Tandem Cycling - 145 mm rear hubbed wheel with disc still dishless?

This is a very dumb question, so much so that I can't find any information on this.

When I true my wheel, I seem to observe less tension on the left (disc) side, but it's within the variation of spoke tension required to achieve lateral and radial truing. If I knew, for example that the right (drive) side was a tight side, then I'd feel confident setting all its spokes at equal optimum tension and then let the left side tensions fall where they may. The problem with that, of course, if that then changes the relative tight side tensions. Welcome to wheel truing, right?

But if the wheel were dishless I could set all spokes at equal tension by working successively on opposite spokes and then when I trued the variations would be minimized or hint that I might need a new rim.

Please help out this confused confused puppy. Thanks.

I see your problem. You bought a spoke tensionometer! :roflmao2:

Unless you're truing a low spoke count wheel, (which at this point in your wheel building career I would not recommend), set your new toy aside. Now grease all the spoke threads if you havent already done so. (Locktite is for people who don't build their wheels tight enough!). Now, round and true the wheel. And keep rounding and truing the wheel until it is pefectly round and perfectly true and as tight as you can get it without rounding spoke nipples. Literally.

Now pre-stress the wheel both vertically and laterally. Now true again and pre-stress again. Now true again and pre-stress again. Now true again and pre-stress again. Repeat as necessary. When you no longer hear any pings and the wheel no longer goes out of true when stressing it, I guarantee you that you will have a strong, durable wheel, regardless of what your new toy says.

Which you may now pick up, incidently, and it should tell you two things. The drive side is tighter than the off side, and both sides are within tolerances.

There is no such thing as a perfect rim or a perfectly matched set of spokes, therefore there is no such thing as a wheel where all the spokes on one side are of "equal" tension. Which is why you build the wheel by sight and feel first, then use the tensionometer to see what the tensions ended up being .... to double-check yourself.

All "dished" wheels have a tighter drive side, and to the best of my knowledge, only the 160mm proprietary spacing Santana uses creates a "dishless" wheel. If I'm wrong there, I'm sure TG will weigh in on the subject as he's seen way more of the current hi-tech stuff than I have.

But you're on the right track. You're building, and you're asking questions. Keep doing both. Trust me, after the first 10,000, they get easy! :thumb:

Thank you for your considered reply. Starting from momma is a very good idea.

And keep rounding and truing the wheel until it is pefectly round and perfectly true and as tight as you can get it without rounding spoke nipples. Literally.


I strongly disagree with this. Tightening spokes too tight can result in rims cracking around the spoke holes.

I used to have my wheels built by a very-well-known shop. About a year after one set was built, I discovered cracks around ~12 of the spokes on the rear wheel. They would not cover it under warranty, and they told me I could not get Mavic to cover it unless it was built by Mavic. So I had to buy a new rim and pay for a new wheel build. I was not happy about this.

About 6 months later, I built a new bike, and used the old bike for parts. I decided to build my own wheels, re-using the hubs from the old bike. I bought all the tools needed to build wheels, including a *tensionometer*. On a whim, I measured the spoke tension on the old wheels before taking them apart. It was OFF THE CHART! Literally! The chart Park includes with the tensionometer did not go high enough to convert the reading I was getting.

If you want something done right, you need to do it yourself.
(I will give Mavic credit for building rims tough enough to handle insanely over-tightened spokes.)



All "dished" wheels have a tighter drive side, and to the best of my knowledge, only the 160mm proprietary spacing Santana uses creates a "dishless" wheel.

Phil Wood will sell you dishless rear hubs in 145 or 160 spacing.

I used to have my wheels built by a very-well-known shop. About a year after one set was built, I discovered cracks around ~12 of the spokes on the rear wheel.

So you had multiple sets of wheels built by the same shop, had a problem with one rim on one set, and it's the shop's fault? I would surmise you had a bad rim. It happens.

As for "too tight", I was building wheels from about 1974 to about 1990, (years after I sold my last bike shop), for a lot of the top riders in this area of the state. They sought me out even after I got out of the biz because they only trusted me to build their racing wheels. To the best of my knowledge, I never had one fail or collapse or have an issue with broken spokes or rim cracking once it left my hands.

To the OP, follow whatever advice you like, but I think if you ask 10 professional wheelbuilders, 9 will tell you that a good wheel is a tight wheel.

So you had multiple sets of wheels built by the same shop, had a problem with one rim on one set, and it's the shop's fault? I would surmise you had a bad rim.

You need to re-read my posting.

