Has anyone laced a 24H rim to a 32H hub (rear)?

I’m trying to build a bad ass set of CX race wheels. The rims I desire are 24H, and I have disc brakes. The problem is that 24H rear disc hubs basically don’t exist (there are a couple out there that apparently aren’t worth the boxes they ship in). Has anyone taken a more standard 32H rear hub and laced it to a 24H rim? The math works out pretty well, just skip every fourth hole on the rim. Would there be a huge trade off in wheel stiffness, or would the necessary spoke tension be way too high?

Thanks for any insight,
-Colin

It would be best to use 16 on the drive side, 8 on the other side. Thats how its usually done, but ask yourself if no reputable make makes a 24 hole disk hub why is that?

It would be best to use 16 on the drive side, 8 on the other side. Thats how its usually done, but ask yourself if no reputable make makes a 24 hole disk hub why is that?

It’s a fair question. I believe that the answer is that there isn’t really any demand at this point. I think that as the disc brake CX market takes off we’re going to see a lot of 20 and 24H disc hubs. I could be wrong.

You don’t many 24 disc mtb hubs which are meant for inherently stronger wheels due to the wider hub dimension in back and the shorter spokes for 26 in wheels. For cross aero doesn’t matter much and the weight of 4 spokes is minor.

I’m sure 24 hole disc cross wheels will work fine but durability will be somewhat compromised.

Just find a standard rim. Really no point in 24 spoke wheels for cross. If you have extra money to spend on CX wheels, much better off going for multiple wheelsets (for various conditions), than one expensive wheelset. Considering how little use a cross wheelset actually gets, it seems silly to go for tricked out stuff.

Yeah, I know, I know. But those 24H carbon rims are oh so purty, and would make me look so good on the start line (before the gun sounds and I’m off the back, that is).

People who lace 24 hole rims to 32 hole hubs typically do so with a 16/8 pattern as was suggested. Campy does this on their wheels stock. Some hubs are better suited than others for this.

The reason almost no one uses a 24 spoke disk rear hub is because with disk brakes you now have very large forces on both drive and non-drive side. Driving torque on the drive side, and braking torque on the non-drive side. While 16 drive/8 non drive makes an excellent wheel for rim brakes, you’re going to break a lot of non-drive spokes with only 8 resisting the braking force. Even 12 on the non-drive side is doubtful, and don’t forget you need 2 cross on the non-drive side to resist braking force, another reason why low spoke counts on that side are a problem.

Brian

Yeah, I know, I know. But those 24H carbon rims are oh so purty, and would make me look so good on the start line (before the gun sounds and I’m off the back, that is).

Looking good on the starting line is overrated. I save my good looks for the podium.

It would be best to use 16 on the drive side, 8 on the other side. Thats how its usually done, but ask yourself if no reputable make makes a 24 hole disk hub why is that?
+1 for occam’s razor

The reason almost no one uses a 24 spoke disk rear hub is because with disk brakes you now have very large forces on both drive and non-drive side. Driving torque on the drive side, and braking torque on the non-drive side. While 16 drive/8 non drive makes an excellent wheel for rim brakes, you’re going to break a lot of non-drive spokes with only 8 resisting the braking force. Even 12 on the non-drive side is doubtful, and don’t forget you need 2 cross on the non-drive side to resist braking force, another reason why low spoke counts on that side are a problem.

Brian

bingo

wheelbuilders have the three strike rule: too few spokes, spokes too thin, and rim too light. With road racing wheels, you can skirt by a few or even all the strikes, but this just won’t fly for a disc-brake CX wheel.

now, that said, you can lace a 32H into a 24H, but wheelbuilders really don’t recommend it. It’s called a crow’s foot, and damn, a google search even turned up a conversation on slowtwitch

if i were you i’d get a 28H stallion build rim and a 28H hub and be done with it

So the 16/8 on a 32h Powertap hub used on the road is safe and reliable? Sorry for the hijack but I have been looking for a 32h carbon hoop in which to install my PT. They are hard to find. If the 16/8 is kosher that will make the search much easier. Thanks

So the 16/8 on a 32h Powertap hub used on the road is safe and reliable? Sorry for the hijack but I have been looking for a 32h carbon hoop in which to install my PT. They are hard to find. If the 16/8 is **kosher **that will make the search much easier. Thanks

that words means differently to orthodox, conservative, reform, and cultural Jews. Similarly, what level of kosher are you seeking? Powertap requires you lace 2x each side, so you’ll probably be voiding your warranty. That said, it does get your NDS tension up, which is good for a powertap.

lots of places are blowing out 24H, 2nd generation powertap hubs. Look around and you’ll probably find one better suited for your needs.

edit

SL+ for $700. http://www.bikeman.com/…_campaign=GoogleBase

PS. found this gem

Great advice. Thank you. And I am truly sorry if I offended anyone. I meant nothing by the term that I meant as highly acceptable. Kosher, to me, has always meant very good quality and within the specified requirements. Once again, I apologize.

Well…

I’m embaressed to admit it, but years ago I attempted to do the same thing; with the only difference being standard caliper brakes. It DOESN’T work and it’s not worth it. I’ve built many wheels both road and mountain bike. I learned to say with what is the norm, in fact I’m a tad more conservative. For example my front training wheel is 24 spoke but I laced it cross 2 instead of radial. Getting radical with wheels just isn’t worth it.

Adding a disk brake to the equation indeed does force the builder to account for much more complex forces. More spokes and cross 3 would be manditory in my book.

I live in hilly/mountains (west side of the Sierras). And, I ask how much does one need to brake in a triathlon? I’ve done Auburn Worlds Toughest more than a few times and if any race requires brakes that’s one for sure. Yet, I never wanted “more” brake.

The only race I’ve DNF’d was the race I tried my new crow’s foot laced wheel 32 hub to 24 rim. I still get teased about that one - and I deserve it!

My two cents.

Happy Holidays to all,
keith

Great advice. Thank you. And I am truly sorry if I offended anyone. I meant nothing by the term that I meant as highly acceptable. Kosher, to me, has always meant very good quality and within the specified requirements. Once again, I apologize.

no no, not offended at all. Heck, i’m not even a member of the Chosen People. I’m just pointing out the fact that even amongst Jews, the definition of what’s dietarily acceptable varies greatly (I have friends who’ll eschew from eating seafood but disregard the rule forbidding dairy and meat in the same meal). Obviously, Saris goes by the letter as they are the ones who may have to deal with warranties, but there are others out there as well.

Also, i don’t know if you are building the wheel or are having someone else building it, but I’d entrust this project, should you decide to follow through on the 32-to-24 crow’s foot, in the hand of a very reputable wheelbuilder such as Peter Vecchio (Colorado), Peter White (NH), Ligero (Tenn), and Joe Young (Texas). I’ve personally dealt with a custom wheel builder by the name of Rob Curtis (Chicago) who is also very good at his craft. That said, many of these builders have their reputation on the line and may refuse to do it as they would deem it too risky.

also to be noted: if you are buying a used hub, it’s even more important not to rock the boat as the spokes will leave their marks on the flanges as they settle in. As such, it’s best for the new spokes to conform to these marks as the flange could be weakened if the spokes are laced different from before.

Well…

I’m embaressed to admit it, but years ago I attempted to do the same thing; with the only difference being standard caliper brakes. It DOESN’T work and it’s not worth it. I’ve built many wheels both road and mountain bike. I learned to say with what is the norm, in fact I’m a tad more conservative. For example my front training wheel is 24 spoke but I laced it cross 2 instead of radial. Getting radical with wheels just isn’t worth it.

Adding a disk brake to the equation indeed does force the builder to account for much more complex forces. More spokes and cross 3 would be manditory in my book.

I live in hilly/mountains (west side of the Sierras). And, I ask how much does one need to brake in a triathlon? I’ve done Auburn Worlds Toughest more than a few times and if any race requires brakes that’s one for sure. Yet, I never wanted “more” brake.

