Spoke counts for thin spokes

Discuss light weight issues concerning road bikes & parts.
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biwa
Posts: 159
Joined: Fri Sep 21, 2018 8:39 pm

by biwa

For thin spokes (think Sapim CX-Ray or Laser), how many would you guys recommend for a 155lb climber with 246w FTP?

These are going onto 36mm-deep carbon clinchers with lightweight hubs (extralite or carbon-ti). 20/24 or 24/28? Thx.

morganb
Posts: 668
Joined: Wed Mar 15, 2017 5:30 pm

by morganb

20/24 should be fine up to 170lbs even for very powerful riders, especially with a carbon rim.

by Weenie


alcatraz
Posts: 2303
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

No problem for cx-ray to make a solid build @20/24 for 155lbs.

If you are a low cadence rider, sprinter, +10 grade climber, frequently out of saddle rider... you might enjoy adding a few more spokes. 24/28 maybe.

I say that because your riding style will torque/stress the wheel a lot more than a high cadence rider that sits down 99% of the time and doesn't climb 20% grades on 40rpm cadence.

Another argument is reliability. A 24/28 setup would possibly suit the more endurance hubs Carbon-ti to have the build of the wheel match the level of the hubs. For extralite with more frequent service intervals and no endurance level components a 20/24 setup is maybe more in line with the hub's intended use. You don't need the spokes and reliability because you wouldn't go touring on this wheelset anyway. Something like this... you get my point.

Will be a nice wheelset. Good luck.

/a

Geoff
Posts: 5259
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

If the question is just what you can get away with, at your weight, you can probably go even lower in the front. The question is, why would you want to? If you want to build a really light set, you could go tubular, instead.

I am lighter than you, but prefer a higher spoke count wheel, myself. My FTP is a bit higher, but for wheel stiffnes, the question is really about your power in the sprint and your riding style. I produce about 1,000 watts, but I only weigh 130ish. I still find that really low spoke count wheels will rub the break pads whilst climbing steep hills. If you really pound up the last 1,000 at 8 or 10%, you may find the same. If it bothers you, you might want a higher spoke count. It bugs me, so I would rather ride 32s simply because they just 'feel' better to me. I doubt that a bit of rubbing during those few hard efforts really matters that much, to be honest.

If you wanted to build a set of 24s, you could also choose build them with Shimano hubs, too, which are a lot better.

Alexandrumarian
Posts: 491
Joined: Mon Mar 28, 2016 6:34 pm
Location: Romania

by Alexandrumarian

I'm 210-215 lbs similar ftp, but as Geoff pointed, it is the sprints (or standing attacks if you wish) that make the wheels cry under me, especially the front. I have a set of home made 32 3x rear 28 2x front, classic alu rims, DT aerolite spokes (same size as cxray) and I consider them pretty much bombproof. But these day I mostly ride on 35mm Bora tubulars which are 18 spokes radial in the front, size very close to rays. I had zero issues with them going out of true even after some masive potholes but as soon as I jump up, I get rub. A lot of this is because I like close pads (less than 2mm to the rim) but not being much into sprinting/aggresive riding, I'm good with the Boras too.

biwa
Posts: 159
Joined: Fri Sep 21, 2018 8:39 pm

by biwa

alcatraz wrote:
Sat Jan 19, 2019 12:12 pm
No problem for cx-ray to make a solid build @20/24 for 155lbs.

If you are a low cadence rider, sprinter, +10 grade climber, frequently out of saddle rider... you might enjoy adding a few more spokes. 24/28 maybe.

I say that because your riding style will torque/stress the wheel a lot more than a high cadence rider that sits down 99% of the time and doesn't climb 20% grades on 40rpm cadence.

Another argument is reliability. A 24/28 setup would possibly suit the more endurance hubs Carbon-ti to have the build of the wheel match the level of the hubs. For extralite with more frequent service intervals and no endurance level components a 20/24 setup is maybe more in line with the hub's intended use. You don't need the spokes and reliability because you wouldn't go touring on this wheelset anyway. Something like this... you get my point.

Will be a nice wheelset. Good luck.