Edited to add:
Mavic recommends 100kgf tension for front spokes, and rear-drive-side spokes.
The highest translated tension meter reading on the chart for those spokes is "25" which translates to 175kgf. So the idiots built my wheels with some in excess of 175kgf tension, and you blame the *rims*???

onegun is right. Tight is good. Stuff is going to stretch.

Mavic recommends 100kgf tension for front spokes, and rear-drive-side spokes.
The highest translated tension meter reading on the chart for those spokes is "25" which translates to 175kgf. So the idiots built my wheels with some in excess of 175kgf tension, and you blame the *rims*???

Now there IS something to read! :thumb:

In spite of their popularity, Mavic has a reputation for cracked rims and spoke pull thru. Their rims tend to be overhardened, and this occasionally is the result on an otherwise well built wheel.

But just for fun, what Mavic rims, what spokes, (brand and diameter), and what tensionometer are we talking about here?

But just for fun, what Mavic rims, what spokes, (brand and diameter), and what tensionometer are we talking about here?

Correction to my previous post: The readings were all over *26* which is 175kgf on the chart.

- Mavic XM719 26" 32H
- DT 14/15 DB
- Park TM-1

- Mavic XM719 26" 32H
- DT 14/15 DB
- Park TM-1

Well, I don't see anything wrong with your numbers, as far as that goes. You did state that *all* were at or over 26, so I'm assuming this was not just a random spoke or two.

However, in looking for a tension spec for your rim, I found nothing. Since a lot of people have come up with this "Mavic recommends 100kfg for all fronts and drive-sides", it must be coming from Mavic and it's utter BS. Probably set to avoid having to replace rims under warranty. Think about it for a minute. Are they trying to tell us that their heaviest duty rim can only take the same amount of tension as their lightest rim?

I'd say that's nonsense. And so does Park Tool, (who I trust more than Mavic!). Here's a link (http://www.parktool.com/repair/readhowto.asp?id=51) to their website where they show recommended tensions for fronts and drive sides for various Mavic rims, (scroll down to last chart). They go up as high as 160kfg.

So, absent any specific specs on your specific rim, we can only guess what the real spec might be. Considering that it is a heavier rim, I would tend to think that the higher end ought to be do-able.

In which case, 175 is still over spec, but "insanely tight", and the builder an "idiot"? Don't think so.

In which case, 175 is still over spec, but "insanely tight", and the builder an "idiot"? Don't think so.

So I should be happy the builder cranked the tension up so high it resulting in the rim cracking in less than a year and then refused to warranty their work???

Yeah....riiiiggghhtttt.....:rolleyes:

http://www.sheldonbrown.com/wheelbuild.html#tensioning

"If it starts to get hard enough that you have to start worrying about rounding off the nipple with the spoke wrench, you are approaching the maximum. Fifteen years ago, this would be the limiting factor, and you would just try to get the wheel as tight as you could without stripping nipples. Modern, high quality, spokes and nipples have more precisely machined threads, however, and now there is actually a possibility of getting them too tight, causing rim failure."

So I should be happy the builder cranked the tension up so high it resulting in the rim cracking in less than a year and then refused to warranty their work???

Never said that. Mavic should have warrantied it, and I believe, (although I can't verify it .. Mavic's site SUCKS!), that the shop's statement to you must be false. The idea that Mavic only warranties their rims on wheels Mavic built themselves MUST be nonsense. That would mean that NO Mavic rims sold as individual rims in the US have any warranty whatsoever. That seems extremely illogical.

But that has nothing to do with building a tight wheel, which is what you originally objected to. My actual statement was "tight as you can get it without rounding spoke nipples". From my own observations, that point seems to occur somewhere between 125 to 150kfg, and I wouldn't ride a rim that couldn't stand up to that.

Mavic's site SUCKS
Did you use this one?
username: mavic-com
password: dealer

http://www.tech-mavic.com/tech-mavic/technical_manual/data/index.php

Did you use this one?
username: mavic-com
password: dealer

http://www.tech-mavic.com/tech-mavic/technical_manual/data/index.php

Thanks!

I will agree with Onegun that Mavic's website sucks. Anyone building a website entirely on Flash, needs to be taken out and tarred and feathered, and never allowed near a computer again.:mad:

Now what I found there, (and why isn't this info available w/o a login???):

XM 719 -> General Points: "Respect the appropriate spoke tensions; Mavic recommends spoke tensions between 70 and 90 kg (for a front or rear wheel on the free wheel side with a crossed 3 pattern). Inappropriate spoke tension can generate too much stress and damage the rim;"

About 12 years ago we were having problems breaking spokes and our LBS called Phil Wood since we were using a Phil hub. Phil Wood told the shop to send the wheel to them and they would build it. When the wheel returned the LBS mechanics thought that the spoke tension was too high and the wheel would not last. After 6000 miles we got rim cracks around the spokes and replaced the rim.

