[Lombard]

Thanks for linking November Dave's posts. I read through that thread.
I get the impression that Dave's main gripe is against the Pacenti SL23's. I don't have SL23's, but I recall these rims have lots of issues due to it being too light.

My understand about offset rims is that they do have to be a tad more robust at the spoke bed due to the spoke angle to the DS spokes. This cause asymm rims to be a tad heavier than their symm cousins.

anyway, here are all the carbon mtb rims I'm looking at:
Carbon MTB Rims,Carbon MTB Rims for sale Carbon MTB Rims wholesalers,factories,sellers


specifically, i'm looking at the V-shape asymm 27.5er, with 30.5mm inner width, 380g (All-mountain) weight, in 28h drilling.
27.5er Carbon MTB Asymmetric Hookless Rims products- 27.5er Carbon MTB Asymmetric Hookless Rims factories,manufactures,27.5er Carbon MTB Asymmetric Hookless Rims suppliers

and this version of asymm:
27.5er Carbon MTB Asymmetric Hookless Rims products- 27.5er Carbon MTB Asymmetric Hookless Rims factories,manufactures,27.5er Carbon MTB Asymmetric Hookless Rims suppliers

yes, they sell TWO versions of asymm rims. Which one is more robust? Their weight in "AM" (all mountain) configuration is the same at 380g (though the latter offers a "DH" (downhill) version at 430g).

What say you? What say the builders in here? My own a bit "uneducated" opinion is that the V-shape asymm rim should be the stouter rim due to a higher depth (28mm vs 25mm) and the spoke bed looks more robust (based on their diagrams).

Could the wheelbuilders in here chime in why/what the pros/cons of the two different versions of asymm.


My current info, riding style:
I'm a lightweight (122-124 lbs), and i'm not an abuser of equipment, but I do like to huck small lips (under 2 feet) and the landing can't always be soft on a hardtail. My current rear wheel is a SRAM Rise 60, carbon
symmetric rim, 21mm inner width, 24h spokes, and running 2.25" tires. Wheel is fast, no complaints about weight. But like I said, it will go out of true on me in the course of a year (of riding 2-3 times/wk, almost year round). I've looked at my strava and some of my descents are close to 30mph top speed going down doubletrack and jeep trails, but I hardly will hit 30mph, but when I do.. and hitting a big bump.. could this be the main thing that knock it out of true more than the hucking stuff? I'm thinking if I go with 28h spoke wheel, all this will be resolved, asymm or symm! But if I were going to build a new wheel, and I have the option to go asymm or symm, then I would like to know which option is better. But on thing is for SURE, I will go carbon rims for mtb, will not go back to aluminum rims in mtb.

Regardless of whether you decide to go symmetric or asymmetric, I would go 32h. Since you are using such a lightweight rim and considering the abuse you are giving it, the extra spokes will spread the load out and keep it round and true longer while hardly adding any weight. That will make more of a difference in stability than whether you use a symmetric or asymmetric rim.

 

[Kerry Irons]

60K miles without brake wear is amazing. Can I assume most of your riding doesn't have a lot of hills? Can I also assume you meant to say concave?

Unless I have something to compare to, feel doesn't work for me. I don't really have good tactile memory for a lack of a better way of describing it. That's why I always use a torque wrench while some mechanics don't.

Uh, yeah, concave. Lots of hills here but no stop signs at the bottom and no switchbacks.

 

[aclinjury]

Regardless of whether you decide to go symmetric or asymmetric, I would go 32h. Since you are using such a lightweight rim and considering the abuse you are giving it, the extra spokes will spread the load out and keep it round and true longer while hardly adding any weight. That will make more of a difference in stability than whether you use a symmetric or asymmetric rim.

yeah i know 32h is more robust, but the thought of having a front wit 24h and rear with 32h somehow doesn't quite fit on an XC rig! I mean, my dirtjumper uses 32h on a kilogram rim!

 

[Lombard]

yeah i know 32h is more robust, but the thought of having a front wit 24h and rear with 32h somehow doesn't quite fit on an XC rig! I mean, my dirtjumper uses 32h on a kilogram rim!

If this is a disc brake bike which I am assuming, I wouldn't do anything less than 32h front AND rear. 28h is pushing it. 24h is crazytown. Disc braking puts tremendous torque on a wheel regardless of whether it's your front or rear. And I don't know about you, but I'd rather have my rear wheel fail than my front while I'm on the bike.

