given that spokes are alive and well on bicycles I have to ask why they are gone from the car wheels.
motorcycles held a little longer than cars it seems, but spokes are long gone in standard, touring and sport triangle (not sure if harley and wannabes have them or not)
so, was it the looks alone the killed them or stamped steel rims have some inherent advantages over them aside from being possibly cheaper to produce and require much less if any maintenance, esp when potholes come into the picture ?
AD wrote in news:8e72d479-bc97-4c06-aa97- snipped-for-privacy@k3g2000vbn.googlegroups.com:
Solid disc wheels are
1) stronger
2) cheaper
3) simpler than spoke wheels.
But spoked wheels are lighter than solid wheels, which is to the advantage of bicycles. Bicycles do not generate the sorts of cornering side-forces on their wheels that cars do; spoked wheels cannot handle side-forces as well as solid disc wheels do, but that's not important for bicycles.
Mag spoke wheels are a modern wire spoke replacement. They don't need periodic truing, can handle side forces, and are lighter. Stamped steel wheels are rare and mainly found on inexpensive cars (like my Kia). Wire spokes were ok back in the 1930's but are not suited to todays needs. Bicycles rarely go over 60 mph for extended distances.
tegger's thinking right, but not saying it right. cornering force on a car wheel are normal to the wheel plane. those forces on a bike are in the wheel plane. [and the vector sum of gravity and the lateral force gives the angle of lean.]
to your original question, the reason is twofold:
initial cost.
maintenance.
re #1, it takes time to build a spoked wheel. they can be assembled and largely tensioned and trued by machine, but they need to be finished by hand. stamped steel or cast aluminum wheels need no manual intervention. in addition, spoked wheels can be vary unreliable unless spoke material quality is high. this again is a prohibitive cost for most car manufacturers.
re #2, training someone to build a spoked wheel isn't that hard. getting them to true it [kinda] isn't that hard either. but getting them to true it in a way where it'll /stay/ true in use is much much harder, and if it needs re-truing, it's nigh-on impossible.
based on my experience of bicycle wheels, i'd say fewer than 1% of wheel builders have the skill to true a wheel so that it stays true from new, and maybe 10% of that 1% know how to correct a wheel that has become untrue so that it doesn't happen again.
bottom line, spoked wheels are fabulous mechanical structures - few others can support 100x their own weight - but they're a pita for someone making an appliance that just needs to work. and that is the car or modern motorcycle. the high end bicycle crowd pay through the nose for their wheel service, and most car owners wouldn't put up with that.
Having driven both, car wheels in pressed steel are stiffer, lighter and much less trouble overall than spoked wheels. Not to mention tubeless!
Bicycle wheels have proportional diameter/width differences and severe weight constraints which are not relevant to motor vehicles.
Splined 'spinner' hubs are cool but one gets past that.
Aluminum wheels in modern alloys are just clearly superior in almost every case[1] but the principle was established well in steel many years ago.
[1] Yeah, everybody can cite one failure or another, especially if we go back to the brittle products of the
1960s, but run a set of wire wheels for a few years and the concept will be clear.
it's not impossible at all, but it's something you need to do carefully and in the right way. like playing a guitar, anybody can thump out the notes in roughly the right order, but to make it sound good is a whole different story.
Actually, listening to the pitch of a plucked spoke is a useful activity when working on a bicycle wheel. ASSuming that you're working on a wheel where all the spokes are the same length (not always a good assumption, but in a standard cross-3 front wheel they are; on a standard cross-3 rear wheel that has a dish to it one side will be shorter than the other but all the spokes on a given side of the hub should be the same length) if they are the same pitch then they are at the same tension. You don't necessarily know what it *is,* but you know it's even.
but even learning was far from a clear path. there are several books on the subject. some focus on an artisinal approach. but one purports to have an engineering approach - and contains some jaw-dropping technical errors.
imo, the easiest method introduction is this:
but don't use his "stress relief" method - use the one recommended by the wheel manufacturing industry's leader, mavic, i.e. pressing the hub against a block of wood and leaning on opposite edges of the rim. it raises spoke tension geometrically as per natural usage, and it doesn't introduce nics or fatigue initiators into the spokes.
wire pitch is not just length, it's also tension and mass. yes, the spokes of each side should be even in the first analysis, but when closing in on a final tension/true, since no rim is perfectly round, there has to be slight variances in pitch to make it so. the art is to make those variances in tune so that no spoke has a tension above one level and none have it below the rim manufacturer's recommended minimum.
average wheel tension should be set with a tensiometer. they're cheap and easy to get, and they allow you to build long-term reliable wheels without rim buckling, rim cracking or spoke fatigue - the three common results of mistakes commonly made.
Cops seem to prefer stamped steel wheels to alloy. Their failure mode is to bend rather than crack. This allows continued (albeit somewhen wobbly) operation in a pursuit, for example.
True, but I was assuming same gauge spokes as well. (I'm certain there has to be an oddball wheel that uses spokes that are the same length but different gauges, but I can't think of why that would be a good idea.)
Agreed and agreed... just found it odd that you used the guitar analogy and that when I've had to true a wheel I find myself plucking a lot.
I would say that the more even you can get the tension in the final wheel - and I know it's not going to be perfectly even unless you started with an exceptionally perfect rim - the longer it'll stay true. Or in other words, if you have two wheels that are both reasonably true but one has far more variation in tension between the spokes, I would bet on that wheel going out of true far sooner than the one with relatively even tension.
I dunno about the late model Impalas and Vickys, but the steel wheels used on the old MoPar cop cars are a lot thicker gauge metal than other steel wheels I've seen. I got a set for my '55 Studebaker because they're the perfect width and offset for using wide modern tires on said car without rubbing and they look cool too (and I had thoughts about adapting '55 dog dishes to the MoPar wheels, but never bothered to spend the time with a die grinder to make the slots for the clips) and they are astonishingly heavy. So I'm not sure how "springy" they are.
I bet they have to be trued a lot less often than the 24's that I saw on a Dodge Magnum yesterday...
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.