Since then the shop uses high spoke tension and we take the wheels back 2 or 3 times to check the tension after a wheel build. We have since started using Velocity rims and don't know the milage on the wheels but it has been several years since they were rebuilt.

From our experience, single bike spoke tensions will not work on a tandem. The additional weight will cause the elbow to flex with each wheel rotation and it will eventually break, usually within 1500 miles.

Sheldon and Martha Hall
Greenfield, IN

XM 719 -> General Points: "Respect the appropriate spoke tensions; Mavic recommends spoke tensions between 70 and 90 kg (for a front or rear wheel on the free wheel side with a crossed 3 pattern). Inappropriate spoke tension can generate too much stress and damage the rim;"

Thanks, DVS! Ain't the internet grand??!!

And I wouldn't have believed it if I hadn't see'd it wit me own two eyes! Shimagnolo, if you check every other wheel, you'll find they all say the same thing. 70 to 90kfg, regardless of whether it's an extreme downhill mtb rim or a road or tri rim, regardless of weight or material or anything. Does that make sense to you?

And it also says at the top, "Conditions of use to be given to your customers", presumably at the time of sale. So it is indeed propaganda to keep Mavic out of any potential warranty or liability situation. Nothing more.

Now what I found there, (and why isn't this info available w/o a login???):


Really! One other piece I found there was something akin to what you were saying about warranty: the parts must be sold by a "Mavic Authorized" shop, and then they are warrantied for 2 years. Now, how exactly is a customer to know if his LBS is a "Mavic Authorized" one?

It's a reasonable assumption that if he had the rims, he was authorized! After all, the distributors shouldn't *sell* him rims if he's not "authorized"!

But even so, they still do not have to be "built by Mavic", like your LBS said.

But even so, they still do not have to be "built by Mavic", like your LBS said.

What LBS? I said it was a "well-known-shop", meaning it has had an Internet sales presence for years, and a glossy catalog for years before that. Needless to say, I no longer do business with them.

OP here.

After struggling for days with my rear wheel, tensiometer measuring, plotting tensions using the Park Tool software, rounding off nipples etc, I followed Onegun's advice by loosening all nipples to the first (inside) thread, squirting lube in the bottom of the nipples through the rim holes, and tightening equally until the wheel was somewhat tensioned. I then laterally and radially trued.

Although the wheel was true (but not dished properly yet) the tensiometer readings, although high at 150 Kgf, had a standard deviation of 40! (love that Park Tool macro!). I normalized the outliers, de-stressed the wheel, trued again, and measured again. I only had to do this four times and ended up after only (!) two hours with a drive-side tension average of 120 Kgf with a standard deviation of 6 and a rotor-side figures of 118 and 8, respectively, after dishing. The truing was perfect, if I can say so myself! But I still don't know for sure whether my 145mm disc wheel is dishless or not. (But who cares!)

With regard to tension targets, as mentioned above, I agree that there is no upside to a rim manufacturer of making tension recommendations that can subject them to liability even though a tighter wheel will stay truer longer. They see cracked rims, dissatisfied customers, and potential lawsuits, the consumer sees more functional and trouble-free wheels - up until rims crack and he/she seeks another "better quality" rim manufacturer, of course.

Onegun, thanks for the calming advice.

I strongly disagree with this. Tightening spokes too tight can result in rims cracking around the spoke holes.

I used to have my wheels built by a very-well-known shop. About a year after one set was built, I discovered cracks around ~12 of the spokes on the rear wheel. They would not cover it under warranty, and they told me I could not get Mavic to cover it unless it was built by Mavic. So I had to buy a new rim and pay for a new wheel build. I was not happy about this.

Yes. I used to do the same as it is the method advocated in Jobst's book before the wide use of tensiometers. I'll tell you from personal experience that you can get an Open Pro to 160KgF and have it perfectly round and true. Only problem is that it will crack in 12-18 months. :(

Now I use the tensiometer and build the the rims specification*. Wheels seem to last much longer. :)

* The last wheels I built were Velocity Aeroheads and I ran them to 120kgf. Didn't know Mavic was going so low. I would still probalby take them to 110 or so.