Blog: FAQ

09 Nov 2017

Updated deflections

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From time to time tensiometer manufacturers update their conversion charts. While changing charts may seem counterintuitive, there can be good reasons to do it.

This week Wheel Fanatyk released a new chart for 2015+ tensiometers and my spoke tension visualizer has been updated in tandem. Download a copy of the latest chart from their official location. (Wheel Fanatyk is the authoritative source but I’ve mirrored the current charts as well: for original model and 2015+ model tools.) This update also includes support for 1.65mm spokes, specifically for Sapim D-Light. D-Light is supported with Wheel Fanatyk 2015+ and Park Tool TM-1 tensiometers.

As of today the conversions in my spoke tension visualizer should be up to date with current manufacturer data for all tensiometers. If you see a discrepancy, please holler.

04 Aug 2017

Which Wheel Fanatyk

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As mentioned before my spoke tension visualizer has two choices for the Wheel Fanatyk tensiometer. Now there’s a new model with an IPIC digital gauge. To clarify configuration I’ve done some renaming in the setup menu. One option is named Wheel Fanatyk Original and covers a single model as seen in the first basket. The other option is named Wheel Fanatyk 2015+, covering Mitutoyo and IPIC models as seen in the second basket.

Also note the conversion data for 2015+ tensiometers has been updated. If you notice a discrepancy with 1.5mm spokes, that’s the source. Ric revised the conversion table and his latest numbers are live in my utility. Contact Wheel Fanatyk for a PDF chart of the revised data. Superseded.

20 Jun 2017

Measuring ERD

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If you have the wrong effective rim diameter (ERD), there’s a good chance you’ll compute the wrong spoke length. A lot of times you can use values from the manufacturer but it’s best to double check the numbers with Google. After a while you’ll find some brands, like Stan’s NoTubes or WTB, are reliable in their ERD numbers (contact me to order Stan’s rims).

You’ll get the most accurate ERD numbers if you measure your rims so I always do. My tools are DIY, which is inexpensive. Here’s how I make them: take two black 310mm Sapim Leader spokes and cut off the elbow leaving a 300mm rod. Screw a silver nipple to each rod using a bit of Loctite so they never move. For my process I make sure the spoke penetrates the nipple until it’s flush with the bottom of the screwdriver flats — spokes stretch a little under tension so they’ll end up in a good place. That’s it. If you’re precision-minded, you can ensure nipple geometry isn’t a factor by making a new set of measuring rods any time you build with a new variety of nipple.

Usage is straightforward. Insert your measuring spokes into opposing spoke holes, counting them to make sure you’re not off by one. Pull the spokes tightly across a ruler. Use one with 0.5mm resolution (such as this one) or eyeball to the same. For most builds the spokes will overlap on the ruler, in which case you deduct the overlap distance from 600mm. If the spokes don’t overlap, add the gap distance to 600mm. Perform at least two measurements 90° apart and average the results to get ERD.

If you’re building with nipple washers, remember to increase spoke length to compensate. As an alternative, you can simply install nipple washers on your measuring spokes and build nipple washers right into your ERD. With this direct approach, no compensation is required.

Most spoke calculators will give you lengths to the tenth of a millimetre, which you’ll need to round to the nearest available length. Since measuring as above targets the bottom of the acceptable range, don’t round down aggressively for low tension builds or on the low tension side of a wheel. When shopping here, you get to round to the nearest millimetre compared to traditional vendors that stock spokes in two millimetre increments. In a followup blog I’ll expand on the topic of rounding, which matters more when available lengths aren’t as good. Stay tuned.

31 May 2017

Rims for new builders

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Sometimes newbies ask about cheap rims to try wheelbuilding, something of a contradiction in a question. It’s thinking about the cost of failure versus the experience and rewards of success. Rim quality sets the stage so inexpensive rims may serve to frustrate more than anything. If you’re apprehensive about wheelbuilding, and there isn’t any reason to be, stay away from ultralight rims and low spoke count rims. Stay away from ultralight spokes (but don’t go nuts with heavyweight spokes either). Buy a quality rim with the attributes you want to ride and you’ll do fine.

10 Sep 2016

Mitigating spoke windup

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One challenge a wheelbuilder faces is managing spoke windup. Windup happens when friction between spoke and nipple causes the spoke to twist instead of tighten. This is bad because a twisted spoke is not in equilibrium and will eventually unwind. When twisted spokes unwind, wheels lose alignment. Windup worsens as spoke diameter decreases, which makes thin spokes like DT Revolutions more difficult (thicker spokes build more easily). The problem worsens as tension increases, which is a bigger issue in the 11-speed era because higher tensions are typically required.

There are a few strategies for dealing with spoke windup. The first and most fundamental is to make sure nipples receive ample lubrication. Sometimes adding more lubrication during a build helps. The second strategy is to detect spoke windup and compensate. Windup can be detected by feeling the spoke rotate in tandem with turns of the nipple (a flag can be fixed to the spoke to provide a visual cue). When you start experiencing spoke windup, it’s helpful to overturn the nipple and then back off. For example to achieve a quarter turn of the nipple, tighten the nipple a half turn then loosen by a quarter turn. Windup is released during the loosening step.

Before a wheel is declared complete it should be free of windup. Windup can be freed by flexing spokes in different ways. One way is to grab roughly parallel pairs of same-side spokes and pull them together. Another more drastic way is to put the wheel on the ground, touch the ground with the hub and press down around the rim. You can often hear pinging noises as spokes unwind. A wheel is complete when these procedures do not change the wheel and other tolerances are met.

Now you know and knowing is 90% of success. Happy wheelbuilding!