All my rim brake road bike wheel builds are 24F/32R. All my disc brake wheel builds are 32F/32R regardless of type of bike.

Remember, there is a difference between whether you can get away with something and whether it makes sense. And if you are going to try and push the envelope on weight, keep in mind that the more spokes you use, the lighter the rim can be and still have a quality wheel.

 

[Enoch562]

I can't say I have ever heard of any wheel failing or breaking spokes because of disk brakes. I'm sure it puts some force in there somewhere, but I have yet to read or hear some one say "I grabed the brakes and spokes died on my disk brake bike." Rider weight and ride conditions should dictate spoke count.

I have to wonder what forces a a spokes sees when using disk. I know I see my fork tucking under and rotors turn purple, felt some torque steer from the fork twisting, even seen some seat stays bend but all the pressure is centered in the axle and mount area. I guess on a full lock up there are friction torque coming back through spoke from the ground up. Other than that, the spoke is just weight bearing.

 

[Kerry Irons]

I can't say I have ever heard of any wheel failing or breaking spokes because of disk brakes. I'm sure it puts some force in there somewhere, but I have yet to read or hear some one say "I grabed the brakes and spokes died on my disk brake bike." Rider weight and ride conditions should dictate spoke count.

I have to wonder what forces a a spokes sees when using disk. I know I see my fork tucking under and rotors turn purple, felt some torque steer from the fork twisting, even seen some seat stays bend but all the pressure is centered in the axle and mount area. I guess on a full lock up there are friction torque coming back through spoke from the ground up. Other than that, the spoke is just weight bearing.

Not saying that disc brakes are a threat to spoke loading and wheel integrity because I have no data, but clearly there is a lot more spoke loading with a disc brake wheel due to braking. With rim brakes, the force of braking is dissipated through the rim/tire combination directly from the ground to the brake pads. With a disc brake wheel, all of the braking force has to be transferred from the hub (where the disc brake is attached) through the spokes to the rim/tire where contacts the ground. Spokes in a rim brake wheel never see that kind of force.

Again, whether this is meaningful I do not know.

 

[aclinjury]

Not saying that disc brakes are a threat to spoke loading and wheel integrity because I have no data, but clearly there is a lot more spoke loading with a disc brake wheel due to braking. With rim brakes, the force of braking is dissipated through the rim/tire combination directly from the ground to the brake pads. With a disc brake wheel, all of the braking force has to be transferred from the hub (where the disc brake is attached) through the spokes to the rim/tire where contacts the ground. Spokes in a rim brake wheel never see that kind of force.

Again, whether this is meaningful I do not know.

all the disc wheels (mtb or road) seem to have 24h minimum, including the front wheel. So, i'd say this is prolly has something to do with braking forces you're talking about. And on a sidenote, all the mtb "XC" wheels have 24h for front/rear wheels; this is what i notice from all the lightweight XC wheelsets from the big brands like Sram, Bontrager, to name a few. This is using carbon rims. Aluminum rims softer than carbon, so they might run more spokes for the rear.

 

[Lombard]

all the disc wheels (mtb or road) seem to have 24h minimum, including the front wheel. So, i'd say this is prolly has something to do with braking forces you're talking about. And on a sidenote, all the mtb "XC" wheels have 24h for front/rear wheels; this is what i notice from all the lightweight XC wheelsets from the big brands like Sram, Bontrager, to name a few. This is using carbon rims. Aluminum rims softer than carbon, so they might run more spokes for the rear.

I don't know where you come up with "all". There are plenty of disc wheels that have 28 or 32 spokes.

Yes, there are plenty of low spoke wheels out there. There are plenty of 16F/20R road rim brake wheels out there too. Can you get away with it? Possibly. Is it a good idea? Probably not.

 

[aclinjury]

I don't know where you come up with "all". There are plenty of disc wheels that have 28 or 32 spokes.

Yes, there are plenty of low spoke wheels out there. There are plenty of 16F/20R road rim brake wheels out there too. Can you get away with it? Possibly. Is it a good idea? Probably not.

i said xc wheels, especially the highend ones, SRAM, Bontrager highend xc have 24h front/rear. Some highend xc wheels use 28h front/rear, no xc wheels with 32h front/rear

highend sets with 24h:

Roval Control SL

Bontrager Kovee XXX Boost TLR 29

Sram Rise 60

 

[Lombard]

i said xc wheels, especially the highend ones, SRAM, Bontrager highend xc have 24h front/rear. I know of zero highend xc wheels with 28h front, and certain no xc wheels with 32h front or rear.

