Autobus

I notice that some lightweight wheel companies construct their wheelsest using radial- lacing instead of cross-lacing.

Advantages /disadvantages to each method?

DrPete 

This is from excel's website--hope it helps:

Autobus

Good man. Thanks!

sogood

Just to throw a spanner into the spokes, Mavic K-ES has radial spokes on the drive side of rear wheel.

kensuf

The new K-Elites do too.

DrPete 

I think the difference is that the Mavic hub is designed specifically for that.

There was also something on excel's site about radial lacing voiding the warranty on some hubs, so it might be worth asking the question before you spend the cash on a wheel build.

cycle17

One other note is that some of the paired spoke type wheels really only cross once instead of 2 or 3 times. The radial and cross mix seems to be becoming more common on the latest model wheels from manufactures as well. Also, My 2006 Race Lites came with mixed spokes on the rear as well. Bladed flanged on the drive side and bladed flangless on the other side.

FormerBMX'er

All my broken spokes have been on the non-drive side. Radial lacing the non-drive side is suppose to eliminate this...according to Sheldon Brown..

jccaclimber

10sp dura ace and some mavic wheels radial the drive side. They do however NOT do the non drive side radial in that case. This is because due to the spoke size (Mavic) or attachment method (Shimano hub nipples) they would have very little dish on the drive side. This is compensated for by passing the torque through the hub and then getting the drive force out to the rim on the non drive side.

waterrockets 

Yeah, radial drive side helps to slightly raise the tension on the non-drive side. The dish is still the same, but if the tensions are more equal, the wheel is stronger. Larger flanges (spoke circle diameter) will also help radial drive spokes to even the tension out more.

skinny

Rear wheel drive side spokes are generally built in a crossing pattern because of something called wrap up, which is the effect created when you torque the rear wheel by stepping on the pedals and of course by applying the brakes(on the front also). When spokes are crossed over each other, they leave the hub in a tangenital direction, or in the direction that the torque is applied, delivering the force from the hub to the rim with a minimum of hub/spoke wrap up. Wrap up is obviously wasted force, so the elimination of it is a desirable thing. The more crosses, the more tangenital the spokes are to the hubs, but the increasing efficiency is offset by the increase in the length of the spokes which produces more flex and more weight. So...drive side spokes in a traditional wheel that is built for lightweight, hill climbing or time trialing applications are usually built drive side 2x, radial on the flip side.

An example of a very light climbing wheel from back in the day might be an Omas or hi-e hub with ti axles and ti skewers with aluminum q/r nuts, Super Champion Medaille d' Or rims(260gr ea.!), and 15 straight guage spokes, 24-28 radial frt, 28-32 2x/radial rear. In more recent applications, rims, spokes, and hub flanges are being built heavier or thicker to withstand the use of fewer spokes, ergo they are also able to build drive side radial, since heavier or thicker = less flex and less wrap up. In some hubs now, all the spokes leave the hubs in a tangenital direction without a spoke head in a spoke hole, which also eliminates wrap up. Most wheels with nipples in the hub are built this way, and all hubs which take spokes that have no bend at the spoke head are like this, so wrap up is completely eliminated, eliminating the need for crossing. Larger drive side flanges do even out tension and tangenital spokes do eliminate wrap up. These are well established principles of wheel building. All the various wheels on the market are different applications of these fundamental principles.

This is why you don't see a traditional style rim like the Mavic Open Pro used in the low spoke count, radially spoked wheels. They are too light. Also, Campagnolo Record hubs are still not warrantied for radial use, since they are a traditional hub with traditional flange thickness. A radially spoked wheel built to tight on these hubs can pull the flanges right off. Of course some of us know how tight to build them but..., don't try this at home.

DrPete 

It's funny how many theories there are about this. My wheels (Fulcrum Racing 1) have 2-cross drive side and radial non-drive, with a bigger flange on the drive side. Other manufacturers claim to be able to even the tension by making the non-drive flange bigger. So much confusion.

Yet more evidence that I should leave the wheel building to others, and I'll stick to taking out gallbladders.

Phantoj

Radial lacing puts the stress on the spoke holes in the hub in a radial (not tangential) direction; they are less strong in this direction, so the hub must be up to the task.

waterrockets 

skinny First off, you've got a lot of great summaries in your post, but a couple points...

It's not wasted, almost all of it gets returned as torque decreases (every pedal stroke). It's most desirable to eliminate because of spoke fatigue. You want as close to a static structure as possible for a durable wheel, so I agree that it's important to eliminate wrap up.

Well, any wire departing the hub radially cannot apply torque to the rim regardless of spoke hole orientation. The wires are just too flexible. If you go radial on both sides, the spokes are only radial when no power is applied. Once the rider applies power, the hub will wind up until the spokes are tangential enough to transfer the torque to the rim. With straight-pull spokes, you can increase the tension enough that this windup is minimized, but it still has to occur, as the thin wire spokes do not have the stiffness to drive the rim.

I believe I've seen rear wheels that appear to be radial both sides, because there are no crossings, but IIRC, the spokes are off of radial slightly to provide torque. I can't remember which wheels I was looking at though

skinny

Well, thank you!

Actually, a wheel as a static structure is only desirable if you have other suspension systems built into the mechanism, as a car does with springs and shocks. The wheel functions as part of the suspension system, which is why solid disc wheels have very limited application in cycling. And unlike the frame, the spokes do not return torque since they are loose in their spoke holes at the hub, the rim, or both. While a frame tube can return torque when it returns to it's original shape, a spoke's movement in the spoke hole dissipates this return. Now if you have one continuous spoke threaded through the hub and rim like I think one manufacturer does, then you could make the argument for a return of torque.

True, the wire cannot apply torque unless it is pulling the rim or leaving the hub tangenitally to the rear, and then it is technically transfering torque. This is why most hubs today have flanges that facilitate the spoke exiting the flange tangenitally to the rear, and also to the front for the transfer of braking torque.

Here is were the inefficiency occurs.

And this is the design conundrum that all manufacturers address in different ways. If you increase the tension to much on to light equipment, you run the risk of component failure. So in the past few years, parts were redesigned, flanges shaped differently and made thicker, rims have deeper cross sections and are heavier, spokes are thicker and leave the rim and attach to the hub. Some alter flange design, some increase the weight of the rim, some offset rim spoke holes, on and on. The bottom line is the elimination of inefficiency in the wheel, while still providing some shock absorption/suspension.

entukay

You guys forgot to mention...


Radial lacing is just plain sexy.

DrPete 

+1!

My front wheel:

waterrockets 

Our shock absorbtion is in the tires. All well-made bicycle wheels are effectively rigid within the plane of the wheel. You can't detect the minimal deformation from the saddle.

Mostly solid disks have a limited application because of crosswinds.

There are two types of torque in play here. One is to the wheel as a system, resulting in the rim turning. The other type of torque is applied laterally to a thin wire spoke. Thin wire spokes do not have the ability to provide off-axis torque -- even if you welded them to the hub flange. They will just flop around with lateral forces applied to them. For a demonstration, clamp a spoke head firmly in a vise, so it sits out horizontally. Get a light weight, and hang it on the spoke. Measure the deflection, then extrapolate to a rider sprinting at 1200W, divided by 20 spokes (common rear count).

For hub torque to transfer to the rim using wire spokes, it can only happen through spoke tension. The spokes have to be off-radial and pull the rim through. If the spokes are all radial when the wheel is built, they will no longer be radial under power.

Don't forget the fact that they have to have a marketing angle too! Marketing has been screwing up sensible engineering for centuries

skinny

True, tires are another component of shock absorption/suspension, but, I know you probably won't believe me when I tell you this, but I can tell the difference in shock absorption between a 4x and 3x wheel, at least if I build both wheels to my standards. No wheel is entirely rigid in the plane of the wheel, no matter the design, just as no structure is entirely rigid. Flex is an inherent characteristic of any structure. All well made bicycle wheels take this into account and exploit it to enhance the characteristics the wheels are being built for.

The lateral forces or off-axis forces as you call them are relevant, but as knowledge of the way wheels work as grown, it has become clearer that lateral forces, or the forces you would encounter in a turn, are less signifcant than the power forces, pedaling, in whether a wheel is designed with radial or cross spoking. It used to be thought that 4x wheels were stronger because their x was extended out more towards the center of the wheel, effectively transfering lateral forces more through the wheel, adding strength. This is true to an extend, especially when cornering, but the majority of torque/energy lost in a wheel is lost through wrap up.

Es Verdad.



Agree here also. Evidence the new wheels on the new Specialized bike I saw a photo of somewhere. Can someone put a shot of that monstrosity up?

bbattle

This thread is useless without pictures:

Shimano's lateral crossover pattern








Lacing info




How this shows up in the Google search for bicycle wheels is anybody's guess

bbattle

Roval's Super Freak wheels



Our seamless FACT full carbon Mid-V clincher blends exceptional weight with a smooth, vibration-damping ride and confidence inspiring lateral rigidity. Its 33mm profile offers exceptional aerodynamics, and ideal race-day performance.
Star Hubs - Our aerodynamically superior star hub design yields 50%less frontal area than a traditional hub, reducing wind drag significantly. Wind tunnel testing has shown Star wheels to be faster than tri-spoke aero wheels, while still performing well in cross winds.
The Roval Hidden Nipples utilize a 3-piece design to improve nipple alignment, reducing spoke fatigue and improving wheel durability. Our exclusive larger diameter nipple design distributes the loads across a wider surface area for further improvements to strength and reliability.
Custom DT Swiss stainless steel spokes are aerodynamically shaped for superior performance over thicker alloy spokes, while the straight-pull design improves reliability.
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waterrockets 

If you can feel it, then you're a lot more sensitive than me I know it's there, but I've never been able to feel, even on the same course, same day, same bike, same tires/pressure, and four vastly different wheelsets. I'm insensitive

I see our disconnect here. I'm not talking about lateral forces to the wheel, I'm talking about lateral forces to a spoke. You were saying that the spokes work like rods to move the rim around, but I'm saying that spokes are not stiff enough to move a rim around, they can only pull the rim around under tension -- off-radial tension.

Say you have a wheel completely laced up, then unlace one spoke, but thread it back into its nipple, so it's not attached to the hub. Get a pair of vice grips and lock onto the spoke head. Try making the wheel spin by just twisting the vice grips. You have to follow the wheel around as it turns, so the spoke remains radial (points to the axle center). If you try any acceleration worthy of an actual ride, you will twist a hook or spiral into the spoke before the wheel even gets halfway around.

skinny

I agree with this. No matter what it may have seemed I said , I meant to communicate this idea. Spokes transmit torque, either braking or pedal, through a pulling force.

Those Roval hubs are the funky ones I was thinking of that I saw on the Specialized.

Autobus

Gawd ...my brain hurts! Thanks guys

sogood

You'll get sick of that soon enough!