Factory vs. handbuilt spoke counts

raymond82

Whenever I look at recommendations for spoke counts for handbuilt wheels I usually see 32 spokes or maybe 28 for a 73 kilo rider like me. However, my Mavic Ksyrium elite rear wheel has only 20 spokes and they seem to be holding up fine. Why should I still go for a higher spoke count when getting a handbuilt wheel? I'm asking cause I saw a 24 hole powertap hub offered and I'm wondering if it makes sense for me to bid on it...

Thanks!

MichaelW

Low spoke-count wheels use special hubs and spokes, often with a straight-pull spoke which eliminates the weakness of the elbow. They have superior spoke design but longer regions of unsupported rim, so the rims are usually stiffer, deeper section, using more metal.
The disadvantage of straight-pull designs is that there is no standard, they are all proprietary and spares support can be patchy. You may not be able to buy the correct spoke at a good bike shop.
Most handbuilt wheels use traditional spokes which are universally available.

Powertap 24 uses DT-Swiss straight pull spokes which are some of the more easily available but still, not at every good bike shop.

raymond82

Thanks for the reply! So it's the the use of straight pull spokes that enables using a lower spoke count, the Mavics indeed have straight spokes. The Powertap I see offered is for normal spokes so I guess that would be too little for me. Or could it be compensated by using a deeper section rim?

ugo.santalucia

MichaelW wrote:

Low spoke-count wheels use special hubs and spokes, often with a straight-pull spoke which eliminates the weakness of the elbow. They have superior spoke design but longer regions of unsupported rim, so the rims are usually stiffer, deeper section, using more metal.
The disadvantage of straight-pull designs is that there is no standard, they are all proprietary and spares support can be patchy. You may not be able to buy the correct spoke at a good bike shop.
Most handbuilt wheels use traditional spokes which are universally available.

Powertap 24 uses DT-Swiss straight pull spokes which are some of the more easily available but still, not at every good bike shop.

The one of the weak elbow is an old rat... yet J spokes fatigue and ultimately fail at the J... but guess what? Straight pull fatigue and fail elsewhere... in fact there is no evidence whatsoever that straight pull spokes last longer or are superior... it's all blah blah and experience seems to suggest the opposite.

For the OP: there are hand built set at 20/24 and even 16/24... all wheels with fewer than 24 spokes at the rear are too flexy unless they use different spokes

Mavic use carbon, big stiff alloy spokes or large section bladed spokes to achieve stiffness in the Ksyrium range with mix results in terms of reliability.
Shimano don't bother and in fact their DA wheels are far too flexy for anyone that exceeds the weight of a fly

The biggest drawback of a wheel with fewer than 24-28 spokes is that one single failure leads to a wheel that can no longer be ridden, so only race day wheels can be built with that construction... unfortunately the industry seems to think that any day is race day and for many time crunched maybe it is...

raymond82

ugo.santalucia wrote:

The one of the weak elbow is an old rat... yet J spokes fatigue and ultimately fail at the J... but guess what? Straight pull fatigue and fail elsewhere... in fact there is no evidence whatsoever that straight pull spokes last longer or are superior... it's all blah blah and experience seems to suggest the opposite.

For the OP: there are hand built set at 20/24 and even 16/24... all wheels with fewer than 24 spokes at the rear are too flexy unless they use different spokes

Mavic use carbon, big stiff alloy spokes or large section bladed spokes to achieve stiffness in the Ksyrium range with mix results in terms of reliability.
Shimano don't bother and in fact their DA wheels are far too flexy for anyone that exceeds the weight of a fly

The biggest drawback of a wheel with fewer than 24-28 spokes is that one single failure leads to a wheel that can no longer be ridden, so only race day wheels can be built with that construction... unfortunately the industry seems to think that any day is race day and for many time crunched maybe it is...

Now that I think about it this is also what I read in Musson's book about straight pull and J spokes. So then I guess the strength in my Ksyriums comes from the fact that they have pretty wide bladed spokes. It's true that a couple of times I had the feeling the wheels are a bit flexy but then on the other hand I'm not giving them too much of a hard time as for me every day is training day and I usually pedal around quite slowly. So can I conclude that the problem with low spoke counts is not in the risk of the wheels collapsing under the weight but more in increased flexibility and the fact that they become useless when a spoke brakes?

I'm still interested to know if using a lower number of spokes can be overcome by using a deeper rim (and maybe using narrow bladed spokes?).

ugo.santalucia

raymond82 wrote:

I'm still interested to know if using a lower number of spokes can be overcome by using a deeper rim (and maybe using narrow bladed spokes?).

Yes of course, Campagnolo pioneered the area with their early Shamal, that only had 12 spokes... they were dreadful and in the 2nd release they went up to 16... you might still be able to see a few around, they are a classic.
Even deep rims need 24 spokes as many 20 are not particularly stiff

ugo.santalucia

madasahattersley wrote:

ugo.santalucia wrote:

Shimano don't bother and in fact their DA wheels are far too flexy for anyone that exceeds the weight of a fly

I have the RS80 C24s which as you know are basically the same as the DA wheels but with a slightly heavier hub, and they are as stiff as anyone could want them to be, and have served me very well racing in a wide variety of conditions and terrains for 2 years, including lots of training use.

And I'm no flyweight...

Same spokes? Not sure...

cycleclinic

The lower the spoke count the deeper/stiffer the rim is needed. Also hub bracing angle are an important factor for wheel stiffness not just spoke count and diameter.

Another important factor is the diameter of the spoke at the eblow or for a stright pull at the head. I do not know for certain but Mavic et.al may use bladed spokes that large than the normal 2.0mm that you find on the elbow of J-bend Sapim and DT spokes. DT Swiss make the alpine spoke (and Sapim the strong) which are 2.3mm at the elbow. For low spoke counts for heavy riders these could be used as they are more fatigue resistant but most builder won't do that as it is felt a better wheel is made by using more spokes for these riders. Sapim for example make bladed spokes with 2.3mm elbows or 2.3mm at the head for stright pulls but Chicken cycle (distributor) do not import these. Easton use a lot of Sapim spokes in there wheels all the ones the Chickens do not import it turns out.

In general think 24 spoke rear for 75kg rider or less 28 spoke rear for 85kg riders or less (90kg with the right rims) and 32 spoke rear for heavier riders. That is to ensure reliablity. Powerful rider may benefit from higher spoke counts too but all this assumes DT Swiss comps/revs spokes or Sapim Race/Laser/CX-ray with there 2.0mm diameter at the elbow.

You can of course ride a 24 spoke rear on a archetype rim if you weigh 100kg but you are at increased risk of spoke failure if you did want that then the DT Swiss Alpine spoke or Sapim Strong would be a good spoke choice. It depends to a large extent on how the rider rides as much as there weight. This is why the poster above is having luck with the RS80's but we do not know how many miles in 2 years and we do not know the weight. Of course the good luck could end tommorrow in 5000 miles time there is no way of telling.

Most Mavic wheels even though they are low spoke count look like they are all spoke given there width and thickness, this is how they make there wheels stiff enough and the spokes fatique resistant.

raymond82

thecycleclinic wrote:

The lower the spoke count the deeper/stiffer the rim is needed. Also hub bracing angle are an important factor for wheel stiffness not just spoke count and diameter.

Another important factor is the diameter of the spoke at the eblow or for a stright pull at the head. I do not know for certain but Mavic et.al may use bladed spokes that large than the normal 2.0mm that you find on the elbow of J-bend Sapim and DT spokes. DT Swiss make the alpine spoke (and Sapim the strong) which are 2.3mm at the elbow. For low spoke counts for heavy riders these could be used as they are more fatigue resistant but most builder won't do that as it is felt a better wheel is made by using more spokes for these riders. Sapim for example make bladed spokes with 2.3mm elbows or 2.3mm at the head for stright pulls but Chicken cycle (distributor) do not import these. Easton use a lot of Sapim spokes in there wheels all the ones the Chickens do not import it turns out.

In general think 24 spoke rear for 75kg rider or less 28 spoke rear for 85kg riders or less (90kg with the right rims) and 32 spoke rear for heavier riders. That is to ensure reliablity. Powerful rider may benefit from higher spoke counts too but all this assumes DT Swiss comps/revs spokes or Sapim Race/Laser/CX-ray with there 2.0mm diameter at the elbow.

You can of course ride a 24 spoke rear on a archetype rim if you weigh 100kg but you are at increased risk of spoke failure if you did want that then the DT Swiss Alpine spoke or Sapim Strong would be a good spoke choice. It depends to a large extent on how the rider rides as much as there weight. This is why the poster above is having luck with the RS80's but we do not know how many miles in 2 years and we do not know the weight. Of course the good luck could end tommorrow in 5000 miles time there is no way of telling.

Most Mavic wheels even though they are low spoke count look like they are all spoke given there width and thickness, this is how they make there wheels stiff enough and the spokes fatique resistant.

Your spoke counts are a bit lower that what I usually read so that's encouraging, I shouldn't weigh more than 75 kilo and I'm not an overly strong rider so that means the 24 hole hub could suit me. I'm going to keep an eye on it, it's on the Dutch equivalent of ebay and I'm curious what people will bid. I can't really afford it now but if I do get tempted I'll consider having it built with e.g. the 42 mm H Plus Son rim and use the spokes with the thicker elbow you mention.

The Mavic wheels I have for sure have special spokes, very wide and straight pull. It's quite interesting these spoke counts, I also saw Bontrager Aeolus wheels offered and they have only 16 spokes in the rear wheel. That looks pretty scary to be honest, dunno if I'd be comfortable with these wheels going downhill...

cycleclinic

The SL42 rim is quite heavy but very stiff. If that is the rim you want you can 20F/24R will be no problems. As an aside just because someone is 75kg or less does not mean they should have a 20F/24R wheelset. A 24F/28R spoke count will often be lighter as the higher spoke count means a lighter rim can be used(by light I mean velocity aerohead light or lighter). The only people who can get away with 20F/24R with light rims are youth rider/racer vary light adults or sub 50kg riders.

I think I would be a bit worried riding a 16 spoke wheel as ugo said campag did that with the 2nd gen Shamel and there is a good reason why there so few left in fact the rim on those is more tank amour plating. Using one for TT's with deep 80mm carbon rims is another matter.

raymond82

Ok, I'll keep that in mind then. I just found out the hub I was after has already been removed from the auction site... Anyway it's good to know what spoke counts I can aim for next time there will be a powertap hub offered. Interesting to realize that a wheel with more spokes can be lighter, it makes perfect sense of course. One day I would like to build my own wheelset but for that I guess I have to start with a 32F/32R.

And I'll stay away from 16 spoke rear wheels!

cycleclinic

Be careful with power taps if it is the old SL+ type then the rear NDS bracing angle is woful 24 spoke rears should be avoided unless you are use a very stiff rim like the DT Swiss RR585, SL42 or something similar the newer G3 hubs are normal in terms of bracing angles and therefore the range of rims opens up. In fact I have built with the SL+ hub 28 spoke (customer supplied hub), Race spokes and the Archetype rim (quite stiff) and the result was not as stiff a a 28 spoke arhctype build normally is. If a 24 spoke hub had been supplied the wheel may have been unstable in the long run.

Go for the G3 hub if you can they are lot better.

raymond82

thecycleclinic wrote:

Be careful with power taps if it is the old SL+ type then the rear NDS bracing angle is woful 24 spoke rears should be avoided unless you are use a very stiff rim like the DT Swiss RR585, SL42 or something similar the newer G3 hubs are normal in terms of bracing angles and therefore the range of rims opens up. In fact I have built with the SL+ hub 28 spoke (customer supplied hub), Race spokes and the Archetype rim (quite stiff) and the result was not as stiff a a 28 spoke arhctype build normally is. If a 24 spoke hub had been supplied the wheel may have been unstable in the long run.

Go for the G3 hub if you can they are lot better.

Thanks for that advice, the hub offered that has now disappeared from the site was a G3. I'll keep it in mind while looking though, I also understood that the SL+ hubs also technically are a bit less reliable than the G3 ones? Not sure where I read that though... I think if I'd have the choice I'd go for a 28H hub but it's good to know that if I find one second hand with a lower spoke count I can still go for it.

Monty Dog

You could be really 'clever' like Corima and use 18 spokes on the front that means that if you damage the rim you're $crewed! Cost of the replacement rim is more than I paid for the wheel!