That is not what your post said. You said:

all the disc wheels (mtb or road) seem to have 24h minimum, including the front wheel.

Furthermore, there are plenty of Bontrager disc wheels here that are 28 spoke. Look and you will see that the number of 24 spoke wheels aren't even most and certainly aren't all:

https://www.trekbikes.com/us/en_US/...ents/bike-wheels/mountain-bike-wheels/c/E418/

You may want to stop shooting from the hip and do a little research before you post.

 

[Jay Strongbow]

I don't know where you come up with "all". There are plenty of disc wheels that have 28 or 32 spokes.

Yes, there are plenty of low spoke wheels out there. There are plenty of 16F/20R road rim brake wheels out there too. Can you get away with it? Possibly. Is it a good idea? Probably not.

And saying they all have 24 MINIMUM in no way says there aren't plenty with more.

 

[aclinjury]

That is not what your post said. You said:

all the disc wheels (mtb or road) seem to have 24h minimum, including the front wheel.

Furthermore, there are plenty of Bontrager disc wheels here that are 28 spoke. Look and you will see that the number of 24 spoke wheels aren't even most and certainly aren't all:

https://www.trekbikes.com/us/en_US/...ents/bike-wheels/mountain-bike-wheels/c/E418/

You may want to stop shooting from the hip and do a little research before you post.

dude you're making a big fuss over nothing, seriously stop the grand standing? I'm talking about lightweight xc stuff (you know, highend stuff).

https://www.specialized.com/us/en/r...971?color=299040-186971&searchText=30121-2600

https://www.trekbikes.com/us/en_US/...ger-kovee-xxx-boost-tlr-29-mtb-wheel/p/27594/

https://cdn.sram.com/sites/default/files/sram_rise_pr-111006.pdf

earlier I was replying to Kerry Ions and noticing about the 24h minimum in mtb disc wheels. I should have said that 24h spokes seems to be the minimum requirement for disc brake wheels, and the fact that some xc wheels use 24h for BOTH front/rear has more to do with braking forces.. rather than for weigh-bearing (thus I'm agreeing with Kerry's notion that more spokes is needed for disc braking vs rim).

so far, you seem to preach 28/32 spokes are stouter... and that's all you seem to care. Well, duh, notice that I have not argue against this point. Do you know how ridiculous and out-of-trend a $7000 XC rig would be if you were to use an Enduro/DH wheel with 32h or even 28h wheels? I know you're all about durability/reliability, but for people who spend $7000+ on a rig, they're not thinking like you. For people who want to haul ass at 21-22 mph on the flat dirt (try to do it on enduro wheelset and get back with me) while still able to confidently rip down a 10-15% slope as fast possible, they're definitely making equipment decision between 24h vs 28h. I know it's your world of thought, but the weightweenies are not thinking like you. If reliability is all there is to mtb, then everyobody would be on 32h rim, with 40mm internal width, and 2.4+" tires.

Shhh, if I didn't enjoy some huck time, then my 24h rear wheel would probably never go out of true as often as it is.. if I was a little more careful about picking my lines going downhill rather than just slam it over the roughs, then the wheel wouldn't go out of true... and if the damn aluminum nipples don't corrode like they do, then I wouldn't have such a hard time trying to true the wheel (it was much easier without corroded nipples). The problem with me is mainly that i'm using an XC wheel in conditions that is probably considered as "unintended" by the manufacturers. Do I know this? Yes I'm aware of it.

 

[Lombard]

Shhh, if I didn't enjoy some huck time, then my 24h rear wheel would probably never go out of true as often as it is.. if I was a little more careful about picking my lines going downhill rather than just slam it over the roughs, then the wheel wouldn't go out of true... and if the damn aluminum nipples don't corrode like they do, then I wouldn't have such a hard time trying to true the wheel (it was much easier without corroded nipples). The problem with me is mainly that i'm using an XC wheel in conditions that is probably considered as "unintended" by the manufacturers. Do I know this? Yes I'm aware of it.

Hmmmm. Let's see. 24 spoke disc wheels are fine as long as I don't do A, B, C, D, E, F, G, etc. Got it! :thumbsup: