, it's the absolute difference that matters, not the percent change.
bwalton said:
So how does a consumer pick a rim if section depth does not equate to beam or bridge strength?
due to the possible sources of error and basic inadequacies in the method that you point out as well as some suspicious results, I'd hold off on drawing conclusions from this work and applying them broadly.
 

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Discussion Starter · #19 · (Edited)
2-2-2011
I appreciate the constructive feedback that I am getting so far—keep them coming. Here are some of the assumptions I brought into the exercise:
1. A bicycle wheel is a pre-stressed structure, which is made up of a rim and thin tensioned wires anchored into a hub. The spokes directly under the rider’s weight (or some portion thereof) bear the majority of the load (i.e. the loaded spokes act like a columns). If the thin wires/spokes were not pre-tensioned then they would buckle under the rider’s weight and the wheel would collapse. 2.0mm diameter or 14 gauged wire spokes that range in lengths of 230mm to 280mm are way too slender to support any weight by themselves if loaded like a column. But a typical bicycle with 32 or 36 spokes is capable of supporting up to 400 Kg or 880 pounds when loaded radially. Also no more than 4 spokes support the riders weight (at the bottom of the wheel above the contact patch) and road dynamic loads (e.g. from pot holes). The spoke tension in the remaining spokes does not deviate more than 5% for clincher tire inflation loads, braking loads or torsional loads from pedaling forces acting through the rear hub/cassette. All of these theories are spelled out in Jobst Bradt’s book The Bicycle Wheel. That is why I only measure the tension of the five spokes in the bottom of the wheel and discarded tension changes less than 10%.
2. I should have listed tires and tire inflation as other possible errors that could affect the tension of the test spokes. Each wheel had a different type of tire installed on it when my wife took the measurements. All of the 700 wheel tires were inflated to 80 psi +/- 10 psi and the two 26er wheel tires were inflated to 50 psi +/- 5 psi.
3. Again based on Jobst Bradts findings, that the wheel stands on the bottom spokes, I portioned my 205 pounds over the few spokes that read more than 10% change in there tension. For example, if four spokes in the bottom of the wheel lost 25% of their tension when I sat on the bike then I divided my 205 pounds by 4 and recorded the resultant as 51 ¼ pounds per spoke. Again this probably is not the correct way to convert tension differences into pounds of weight carried per spoke but it gives me and the reader of this post a rough order of magnitude or feel of what portion of the rider’s weight each spoke must support. Note; that the rear wheels in this exercise did not see my full 205 pounds because my upper torso was bent forward with my hands on the handle bars in a riding position.
4. Here is a list of the unsupported rim distances between each spoke or a simple rim span of the wheels used in this exercise:
622 x19 Alex DH19 (ERD 599.7mm) with 36 spokes: span=52.337mm or 2.0625”
622 x17 Alex ACE17 (ERD 603mm+/-) with 32 spokes: span=59.1994mm or 2.3125”
622 x 14 Alex R500 (ERD 598mm) with 32 spokes: span=58.7085mm or 2.3125”
559 x 17 Mavic 223 (ERD 538.5mm) with 32 spokes: span=52.867mm or 2.0625”
559 x 19 Mavic Crossride (ERD 535.5mm +/-) with24 spokes: span=70.0968mm or 2.75”

According to the tension reading taken yesterday, the Crossride rim with the longest span between spokes distributed my weight across only two spokes whereas all of the other four wheels with shorter rim spans distributed my weight across 3 or 4 bottom spokes. This conclusion is not earth-shattering but a deep sectioned rim that has a large bending stress capacity can span over larger distances than a shallow rim and most likely can be built with few spokes. The durability of a wheel with fewer spokes would driven by the fatigue cycle of the spokes and the rim and if the spokes are stress relieved by the builder because only one or two spokes will carry the riders weight and road shocks in the load effective zone at the bottom of the wheel.


It seems like a strong rear wheel is built with a medium sectioned rim and lots of thin or swaged spokes. The rim would deflect over a long distance and transmit the rider’s weight into many spokes. Of course the rim and spokes would need to be build from materials that have a long fatigue cycle (in the millions) and built properly so that its spokes or rims are not stressed to the materials yield point.
 

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Without getting into the good reading above:

Yes, Mavic Crossride wheels can support 200 pounds safely. So can the CrossMax USTs which reportedly were weaker than the Crossrides.

I've ridden both, and I currently have Crossmax USTs on a bike.
 
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