TransWikia.com

15g / 1.8mm spokes compatibility

Bicycles Asked on June 18, 2021

I usually use double butted 2mm spokes that are 1.8mm in the middle.

In the past, though, I have used 1.8mm straight guage spokes when I was able to drill the holes in the hub flanges myself to a smaller diameter of about 2mm in order to fit the smaller spokes.

However it seems like almost all commercial hubs have holes about 2.5-2.6mm for use with 2mm spokes.

Is it ok to use 1.8mm spokes on normal hubs drilled for 2mm spokes? I still have some 1.8 spokes and I would like to use them.

If not, why do 1.8mm spokes exist, because I don’t see any special hubs drilled to fit them? 1.8mm spokes are easy to find, but hubs with special spoke holes are not, so does that mean it’s okay to use 1.8mm spokes in normal hubs? Is there a certain largest diameter of spoke hole that is recommended (i.e. no larger than 2.5mm)?

One Answer

The exact size of spoke holes in hubs is a little all over the place. There is some history involved, as well as dynamics with how manufacturers bias things for different most probable use cases.

Spokes with 1.8mm elbow areas used to be more common. The ubiquity of 2.0/1.8mm as the default butted spoke profile in particular is a fairly recent thing in the history of bikes. The 1.8/1.6 profile used to be way bigger, and a case for it can still be made in many applications. Aerolites and CX-Rays with 1.8mm elbows are still fairly common within their niches.

Manufacturers hate doubling the number of things they need to produce or creating compatibility gotchas (or at least some do, or used to, or whatever), so hub manufacturers are incentivized to make their holes work with both. There are no hubs I can think of that are 1.8mm-specific, but there are a number of higher end road hubs that are sized down small enough to barely work with 2.0 and be ideal with a 1.8. The holes on these are in the 2.3-2.4mm range.

Building such a hub with 2.0s is not a big deal for a handbuilder. It makes the spoke feel a little tighter going in and requires good aggressive technique to get them conformed around the flange, but it's commonly done and not remarkable. For a wheel production center it's a different story though. Human and machine hub loading both work better with a little more generous sized hole. 2.6mm is kind of the baseline for most modern hubs, but a lot of the most common OEM type hubs have 2.7mm-2.8mm holes. Some makers probably feel caught in the middle between the technical versus commercial advantages of each.

Running a 1.8 in a hole more optimized for a 2.0 doesn't have critical disadvantages. In my experience the main deal with it is that it takes more work to get the groove as established as it's ever going to be during the build process, since the mismatch in diameter means the elbow is going to dig in more. A fair number of wheels are built this way without major disadvantages.

Answered by Nathan Knutson on June 18, 2021

Add your own answers!

Ask a Question

Get help from others!

© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP