Spokes length on Pulstar hubs...

freddok

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Hi All,

Is someone know the spoke length on a 32 holes Pulstar rear hub on a 26' rim ? I find it for the front (265,6, correct me if I'm wrong...) but no infos for the rear hub.... If someone know it...I take it... Thanks :cool: (I admit know how to measure a normal hubs, but 've no idea for a straight Pulstar...)

Thanks in advance
 
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Tootyred

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At the risk preaching to the choir....

The spoke length depends on the ERD of the rim not its size...ie 26" . ERD can be very different on differing 26" wheels.

The spoke calculator will tell you the spoke length based on the hub AND rim variables.

If you guess at about 264/ 265/ 266 /267, that would cover loads of retro rims, but you could be missing 3 or 4 mm of spoke engagement, or worse run out of thread in the nipple, or have the spoke sticking out to puncture your tube.

The table above is ok as a starting point, but gives ERD in 4 or 5 mm bands. Again you could end up 2.5mm the wrong length as a result.

Calculators normally work to min 1/10 mm.

You will get a much better, stronger wheel if you take your own measurements and plug them into a calculator.

Personally i never trust anybody else's figures.....that especially includes rim manufacturers!

Have fun and good luck. Wheel building or repairs are very rewarding.
 

freddok

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Bikepro has very different values: http://www.bikepro.com/products/spokes/pulstar_spoke_table.shtml
This is where I got the length for the front Pulstar hub of my Rocky Mountain Cirrus.
At the risk preaching to the choir....

The spoke length depends on the ERD of the rim not its size...ie 26" . ERD can be very different on differing 26" wheels.

The spoke calculator will tell you the spoke length based on the hub AND rim variables.

If you guess at about 264/ 265/ 266 /267, that would cover loads of retro rims, but you could be missing 3 or 4 mm of spoke engagement, or worse run out of thread in the nipple, or have the spoke sticking out to puncture your tube.

The table above is ok as a starting point, but gives ERD in 4 or 5 mm bands. Again you could end up 2.5mm the wrong length as a result.

Calculators normally work to min 1/10 mm.

You will get a much better, stronger wheel if you take your own measurements and plug them into a calculator.

Personally i never trust anybody else's figures.....that especially includes rim manufacturers!

Have fun and good luck. Wheel building or repairs are very rewarding.
About rims, it's Specialized Z21 rims with a 545 ERD. Spoke Length Calculator give me a 265.1 for the front but don't have the rear in his database... The flange diameter is the same but I'm unsure to take a correct measure of the offset... I think I'll pass some time here to get the correct length : https://spokelengthcalculator.com/how-to-measure-rim-diameter-hub-dimensions.php
 

Tootyred

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If you want a really simple and great guide, i would recommend this. Its not free, but it might be the best £9.00 you spend ! Ive built wheels for just on 30 years now, but still learned a thing or two from it.

It explains hub/ rim measuring, using spoke calculators the lot. I believe it also has a section on straight lace hubs such as pulstar.

Even if you get nothing else from it, and you never build a wheel, it might save you a few quid, as next time you buy a second hand set of wheels, you will better understand if they are any good or not.


Best of luck
 

freddok

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If you want a really simple and great guide, i would recommend this. Its not free, but it might be the best £9.00 you spend ! Ive built wheels for just on 30 years now, but still learned a thing or two from it.

It explains hub/ rim measuring, using spoke calculators the lot. I believe it also has a section on straight lace hubs such as pulstar.

Even if you get nothing else from it, and you never build a wheel, it might save you a few quid, as next time you buy a second hand set of wheels, you will better understand if they are any good or not.


Best of luck
Many thanks for the link !! 👍
 

FluffyChicken

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Retrobike Rider
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If you want a really simple and great guide, i would recommend this. Its not free, but it might be the best £9.00 you spend ! Ive built wheels for just on 30 years now, but still learned a thing or two from it.

It explains hub/ rim measuring, using spoke calculators the lot. I believe it also has a section on straight lace hubs such as pulstar.

Even if you get nothing else from it, and you never build a wheel, it might save you a few quid, as next time you buy a second hand set of wheels, you will better understand if they are any good or not.


Best of luck
That would be the website I linked to, I just linked to his improved calculator (the book hasn't been updated)
The line has a straight spoke option (it's no different in reality) and instruction on measuring the important stuff for straight pull.

I've had that book for ages, though a few version now. Great read and you get all updates


Here's an insight to different calculators by Roger https://www.wheelpro.co.uk/support/spoke-length-calculators/

and a Cut and Paste of
For cross laced straight pull hubs, the measurement is taken at the extended crossing point of two spokes. If the spokes are close to tangent then the diameter can be measured to the centre of the spoke holes, if they are not tangent (as shown in this diagram) then it's the midpoint between the diameters of the spoke entry and exit holes. A small error when measuring the diameter on cross laced wheels will not affect the spoke lengths

sp-diameter.png


For radial straight pull hubs the diameter is measured at the position where the spoke seats.

obtained by selecting straight pull in the first box and clicking on Hub Diameter.
 
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