Spoke count for a light rider?

Everything about building wheels, glueing tubs, etc.
RocketRacing
Posts: 941
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

At 135lbs, how many spokes should i get? I was thinking 20/24, but bet i would be fine with 16/20. Thoughts? Are their guidelines?

To clarify, carbon, clinchers, 25(27) wide likley 40mm or so, for ok roads, hilly and short agressive climbs, prolonged braking unheard of. I am no a power rider. Not really considering resale. Cxray spokes. They wont be for hard cornering/racing.
Last edited by RocketRacing on Fri Jan 04, 2019 1:12 pm, edited 2 times in total.

by Weenie


flying
Posts: 1996
Joined: Mon Dec 19, 2005 9:16 am

by flying

Hi
It is not that simple meaning weight of rider = X amount of spokes

Look for instance at Campagnolos fine Zonda wheels
16F 21R spokes & I dont think it even has a weight limit?

I'm sure one of the many wheel builders here will see your post & explain in greater detail
But basically it is a sum of all the parts & type/weight/strength of those parts
Rim,spokes,hubs :thumbup:

vanmatthew
Posts: 82
Joined: Thu Jul 14, 2016 5:20 am

by vanmatthew

Where are you getting your wheels? Out of the box from a big brand or having it built?

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rainerhq
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Location: Estonia

by rainerhq

Why not go for 20/24 and done. In the future you can sell these wheels for a heavier rider etc.
You wont get any benefits going 16/20.
Domane
Speed Concept
"Nothing compares to the simple pleasure of a bike ride"

alcatraz
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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

For a custom build using the common available standards of spokes/nipples/rims you would at least need 20f/24r for a rim brake wheelset. If you are a rider that appreciates a stiff wheel that can take more torque, avoid brake rub, accelerate very fast for a powerful rider, then you might even go 28 spokes in the rear.

What do you want this wheelset to do first and foremost? Prioritize a bit for us.

Like sprinting, climbing, time trialing, handle rough roads, cruising on centuries around your home, touring the world, racing, winter commuting to work 5km.

Give us an idea of how it will be used most of the time.

A wheelset for short intensive effort racing and a recreational lightweight cruising up some hills is very different.

Is it a shallow alloy rim or a deeper carbon rim? Also very different.

Is it a disc brake bike?

RocketRacing
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by RocketRacing

Good points, op edited for more info

alcatraz
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by alcatraz

Do you like to climb out of the saddle at low rpm? Do you think you
put out like 4-500w at times?

If the answer is yes then I'd lean somewhat towards a 28h rear.

24h should be fine on a carbon build for a recreational rider. For high reliability or performance 28h.

I'm building a 21h rear for climbing but I do it as an experiment (65kg 400w ~ 5min climber). I'm curious to try 2:1 with 90% spoke tension on nds instead of ~50% like on standard 1:1 builds. Still it's not laterally as stiff (towards the ds side) but I like that I can get more of the spokes to work at fuller capacity. I haven't received the wheel yet so it's still all just theory. I keep my fingers crossed. :)

bm0p700f
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by bm0p700f

the question should be how stiff do i need my wheels to be @135lbs. spoke contribute to wheel stifness (lateral radial and torsionals) but so does spoke gage, bracing angle and rim prosile, wall thickness e.t.c

campagnolo dont put weight limits on there wheels because if they did and a 135lb rider got a spoke failures then they get a warranty for that.

how a rider rides is more important to spoke life than rider weight. alcatraz, you really need to think about the structure of a wheel. just increaing the NDS spoke tension does make a better wheel by itself. lateral wheel stiffness (or torsional or radial) is not related to spoke tension on little bit. to improve the wheel you have to increase it stiffness. 2:1 lacing works if you have a stiff wheel because it then take enornous loads to make the spokes go slack. If you have a 2:1 laced wheel with a 90% tension balance, with a symmetric rim your hub geometry will mean your wheel is less stiff than with a conventional hub and while high loads are still required to get the spoke to go slack under normal loading, there will be more flex and therefore more fatigue in the spokes due to the lower lateral stiffness.

Campagnolo use a hub that has proper 2:1 flange spacing and asymmetric rim. That way they get 95% tension balance. They way most people on this board do triplet lacing is utterly pointless and they might as well not bother and have built a conventional wheel instead for less effort and expenense. What do I know, the internet tell you its a good idea.

To get the same lateral stiffness with a normal 11 speed hub with 37/17mm flange spacing (shimano dura ace 9000 24H) you need ~ 17/46mm spacing for 2:1 lacing. Maths tells you that if the same rim is used of course. Therefore to be any good a 2:1 hub needs to give a tension balance of 74% or less or it not worth using. Obviously iuf you compare a 2:1 hub to the woeful for NDS bracing angle - DT Swiss 240 then the 2:1 hubs flange spacing can be more modest.

Stiffer wheel are better wheels (from a spoke life point of view). The goal is to maximise the three types of stiffness while minimising weight but still keeping the whole thing useable for rougher roads.

