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Will these wheels be strong enough to bikepack with ?

Old 07-17-19, 07:23 AM
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Will these wheels be strong enough to bikepack with ?

Hi there , just looking for opinions on whether or not these wheels will be up to the task of bike packing with say , mat and sleeping bag on handle bar , frame bag with some food and clothing and a bag on seastpost too with some bits. I found the tech docs for these wheels but they don't state a max weight.

They are a 2007 Mavic crosstrail Disc as pictured below , 26 incher wheel , 24 thin bladed spokes , , my bike is the black hardtail with the gravity dropper.

I think these are a light XC mountain bike wheel designed for racing etc so maybe loading a bike up with them on it would mean broken spokes out in the wild ?



I'm on a budget so would like to use these if I there is a chance they can handle the odd two day trip once or twice a year .
Any opinions most welcome,

J





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Old 07-17-19, 07:43 AM
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you weigh 290 lbs right?
or was it 125?

so yes, as you didnt mention your weight, who knows, but it is going to be a big factor here.

Ive toured fully loaded up on 32 spoke mtb stuff with 2in slicks and lower pressures and been fine, but lets be realistic--there are so many factors that will make a difference
-rider weight
-tire size and pressures
-stuff weight
-and finally, and most importantly in my opinion, is how you ride--if you are careful and unweight the bike properly when hitting stuff, thats one thing, but some people are "bull in a chinashop" riders, so really, no black and white answer here.

my suggestion is to put the junk on the bike, round around and over stuff and listen and feel how the wheelset is responding.
Other than getting some sort of "perfect condition of spoke tensions and rim strength when new" weight recommendations , and perfect isnt the case here, they are not new and who knows what conditions everything is in, I suspect its a bit of a crapshoot here.

good luck on trying out the bike in real life with stuff on it to get an idea of what the wheels and spokes are telling you

also, it would make sense to get a good wheel guy to go over them and let you know how they are, and to retension spokes if needed, align etc , as well as inspect.

ps edit--I used 26in XC rims with 32 spokes, lightish rims, but I only weigh 135, but probably had 60lbs of stuff on bike at times. Tires 2in at just over 40psi which had a good amount of tire suspension effect from supple tires and the pressures, so this helped a lot.
Your wheelset is obviously lighter than mine, but maybe the total weight thing for you is a lot less than for me and my load, so it could work, but then if you weigh 100lbs more than me, thats a diff story.....

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Old 07-17-19, 07:50 AM
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Originally Posted by jambon
Hi there , just looking for opinions on whether or not these wheels will be up to the task of bike packing with say , mat and sleeping bag on handle bar , frame bag with some food and clothing and a bag on seastpost too with some bits. I found the tech docs for these wheels but they don't state a max weight.

They are a 2007 Mavic crosstrail Disc as pictured below , 26 incher wheel , 24 thin bladed spokes , , my bike is the black hardtail with the gravity dropper.

I think these are a light XC mountain bike wheel designed for racing etc so maybe loading a bike up with them on it would mean broken spokes out in the wild ?



I'm on a budget so would like to use these if I there is a chance they can handle the odd two day trip once or twice a year .
Any opinions most welcome,

J
As you say those are made for racing so they aren't made for the kind of strength you need for carrying a load. That said, if the wheels were regular J-bend spokes, I would say that they are unequivocally wrong. But the spokes are straight pull which makes them slightly less prone to breakage due to the lack of that J-bend. The J-bend on a spoke makes for a stress riser which makes them vulnerable to kind of breakage we are all familiar with. I would think a straight spoke has less of a problem because the spoke doesn't have that stress riser.

But, after saying that, you are loading up the bike with extra weight. The wheels should be able to take a wide range of load but if you (your weight) are on the higher end of the scale, you could be exceeding the limits of the wheel. Keep the load lighter and see what happens.

Alternatively, just get a set of 32 hole J-bend wheels. If you have a local co-op around, you should be able to pick up a set for cheap. Tune them up before you use them so that you don't have problems with them.
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Old 07-17-19, 07:56 AM
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Originally Posted by djb
-and finally, and most importantly in my opinion, is how you ride--if you are careful and unweight the bike properly when hitting stuff, thats one thing, but some people are "bull in a chinashop" riders, so really, no black and white answer here.
The proper analogy is "ballerina who rides like a gorilla". Bulls in china shops are quite careful...see episode 85 of Mythbusters
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Old 07-17-19, 08:39 AM
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I would not let the wheels stop me from doing an occasional backpacking trip, providing you are not on the far end of the heavy scale as mentioned above.

If, for example, you weight 170 and take 30lb's of gear it would be like a rider 200lb on the bike - not unreasonable (yes there is a slight difference between static and dynamic weight but not that much).

Also, the bike has front suspension to lessen the impact stress somewhat and one would assume you'd not ride as aggressively with a backpacking load as you would racing XC.

Just be sensible about the weight and getting airborne.

One problem with the internet is that it gathers all information together and can easily highlight optimal equipment solutions. In the "good ol days" people often didn't know better and simply set off touring with what they had. Imagine pre 70-80's when folks were using stainless steel rims and caliper brakes and still criss-crossing the country or world. Now it is easy to succumb to decision paralysis because all our gear is not top tier.

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Old 07-17-19, 08:41 AM
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Originally Posted by cyccommute
The proper analogy is "ballerina who rides like a gorilla". Bulls in china shops are quite careful...see episode 85 of Mythbusters
chuckle, I will look it up and watch it.
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Old 07-17-19, 08:54 AM
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Originally Posted by Happy Feet
One problem with the internet is that it gathers all information together and can easily highlight optimal equipment solutions. In the "good ol days" people often didn't know better and simply set off touring with what they had. Imagine pre 70-80's when folks were using stainless steel rims and caliper brakes and still criss-crossing the country or world. Now it is easy to succumb to decision paralysis because all our gear is not top tier.
On the other hand, the Internet gathers information from those of us who have done it in the "good ole days" and learned a lot of lessons along the way. I'm not saying that you should succumb to analysis paralysis but some analysis before hand can save you in the long run.
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Old 07-17-19, 09:16 AM
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I have no specific opinion on your wheelset, but in generic terms although I have not broken a spoke for over a decade and a half I still carry a couple spokes per wheel when I tour and I carry the proper spoke wrench for that wheel and the other necessary tools. And most important, I also carry the knowledge on how to true up a wheel.

With that, if you broke a spoke or two on a trip that is only a couple days long, you would still get home.

I have several touring bikes, so I keep the spokes with the bike to avoid having the wrong spokes in a pannier. I carry the spokes in the seatpost held in with a wine cork. Sometimes the cork dries out an shrinks, I wrap electrical tape around it to make it fit tight again. On 700c wheels with longer spokes I have drilled holes into the cork to make the spokes fit better in a too-short seatpost.

And several years ago I wrote up this piece on a lightweight substitute for a chain whip, this thread also has some other good comments by others too.
Chain Whip for Travel

And I carry the proper cassette tool with a wrench for it. I used to use a Nashbar Shimano cassette tool that was just a hair to big to fit on a small adjustable wrench, so I filed two of the flats down on the cassette tool so that the wrench will fit on it. That wrench and cassette tool are pictured at the link above. (I now use a Park tool instead, but that is off topic.)
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Old 07-17-19, 09:48 AM
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I have a similar wheelset for commuting. Not the best design, as too much stress is concentrated on the rim where the spokes connect. Check carefully for cracks, and throw away if you have any.
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Old 07-17-19, 09:57 AM
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Originally Posted by cyccommute
On the other hand, the Internet gathers information from those of us who have done it in the "good ole days" and learned a lot of lessons along the way. I'm not saying that you should succumb to analysis paralysis but some analysis before hand can save you in the long run.
True.. some. But that experience was gained ultimately by doing.

I think of a certain squishy former poster who had convinced himself that only the best would do.. preferably custom and argued against anything less, yet he never actually went anywhere.