/a
These are not racing wheels, and I intend to put 150-200km per week for ~40 weeks a year.

Speaking of carbon-ti road hubs, given they're straightpull, what kinds of lacing pattern does it accomodate for the rear wheel (left and right side)? Does 24 or 28 make a difference there?

biwa
Posts: 159
Joined: Fri Sep 21, 2018 8:39 pm

by biwa

Geoff wrote:
Sat Jan 19, 2019 6:39 pm
If the question is just what you can get away with, at your weight, you can probably go even lower in the front. The question is, why would you want to? If you want to build a really light set, you could go tubular, instead.

I am lighter than you, but prefer a higher spoke count wheel, myself. My FTP is a bit higher, but for wheel stiffnes, the question is really about your power in the sprint and your riding style. I produce about 1,000 watts, but I only weigh 130ish. I still find that really low spoke count wheels will rub the break pads whilst climbing steep hills. If you really pound up the last 1,000 at 8 or 10%, you may find the same. If it bothers you, you might want a higher spoke count. It bugs me, so I would rather ride 32s simply because they just 'feel' better to me. I doubt that a bit of rubbing during those few hard efforts really matters that much, to be honest.

If you wanted to build a set of 24s, you could also choose build them with Shimano hubs, too, which are a lot better.
My goal is to have a lightweight hassle-free wheels I can put miles in. Lightweight because I primarily climb rather than sprint. Two things I want to avoid: lack of robustness/confidence on the descent; re-truing the wheels. The roads around my region are average condition, some potholes here and there.

I don't put 1,000w when climbing, but there is no shortage of 8-13% and I do ride out of saddles slightly more often than average riders. And I don't intend to race on these.

alcatraz
Posts: 2303
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

biwa wrote:
Sun Jan 20, 2019 12:01 am
alcatraz wrote:
Sat Jan 19, 2019 12:12 pm
No problem for cx-ray to make a solid build @20/24 for 155lbs.

If you are a low cadence rider, sprinter, +10 grade climber, frequently out of saddle rider... you might enjoy adding a few more spokes. 24/28 maybe.

I say that because your riding style will torque/stress the wheel a lot more than a high cadence rider that sits down 99% of the time and doesn't climb 20% grades on 40rpm cadence.

Another argument is reliability. A 24/28 setup would possibly suit the more endurance hubs Carbon-ti to have the build of the wheel match the level of the hubs. For extralite with more frequent service intervals and no endurance level components a 20/24 setup is maybe more in line with the hub's intended use. You don't need the spokes and reliability because you wouldn't go touring on this wheelset anyway. Something like this... you get my point.

Will be a nice wheelset. Good luck.

/a
These are not racing wheels, and I intend to put 150-200km per week for ~40 weeks a year.

Speaking of carbon-ti road hubs, given they're straightpull, what kinds of lacing pattern does it accomodate for the rear wheel (left and right side)? Does 24 or 28 make a difference there?
Only 2x:0x on carbonti.

It's a very common pattern. 2x:2x would be it's competitor with a bit higher nds tensions and a bit of lateral stiffness sacrificed.

24/28 might prove hard to find. They exist but carbon-ti has been 20/24 only for many years.

For build and forget I'd use brass nipples, not internal.

biwa
Posts: 159
Joined: Fri Sep 21, 2018 8:39 pm

by biwa

alcatraz wrote:
Sun Jan 20, 2019 1:23 am
biwa wrote:
Sun Jan 20, 2019 12:01 am
alcatraz wrote:
Sat Jan 19, 2019 12:12 pm
No problem for cx-ray to make a solid build @20/24 for 155lbs.

If you are a low cadence rider, sprinter, +10 grade climber, frequently out of saddle rider... you might enjoy adding a few more spokes. 24/28 maybe.

I say that because your riding style will torque/stress the wheel a lot more than a high cadence rider that sits down 99% of the time and doesn't climb 20% grades on 40rpm cadence.

Another argument is reliability. A 24/28 setup would possibly suit the more endurance hubs Carbon-ti to have the build of the wheel match the level of the hubs. For extralite with more frequent service intervals and no endurance level components a 20/24 setup is maybe more in line with the hub's intended use. You don't need the spokes and reliability because you wouldn't go touring on this wheelset anyway. Something like this... you get my point.

