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Discussion Starter · #1 · (Edited)
Just finished up a build with T-11 hubs and Pacenti rims. It's a 28 hole rear with 2X on both sides using CX Rays. My Non drive side spokes are sad. I bet they only have about 53 kgf on them at best. I ended up with 125 on the drive side. Is this about the norm? Is this going to be o.k. for 150 lb rider?

I did a build earlier this week on the same rim and hub with 3X on the drive using Race Spokes, and 2X NDS Lasers. I don't remember the NDS being that slack.
 

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Discussion Starter · #4 ·
That's just spooky. I had to make a bunch of trips around the wheel to negotiate that out of it. I was eeking every bit of tension I could find out of the NDS spokes. This 11 speed offset just isn't very promising.

After looking at dcgriz charts on another thread, it doesn't look like there is much more tension to be had regaurdless of the pattern.
 

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2x/2x on a 28h Pacenti with T-11 will give you a calculated Tnds of 53.8 kgf when Tds is at 125 kgf so your 53 kgf is spot on.

However, I would not dismiss your feeling that the spoke feel too loose. The accuracy of your measured 53 kgf value depends on the accuracy of your tension meter. Meters like the Park Tools are best used to measure relative tension between spokes rather than absolute. Furthermore, if we are to reliably measure up to that accuracy level then the meter should be calibrated for the specific spoke at hand.

Some time ago I read Musson's impressions on meters and how dispersed the readings are even within the same gauge spokes of different manufacture because of manufacturing tolerances. So the chart that Park shows for every possible spoke in existence may be a far cry if accuracy of absolute values is in question.

If your DS spokes feel nice and tight, leave it alone. The NDS is what it is and at least theoretically you've reached nirvana. When down to these values, I have started using spokeprep for added insurance but no goo can replace proper balance and stress relief. If you think your DS needs a bit more tightening, I would not be afraid to do so although my Park showed 125 kgf.

You are absolutely correct on the 11 speed. This thing "fixed" a problem that did not exist and created a whole bunch of new ones, but that's the bike industry, isn't it? I think 135 mm OLD road hubs are getting closer and closer.
 
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Sounds like producers of spokeprep and OC-rims should now start increasing their production.
.....or the other way to look at that is to optimize the balance between the hub geometry stiffness and stability. The T-11, at a BAR range between 2.3 and 2.4, shows pretty good stiffness but its doing so at the expense of Tnds.
A person like myself would prefer the preference on stiffness, but a person that does not need it would do better choosing a hub that puts more emphasis on compromising the lateral stiffness in favor of higher tension at the NDS.
 

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Which would results in:

Tds Tnds BAR
125 66.9 1.87


I'm getting totally different numbers than yours for the 28h Pacenti SL23, T-11, 2x DS and radial NDS.
Radial NDS bracing angle is 7.9 deg, 2x DS bracing angle is 3.5 deg, that makes the BAR 2.3. The Tnds comes out at 52.3 kgf with Tds=125 kgf.

2x DS / 3x NDS shows me the highest Tnds at 55.4 kgf with Tds=125kgf
3x DS / 2x NDS shows me the lowest Tnds at 51.7 kgf.
 

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Discussion Starter · #12 ·
I got a chance to check the set I built earlier this week . THe 3X Race spokes on the drive side seems to help a little. I was getting closer to 56 kgf on the 2X NDS Lasers.

I think Ergot is correct in using heavy spokes/ radial lacing in order to get every once of tension on these hubs. It's like you have to use every trick in the book to squeeze the max out of these new offsets.
 

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I'm getting totally different numbers than yours for the 28h Pacenti SL23, T-11, 2x DS and radial NDS.
Radial NDS bracing angle is 7.9 deg, 2x DS bracing angle is 3.5 deg, that makes the BAR 2.3. The Tnds comes out at 52.3 kgf with Tds=125 kgf.

2x DS / 3x NDS shows me the highest Tnds at 55.4 kgf with Tds=125kgf
3x DS / 2x NDS shows me the lowest Tnds at 51.7 kgf.
Not in front of calc.

Are you checking radial heads in or out? Heads out is a smaller bracing angle which makes tension closer to DS than 2X will.
 

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I got a chance to check the set I built earlier this week . THe 3X Race spokes on the drive side seems to help a little. I was getting closer to 56 kgf on the 2X NDS Lasers.

I think Ergot is correct in using heavy spokes/ radial lacing in order to get every once of tension on these hubs. It's like you have to use every trick in the book to squeeze the max out of these new offsets.
Every time I hear about those T-11 hubs, it brings back bad memories:
http://forums.roadbikereview.com/wheels-tires/wheel-re-lacing-need-help-293550.html

Radial lacing plus a liberal amount of spoke adhesive might work for you.

But I can't shake the thought the the hub is poorly designed WRT to flange spacing and dimensions and that the T-11 will never build a strong and durable wheel. Others seem to be happy with it though so it may just have been my bad luck of getting a poorly built wheel to start with.

I now own Fulcrum Racing Zero and have done zero maintenance in 4 months of owning them. These wheels have zero flex and I paid less for them than I paid for my T-11/C2 wheels.
 

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Not in front of calc.

