OK, so how risky is radial lacing?

In article <[email hidden]>, Simon Brooke
[email hidden] says...

Quoted message said:

Leave discussions of comfort out of this. Two of my current three road front
wheels are radial laced, and both my current two road back wheels are
half-radial. I like 'em that way. But they're all factory built Mavics with
fancy hubs which are designed for it.

That's the problem, the flange on a conventional hub just isn't designed
for radial lacing - there isn't enough material to support the spoke
head and flanges /do/ get ripped off. But plenty of people used to get
away with it too. Do people still bother with exotic lacing on
conventional wheels now that there are so many fancy wheels available?

Quoted message said:

Also: radial lacing, should the spoke heads be inside the flange or outside?

Usually heads on the outside, especially on the rear where it
effectively reduces the dish slightly. I suppose heads on the inside
would produce a slightly more stable front wheel, but fronts aren't as
stressed as rears, heads on the outside looks better and you don't need
to adjust the set of the spoke elbow when building that way.

Simon Brooke said:

Sitting on my table in front of me I have a shiny (black) Record rear
hub, and a pair of shiny (black) DT Swiss 1.1 rims. The theory is
that this is my new audax wheelset... The original plan was to build
three wheels, one front with a Record hub to match the rear, one with
a SON. The budget won't stretch to that just now, and I haven't yet
decided which front to build.

Now, clearly, if I get a SON front hub, it needs to be laced with a
cross lacing, probably 2-cross. If I get a Record front hub, it could
be radial laced. And in any case I'd like to lace the rear half
radial.

The Campag instruction leaflet comes with awful warnings against
radial lacing. I know this. I know I will void my warranty if I lace
radial. But actually, how much increased risk of failure will I get?
I'm about 80Kg but I very rarely break things on my bikes. I've never
broken a spoke, for instance.

It's related to spoke tension. The fewer spokes, the higher the tension
needs to be, so the risk must be greater with 28 holes than 32. (I'm
guessing you don't have a 36h).

There have mixed been reports on rec.bicycles.tech of radially laced front
wheels with Campag Record and similar hubs. Some no problems, some flange
failure. I couldn't put a percentage on it. Rear non-drive side should be
no problem as tension is not high there.

~PB

]apologies if I've posted this already - managed to crash my screen driver]

Pete Biggs said:

Simon Brooke said:

Sitting on my table in front of me I have a shiny (black) Record rear
hub, and a pair of shiny (black) DT Swiss 1.1 rims. The theory is
that this is my new audax wheelset... The original plan was to build
three wheels, one front with a Record hub to match the rear, one with
a SON. The budget won't stretch to that just now, and I haven't yet
decided which front to build.

Now, clearly, if I get a SON front hub, it needs to be laced with a
cross lacing, probably 2-cross. If I get a Record front hub, it could
be radial laced. And in any case I'd like to lace the rear half
radial.

The Campag instruction leaflet comes with awful warnings against
radial lacing. I know this. I know I will void my warranty if I lace
radial. But actually, how much increased risk of failure will I get?
I'm about 80Kg but I very rarely break things on my bikes. I've never
broken a spoke, for instance.

It's related to spoke tension. The fewer spokes, the higher the tension
needs to be, so the risk must be greater with 28 holes than 32. (I'm
guessing you don't have a 36h).

32 hole.

Quoted message said:

There have mixed been reports on rec.bicycles.tech of radially laced front
wheels with Campag Record and similar hubs. Some no problems, some flange
failure. I couldn't put a percentage on it. Rear non-drive side should
be no problem as tension is not high there.

Having thought about it I think I'm going to go 2 cross for these ones.
They're going to end up being quite expensive - and very nice - wheels, and
I don't want to spoil them out of cussedness. Thanks Pete (and Rob) for the
advice.

Incidentally, I'm forced to take issue with the blessed St Sheldon of
Newtonville. He says (http://sheldonbrown.com/wheelbuild.html)

The Great Spoke Scam: In the early '80s a clever marketeer hit upon the
idea of using only 32 spokes in wheels for production bikes. Because of
the association of 32 spoke wheels with exotic high performance bikes, the
manufacturers were able to cut corners and save money while presenting it
as an "upgrade!" The resulting wheels were noticeably weaker than
comparable 36 spoke wheels, but held up well enough for most customers.

Since then this practice has been carried to an extreme, with 28, 24, even
16 spoke wheels being offered, and presented as it they were somehow
an "upgrade."

Actually, such wheels normally are not an upgrade in practice. When the
spokes are farther apart on the rim, it is necessary to use a heavier rim
to compensate, so there isn't usually even a weight benefit from these
newer wheels!

This type of wheel requires unusually high spoke tension, since the load
is carried by fewer spokes. If a spoke does break, the wheel generally
becomes instantly unridable.

That may have been true when it was written. Now, however, comparing my
not-yet-built new wheels with my Ksyriums, which have 18 spokes front and
20 rear, it's simply not so.

My new wheels will come out, according to the DT Swiss calculator, at 816
grammes front/823 grammes rear, total 1739 grammes (DT Swiss RR1.1 rims, DT
Swiss competition spokes, Campag Record hubs). That compares with 650
front/ 805 rear, total 1455 grammes for the Ksyriums. That's 280 grammes
less, which is not trivial. And however carefully I build my new wheels,
they are not going to come out as strong as the Ksyriums.

I knew that before I started, of course. This is mainly an aesthetic
exercise - I want to ride on wheels I've built. And the spare front wheel
with the SON hub was going to have to be hand made anyway. But, /except/
for the case of odd sizes and specialist hubs, there's really no economic
justification for hand building wheels any more. Cost for cost, the good
factory build wheels are better.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
;; If any council in the country has anything to say to cyclists
;; about cycle paths, it should be: "We are terribly, terribly sorry."
- Zoe Williams, The Guardian, 13th Sept 2006

Simon Brooke said:

Also: radial lacing, should the spoke heads be inside the flange or outside?

Conventionally, on the outside, but it depends on the hub. If the holes
in the hub are only countersunk on one side, then that's the side you
put the bend on. I once ended up building a radial wheel with spokes
heads alternating because of this. Probably only occurs with ancient hubs.

--
Andrew

In news:[email hidden],
Simon Brooke <[email hidden]> tweaked the Babbage-Engine to tell us:

Quoted message said:

Incidentally, I'm forced to take issue with the blessed St Sheldon of
Newtonville. He says (http://sheldonbrown.com/wheelbuild.html)

The Great Spoke Scam: In the early '80s a clever marketeer hit upon
the idea of using only 32 spokes in wheels for production bikes.
Because of the association of 32 spoke wheels with exotic high
performance bikes, the manufacturers were able to cut corners and
save money while presenting it as an "upgrade!" The resulting wheels
were noticeably weaker than comparable 36 spoke wheels, but held up
well enough for most customers.

Moreover, right-thinking BRITONS would historically have had 32H front
wheels and 40H rears...

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
Mushroom! Mushroom!