Will be a nice wheelset. Good luck.

/a
These are not racing wheels, and I intend to put 150-200km per week for ~40 weeks a year.

Speaking of carbon-ti road hubs, given they're straightpull, what kinds of lacing pattern does it accomodate for the rear wheel (left and right side)? Does 24 or 28 make a difference there?
Only 2x:0x on carbonti.

It's a very common pattern. 2x:2x would be it's competitor with a bit higher nds tensions and a bit of lateral stiffness sacrificed.

24/28 might prove hard to find. They exist but carbon-ti has been 20/24 only for many years.

For build and forget I'd use brass nipples, not internal.
Got it. Just curious, why most (if not all) straightpull rear hubs only have 24H not more? Is there any downside for going up?

alcatraz
Posts: 2303
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Good question. I don't know.

Maybe carbonti doesn't like to stock up on many configurations?

It's also probably harder to manufacture straightpull hubs. It's more than just drilling a flange. So maybe it's also a cost and quality control measure for a low production item.

NickJHP
Posts: 296
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

I'd go for 24/28 myself - with carbon rims rather than aluminium rims you are more likely, not less likely, to get brake rub with low spoke count wheels. This is because the rim is so stiff that when the bottom of the rim is deflected sideways when sprinting or climbing out of the saddle, the top of the rim is more able to overcome the spokes and deflects more in the opposite direction than would an aluminium rim.

Four additional spokes+nipples per wheel compared to 20/24 is going to add ~20g per wheel for CX-Ray spokes and Squorx nipples. I weigh 65kg (143lbs), and I used 24/28 last year when I built a pair of wheels using CX-Ray spokes, Squorx nipples, DT Swiss 240s rear hub, Hope RS4 front hub, Light Bicycle RRU25 rims. I'm actually riding those wheels in the mountains at the moment (Victorian Alps, Australia).

Image

alcatraz
Posts: 2303
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

NickJHP wrote:
Sun Jan 20, 2019 9:24 am
I'd go for 24/28 myself - with carbon rims rather than aluminium rims you are more likely, not less likely, to get brake rub with low spoke count wheels. This is because the rim is so stiff that when the bottom of the rim is deflected sideways when sprinting or climbing out of the saddle, the top of the rim is more able to overcome the spokes and deflects more in the opposite direction than would an aluminium rim.

Four additional spokes+nipples per wheel compared to 20/24 is going to add ~20g per wheel for CX-Ray spokes and Squorx nipples. I weigh 65kg (143lbs), and I used 24/28 last year when I built a pair of wheels using CX-Ray spokes, Squorx nipples, DT Swiss 240s rear hub, Hope RS4 front hub, Light Bicycle RRU25 rims. I'm actually riding those wheels in the mountains at the moment (Victorian Alps, Australia).

Image
Good point for a heavier/stronger rider.

Aren't those disc brake wheels? So no brake rub then or do you have really narrow clearance by the stays?

Just curious...

Nice looking wheels by the way. Are those the new 30mm wide carbon clinchers?

NickJHP
Posts: 296
Joined: Wed Feb 14, 2018 2:22 am
Location: Canberra, Australia

by NickJHP

@alcatraz - Yes, those are disc wheels, so brake rub wasn't an issue, but I went 24/28 as I wanted the wheels for general riding. I don't think the OP specified whether his wheels were going to be disc or rim brake. The RRU25 rims are 18mm internal 25mm external width.

biwa
Posts: 159
Joined: Fri Sep 21, 2018 8:39 pm

by biwa

NickJHP wrote:
Sun Jan 20, 2019 8:01 pm
@alcatraz - Yes, those are disc wheels, so brake rub wasn't an issue, but I went 24/28 as I wanted the wheels for general riding. I don't think the OP specified whether his wheels were going to be disc or rim brake. The RRU25 rims are 18mm internal 25mm external width.
Mine is going to be rim brake, so probably more susceptible to the issue you've described

by Weenie


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