So the OP's question is flawed and so are all the answers.

To answer the OP's question. there is no answer it really depends on how much side loading you give the wheel and even knowing that there is no answer. 20F/24R is about as low as is practicle to build. also dropping the spoke count saves so little weight there really is no point.

RocketRacing
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Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Thanks, like much in cycling... it depends.

I will probably stick with a more traditional 20/24.

I do some low cadence out of saddle climbing, but i limit it. My 5s ftp is in the 500-600w range, but true ftp is 177w. Not a power rider, but i hate the idea of brake rub, so i won’t push things.

I was just wondering what lighter riders might be able to get away with as much out there seems engineered for the average joe, or the heavier rider. So i assumed things are overengineered for someone my size/power, and i might be able to push limits. 20/24 seems like a decient compromise given the multifactorial nature of wheels builds.

jfranci3
Posts: 748
Joined: Tue Jul 26, 2016 5:21 pm

by jfranci3

Power doesn't take out spokes, pot holes do. 800w is about 18lb of torque at the tire for example. There's essentially not a penalty for adding 4 more spokes. Spoke shape is more important with Round < Rectangle < Oval . Zipp has some white papers out there.
At 135lb on 25 or 28c tires under 100psi, you can ride any wheel on the market.


As a datapoint, I went lots of miles on 110psi tires Fulcrum 20/24 aero spoke wheels at 190lb on super bad potholed streets before I started losing rear spokes. I had a set of mavic ksyrium elites 18/20 from ~2011 that went potato chip almost instantly. I now ride 24/24 DT aero spokes with deeper dish rims with discs at lower pressures without an issue.
Last edited by jfranci3 on Sat Jan 05, 2019 5:56 pm, edited 1 time in total.

Jugi
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Joined: Sun Jun 24, 2018 8:10 am

by Jugi


jfranci3 wrote:There's essentially not a penalty for adding 4 more spokes.
To put that into context, a spoke can be estimated to weigh 5 grams. So four spokes is 20g, four spokes front and rear is 40g. No real penalty, and additional four spokes in a wheel may deliver much better structural integrity.

I (<80kg) don't like to ride rear wheels with less than 24 spokes, as historically that has been a clear tipping point between relatively trouble free wheels and wheels which need constant attention. I'm a pretty cautious rider, but apparently there is something in my riding technique or style which sends structurally questionable wheels out of true quite fast. Then again I haven't ridden every wheel ever manufactured, so there may be many less than 24 spoke durable rear wheels out there.

alcatraz
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by alcatraz

Jugi wrote:
Sat Jan 05, 2019 10:16 am
jfranci3 wrote:There's essentially not a penalty for adding 4 more spokes.
To put that into context, a spoke can be estimated to weigh 5 grams. So four spokes is 20g, four spokes front and rear is 40g. No real penalty, and additional four spokes in a wheel may deliver much better structural integrity.

I (<80kg) don't like to ride rear wheels with less than 24 spokes, as historically that has been a clear tipping point between relatively trouble free wheels and wheels which need constant attention. I'm a pretty cautious rider, but apparently there is something in my riding technique or style which sends structurally questionable wheels out of true quite fast. Then again I haven't ridden every wheel ever manufactured, so there may be many less than 24 spoke durable rear wheels out there.
That's a good observation. Maybe your riding style could benefit from a more solid build. Then again it's not hard for a light alloy wheelset to come out of true. Was it an alloy wheelset?

/a

alcatraz
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Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

bm0p700f wrote:
Fri Jan 04, 2019 3:35 pm
I might be thick but I'm trying to learn. I refuse to give up. :thumbup:

Jugi
Posts: 571
Joined: Sun Jun 24, 2018 8:10 am

by Jugi


alcatraz wrote: That's a good observation. Maybe your riding style could benefit from a more solid build. Then again it's not hard for a light alloy wheelset to come out of true. Was it an alloy wheelset?
The best example of this was an Easton EC90 Aero rear wheel, as I had (and still have) a comparable Easton EC90 SL rear wheel. Both tubular, both had the same model hub, the Aero had 20 spokes (55mm carbon rim) and the SL has 24 spokes (38mm carbon rim). The Aero wouldn't stay completely straight for more than 500 km at a time. The SL stays straight easily for 1-2 seasons (4000-6000 km). Only problem with that wheel is that it drifts out of dish slowly, so it needs some work once a season.

That particular Aero rim may have had some kind of a fault in it, but again it was a good example as I had something to compare it to which was used and maintained in the same fashion.

alcatraz
Posts: 2301
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

You could try loctiting the spoke nipples.

What was the weight limit?

Maybe some carbon rims aren't very stiff. Could that happen? Maybe something with the layup or? Sounds like the rim isn't stiff enough to support that spoke configuration. Or the nds spokes are below the minimum tension so they loosen with time.

It'd help to know which side it loses its dish towards.

/a

by Weenie


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