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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 01-31-09, 09:04 PM   #1
coppertop4646
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Radial Lacing

I want to re lace my rear wheel and radial lace it but I've heard that radial lacing is weaker than traditional lacing so it's not a good idea to have a rear radial laced wheel on a fixed gear....is this true? I don't really skid much because I have brakes so putting extra stress on the wheel isn't really a problem in my case. Also can anyone link me to a video on how to radial lace just so I can see it done before I go do it
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Old 01-31-09, 09:05 PM   #2
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Radial lacing a rear wheel is a bad idea.
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Old 01-31-09, 09:07 PM   #3
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save bet: just donīt
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Old 01-31-09, 09:13 PM   #4
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Just make sure you carry a full wheel worth of extra 3 or 4 cross length spokes and extra hub around.
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Old 01-31-09, 09:14 PM   #5
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Do it!
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Old 01-31-09, 09:21 PM   #6
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You can half-radial a rear wheel on the non-drive side. For drive side, though, racial is a very very bad idea.
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Old 01-31-09, 09:22 PM   #7
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the bob yak trailer has a radial laced rear wheel, and some folks use it on transcontinential expedititions.
my shamal rear wheel is radially laced on one side too...
but donīt do it.
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Old 01-31-09, 09:29 PM   #8
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A trailer wheel can't be compared to a drive wheel.
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Old 01-31-09, 09:41 PM   #9
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i didnīt say it is.
seriously could anyone post a valid link to help the OP.
iīm from germany, i donīt know any helpfull databases...
ignore me...
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Old 01-31-09, 09:45 PM   #10
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Sheldon says:

More and more rear wheels now are built "half-radial" with semi-tangent spoking on the right side and radial spoking on the left. Radial front wheels offer mainly esthetic benefits, but half radial rear wheels can be substantially more durable than conventional ones, in cases where the wheel is highly dished. The high amount of dishing called for to make room for more and more sprockets has caused an increase in spoke breakage on the left side of rear wheels. This is caused by metal fatigue.

A spoked wheel relies on having all of the spokes in constant tension. A highly dished rear wheel starts with very light tension on the left side spokes. The torque of hard pedaling combined with cyclical weight loading can cause the left side "leading" spokes to occasionally go completely slack momentarily.

Repeated cycles of tension and slackness cause these spokes to fatigue at the bends, and ultimately break.

With half-radial spoking, the amount of dish is very slightly less to begin with if you run the radial spokes up along the inside of its flange ("heads out.") In addition, since there are no "leading" spokes, no amount of torque on the hub can reduce the tension on any of the spokes. In fact, if you have an old wheel that has been breaking left side spokes, "half rebuilding" the wheel into a half radial will solve the problem once and for all.

I used to think that this was exotic, cutting edge technology, until I happened to look at a couple of Model A Fords in a local parade. Their wheels were highly dished inward, and were laced in the same half-radial pattern, for the same reason.

Wrong-way Half Radial
Sometimes, rear wheels are spoked half-radial with the radial spokes on the right. This is generally done for reasons of improving derailer clearance, particularly on wheels with unusually thick spokes or unusual flange designs. Such wheels require hubs with greater torsional stiffness since most of the driving torque must then be transferred by the left side spokes.


Seriously, youth of today. Before going to bikeforums.net, go to sheldonbrown.com ... that's how we did it back in the 2000s.
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Old 01-31-09, 10:38 PM   #11
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Sheldon also said that crows foot for rear wheels is good too, and so I did it. Then after a few of the radials broke I rebuilt as a 4x.
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Old 01-31-09, 11:05 PM   #12
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hub brakes, disc brakes, or skid braking puts lots of load on wheel, and thus radial lacing is not the best choice. For example my old ATB had v brakes and the front hub was radial laced from Specialized. My new ATB had Disc Brakes and the front wheel is 3 cross, as the spokes must carry the braking load. With V brakes the spokes don't carry the braking load.
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Old 02-01-09, 01:36 AM   #13
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If you look at the red marks, that is how much metal is between the spoke drilling and edge of the flange.