The only race I’ve DNF’d was the race I tried my new crow’s foot laced wheel 32 hub to 24 rim. I still get teased about that one - and I deserve it!

My two cents.

Happy Holidays to all,
keith

That’s a very sound advice, and i hope that there was no physical damages as a result of that wheel. I contacted Vecchio regarding a wheel build, and he was the one who mentioned the three strike rule. On my latest build, the only area from which I strayed from his suggestions was using 2x NDS as opposed to 3x NDS on my 28H alloy rear wheel for road races. This was done to get more tension on the NDS, but needless to say, i got a bit too smart as i tried lacing the NDS as a 3x and struggled for an hour trying to figure out why the spoke was too short.

…should you decide to follow through on the 32-to-24 crow’s foot…

A 32 hub 24 rim in crowsfoot results in a bit of twist in the pattern. If you map it out you see that the holes don’t/can’t line up. It will work ok but I wouldn’t advise it.

16-8 triplet is only a good idea if you have a hub with wide spacing. Normal hubs are made to have the same number of spokes on each side.

It would be best to use 16 on the drive side, 8 on the other side. Thats how its usually done, but ask yourself if no reputable make makes a 24 hole disk hub why is that?
+1 for occam’s razor

The reason almost no one uses a 24 spoke disk rear hub is because with disk brakes you now have very large forces on both drive and non-drive side. Driving torque on the drive side, and braking torque on the non-drive side. While 16 drive/8 non drive makes an excellent wheel for rim brakes, you’re going to break a lot of non-drive spokes with only 8 resisting the braking force. Even 12 on the non-drive side is doubtful, and don’t forget you need 2 cross on the non-drive side to resist braking force, another reason why low spoke counts on that side are a problem.

Brian

bingo

wheelbuilders have the three strike rule: too few spokes, spokes too thin, and rim too light. With road racing wheels, you can skirt by a few or even all the strikes, but this just won’t fly for a disc-brake CX wheel.

now, that said, you can lace a 32H into a 24H, but wheelbuilders really don’t recommend it. It’s called a crow’s foot, and damn, a google search even turned up a conversation on slowtwitch

if i were you i’d get a 28H stallion build rim and a 28H hub and be done with it

Thanks to all for this little dose of sanity. I’ll try to get these silly project ideas out of my head. Two followup questions:

  1. You mentioned above going 28H rim and hub. I assume that this would solve most if not all of the mentioned problems, and that so many reputable hub makers (DT Swiss, etc) wouldn’t make 28H disc hubs if that were not the case.

  2. Would you advice be different regarding the 24H rim if I had a 24H hub as well? What about for a front rather than rear? That is, is the problem in the lack of spokes, or is the problem in having different numbers of spokes?

Thanks very much.

…should you decide to follow through on the 32-to-24 crow’s foot…

A 32 hub 24 rim in crowsfoot results in a bit of twist in the pattern. If you map it out you see that the holes don’t/can’t line up. It will work ok but I wouldn’t advise it.

16-8 triplet is only a good idea if you have a hub with wide spacing. Normal hubs are made to have the same number of spokes on each side.

out of curiosity, how did that quasi-crow’s foot powertap wheel you mentioned in the WW thread turn out?

for the record, rruff is much more experienced as a wheelbuilder. When building up my current rear wheel, my searches turned up many of his posts, and they’ve been quite helpful.

since rruff is posting, i’d defer the more technical question to him

as for hubs, i think CK has a mountain hub in 28H (i assume you are using 135mm spacing?). it’ll cost you a few pretty pennies, but CK hubs are pretty, and ZOMG an apiary in my hub :wink:

if you are looking for a less expensive option, there’s Rotaz, and bikehubstore sells them. Brandon at bikehubstore is very helpful, and the site is highly recommended. That said, you will need to do quite a bit more maintenance as the hub probably won’t be as durable as a CK, but the entire set is ~1/3 that of a CK rear hub, and even if the bearings are shot, they are cheap to replace.

fortunately a very reputable brand of hub Alchemy does exactly this.