coyotecrust

does anyone know the target spoke tension in kgf for a mavic open pro?

double butted, dishless, 3x, 36h...

Thrifty1

According to Barnett manual, 90 to 110 kg for all Mavic rims.

Al1943

I've got 157 kgf on my drive side rear spokes with no problems after 5 years. But that number is from the Park deflection measurement conversion chart using the 1.5 mm diameter at the center of 2.0-1.5-2.0 double butted spokes, don't know about the accuracy of the conversion on double butted spokes.

Al

Primo Tiki

Wow, thats a lot of tension. Any cracks in the rim yet?

cascade168

I talked to Mavic tech support on the phone with the exact same question. They told me the spokes should be tensioned in the "90-110KgF" range. So, I shoot for 110 when I build OPs. There are always a few spokes that are a tad over and I have never had a problem. On the Mavic "dealer-only" tech support site it says the same thing. As Thrifty1 stated, Mavic quotes that same spec for ALL of their rims (amazing!!!).

Nessism

I always wondered how to translate tension numbers on the Park gauge into actual tension values when using butted spokes. So we just disregard the butted end thickness and read the value off the chart?

cascade168

While it's not obvious and stated plainly, the directions say to "measure the spoke at the smallest diameter".
According to Park (via email), this translates to "tension the spoke according to the smallest diameter". So, your assumption is correct. Tension the spoke's thinnest diameter/gauge.

For example, if you have 14/15/14ga (2.0/1.8/2.0mm) double butted spokes, you tension assuming 15ga(2.0mm). The TM-1 range (according to the chart that comes with the tool) for a 1.8mm round steel spoke would be 54-175KgF (or 15-26 on the TM-1 scale).

Deanster04

Go till they are giving A440 when you ping them. Open Pro rims are pretty tough. The recommendations above are pretty good. The tighter the better and the less of a difference between the spokes so they won't loosen. Nessim, I use about the same average tension on the drive side of the rear wheel on my 10 spd record with 14/15 spokes and mavid open pro rims. Less tension on the front and non-drive side.
The spoke prep you use is critical. There is a new one that is on the market (name excapes me) that uses a lube and a loc tite product combined. A friend who has used it thinks it is the cats meow and he is one of the best local builders. I have tried them all and have gone back to linseed oil...real old school.

cascade168

I use spoke prep on the spoke threads and linseed oil on the rim/nipple interface. When the linseed oil drys out it resists any turning of the nipple, as does the spoke prep. The thing I like about spoke prep is that it is an excellent corrosion preventative. Plus, even those tiny little jars can do a LOT of wheels' worth of spokes.

Is the (name escapes you) item possibly DT Spoke Freeze or Rock 'n Roll Nipple Cream? I'm a little intrigued with the DT Spoke Freeze as you use it after tensioning and it's supposed to wick down into the threads and then set up. The problem I see with it is that it does nothing for lubricating the spoke threads for the tensioning process like Spoke Prep does. Also, it makes the Wheelsmith Spoke Prep look cheap. Any Spoke Freeze users or proponents out there?

Deanster04

I think it might be DT spoke freeze. Another method I used was silicone lube followed by the LocTite product that is green and works its way down the threads to setup( not too securely that you would need a pair of dikes to loosen the wheel). You can get it from the automotive store. Most of the stuff on the market works well. Linseed is what I started with years ago and is readily available. No real axes to grind here. Spokes, hubs, rims, lubestuff, a bottle of wine, and some good music and I am in heaven.

cascade168

A great reference for different Loctite "flavors":

https://www.loctite.com/int_henkel/lo...Treatments.pdf

- see the chart on page 5.

I'd guess you used the #290 which is wicking. I would not be surprised if the DT Spoke Freeze is actually Loctite 290 with a new label (and higher price) on it. Anybody know if DT Spoke Freeze is green?

Deanster04

Yes, I believe that's true on the loctite. I'll have to ask my friend about the DT prep. Thanks for the reference.

TallRider

You mind telling us what you weigh, and what surfaces other than dandelions you ride on?

Yeah, there's certainly unacknowledged differences here. OP's can take higher tension than MA3, for example.

Al1943

Like I said, no problems after 5 years and several thousand miles.

On my Open Pros and also DT RR 1.1 rims with Revolution spokes, 2.0-1.5-2.0 (14-17-14) I'm running Park deflection values of 22 on the driveside rear spokes IF the 1.5 is the correct spoke diameter for making the conversion. According to the chart that equals 157 kgf, but I have some doubts about the conversion accuracy. I certainly would not recommend that anyone shoot for 157 kgf for any other spoke/rim combination. But this seems to be what it takes to avoid broken spokes due to excessive flexture on the non-driveside spokes with Revolutions. I'm running 12 - 13 Park deflection values on the non-driveside.

Al

Deanster04

I weigh 225lbs and ride some of the dirt back roads with severe washboard. No problems with the rims. I would be very surprised if there were many reported problems with the Mavic Open Pro rims as they use the double steel insert for the nipples. Conventional spoking is far less severe than the asymmetrical wheels found in the boutique sexy wheel sets where a lot more strength has to be built into the rim to support the rider. Simple physics.

Pete Hamer

Dt spoke freeze is red but I wouldn't be suprised if they just use a different color in the same formula. You are supposed to oil the nipples before building the wheel and add the spoke freeze afterward if you want the nipples to turn later. I've tried it for wheelbuilding but don't care for it. I use it now for repair type work on wheels as a bandaid on bad builds or to keep wheels going a bit longer that are on their las leg. I find that if a wheel is designed well and built right the you won't have a problem with spokes loosening up. Usually the reason that spokes are problematic about loosening up is that the rim is too light for the rider/application or spoke tension is too low.

Pete Hamer

One thing I have noticed is that when building a wheel with new, high quality parts is that their seems to be 'sweet spot' for spoke tension. I add tension in small increments then stress the wheel, then true/round, then add another layer of tension, and repeat. I measure the spokes tension between cycles. What happens is that the spoke tension is not balanced at first, but at some point all the spokes end at the same exact tension. This usually happens in the 100-120kgf range. If I continue to add tension after hitting the 'sweet spot' the spokes go out of balance.
I am curious to know if anyone else has noticed little phenomina.

dafydd

my exact suspicions and usage of the stuff.

Deanster04

Yes I have had a wheel go bad by running the tension up too much. Not often, but I have been able to relate it to a questionable rim. Otherwise not often.

johnlink

How should this be interpreted for the rear wheel, where the tension between the spokes on the two sides can be substantial?

davidad

On the rear the tension on the drive side is the only one that's important unless there is extra dish from 11 sp or higher hubs. Then go for higher drive side tension and raise the NDS to 55 or 60Kg.

johnlink

Thank you, davidad.

mrrabbit 

You don't use sound for final tension, you use to check for rogue spokes when doing relative tension.

Open Pros are not pretty tough, they are light weight race training clinchers - not designed for heavy duty use or longevity.

90-110 kgf for drive side, try to aim for 110, but be prepared to settle for 103-107 on some.

Most can be built on 36 / 18 offset rear hubs without the need for spoke prep or loctites.

2.0 / 1.7 / 2.0, 2.0 / 1.65 / 2.0 and 2.0 / 1.6 / 2.0 butted spokes are excellent with the Mavic Open Pro.

=8-|

mrrabbit 

All 11 spd hubs I have worked with so far have .8 to 1.2mm LESS asymmetrical dish than 10 spd hubs - 11 spd hubs were specifically designed this way.

=8-|

mrrabbit 

It's not a sweet spot, it's the point at which the rim starts to yield.

For old super lightweight tubalars from the 70s, could be as little at 50 kgf such as with Martano's.

Nowadays, it's mostly in the 110-130 range.

If you have barely started to force the rim to its yield point, you'll know this when you realize you are re-truing the same 2-3 spots every you do a stress relief cycle. That's the rim telling you to back off a 1/4 turn to 1/2 turn.

If you inflate a tube and tire, and the wheel develops an "s-wave" when spun, but returns to true after deflating the tube/tire, then the over tension state is considerable. As much as a full nipple turn will be required.

If that happens with a used rim at very low tension, then the rim has probably fatigued to the point where it simply cannot hold a high yield point any further. Most people are not lucky enough to experience this - either sidewall is worn out first, or an accident happens - though your chances are much higher with a disc rim.

=8-)