[bobonker]

Hi All,

I built up a set of Kinlin XR19W rims with BHS hubs and Sapim spokes. They tensioned up pretty evenly.

My average DS tension is ~145 kgf (min 131, max 150). Spokes are Sapim Race laced 2x.
My average NDS tension is ~58kg (min 52, max 60). Spokes are Sapim Laser laced 2x.

If I lower the DS tension, I'll have to lower the NDS tension to maintain proper dish. I really don't want to go much (if any) lower on the NDS because I'm worried the spokes will be too loose and be prone to breaking. However, the DS tension is quite a bit over my target of ~120kgf. I used linseed oil as spoke prep so there is a light locking agent on all nipples.

The wheel has about 100 miles of hard riding on it so far and has been totally solid.

What would you veteran wheelbuilders do? For future builds using these rims/hubs, would 2x DS and 3x NDS or maybe 1x DS and 2x NDS yield better tension balance?

Thanks,
Bob

 

[looigi]

145 doesn't sound that far out of line. The last rear I built was 140 on the DS (gauge is probably no better than 10% accurate) . I didn't bother to measure the NDS. I'd most likely leave it unless there was a compelling reason to not to.

 

[cxwrench]

you tension the DS to what it should be and the NDS is what it is. the number doesn't matter, proper DS tension and a centered rim do.

 

[dcgriz]

Hi All,

I built up a set of Kinlin XR19W rims with BHS hubs and Sapim spokes. They tensioned up pretty evenly.

My average DS tension is ~145 kgf (min 131, max 150). Spokes are Sapim Race laced 2x.
My average NDS tension is ~58kg (min 52, max 60). Spokes are Sapim Laser laced 2x.

If I lower the DS tension, I'll have to lower the NDS tension to maintain proper dish. I really don't want to go much (if any) lower on the NDS because I'm worried the spokes will be too loose and be prone to breaking. However, the DS tension is quite a bit over my target of ~120kgf. I used linseed oil as spoke prep so there is a light locking agent on all nipples.

The wheel has about 100 miles of hard riding on it so far and has been totally solid.

What would you veteran wheelbuilders do? For future builds using these rims/hubs, would 2x DS and 3x NDS or maybe 1x DS and 2x NDS yield better tension balance?

Thanks,
Bob

The tension ratio on the newer hubs is typically between 43% and 50% depending on which hub you choose. Changing the crossing between DS and NDS will add or subtract a few kgf, up to 5 at the most for the extremes, most often 1 to 3. Your 2x/2x is at the middle.
If I was to build with the XR19w rims and BHS hub with a DS offset ~17mm, I would try to be around 130 kgf, keep the tension deviation to no more than ~ 5kgf and then use spoke prep to keep the NDS spokes from unwinding.

 

[c_h_i_n_a_m_a_n]

Built mine using the same rims and hubs. Had tension thereabouts of what you had. Went with 3x DS and 2x NDS. Just done about 1000 miles to date over potholes and gravel on standard UK roads. All looking well to date. :thumbsup:

 

[rruff]

You were smart to use lighter NDS spokes... that will reduce the chance of them going slack.

If you did a good build and stress-relieved well... and you have enough spokes for your weight and riding style, then you should be ok with less tension. I have minimal experience with that rim, but I wouldn't put >120kg in without good reason.

I'd also try to get the tension more even... shoot for even tension first, then see how much you need to deviate for acceptable true.

 

[Peter P.]

I agree entirely with cxwrench.

Also, spoke length or the number of crosses has no bearing on the tension number.
The reason both your drive and non-drive side numbers don't fall with the range you're trying to hit at the same time is due to the flange spacing of your hub. Or more accurately, the flange location of each side relative to the hub centerline. Campy hubs result in worse numbers than Shimano. Off-center rims such as Velocity makes produce numbers roughly 25% closer than using standard rims.

So get the drive side within range and don't worry about the non-drive side; it is what it is. Or switch hubs/rims.

 

[engineer1]

I just finished building the same wheels. I have about 140 kgf on the DS and 60-70 on NDS.

correction: DS is about 130 kgf. Not sure about NDS.

 

[TomH]

Your tension balance is pretty bad. Average tension doesnt really matter at all, its not even worth calculating. As it stands, you've got one spoke at 130 and one at 150. 20kgf difference on the same side is too much. Way too much. Its also way over the max tension rating for the rim.