My vote is always go with what you've got until you can afford something better and don't let theoretical inferiority stop you in the mean time.
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Old 07-17-19, 10:09 AM
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The most important things for touring wheel durability are deep, strong rims and correct and even spoke tension. Those rims look plenty strong. You might take the wheels in for a tension check or re-tension. Good to go. MTB racing wheels are very strong. One assumes you won't be getting big air or flying down a talus field while touring. Additional bikepacking loading is insignificant compared with g-loading on a drop.
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Old 07-17-19, 01:56 PM
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Originally Posted by Carbonfiberboy
The most important things for touring wheel durability are deep, strong rims and correct and even spoke tension. Those rims look plenty strong. You might take the wheels in for a tension check or re-tension. Good to go. MTB racing wheels are very strong. One assumes you won't be getting big air or flying down a talus field while touring. Additional bikepacking loading is insignificant compared with g-loading on a drop.
and lets say the fellow puts 25lbs of stuff on the bike, depending on his weight, that won't be a huge amount more of weight on the wheels, so taking it easy and being aware not to thrash the wheels, would most likely be fine for reasonable riding.

and its easy to just slow down a bit for rough stuff, or not jump over edges or whatever, and will have no real difference in your riding time over a days ride, seconds or mere minutes--but your spokes will thank you.
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Old 07-17-19, 04:00 PM
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Originally Posted by Carbonfiberboy
The most important things for touring wheel durability are deep, strong rims and correct and even spoke tension. Those rims look plenty strong.
(Sigh. Do I really want to go down this road? I don't want to but I guess I'll have to. Here goes...)

Even spoke tension? Yes. Correct spoke tension? What is that? Strong rims? What does that have to do with wheel strength?

Yes, by all means the spoke tension should be even and consistent. But show me a chart that tells a wheel builder what the "correct" spoke tension is. The variables are too many...what rim, how many spokes, what hubs, what spoke gauge, what spoke nipples, rider weight, rider use, etc?...for any rim manufacturer to give you a "correct" spoke tension. Even the tensions that they suggest are across an extremely broad range and I would take as more of a CYA on their part than a real number. The real number may exist but I really doubt it. I've been building wheels for 40 years and I have yet to find that elusive chart.

As for the rim, first, you can't tell by looking that the rim is strong or weak. That depends on the thickness of the metal and the number of spokes the rim is supposed to be laced to. The rim doesn't do much in terms of resisting the forces that are placed on a wheel because the metal used...aluminum...is soft and small changes in the configuration won't make that much difference. Deep rims might resist upward deflection slightly more than a shallow rim but most of the deep rims are also narrow rims which means they don't resist sideways deflections as well. Wide rims might resist sideways deflections but they don't do much to resist upward deflection. Basically, any rim out there is probably adequate for the (fairly easy) job that rims have to handle.

The real work done to make a wheel strong is done by the most overlooked part of the wheel...the spokes! Spokes do all the work to keep the rim from bending side-to-side. Spokes do all the work of spreading around the load as the rim is loaded, deflected upward detensioning the spokes and then picking up the tension as the rim is unloaded. And the spokes do all of the work of driving the wheel forward or stopping the wheel as the hub goes around and pulls the spokes in the respective direction. Rims get all the glory but spokes do all the work.
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Old 07-17-19, 04:21 PM
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Originally Posted by cyccommute
Even spoke tension? Yes. Correct spoke tension? What is that?
I would imagine that "correct" spoke tension is tension that's high enough that the spoke doesn't fatigue rapidly from slackening in use, and low enough to not create issues at its interfaces (such as damaging the nipple or the rim). Obviously that's a pretty wide range, and dished real wheels with equal numbers of spokes on each side necessarily require a wide range.

I'd actually kind of flip the order. "Correct" spoke tension is probably more important than even tension. A wheel with spoke tensions all over the map (but all individually reasonable) will be more durable than an evenly-tensioned wheel where all the spokes are badly undertensioned. But, correctness and evenness tend to go hand-in-hand in a well-built wheel.
Start with an untrue rim, and then you need to compromise between wheel true and appropriate tension...
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Old 07-17-19, 10:02 PM
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Originally Posted by cyccommute
(Sigh. Do I really want to go down this road? I don't want to but I guess I'll have to. Here goes...)

Even spoke tension? Yes. Correct spoke tension? What is that? Strong rims? What does that have to do with wheel strength?