Are you checking radial heads in or out? Heads out is a smaller bracing angle which makes tension closer to DS than 2X will.
When I measure the hubs myself, I measure the center-flange to the inside of the flange however I have found that this is not always the case with the published hub specs.

The T-11 published data shows 38 mm as the C-L offset. I don't know where on the flange this is taken from and unfortunately I did not confirm the measurement when I had a chance. So I experimented running the numbers from 38 down to 36mm in steps of 0.5mm to allow for the heads out; when at 37mm I saw a very small increase to the Tnds (0.7 kgf to be exact, Tnds=53) and a reduction to BAR by 0.1 (2.2). At 36mm, Tnds=55 and BAR=2.2. When 2x/2x at 38mm C-L, I calculate the Tnds=53.8kgf. So the difference appears to be very small at best and only if we accept that heads out imposes an effective offset reduction by 2mm.

I think the radial spoking is more effective in reducing the effective flange diameter to a theoretical 0 and in doing so reduces spoke stretch which in turn adds a degree of safety on maintaining the Tnds as the wheel turns.


Edit to add: at 36mm the bracing angle is 7.5 deg from 7.9 deg at 38mm
 

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I'm getting totally different numbers than yours for the 28h Pacenti SL23, T-11, 2x DS and radial NDS.
Radial NDS bracing angle is 7.9 deg, 2x DS bracing angle is 3.5 deg, that makes the BAR 2.3. The Tnds comes out at 52.3 kgf with Tds=125 kgf.

2x DS / 3x NDS shows me the highest Tnds at 55.4 kgf with Tds=125kgf
3x DS / 2x NDS shows me the lowest Tnds at 51.7 kgf.
Using Spoke calc, radial nds angle heads out is 6.2deg and 2x ds is 3.3deg

I am using specs posted by Fairwheel's website.

This results in the numbers I posted. 1x nds is 7.9deg like you posted. You might check your formulas and make sure they are referencing the correct cells.
 

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Using Spoke calc, radial nds angle heads out is 6.2deg and 2x ds is 3.3deg

I am using specs posted by Fairwheel's website.

This results in the numbers I posted. 1x nds is 7.9deg like you posted. You might check your formulas and make sure they are referencing the correct cells.
I see where you got the 6.2 number from. I'm trying to understand what the 3.5/2,1 portion of his formula stands for. Flange thickness?
Now look at the spreadsheet cell c31. If you input 0 (for radial) then the bracing angle it gives you is 7.9. Also notice that now he is also giving you the tension ratio (44%) which he did not before for either case of heads in or head out. If you calculate it using the 6.2 and 3.3 values, its value is 53% and that's a 23% increase in tension which I find humongous. If you were to use alternating head placement, the left hub offset would have to be reduced to 29.5 mm from 38 mm to give you the 6.2 bracing angle. That's a 8.5mm reduction and looking at the laced hub I can not comprehend how such reduction could be possible just by flipping the spokes.
So something else its going on and I believe it's on our interpretation of what Rinard is trying to tell us. I don't think it's accidental that he did not list the R/L tension on the spreadsheet using the radial heads in/out angles considering the outmost detail he included on everything else.

Now, lets approach this a different way; leave the bracing angle degrees alone and look at deriving to the Tnds by using the hub offset W and the spoke length L (which are the entities defining the bracing angle). The spoke length is the spoke length regardless of head placement. The offset will change somewhat when the heads are out. I create a sequence of iterations by progressively reducing W in steps of 0.5mm and determine the effect on Tnds until an offset reduction of 2 to 3mm is reached
My formula is Tnds=Tds (Wds/Wnds) (Lnds/Lds)
 

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3.5/2,1


"3.5/2" im guessing is the change in angle depending on heads in or out (+-1.75deg), the ",1" is just denoting how many significant digits to round the result to. So he more or less is adding or subtracting 1.75deg.

Im guessing when you alternate the heads (2x) they are effectively canceling each other so you just take center to flange.

I wonder if his equation is a little messed up.

Playing around with a caliper and a wheel I have (which is laced radial heads out on the nds) the only way I come up with 1.75deg which is ~8mm difference is:

Spoke thickness + Flange thickness + Spoke thickness (2mm+3.5mm+2mm)=7.5mm difference between heads in and out

=ROUND(DEGREES(ASIN(7.5mm/spokeLength)),1) <---1.6deg for 269.5mm spoke

So the difference in the inner most part of a heads out spoke vs the outer most part of a heads in spoke is ~7.5-8ish mm which equates to a total difference of 1.75deg heads in vs out. Which means you should add half of 1.75 for heads in and subtract half of 1.75 for heads out. He adds 1.75deg for heads in and subtracts 1.75deg for heads out, which is where I think he might be off.

He is more or less saying there is a 3.5 deg difference in in vs out, which seems like a bit much and would result in a ~16mm difference and I cant find a possible 16mm difference on the wheel I have.

I could be be wrong though.

So if im correct his formula should be

=CONCATENATE(ROUND(DEGREES(ASIN($D$32/E24))-1.75/2,1)," heads out; ",ROUND(DEGREES(ASIN($D$32/E24))+1.75/2,1), " heads in")
 
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