With ~50 and ~150 kgf on both sides, you've got somewhere around ~35% tension balance. Thats not correct for those hubs and emphasizes that the build quality is poor. The new BHS hubs are a under 50% if I remember right. Even the older ones with a narrower geometry were over 40%... so something isnt adding up.

That wheel needs to be taken down and rebuilt. You could try to retension it, but it might be easier to just start over.

I usually do kinlins to 125 kgf on the DS. Ill accept a 5 kgf variance for the seam, so a few spokes might hit the 130 kgf max tension. I aim for every single DS spoke to be 125kgf though, and I typically get pretty close. Not saying im the best builder around, but I do think those tolerances are pretty easy to achieve.

In short, you should be able to lower the DS tension and raise the NDS tension at the same time. This is only possible when a wheel is built so far out from being even!

Theoretical numbers dont always work, but for wheelbuilding, the theoretical tension balance calculated from the hub flange spacing is really pretty accurate to real world results. You should be within a few percent of the calculated value.

 

[TomH]

Also, spoke length or the number of crosses has no bearing on the tension number.

They definitely do! 2:1 lacing doubles the NDS tension, and 1x lacing on one side and 2 or 3 x on the other will change tension quite a bit. On BHS hubs, its about 10kgf more NDS tension using 1x heads in lacing on the DS.

 

[bobonker]

The accuracy of this TM-1 is really suspect (see thread I started on feedback for Wheel Fanatyk tension meter).

I have a carbon rear wheel that a local wheelsmith re-dished for me awhile back. I was reluctant to mess with it. When he re-dished it, he listed the tensions for each spoke. I know his readings are accurate because he's got a couple of a high end tension meters that he always keeps calibrated.

My gauge is reading ~20 kgf high on the DS spokes and ~5 kgf high on the NDS spokes. 2 points and 1 point on the gauge, respectively.

So, I think:

1. My DS tensions aren't as high as I think
2. The imbalance isn't as bad as I thought
3. I'm done with the TM-1

I'm going to see the same wheelsmith today and get a better picture of the health of this wheel.

Bob

 

[dcgriz]

IMO, the best use of the Parks TM-1 is to measure the relative tension between spokes rather than the absolute tension of a spoke.
I find its best to be used to help equalize tension between spokes.

 

[TomH]

The TM1 is kind of a "i hope this is right" tool, yes... but its consistent at least, even if its off from the real numbers. If it says every spoke is 100 kgf, every spoke is at least evenly tensioned, all though it might not really be 100 kgf.

You can calibrate the TM1 by the bolt on the tool. If your wheel builder has a known-good and accurate tension meter, you can calibrate your tool to his pretty easily. The TM1 is very consistent (as long as its lubricated), just questionably accurate. Precise, but not accurate.

 

[bobonker]

TomH: My local wheelsmith has a several calibration rods that were made by using a 16" steel rim and a 2.0 spoke threaded on both ends. He's got several with varying levels of tension. They were checked against his DT Swiss and Wheelsmith spoke tension meters. He calibrates his TM-1 this way and I know he uses the TM-1 to get spokes evenly tensioned.

What part of the TM-1 are you lubricating? The spring or the area that the plastic bushing (where the pointer is) drags on?

Thanks,
Bob

 

[TomH]

If it moves, I lubed it! On mine, the top part with the gradients that slides the pointer was pretty rough, so I sanded the edges and lubed the pointer. I also lubed the pivot. I also lubed the spring pivot and the metal between it.

After my work, its absolutely more repeatable. Repeated testing of the same spoke gives the exact same number. Before, depending on how it was released, it would give different numbers. I strongly suggest cleaning up sharp edges and a little lube on anything that slides. IMO, its a good and valuable tool... after lubing.

 

[bobonker]

Well, good and bad news.

Good news: My wheels are healthy. The front spokes (24h, radial) measured between 97-102kgf. The rear DS was between 117-125kgf.

Bad news: My TM-1 (my 3rd one!) is reading high and inconsistently. We noticed some differences in the construction of my new one vs his 4 year old TM-1 (which has been used to build over 1000 wheels and checked before each build) and mine. The blue metal body of the older one is much smoother. This combined with the years of use means that there is much less "drag" when the pointer settles after being released. The adjustable bolt that the spring rests against meets the edge of the spring so that the spring rests fairly flat across the slot in the screw. On mine, the contact is much less parallel.

TomH: Thank you for outlining what you've done to your TM-1. That sounds like it is exactly what I need to do, too.

Bob