Yes, by all means the spoke tension should be even and consistent. But show me a chart that tells a wheel builder what the "correct" spoke tension is. The variables are too many...what rim, how many spokes, what hubs, what spoke gauge, what spoke nipples, rider weight, rider use, etc?...for any rim manufacturer to give you a "correct" spoke tension. Even the tensions that they suggest are across an extremely broad range and I would take as more of a CYA on their part than a real number. The real number may exist but I really doubt it. I've been building wheels for 40 years and I have yet to find that elusive chart.

As for the rim, first, you can't tell by looking that the rim is strong or weak. That depends on the thickness of the metal and the number of spokes the rim is supposed to be laced to. The rim doesn't do much in terms of resisting the forces that are placed on a wheel because the metal used...aluminum...is soft and small changes in the configuration won't make that much difference. Deep rims might resist upward deflection slightly more than a shallow rim but most of the deep rims are also narrow rims which means they don't resist sideways deflections as well. Wide rims might resist sideways deflections but they don't do much to resist upward deflection. Basically, any rim out there is probably adequate for the (fairly easy) job that rims have to handle.

The real work done to make a wheel strong is done by the most overlooked part of the wheel...the spokes! Spokes do all the work to keep the rim from bending side-to-side. Spokes do all the work of spreading around the load as the rim is loaded, deflected upward detensioning the spokes and then picking up the tension as the rim is unloaded. And the spokes do all of the work of driving the wheel forward or stopping the wheel as the hub goes around and pulls the spokes in the respective direction. Rims get all the glory but spokes do all the work.
You were right to begin with: you shouldn't have.

Correct spoke tension is near the max specified by the rim manufacturer, duh. Any decent bike shop will know what is correct for that rim. No great esoteric knowledge required, just a little curiosity. Gauge makes no difference. Number of spokes makes no difference. Rider weight makes no difference. One uses somewhere near the max DS tension specified for that rim in back, and about 85% of that up front. Basically, you want to use about as much tension as the spoke bed is designed to take. The manufacturer can quote you that. There are no "charts," unnecessary, which is why you've never seen one. There's no greater tension than max and no reason to use less than about 10 lbs. off max. You're making it way more complicated than it is, just to make it seem like it takes an expert. It does not, just someone who can read.

If you knew statics, you'd know that the changes in spoke tension and thus spoke longevity are dependent on rim stiffness. If it were a perfect box section, rim stiffness would go up by the 4th power of its depth, but in reality is somewhat less as the top of the section has less material than the bottom. In any case, that's not "slightly more" stiff. One can tell just by looking that these are relatively deep rims and the width of the deep section will make them extremely stiff.

We run CX-Ray spokes on our tandem, 36H rims, could be fewer, all up 335-400 lbs. Never broke a spoke. Cobbles, potholes at speed, etc., no problem. Some of that's from the 28mm deep rims and some because these are thin, fatigue resistant spokes.
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Old 07-18-19, 12:10 AM
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Originally Posted by jambon
Hi there , just looking for opinions on whether or not these wheels will be up to the task of bike packing.....

light load (15 lbs max) + you (?? lbs)


where will you be riding?.....pavement? groomed trails? dirt roads? lunar surface potholes....?
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Old 07-18-19, 03:28 AM
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It is kind of hard to evaluate what your actual needs are. As has been pointed out we don't know what you weigh, what kind of terrain you will ride, or how you will ride it. Heck the load you describe could range pretty widely. People will describe it the same way and be carrying 10-15# or 20-25#.

That said... If it was me and that setup was what I had I wouldn't hesitate to go out for short trips like you describe a few times a year. I am probably at the upper end of the weight range at 205#, maybe I am foolish, but I'd have likely done the same when I was 25# heavier.

If in doubt, keep the load as light as possible. You really can get by with very little unless you have to carry a lot of water. It looks like your location is Ireland so I assume you won't need to ride in the desert. Carrying a 2 ounce filter helps a lot in reducing the load as long as there is surface water. If you keep the base gear weight down to 10-12# (less is possible) and keep the food light (2.5# per day is pretty easy) the total load can be pretty reasonable. Ultralight may not be everyone's cup of tea, but it can be quite comfortable and riding an unladen bike can be liberating.
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Old 07-18-19, 12:08 PM
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Originally Posted by HTupolev
I would imagine that "correct" spoke tension is tension that's high enough that the spoke doesn't fatigue rapidly from slackening in use, and low enough to not create issues at its interfaces (such as damaging the nipple or the rim). Obviously that's a pretty wide range, and dished real wheels with equal numbers of spokes on each side necessarily require a wide range.
I took Carbonfiberboy's "correct tension" to mean the manufacturer's suggested tension (see below). There is no manufacturer's "suggested" tension that is meaningful. Basically, wheelbuilding is more art than science. You are correct in your assessment but there just no hard numbers that you can turn to.

Originally Posted by Carbonfiberboy
Correct spoke tension is near the max specified by the rim manufacturer, duh. Any decent bike shop will know what is correct for that rim. No great esoteric knowledge required, just a little curiosity.
Where do you find the "max specified by the rim manufacturer". I have yet to see any kind of chart for a given rim much less a /hub/spoke combination. There are sometimes generic tensions like Velocity's "110kgf and 130kgf" which covers 15 models of rims and 38 different diameters. A Velocity A23 is very different in construction and configuration than a DeepV or NoBS but they use the same spoke tension. That doesn't seem right.

Mavic doesn't even go that far and list no spoke tension ranges for their rims that are easy to find. If it were so important, I'd think they would put it right up front.

Park Tool has some tension recommendations but they are rather broad suggestions...and I look on them only as "suggestions". Giving a range like for the Bontrager rims, for example, of from 50 to 130 kgf is far too broad to be useful. That's 490 N to 1274 N (110 lb to 286 lb). That's a very broad range.

I also happen to work with people who operate a shop and not one of them can tell me what spoke tension to use. It's simple not listed.

Originally Posted by Carbonfiberboy
Gauge makes no difference. Number of spokes makes no difference. Rider weight makes no difference. One uses somewhere near the max DS tension specified for that rim in back, and about 85% of that up front. Basically, you want to use about as much tension as the spoke bed is designed to take. The manufacturer can quote you that. There are no "charts," unnecessary, which is why you've never seen one. There's no greater tension than max and no reason to use less than about 10 lbs. off max. You're making it way more complicated than it is, just to make it seem like it takes an expert. It does not, just someone who can read.
Well I'm not sure what you are saying makes no difference. All of those factors make a difference to the durability of a wheel and they make a difference to the way the wheel is built. Again, there is no "specified" tension for rims...only ranges. And just running the tension up on spokes until they are as tight as you can get them can lead to cracking of the rim is some cases. The rim construction will make a difference.



Originally Posted by Carbonfiberboy
If you knew statics, you'd know that the changes in spoke tension and thus spoke longevity are dependent on rim stiffness. If it were a perfect box section, rim stiffness would go up by the 4th power of its depth, but in reality is somewhat less as the top of the section has less material than the bottom. In any case, that's not "slightly more" stiff. One can tell just by looking that these are relatively deep rims and the width of the deep section will make them extremely stiff.
That's only stiffness in one direction. Wheels are subjected to bending forces in multiple directions. Making the rim taller makes it stiffer only in the vertical direction not in the horizontal. The rim can be bent out of plane fairly easily and would be if it didn't have spokes resisting that out of plane bending. And the increase in stiffness is fairly small since aluminum (and most wheels are still aluminum) is fairly soft.

But even when the rim is taller, there's really no advantage to it being stiffer vertically. That's because the rim isn't attached to the spoke. The rim floats on the spoke and even though the rim is stiffer, it is still deflected upward when loaded. The spoke detensions and retensions as the contact patch is loaded and unloaded. The spoke still does all the work of keeping the wheel strong.

Originally Posted by Carbonfiberboy
We run CX-Ray spokes on our tandem, 36H rims, could be fewer, all up 335-400 lbs. Never broke a spoke. Cobbles, potholes at speed, etc., no problem. Some of that's from the 28mm deep rims and some because these are thin, fatigue resistant spokes.
People seem to think that potholes are the cause of broken spokes. Nothing could be further from the truth. Hitting potholes at speed doesn't break spokes because the spokes aren't the thing hitting the pothole. Again, the rim is floating on the spokes. A pothole causes a momentary upward deflection of the rim and detensioning of the spoke followed by a retensioning. The cycle of tensions changes on the spoke are what break spokes and breakage of spokes usually isn't something that happens because of a one time event.
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Old 07-18-19, 01:04 PM
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Originally Posted by cyccommute
People seem to think that potholes are the cause of broken spokes. Nothing could be further from the truth. Hitting potholes at speed doesn't break spokes because the spokes aren't the thing hitting the pothole. Again, the rim is floating on the spokes. A pothole causes a momentary upward deflection of the rim and detensioning of the spoke followed by a retensioning. The cycle of tensions changes on the spoke are what break spokes and breakage of spokes usually isn't something that happens because of a one time event.
I simply don't have the wheelbuilding experience to comment about this stuff, but would like to relate this personal experience to the fellow asking the question, and you guys too, Ive mentioned this before, but it is directly connected to this statement, and may be of interest to the fellow asking about his wheels.

a few years ago, I was descending a paved road in Guatemala, my first day in the country after being in Mexico, and whacked into a pothole.
The combination of early morning light, ie deep shadows here and there, so bright / dark, overly dark sunglasses, not paying enough attention to the road cuz I was gawking at the amazing mountains around me, and finally, still being accustomed to the rather good Mexican road conditions of the previous weeks, I got caught out by the number of really bad potholes in Guat.

So smacked into a bad one, a rather good smack at maybe 30-40kph, but was totally amazed when I stopped, to not have any broken spokes. A tiny amount of out of round, but really small, and it was only much later when cleaning the bike, that I saw the rim had crimped slightly, right where the rim was joined together. I guess I had the bad luck of hitting the pothole right at the joint.

The following winter, had the wheel retrued and retensioned before my next trip, and the mechanic figured it was probably ok. No issues on that trip, and again no issues on a third trip. Spokes fine, and so far (touch wood), the rim hasnt changed.

these are the mavic XC 26in rims I referred to earlier Mr Ham, Mavic 717, if this helps in any comparison to yours. I dont know enough about specific rims to give any informed comparisons.

and of course, every incident is unique, so take all this with a grain of salt.
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Old 07-18-19, 01:37 PM
  #20  
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Originally Posted by cyccommute
I took Carbonfiberboy's "correct tension" to mean the manufacturer's suggested tension (see below). There is no manufacturer's "suggested" tension that is meaningful. Basically, wheelbuilding is more art than science. You are correct in your assessment but there just no hard numbers that you can turn to.



Where do you find the "max specified by the rim manufacturer". I have yet to see any kind of chart for a given rim much less a /hub/spoke combination. There are sometimes generic tensions like Velocity's "110kgf and 130kgf" which covers 15 models of rims and 38 different diameters. A Velocity A23 is very different in construction and configuration than a DeepV or NoBS but they use the same spoke tension. That doesn't seem right.

Mavic doesn't even go that far and list no spoke tension ranges for their rims that are easy to find. If it were so important, I'd think they would put it right up front.

Park Tool has some tension recommendations but they are rather broad suggestions...and I look on them only as "suggestions". Giving a range like for the Bontrager rims, for example, of from 50 to 130 kgf is far too broad to be useful. That's 490 N to 1274 N (110 lb to 286 lb). That's a very broad range.

I also happen to work with people who operate a shop and not one of them can tell me what spoke tension to use. It's simple not listed.



Well I'm not sure what you are saying makes no difference. All of those factors make a difference to the durability of a wheel and they make a difference to the way the wheel is built. Again, there is no "specified" tension for rims...only ranges. And just running the tension up on spokes until they are as tight as you can get them can lead to cracking of the rim is some cases. The rim construction will make a difference.





That's only stiffness in one direction. Wheels are subjected to bending forces in multiple directions. Making the rim taller makes it stiffer only in the vertical direction not in the horizontal. The rim can be bent out of plane fairly easily and would be if it didn't have spokes resisting that out of plane bending. And the increase in stiffness is fairly small since aluminum (and most wheels are still aluminum) is fairly soft.

But even when the rim is taller, there's really no advantage to it being stiffer vertically. That's because the rim isn't attached to the spoke. The rim floats on the spoke and even though the rim is stiffer, it is still deflected upward when loaded. The spoke detensions and retensions as the contact patch is loaded and unloaded. The spoke still does all the work of keeping the wheel strong.



People seem to think that potholes are the cause of broken spokes. Nothing could be further from the truth. Hitting potholes at speed doesn't break spokes because the spokes aren't the thing hitting the pothole. Again, the rim is floating on the spokes. A pothole causes a momentary upward deflection of the rim and detensioning of the spoke followed by a retensioning. The cycle of tensions changes on the spoke are what break spokes and breakage of spokes usually isn't something that happens because of a one time event.
Really. The interaction of spokes and rims is much better understood than that now.

Spoke tensions are readily available from the manufacturer. Mavic says for front or DS rear, 90-110kgf. Obviously one could use 110 in back and 90 in front. Velocity thinks that theirs can handle higher tension: 110-130kgf, same locations.

Truly weird that the operators of your bike shop are unaware of published spoke tension specs. Don't know what to say to that. Took me 3 minutes to find the above two specs on the web. If you can't find it on the web, an email works well. Put the replies in a file for reference. Manufacturers have a strong interest in their rims performing reliably.

I strongly recommend using the rim manufacturers specs and not altering tension depending on the number of spokes, type of spoke, the particular rim from that manufacturer, or the weight of the rider or gear. I've never seen a broken spoke that was not on an undertensioned wheel. I have seen a cracked rim which had the specified spoke tension. Rolf had a run of tandem wheels which were poorly engineered. Yeah, don't use that rim or maybe that wheel next build. Manufacturers do make mistakes, but they're rare.

"running the tension up on spokes until they are as tight as you can get them" is a straw man. No one here has suggested that. One follows the rim's specs, simple as that. IME running 110 kgf on DS works at least up to 400 lbs. and no sense using less for lighter loads. I don't think any rims are rated lower than that. I use 100 kgf in front simply because why not.
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Old 07-18-19, 01:58 PM
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Three years ago on a really bad road full of rocks and cobbles in the interior of Iceland, something happened to cause a rock to briefly jam between a spoke and the frame on my rear wheel. I assumed the front wheel threw a rock into the rear wheel but do not really know. At first I did not know what happened, heard a sudden noise and the bike shook a bit. Later I could tell that a rear brake was rubbing on part of the wheel revolution. That was a 14 hour day, did not look at the wheel until the next day which I decided to take as a rest day.

You can see one bent spoke in my wheel. And that spoke was quite loose.



I did not know what happened, but I suspected that the nipple threads had been stripped. But decided to try to tighten it with the spoke wrench as I did not want to dig out my spares, pull the rim tape off, etc. And found I got lucky, the spoke nipple tightened up just fine. I trued the wheel and kept going, the nipple threads were not stripped. I then concluded that the spoke must have been stretched under the tension from the rock jamming in it, and it is a 2.0mm straight gauge Wheelsmith spoke so that must have been a LOT of tension to cause that kind of damage.

I finally replaced that spoke about half a year ago when I was doing some other work on the wheel and had the rim tape off. The spoke was still holding tension, but the big nick in the metal where the dent had been suggested to me that since I had the rim tape off, I might as well replace it.

My point is that at times I am amazed how well spokes hold up. I noted above in post 8 that I have not broken a spoke for over a decade and a half. And the wheel that I broke that spoke years ago was in an old tubular tire wheel with a Campy hub that had a 1961 date code. I have no clue how many owners that bike had before I bought it.

As I noted in a post 8, I still carry spare spokes and the tools to replace them on a tour, but I really think that modern wheels are pretty good and a broken spoke would surprise me greatly.

***

One point that I think many people are missing in this post is that the OP does not have a normal set of wheels with a normal set of straight gauge or butted spokes. He has some special bladed ones that are direct pull, and a small number of them.


