Radial Spoking?

[Duracellis]

I have noticed that just about every new set of wheels is spoked radially. I assume this is because the spokes can be shorter and, thus, lighter. However, all I have read and heard about wheel building is that radial spoking is bad for this that and the other reasons.
Are spokes and hubs that much stronger that they can now spoke radially, or is this just a fad?

 

[BikingBrian]

Just a fad. Most hub manufacturers don't warrantee their hubs when they are built up radially. However, boutique wheels which are built up radially from the beginning are assumed to have been made using hubs which were specifically made to withstand radial building (presumably!). Although DT Swiss makes radial-specific hubs if you are interested.
Most of what I have read also doesn't seem to attribute any qualities, good or bad, to radial building (search through the rec.bikes section...lots of posts on this subject). Yes, they look cool....but perhaps harder to true or get up to proper tension if you have to replace a broken spoke??? I don't build wheels, so I'm just guessing.

 

[Bobby Lex]

I have noticed that just about every new set of wheels is spoked radially.

Which ones?

Your standard OEMs (Bontrager, Mavic, Easton) are all pretty much 2x or 3x. Some front wheels come radially laced--because front wheels are not subjected to torque.

But it is rare to see a rear wheel that is radially laced. (Although the Mavic Ksyrium is radially laced on the drive side only). Campy makes a radially laced rear wheel, too. But those are rare exceptions.

Jobst Brandt (The Bicycle Wheel) does not speak highly of radial spoking.

Bob

 

[artmichalek]

But it is rare to see a rear wheel that is radially laced. (Although the Mavic Ksyrium is radially laced on the drive side only). Campy makes a radially laced rear wheel, too. But those are rare exceptions.

You can't go full radial on a rear wheel because the spoke tension would go up too much under torque. Same deal with a front wheel with a disk brake. A lot of rear wheels are starting to come with crossed DS and radial NDS in order to compensate for some of the flange offset. The Ksyrium and some of the new Shimano wheels are radial drive side simply because it's the only way to fit the nipples on the hub flange. The point is that only one side of a drive wheel can be radial.

I've built and ridden both crossed and radial wheels and the only advantages of radial spoking that I can see is that it looks cool and it makes building easier. (As an aside pretty much all boutique wheels are machine made, and I can imagine radial spokes are much easier for a machine to insert and tension.) The down side is that when the spokes are pulling straight out, they put a higher tensile stress on the outer edge of the flange than if they were pulling tangentially. Shimano has recently started allowing radial spoking on their upper end hubs, but Campy hasn't. Unless you're really hard on your wheels, the risk of ripping a hub flange is low.

 

[free_rideman]

Aside from the other problems, radial laced wheels are very stiff in the vertical plane. So unless you need one stiff, and precise bike, there is no reason for such stiffness. Two cross pattern is my favorite for road bikes. My wheels are two cross everywhere and then the rear drive side is three cross.

If getting radial, at least get it with 28 spokes or so. If you mix radial lacing with low spoke counts, than you got one poopy wheel.

 

[artmichalek]

Aside from the other problems, radial laced wheels are very stiff in the vertical plane. So unless you need one stiff, and precise bike, there is no reason for such stiffness. Two cross pattern is my favorite for road bikes. My wheels are two cross everywhere and then the rear drive side is three cross.

If getting radial, at least get it with 28 spokes or so. If you mix radial lacing with low spoke counts, than you got one poopy wheel.

Not really. The average wheel only deflects around 0.005" vertically under normal riding conditions. Because it's shorter, a radial spoke will stretch about 5% less under a given load. All else being equal it would be easier to tell by feel if that leaf you just rode over came from an oak tree or a maple tree. On the other hand since most radial wheels are laced heads out, there's about a 5% decrease in lateral stiffness due to the lower bracing angle. That you will be able to feel. You're right about the spoke count though.

 

[DannoXYZ]

From the test-data, it appears that lateral wheel-stiffness with radial-lacing is across the board compared to crossed wheels. Some are stiffer than crossed-laced wheels and some are softer:
Damon Rinard's Wheel Stiffness Test
Wheel Deflection Test Results
However, the two stiffest wheels have radial lacing with deflections of less than 1.0mm. Interesting comparison on wheels #94 & 95 with the ones having the elbows out being stiffer. Makes sense as the spoke-angle's wider, like having a wider flange-spacing. Although the number of spokes probably makes a bigger difference in wheel-stiffness than lacing-pattern.

There's not much advantage to radial other than ease of building and looks. Then again, there not much of a disadvantage either. The lack of torsional rigidity's not that much of a deal because the hub will just wind up and the spoke-tension will increase to the point where it stops the wind-up. I haven't felt much of a difference in rear-wheel stiffness between crossed vs. radial wheels (and I've snapped handlebars & stems in sprints too). The main issue is probably breaking the hub-flanges. Here's a front-hub on my track bike made specifically with radial-lacing in mind. Notice that there's more material on the flanges outside of the spoke-holes to deal with loads pulling straight outwards:

 

[Duracellis]

Well from what i read that main disadvantage to radial spoking is a decreased spoke life due to the added stresses and fatigue

 

[DannoXYZ]

Well from what i read that main disadvantage to radial spoking is a decreased spoke life due to the added stresses and fatigue

Yeah, on a rear-wheel maybe with the higher variations in spoke-tension due to the on/off torque. On a front-wheel, I doubt spoke-life would change by much.

Another variable that needs to be taken into account is the spoke-diameter as well. On low spoke-count wheels, the spokes have to be larger since each one will be facing higher stress (more spoke-tension needed). The rims also have to be more vertically rigid to spread the loads between the low number of spokes evenly. I've seen people build 16-18 spoke wheels using 2.0mm spokes and those have lasted about 3-4 years. Personally I wouldn't use anything smaller than a 2.5mm diameter spoke for that kind of wheel.