Notice how much more there is in contact on the cross laced wheel.

Now imagine mashing down on the pedals and where forces are going to go as the hub tries to spin and the tire tries to stick to the ground.... One is much, much stronger.
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Old 02-01-09, 06:29 AM   #14
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Quote:
Originally Posted by peabodypride View Post
You can half-radial a rear wheel on the non-drive side. For drive side, though, racial is a very very bad idea.
A half radial rear wheel only makes sense on a geared bike with a dished rear wheel. Drive side radial isn't necessarily a bad idea, depending on the hub and how the left side is laced. At any rate, don't do this with a FG or SS wheel. Keep it 3x on both sides or 2x for lesser spoke counts. A full radial rear wheel (or any wheel in which the hub is subjected to torque, such as a front wheel with a disc brake) is almost universally considered to be a very bad idea.

On the other hand, radial is fine on the front wheel, as long as you are not using any sort of hub brake. It is not necessarily "weaker" as many people mistakenly claim. Radially laced wheels are lighter (barely), more aero (again, barely), and possibly stiffer both laterally and radially (but probably barely). But they look better to many (subjective), and are easier to build and true. You certainly don't need a video to lace a wheel radially. The "weaker" argument is based on the greater stress that radially projecting spokes exert on the hub flange, although there are lots of hubs out there that are built to withstand radial lacing. If you've got an appropriate hub, there's no reason not to build a radially laced front wheel. Most high flange track hubs are not built specifically for radial lacing, but most are generally able to withstand it. At any rate, I've never heard of one failing under normal riding conditions, other than one single instance of an old Campy hub that is widely circulated on the web.
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Old 02-01-09, 07:38 AM   #15
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if u were a rear weight weenie and rode on the track 24/7 i'd say radial lace non drive side....

but radial lacing a rear wheel would be epic fail if u ask me.
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Old 02-01-09, 09:18 AM   #16
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even on the track there really are no weight advantages to a half radial rear track wheel. the length difference between a radial and a 2x lacing on the same hub and rim is ~10mm for 32h; basically over the course of the wheel you're saving less than the weight of a spoke. we're talking tens of grams— which you could more effectively save, again with the same hub and rim, by using a lightweight tube and/or tire. not only is one likely to save more weight this way, but it's also the furthest radius from the axle.

if it's that important to you to save the weight of a spoke, from the location where spokes typically exist in a wheel, it's more effective to lace up a 24/28h wheelset for track use.
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Old 02-01-09, 03:57 PM   #17
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I can't seem to find the links, but I know of one radial rear wheel having been used on a street bike.

It failed..... bad.

Another guy rode one on the track, he said he could feel the wheel "wind up" when he tried to accelerate... not exactly something you want happening.


But go ahead, be a unique snowflake, stand out from the rest of the crowd, just make sure you have good insurance and realize that out of the millions of rear wheels out there, only a couple are laced full radial, for good reason.
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Old 02-01-09, 09:42 PM   #18
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as sheldon sort of said, spokes have way more stiffness along their axis than they do perpendicular to it. i mean, pull on a spoke. does it deform (stretch)? now push it sideways. sure, they're stiffer under tension...so push a spoke on a built wheel sideways. it still moves a hell of a lot more than it does axially.

that's why radial spoking in the rear is a bad idea.

up front, the primary stresses on the wheel are in line with the spokes. your weight bearing down on the hub, pushing on the spoke(s) at the bottom of the wheel and pulling on the one(s) at the top. even cornering or rocking the bike in a sprint the lateral loads on the rim are still in line with the spokes as they are stretched or compressed. no problem for a radial build.

the same is true in the rear, but there is an additional force...you pedaling and pulling on the chain, trying to spin the hub independently from the rim/tire, which is stuck to the ground. it's a job for the spokes to transfer this force to the rim. a radial lace has the hub pushing on them sideways, just resulting in flex. whereas a crossed lacing places the spokes more or less tangent to the hub flange, aligning the hub's rotational torque with the axis of the spoke. no flex.
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Old 02-02-09, 01:13 AM   #19
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!

Quote:
Originally Posted by dookie View Post
as sheldon sort of said, spokes have way more stiffness along their axis than they do perpendicular to it. i mean, pull on a spoke. does it deform (stretch)? now push it sideways. sure, they're stiffer under tension...so push a spoke on a built wheel sideways. it still moves a hell of a lot more than it does axially.

that's why radial spoking in the rear is a bad idea.

up front, the primary stresses on the wheel are in line with the spokes. your weight bearing down on the hub, pushing on the spoke(s) at the bottom of the wheel and pulling on the one(s) at the top. even cornering or rocking the bike in a sprint the lateral loads on the rim are still in line with the spokes as they are stretched or compressed. no problem for a radial build.

the same is true in the rear, but there is an additional force...you pedaling and pulling on the chain, trying to spin the hub independently from the rim/tire, which is stuck to the ground. it's a job for the spokes to transfer this force to the rim. a radial lace has the hub pushing on them sideways, just resulting in flex. whereas a crossed lacing places the spokes more or less tangent to the hub flange, aligning the hub's rotational torque with the axis of the spoke. no flex.
Being a mechanically inclined person and a mechanical engineering major, I've always understood this clearly, but have never been able to explain it to my friends without getting stuck. Thanks!
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Old 02-02-09, 06:34 AM   #20
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radial lacing a rear wheel is a bad idea.
+1000
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Old 02-02-09, 10:44 AM   #21
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Quote:
Originally Posted by dookie View Post
as sheldon sort of said, spokes have way more stiffness along their axis than they do perpendicular to it. i mean, pull on a spoke. does it deform (stretch)? now push it sideways. sure, they're stiffer under tension...so push a spoke on a built wheel sideways. it still moves a hell of a lot more than it does axially.

that's why radial spoking in the rear is a bad idea.

up front, the primary stresses on the wheel are in line with the spokes. your weight bearing down on the hub, pushing on the spoke(s) at the bottom of the wheel and pulling on the one(s) at the top. even cornering or rocking the bike in a sprint the lateral loads on the rim are still in line with the spokes as they are stretched or compressed. no problem for a radial build.

the same is true in the rear, but there is an additional force...you pedaling and pulling on the chain, trying to spin the hub independently from the rim/tire, which is stuck to the ground. it's a job for the spokes to transfer this force to the rim. a radial lace has the hub pushing on them sideways, just resulting in flex. whereas a crossed lacing places the spokes more or less tangent to the hub flange, aligning the hub's rotational torque with the axis of the spoke. no flex.
mostly true, i just want to clarify a couple things:

spokes function only in tension. a wheelbuild has a certain amount of static pre-tension that keeps it together; riding it applies a range of dynamic tension that depends on rider weight, rim/spoke type, pattern, etc. with a normal build the dynamic tension is absorbed by the elasticity of the system. however, if you break a spoke on a 16-spoke wheel, it's possible for the remaining forces to exceed the capacity of the rest of the system, and then you get overall failure.

a radial laced drive wheel doesn't push spokes sideways, per se; rather it provides leverage for the hub to apply a large dynamic load on the spoke, radically changing its tension with only a small torque. this can fatigue all parts of the system prematurely. conversely, in a cross lacing, there are always a series of spokes that are tangent to those rotational forces and can absorb them without significantly altering their tension. this is sometimes claimed as the reason for high-flange track hubs in the rear— the moment arm between the axle and the spoke drilling is longer, so each spoke has more effective leverage to resist the changing torque of a fixed drivetrain.

but as long as you remember not to radially lace a drive wheel, you'll be ok.
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