Yet I still think that the OP could easily do a few multi-day bikepacking rides with his wheels if he had the spares, tools and knowledge to replace a few spokes because he would still get home, as I noted in post 8 above. I do not think he would break a spoke, but if he did and could replace it, then it is not a big deal.
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Old 07-19-19, 07:25 AM
  #22  
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hey Mr Jambon, do you already own the bike packing bags and all the kit?
Have you fit them on the bike yet to get an idea of how heavy your load would be?
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Old 07-19-19, 09:08 AM
  #23  
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Originally Posted by Carbonfiberboy
Really. The interaction of spokes and rims is much better understood than that now.
?

Originally Posted by Carbonfiberboy
Spoke tensions are readily available from the manufacturer. Mavic says for front or DS rear, 90-110kgf. Obviously one could use 110 in back and 90 in front. Velocity thinks that theirs can handle higher tension: 110-130kgf, same locations.

Truly weird that the operators of your bike shop are unaware of published spoke tension specs. Don't know what to say to that. Took me 3 minutes to find the above two specs on the web. If you can't find it on the web, an email works well. Put the replies in a file for reference. Manufacturers have a strong interest in their rims performing reliably.
I saw the same value that value found for the Mavic but that is in a tech manual for their prebuilt wheels. Where's the spoke tension specs for the rims that Mavic makes? They certainly aren't listed with the rims. And, again, the "listed" tensions like those of Velocity are a very wide range and cover all of the rims that they make. If the rims vary in strength (and if strength of the rim had any bearing), there should be much more detail than just a vague and wide range. Each rim should have it's own range of values at the very least.

Originally Posted by Carbonfiberboy
"running the tension up on spokes until they are as tight as you can get them" is a straw man. No one here has suggested that. One follows the rim's specs, simple as that. IME running 110 kgf on DS works at least up to 400 lbs. and no sense using less for lighter loads. I don't think any rims are rated lower than that. I use 100 kgf in front simply because why not.
That's what you were suggesting. "Correct spoke tension is near the max specified by the rim manufacturer" says to run them up just about as tight as you can get. On the Park Tool tension meter, a 2.0mm spoke would need a reading of about 25 to get that 110 kgf tension on a Mavic and would need to be at 30 to get the 130kgf force suggested by Velocity. From long experience, I know that square brass spoke nipples start to round off at around 25 on the tension meter. Most rims are at risk of cracking at tensions higher than 20 to 25 on the tension meter.

And, again, there are no "specifications" only wide ranges of tension.

Just to clarify, my problem with the “specification” on tension is where they are listed. Manufacturers list all kinds important specifications like outside width, depth of the rim, inside wide, ERD, type of sidewall, etc. on the pages with the rim. But they bury tension “specifications” in technical manuals and other web pages. If the tension specifications had any real meaning...or if they had ever really been measured...they should appear on the same page as the rims.

As with most things on the Bike Forums, I’ve discussed this topic numerous times before. Lots and lots of people have tried to justify the use of “strong” rims by saying that you can put more tension on the spokes. But both Mavic and Velocity put that argument to rest by stating a wide, single, and meaningless range for tensions.
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Old 07-23-19, 03:18 PM
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Folks thanks for all the replies , very helpful and paranoia reducing

I am a heavy ish person at 220 lbs , I will keep the bikepacking weight down to a minimum and will not be going hard off drops on these wheels . Ill also take the advice above and try minimise the water I carry .

With any luck it should hold , I have spare spokes and a wrench but will not carry cassete removal tools as thats just a lot of dead weight that il risk without , first tripis a one nighter abd if wheels explode I can walk out fairly easily and get family to pick me up
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Old 07-23-19, 05:47 PM
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Originally Posted by jambon
... . Ill also take the advice above and try minimise the water I carry .
...
NO !!!

Too many times I have been camping at a campground and watched bikepackers trying to minimize weight come dragging into a campsite badly dehydrated and the first thing they say is - where is the water?

On one day ride I did on Maah Daah Hey trail, I was about a quarter mile from the campground and a bikepacker trying to go to the campground was so dehydrated that I gave him some of my water because I was not sure if he could make it the last quarter mile.
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