I've built a 18-spoke radial front-wheel from a cheapo commuter 27" wheel using the original non-stainless cadmium-coated spokes and single-section Araya rim... Worked OK, couldn't tell any differences in stiffness, probably because the 27" tyres at 80psi had more flex than the wheels and frame combined. But it certainly wasn't as strong, it tacoed after just 1-year when I rear-ended a parked car... Again, the number of spokes most likely had more to do with the lower-strength than lacing pattern. A 36-hole radial wheel probably would've survived the impact just as well as the original 3x wheel, but it would look too busy with so many radial spokes....

 

[kleng]

Some manufacturers have been successful with radial spoking, I find the dura-wheelset stiff but bullet proof.

http://www.cyclingnews.com/tech.php?id=photos/2004/tech/reviews/shimano_dura-ace_wheels/DSCN1825

http://www.cyclingnews.com/tech.php?id=photos/2004/tech/reviews/shimano_dura-ace_wheels/DSCN1832

http://www.cyclingnews.com/tech.php?id=photos/2004/tech/reviews/shimano_dura-ace_wheels/DSCN1832

 

[Wurm]

Campy's been doing radial-spoked wheels for years, and they're known as some of the toughest wheels out there.

 

[Dietmar]

Some manufacturers have been successful with radial spoking, I find the dura-wheelset stiff but bullet proof.

Notice, however, that the rear wheel is not radially spoked...

 

[Dietmar]

Campy's been doing radial-spoked wheels for years, and they're known as some of the toughest wheels out there.

I find their Eurus wheels very interesting. In a strict sense, because of the sets of three parallel spokes, those wheels are not radially spoked, either. They do look way cool, though... Anybody has any experience with those?

 

[DannoXYZ]

I find their Eurus wheels very interesting. In a strict sense, because of the sets of three parallel spokes, those wheels are not radially spoked, either. They do look way cool, though... Anybody has any experience with those?

That rear wheel is funky... I count 21 spokes!@??? How does that work???

 

[DannoXYZ]

Ok, I figured it out:

The drive-side on the rear has 14 1x spokes. Then the non-drive side has 7 radial spokes. Kinda like my crows-foot lacing on the track wheel above. Just leave off the crossed spokes on one side completely.

 

[Deanster04]

I have noticed that just about every new set of wheels is spoked radially. I assume this is because the spokes can be shorter and, thus, lighter. However, all I have read and heard about wheel building is that radial spoking is bad for this that and the other reasons.
Are spokes and hubs that much stronger that they can now spoke radially, or is this just a fad?

More Sex appeal is about the only definitive statement one can say for radial spoked wheels. I build my own wheels and pretty much stick with Campy hubs, Open Pro Rims, and 32 14/15 spokes. Can't be beat for durability, comfort, ease of repair (don't need special tools to true), reliability and low cost. Of course I have to say that at 225 lbs and a love of fast descents that I really feel safer on the standard 3X lacing pattern. Weight on my Record hub built bikes is more than adaquate for my TiC Dean el Diente. I have found that the ride on most radial spoked wheels "harsh" and I have ridden quite a few different brands (including the high priced spread). For the most part, unless you get up into the very high end wheels radial spoket wheels are pretty heavy relying on a beefy hub and rim (where you DON'T want the Wt).
Tension on radial spoked wheels is much higher than conventional wheels to keep the thing straight. If you are going to use standard or conventional hubs and standard rims intended (sic designed for conventional spoking) you had better be a fly wt. And, you should plan on replacing the hub and rim often (no advantage of cost there). Wheels that are engineered for low spoke count and radial spoking are generally safe but, weight and cost are in a steep inverse relationship.
The only common sence idea I have ever heard expressed is if you are going radial and botique go high end and keep the wheels for race day. Also, use regular conventional wheels for your training and daily use. Nuf said.

 

[hd reynolds]

Which ones?

But it is rare to see a rear wheel that is radially laced. (Although the Mavic Ksyrium is radially laced on the drive side only). Campy makes a radially laced rear wheel, too. But those are rare exceptions.

Bob

Mavic Ks are not radially laced on the drive side - they are radially laced on the non-drive side. Drive sides should and are always crossed laced.

 

[artmichalek]

Mavic Ks are not radially laced on the drive side - they are radially laced on the non-drive side. Drive sides should and are always crossed laced.

No. It's drive side. Same with some of the new Shimano wheels:
http://www.mavic.com/ewb_pages/t/techno_detail_35.php?tec=35

 

[artmichalek]

The drive-side on the rear has 14 1x spokes. Then the non-drive side has 7 radial spokes. Kinda like my crows-foot lacing on the track wheel above. Just leave off the crossed spokes on one side completely.

Great idea in theory, but the span between spoke groups is too big. The tension is so high on the new aluminum spoked version that they had problems with the rim bulging out between spokes on the prototypes. The problem was "solved" by forming the rim into a sort of rouned off heptagon so that when the spokes are tightened up it becomes round. You really do not want to break one of those spokes. If you want to get something similar with off the shelf parts you can go 16 right and 8 left with a 32h hub and a 24h rim. It would have the balanced spoke tension with a more reasonable span between holes.

 

[Dietmar]

The problem was "solved" by forming the rim into a sort of rouned off heptagon so that when the spokes are tightened up it becomes round. You really do not want to break one of those spokes.

Hah, that's the kind of information I was after. Any thoughts on how well those things might hold up? Would it be a stupid idea to replace, say, my trusty standard 36-spokers with a pair of these, and still expect them to last some 10k miles without any major trouble? How about a pair of Mavic Ksyriums?