Blog: FAQ

27 Nov 2018

ERD seriously

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Because spoke lengths depend on ERD, I always measure my rims. People tell me they’ve ordered spokes for use with XYZ rim and sometimes it leads to conversations like this:

Wheelbuilder: These spokes are for my build with XYZ rim.
SpokeService: Did you measure your XYZ rim?
Wheelbuilder: No I used the numbers from the website.
SpokeService: Sorry your spoke lengths are wrong — the site is confusing.

There are two ways ERD goes wrong.

First there are variances in rim manufacturing. Some manufacturers are better than others and to some extent you get what you pay for. But I always measure and frequently find rims out of spec or find differences between pairs of identical rims. If you know what you’re working with, variances are not a big deal. If you input correct dimensions, you’ll get correct spoke lengths.

The second issue is differing definitions of ERD. Typical definitions include penetration of the spoke into the nipple head, which is important for maximum strength. But how far the spoke extends beyond the nipple seat (into the rim) is unclear. It depends on nipple geometry and encodes some preference for how much penetration is ideal. In other words ERD is relative to an undisclosed nipple and opinions regarding its use.

Typically the magnitude of these errors is pretty small, maybe 0.5mm each. Additional error is introduced when you round spoke lengths to match availability (why buying spokes in 2mm increments is rough). Maybe these errors add up to a problem and maybe they cancel each other out.

This sounds like a pain but it’s not at all. You simply make your own tools and take your own measurements. The parts cost next to nothing, assembly takes 10 minutes and you’re left with tools you can use forever. Maybe it seems like a pain because you want your spokes and rims to arrive at the same time. That’s fair but getting it right the first time is always fastest. SpokeService is here to help with spokes in 1mm increments, shipped daily from Canadian soil for only five bucks.

(If you like this idea but don’t have the time to put the parts together, I’ll do it for you. Click here to order the spokes and nipples for your measuring tool. They’ll ship completely assembled. Use the checkout comments box to indicate which nipple you intend to glorify with use on your wheels.)

25 Jun 2018

Spoke shortening

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If you bought spokes here but need shorter ones, I can help depending on the situation. I can cut them shorter and roll new threads so you end up with the length(s) you need. Maybe you realize your hub/rim dimensions were wrong, calculated incorrectly, abandon a project and start another, etc. The catch is you need to identify the issue before using them. Once spokes have been laced into the wheel, even without tension, the spoke cutting machine is liable to reject them. Send me an email with the details and we’ll go from there. I do this a few times a year but it’s not meant to be a secret handshake kind of thing.

30 May 2018

Using beefy spokes

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The typical spoke decision is between straight gauge and some double-butted model. For conditions outside the bell curve, there are two specialty models.

Sapim Force is a triple-butted spoke with a 2.18/1.8/2.0mm profile. They are similar to Sapim Race with a little more meat on the vulnerable elbow section. There is a cost penalty but weight and stiffness are about the same. Fatigue life is better — if you’ve been burned by broken elbows, Force might be the ticket. I often use Force on touring and bikepacking wheels to work with 32 spoke wheels when 36 might be more conventional (opening up more choices for hubs and rims).

Sapim Strong is a single-butted spoke with a 2.3/2.0mm profile. These are the biggest bicycle spokes I sell and I stop at this gauge because it’s the biggest spoke that works with regular nipples. Strong shares the massive stiffness of Sapim Leader but has a serious amount of extra material on the elbow. People use Strong for e-bikes, cargo bikes and the heaviest touring applications. For regular day-to-day use they’re overkill though I’ve used them for riders >400 pounds.

13 Feb 2018

New nipple washer

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There’s a new nipple washer available from Sapim — the Sapim MS washer has a generic V-shape profile compatible with all nipples (compare to Polyax washers with a Polyax-shaped cup). It has a thick, flat bottom for superior weight distribution however needs a flat resting spot 7.7mm in diameter. Where applicable, these stainless washers will impart a lot of strength.

Not much information is searchable for Sapim MS washers so I’m posting the product sheet to give you information from the source. Note carefully: my measurements put the diameter at 7.7mm compared to the nominal 7.4mm. Get MS washers and three other types of nipple washer here.

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.