Minimum number of spokes for single crossed lacing

earth

Is there a minimum required to have single crossed lacing on a wheel?

How about double crossed?

ugo.santalucia

There is no maximum, there is a minimum... you can single cross any wheel, if you so wish and any 20+ can go two cross.
Why you want single crossing? It's not a great pattern

Giraffoto

Can you go cross four with 32 spokes? I've occasionally thought it would be a good pattern to use with disc brakes.

ugo.santalucia

Giraffoto wrote:

Can you go cross four with 32 spokes? I've occasionally thought it would be a good pattern to use with disc brakes.

No, you need 36 for that... the old school rule is number of cross X 9 gives you the minimum number of spokes you need

earth

I ask because I read somewhere you cannot make radial spoked wheels that are disc compatible and I have certainly never seen any. The wheels on my new CX bike are double crossed (forgot to count the number).

Can single crossed spokes be used with discs?

ugo.santalucia

earth wrote:

I ask because I read somewhere you cannot make radial spoked wheels that are disc compatible and I have certainly never seen any. The wheels on my new CX bike are double crossed (forgot to count the number).

Can single crossed spokes be used with discs?

Not a good idea... 3 cross is ideal and 2 is acceptable... anything less is uncharted territory with disc brakes wheels

earth

So by using your formula of number of crosses * 9 that gives a minimum of 18 spokes for a 2 cross pattern or 37 (round to 36) for a 3 cross pattern.

So a front disc compatible wheel can be achieved as a 2 cross wheel with 18 or 20 spokes. This is similar to a typical 20 radial spoke front wheel that we have today. But 2 cross is just acceptable and 3 cross equals 36 spokes.

The argument that disc wheels are going to be lighter due to no braking surface is a fallacy for two reasons.

1. If the disc wheel needs more spokes then it is heavier for that reason and of course more spokes means more nipples in the rim.

2. The braking surface does not add significant weight. Tubular rims have a braking surface but their weight can be significantly lower than clincher versions because the clincher has to be built to withstand the pressure of the tyre pushing outwards on the rim. This is where the weight comes from.

ugo.santalucia

earth wrote:

So by using your formula of number of crosses * 9 that gives a minimum of 18 spokes for a 2 cross pattern or 37 (round to 36) for a 3 cross pattern.

So a front disc compatible wheel can be achieved as a 2 cross wheel with 18 or 20 spokes. This is similar to a typical 20 radial spoke front wheel that we have today. But 2 cross is just acceptable and 3 cross equals 36 spokes.

The argument that disc wheels are going to be lighter due to no braking surface is a fallacy for two reasons.

1. If the disc wheel needs more spokes then it is heavier for that reason and of course more spokes means more nipples in the rim.

2. The braking surface does not add significant weight. Tubular rims have a braking surface but their weight can be significantly lower than clincher versions because the clincher has to be built to withstand the pressure of the tyre pushing outwards on the rim. This is where the weight comes from.

Ehm... maybe 27, that you round to 28 for 3 cross? :roll:

Who said disc wheels are lighter? Rims can be lighter, wheels are probably going to be a tad heavier as a whole...

Read here

http://paolocoppo.drupalgardens.com/con ... isc-brakes

t4tomo

earth wrote:

So by using your formula of number of crosses * 9 that gives a minimum of 18 spokes for a 2 cross pattern or 37 (round to 36) for a 3 cross pattern.

I know nothing about spoke patterns but a thing or two about maths. If you are following "no of cross *9" per Ugo above I suggest you check your maths, you can't multipy something by 9 and end up with a prime number (37).



Hint try 27. Yes ending up with a wrong answer that is a prime number, rather than just a wrong answer is funny to a very small percentages of the population.

earth

Sorry moment of numerical failure there :oops: Normally I only deal with 0's and 1's.

Either way 27 or 28 spokes is still higher than 20 or 24 for a rear and that means more nipples in the rim. I don't believe the rims are going to be lighter and even if the bare rim is, the extra nipples will make it heavier.

ugo.santalucia

earth wrote:

Sorry moment of numerical failure there :oops: Normally I only deal with 0's and 1's.

Either way 27 or 28 spokes is still higher than 20 or 24 for a rear and that means more nipples in the rim. I don't believe the rims are going to be lighter and even if the bare rim is, the extra nipples will make it heavier.

A 12 mm brass nipple weighs exactly 1 gram... 4 extra grams are hardly something you will notice... you can potentially have a disc specific rim which is 100 grams lighter than the same rim for pads... that's more interesting

earth

ugo.santalucia wrote:

earth wrote:

Sorry moment of numerical failure there :oops: Normally I only deal with 0's and 1's.

Either way 27 or 28 spokes is still higher than 20 or 24 for a rear and that means more nipples in the rim. I don't believe the rims are going to be lighter and even if the bare rim is, the extra nipples will make it heavier.

A 12 mm brass nipple weighs exactly 1 gram... 4 extra grams are hardly something you will notice... you can potentially have a disc specific rim which is 100 grams lighter than the same rim for pads... that's more interesting

That's not what I see when I compare recent disc and non disc clinchers from Reynolds. They are not the only manufacturer but they do have the expertise to make light wheels:


Disc Assault SLG clincher:
http://www.reynoldscycling.com/index.ph ... itm_pk=719

Non Disc Assult SLG clincher
http://www.reynoldscycling.com/index.ph ... itm_pk=705


They quote a bare rim weight of exactly the same 445grams. The disc version has a 24 spoke front wheel and the pair 90grams more.

I noticed the rims are now wider and most of their tubular range has disappeared. Perhaps they have made new molds for the rims and decided to do clincher versions first.

Their tubular rims were about 250 grams each and they had traditional spoked wheels down to 1075 grams. Yet they have not succeeded in making the disc wheels lighter than the non discs or lighter than the previous range of tubulars.

earth

ugo.santalucia wrote:

you can potentially have a disc specific rim which is 100 grams lighter than the same rim for pads... that's more interesting

Well... OK. How is it done?

ugo.santalucia

Is this a crusade of yours? You appear to bear a grudge against disc wheels... nobody has ever said they will be lighter... the rims can be made lighter and will come down in weight... how much? I don't fucxxng know how much... I have seen some 330 grams alloy ones, but I have no idea how good they are

Ultimately, if you have a problem with discs, stick to rim brakes, nobody is forcing you to go discs

cycleclinic

Disc brake MTB wheels can be made lighter than rim brake variety mainly becuase there is a good choice of rims. As the choice in rims becomes bigger for road disc then you will find some builds being lighter than the equivalent rim brake version.

Take for example the DT Swiss XR350 -350g disc brake 26" rim. The rim brake equivalent is 425g. Wider rims are meant to minic tubulars well they do to a point but they don't really unless they are 25mm wide or more then you get quite close. So Renoylds may not make a tubular rim. Unfortunatley I can see this as a trend in the future.

Also a large flange road wheels with an alfine hubs 36H still has to be done 2x I think. One 28H electric bike wheel I did 26" had to be done 1x the spokes were short 188mm I think. So hub flange diameter also influence the maximum and minimum number of crossings thats works.
http://www.machinehead-software.co.uk/b ... lator.html
I do not use this program as a calculator but I do use it if I have a drilling I am not used to or usual flange diameter that means I need to check what crossing actually works as it shows you visulally. Have a play at least you will see what factor influence the crossings builders go for.

Wirral_paul

earth wrote:

ugo.santalucia wrote:

you can potentially have a disc specific rim which is 100 grams lighter than the same rim for pads... that's more interesting

Well... OK. How is it done?

You seem to be forgetting that we're in the very early days of road disc wheels. Give them time to actually design and test the rims at least - Ugo isnt responsible for what the rim manufacturers havent all done yet is he. All he's done is stated POTENTIALLY with a very educated best guess what could be done when the manufacturers dont have to put beefed up parallel (or near to) braking surfaces on their rims.

earth

ugo.santalucia wrote:

Is this a crusade of yours? You appear to bear a grudge against disc wheels... nobody has ever said they will be lighter... the rims can be made lighter and will come down in weight... how much? I don't fucxxng know how much... I have seen some 330 grams alloy ones, but I have no idea how good they are

Ultimately, if you have a problem with discs, stick to rim brakes, nobody is forcing you to go discs

There are people all over saying rims will get lighter.

I want to debunk the argument that the rims are going to be lighter due to not having a braking surface. Then I noticed you cannot have radial spoked wheels that are disc compatible.


http://www.youtube.com/watch?v=q2I8XZTO4F0

1:42 - Ridley, 'You can make your wheels lighter, actually pull braking force away from the rim so you can totally redesign the wheel and put all the braking in the disc'.

The next guy in the video from Zipp knows better.

Then there is the guy at 2:56 suggesting that you get fade and ticks from rim callipers because the rims are not perfectly straight on carbon and alloy rims. I have my pads 1mm from the rims on both my carbon and alloy rims. On my disc CX bike I can see the gap between the pad and the rotor from half a meter away. I have to back the pads off so far that 2/3 of the lever travel is dead otherwise they drag on the rotor. I can actually see the warp in the rotor after about 175 miles of use. When I apply them they judder.

It's not just people in video's making unfounded claims. Shop assistants are at it as well because they get it all from these guys.

Then you find there are so many other things that are compromised like quick release skewers, radial spoke patterns.

earth

Wirral_Paul wrote:

earth wrote:

ugo.santalucia wrote:

you can potentially have a disc specific rim which is 100 grams lighter than the same rim for pads... that's more interesting

Well... OK. How is it done?

You seem to be forgetting that we're in the very early days of road disc wheels. Give them time to actually design and test the rims at least - Ugo isnt responsible for what the rim manufacturers havent all done yet is he. All he's done is stated POTENTIALLY with a very educated best guess what could be done when the manufacturers dont have to put beefed up parallel (or near to) braking surfaces on their rims.

You're right - not every change is progress. I never said anyone here was responsible where did that come from? When I asked how is it done it was a genuine question not rhetorical. I'm glad for the wheel building knowledge.

But I don't believe its the braking surface that adds significant weight. The clincher rim has to be built up to withstand the tyre forcing outward against the rim. My proof is that both tubular and clincher rims have braking surfaces but clinchers are 200 grams heavier in some cases because they have to be built up to take the clincher tyre.

ugo.santalucia

If I told you that you are right, the rims will only be marginally lighter and the wheels significantly heavier, would that make you feel better?
I am not sure where you read the blurb about disc wheels being lighter, but you can rest assured it's probably bollox...

cycleclinic

The braking surface does add weight as I pointed out above - DT Swiss XR350 -350g disc only rim. XR-425 is 425g and is for rim brakes. also take a look at this from Dash 26mm wide clincher for tubeless tyres 280g these have been confirmed to handle the pressure narrow road tyres can. Rims will be lighter and sesible spoke count wheels will be lighter too. You can bet with carbon rims thin aero spokes will remain present to keep weight down. I figure with those Dash rims and a 28F/28R spoke count 1200g wheelset is doable with the right hubs, maybe less as I have seen some stupidly light disc brake hubs.
http://www.cxmagazine.com/mercury-cycli ... oss-wheels

I have been riding discs for years on MTB's and no warped rotors. Rotor's can warp on mechanical disc because as you brake you bend the rotor, so when it gets hot and small warps can start to happen. Mechanical disc brakes should therefore be set up with the most minimal of clearance between the fixed pad and the disc. If a bit of rub results then so be it as setting up that way stops your disc warping and you get better braking performance. This is why hydraulic disc brake are a step up. When UCI disc brake bikes get approved then they will all have hydraulic brakes.

earth

ugo.santalucia wrote:

If I told you that you are right, the rims will only be marginally lighter and the wheels significantly heavier, would that make you feel better?
I am not sure where you read the blurb about disc wheels being lighter, but you can rest assured it's probably bollox...

I re-read one of my previous posts. I did say wheels when what I meant was rims. Sorry for that confusion. If I hadn't been skiving off at work maybe I would have spent more time writing my posts.

The argument put forward by these industry gurus is that although the wheel is heavier the braking surface is gone so the weight is at the hub. My point is I don't believe it for the afore mentioned reasons. You don't have to feel responsible for making me feel better. It's not that I bought a disc brake CX bike. I read up on the model of brake and knew the risk I was taking. It's more that the _is_ a crusade on and I think at least some of the reasons are false.

earth

thecycleclinic wrote:

I have been riding discs for years on MTB's and no warped rotors and believe I do not hold back. Rotor can warp on mechanical disc becuase as you brake you bend the rotor do that when it gets hot and small warps can start to happen. Mechanical disc brakes should therefore be set up with the most minimal of clearance between the fixed pad and the disc. If a bit of rub results then so be it as setting up that way stops your disc warping and you get better braking performance. This is why hydraulic disc brake are a step up. When UCI disc brake bikes get approved then they will all have hydraulic brakes.

All this guff about disc brakes was settled years ago by MTB user's we are not looking back unless you are doing a retro build. At the weight weenie end of the MTB wheel market disc brake wheels have got lighter than the rim brake wheels ever where in the 90's (and MTB kit in the 90's got silly light so much so that modern MTB's have got heavier). 26" rims got down to 385g in the 90's Sun did a 350g but they all broke. Stans make a 290g disc brake only rim for weight weenies and Ryde have been doing 263g 26" disc rims (a bit flexy) and there 29er version is a bit over 300g. When carbon road disc brake rims hit the market and they will (Dash are doing one that is 300g and deep) wheel weight for sensible spoke counts will drop. Weight weenies rim brake wheels will always be lighter but then again these are not sensible.

If I were you I would stop wathcing Zipp video's.

Sounds impressive. But I don't want to have to go through all the production prototype iterations. So I will wait and watch until the technology matures.

cycleclinic

The tech is know 29er disc rims are mature tech all that needs to happen is manufacurer need to make narrower rims for standard clinchers. No need for tech to mature just a need for the rims and the demand will sort that out.

Until new materials arrive there will be no major advancements in rim technology.