Target Spoke Tension
 

I'm building a set of wheels and am looking for advice on ideal average spoke tension. The wheelset is for my fixed gear bike and is intended to be strong and durable. Here are the specs:

36 hole hubs
Mavic MA3 rims
14 gauge straight DT stainless spokes

I am using a Park Tension meter to build them. I've looked at the Park Tool site and Mavic site, and neither one provides a 'recommended' avg spoke tension for the rim with 14 gauge (2.0mm) spoke.

Does anyone have a specific 'kgf' rating for this wheelset?

Many thanks in advance.

I don't know the answer to this question. Jobst Brandt proposes that max tension will depend on the rim. He implies you'll eventually know it by tone. And he describes a process whereby stress relieving will indicate whether tension was too high. So that doesn't really tell me much. Using typical spokes (2.0, 1.8, etc) I tend to try to get the non-drive side above 15 (on the Park deflection reading) and the drive side less than 25. It will take me some more years of trial and error riding on my own wheels before I find out whether I should change those tendencies. Anybody else have ideas?

Yeah, it depends upon the rim. With normal box-section rims, I aim for 80-100 kgf and aero-profile rims about 100-120 kbf. Rims tend to stay straighter and handle more load on the tight end of the spectrum. That's because load on the hub will loosen the spokes at the bottom in contact with the road. With spoke-tension that's too loose, the 3-5 spokes at the bottom lose all their tension. Then this allows the nipples to rattle and unscrew themselves when you hit hard bumps leading to wheels going out of true.

The highest load on wheels is not carrying weight, no matter how heavy you are, the wheels are more than strong enough to carry your weight. It's when you hit bumps suddenly that loads up wheels. Such as hitting speed-bumps or the up-side edge of drainage-ditches at speed. Then each wheel can experience 800lbs of force or more.

Mavic keeps their site (http://www.mavic.com) intentionally vague with respect to a lot of specs. This is so that their dealers can spoon feed people with this "top secret" information(like rim diameter and weight). This aspect of their marketing has been regularly ripped on other forums. It's pretty dumb, IMHO. There is a dealer-only tech support page that any Mavic dealer will have access to and they can answer your question. Or, you can just call Mavic tech support and they will tell you (in the US it's : 888-466-2842).

That site says to pretension the spokes at 40-60 KgF and final tension them in the 90-110 range. I do my OPs at 110 and that seems to work just fine.

Update: When I looked this up I did not get challenged for a password, so maybe Mavic decided the world will be safe with this kind of data. You can try yourself at: http://www.tech-mavic.com
Once you see what they were hiding it's pretty disappointing. PM me if you can't get in. There was a nice person at the US office in Haverill, MA that I have talked to on a couple of occasions, so don't be afraid to call them. Plus, you can request a cataloge on that line, as well. Hope this helps, BB. Good luck.

mavic recommends
90-110kgf for all of their rims

~883-1079N

Yes, I forgot to mention that is a generic spec for all of their rims. I'd be curious to hear some comments from others as to why that is. It's just a tad hard to believe that they actually have that as a design requirement for all rims. But, I may be wrong about that. I'm more inclined to believe that the 90-110 KgF range is conservative and works ok. As I said earlier, I always use 110 for Open Pros and they seem to stand up quite nicely. I'm very fussy about relative tensioning and pretty much never have to revisit them unless they get abused.

If anyone actually has some knowledge of Mavic's design process, please speak up.

I've built three sets of wheels with a Park tensiometer and Revolution (2.0-1.5-2.0; 14-17-14) spokes. On the 9 and 10-speed wheels, in order to put enough tension into the non-driveside spokes to avoid breakage I've had to run the driveside rear spokes up to a declination number of 22 1/2 which according to their chart is 160 kgf on a 1.5mm spoke. But on a 2.0mm spoke that declination number is only 85 kgf. To me this is a bit confusing, but I've not had any problems with the rims, OP and DT RR 1.1, and I quit having broken spokes. Actually I've only had two spokes break and they were on the non-driveside at the "J" bend, indicating low tension. Since I've cranked the tension up, no more problems after several thousand miles.
I think Revolution spokes are difficult to build with due to windup and stretch, but after a thousand miles and a couple of tuneups the wheels are now rock-solid. I'm sure it would be easier to use 14-15-14 gauge on the driveside rear.

Al

Thanks everyone for your suggestion! They're helpful. I called Mavic and they told me 95 kgf. That seems way too loose to me. Based on the feedback you all have shared and spoke tension on my other wheels, I think I'm going to shoot for 110-120. MA3 are pretty beefy so they should be able to withstand it...at least I hope!

Beware that a lot of people have reported pulling spokes through MA3 rims under tension that wouldn't cause this in a normal rim (i.e. too much). I'd be inclined to follow Mavic's suggested limit, or different rims.

Those are some of the sweetest , highest quality, greatest combinations of parts a Sydney muppet has heard of in 20 years. If only the first line would have inlcuded the words: Campy, or Dura-Ace, or Mavic... or.... in a moment of USA glory .. "Phil Wood" .

So awesome.

Get a grey haired old bike pro to build these wheels for you . pay whatever he wants. You will be happy for many an muppet life.

I don't mean to bag on you but straight 14's on a 36h wheel are overkill. Straight 15's would be more than strong enough, even on the drive side rear, unless you are over 220 lbs.

Regarding tension, stay with Mavics recomendation; the MA3 has a relatively poor reputation for spokes pulling through as Juicemouse has indicated.

Good luck.

Ed

Agreed. I have seen this too. But I have also seen well built, well tensioned 36h mavics give long multi-thousand mile service on quality Santana and Paramount tandems that run primarily in hilly terrain with powerhouse captains and stokers. Overtensioning kills mavics of this variety, but skilled builds can go and go.

The MA3 suffers pullthrough because it features single eyelets and a hard anodization. The installation of the eyelets requires the removal of a good deal of material without actually adding much in the way of structural support. Contrast this with Open Pros which feature double eyelets / sockets where the eyelet is actually a continuous sleeve that rests on both the interior and exerior part of the box section. As for the hard ano, just look up Jobst Brandt's rant on the subject.

Having said that, I've built MA3 wheels on the upper end of that range, around 110 kgf, and they seem to be doing ok after about 1,000 miles or so.

Well said.

The hard anodized Mavic rims are denoted with CD in the name. For example, MA3 CD. The regular, more common MA3 has a thin cosmetic anodizing which is not as damaging to the aluminum as the thicker CD anodizing.

I'm convinced that it's not the degree of anodizing that's the root cause of most MA3 failures, it's the cross section. In other words, it's just a sub-par design with not enough material at the spoke bed. But that's just speculation/hearsay, as I have no personal experience with these rims.

i think you're all just a bunch of ninnies that choose the wrong rim and build crappy wheels.


just kidding :)