cheapracer wrote:
Turning left only has nothing to do with tyre contact patch for a beam as both sides are flat 99% of the time but ironically and totally against your stance it has everything to do with IFS - you can set up the right and left cambers/caster etc. as they do in NASCAR and INDY to get a very good contact patch for only left handers but if you need to turn right as well then it's back to a compromised setup.
Everything is a compromise...But IFS is less compromised than a beam axle when turning
both directions, as well as on the street as noted below. I suppose that your axle might be level to the road, and that this trait might be desirable...IF tires were rigid objects. However, they are not. As load transfers and the tires deflect, the outside tire will compress more than the inside (just like a spring), causing the axle itself to 'camber' the
wrong way. Additionally as the tires deflect, they roll under on to the edge towards the outside of the turn, increasing the 'camber' problem. These are the same problems fought by drivers of poorly designed (from a performance perspective) strut suspended economy cars. So now you camber your solid axle. While an IFS will send
both the inside and outside wheels cambering the
desirable way to at least some degree proportional to the amount of cornering force experienced, the solid axle will now only be cambered in a fixed manner such that only the outside wheel is cambered in the desirable direction. This does not maximize grip. The solid axle can however be setup with both wheels cambered for a singular turn direction only, such that
both wheels are cambered the correct direction. This is precisely why the solid front axle isn't used
anywhere in modern road racing classes, but makes for an easy and effective design on circle track cars like Supermods.
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Again and ironic that some of the shitty handling cars around that I see with wheels in all sorts of awkward angles are based on F1/racing designs and that includes here - I'll post a picture when I get home as an example tonight. The amount of cars that are built on track tech/theory around here and everywhere else rather than building for the real world street is ridiculous. Miniturisation of SCORE designs would probably suit more builders here than F1 designs.
NO BUILDER should base their geometry on pure-bred racing vehicles (Supermodified, F1, SCORE, etc) as they all make compromises specific to their constructed purpose, and within a given set of rules (often prohibiting better solutions) which street cars don't have to adhere to.
That being said: A well setup lesser technology is capable of being as good ,or better, for many purposes than a poorly setup superior technology. That is the case for anything. And yes solid front axles appear to be a fairly simple device to build and setup such that it could make for a fairly decent vehicle right out of the box with somewhat less planning, effort, and design work than an IFS. These attributes could certainly suit
some builders quite well!
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You make a point that beams are well developed for speedway but I counter that for IFS as it was well developed because of bad roads 70 years ago and the IFS gave a far superier ride to heavy cast iron beams - since then of course the car has been totally developed and designed around the IFS but even today it's still a compromised mystery/black art how to get one to work properly where as out of the box a beam will offer 95% of it's potential immediately.
A poorly executed design is a poorly executed design. Period. There are plenty of poorly executed solid axles setups out there too. Big deal. See above comments on the "compromise" a solid axle
must makes for anything other than unidirectional turning. It may offer 95% of
its potential out of the box, but even at 100% potential is not capable of offering similar multidirectional capabilities to a 90% potential IFS...For which the information needed to build is readily available to those willing to put the time and effort into researching it. Admittedly because there are so many variables, it does mean that there is no simple/singular 'best' solution to the IFS geometry, which does make it more challenging to design and a little bit of a black art to dial in.
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And lastly unsprung weight is hugely overated for our needs not that I can't build a beam that isn't lighter than say a standard Toyota suspension package.
Above you mention the superiority of IFS on bad roads, yet ignore the fact that most Locosts are street driven on less than ideal roads. Unsprung weight may be over emphasised by some people, but is certainly
not 'over rated' for our needs either. The lighter the car, the greater of an impact unsprung weight has...And these are some of the lightest cars out there. Sure a custom solid axle sized specifically for the car could be lighter than an IFS using production components from cars 2x-3x the weight. But your argument fails to hold water when you start comparing apples to apples.
I'm not saying that the solid axle is necessarily a bad way to go, depending on the wants and needs of any specific builder...Especially if it's reasonably well executed. But the decision of which path to take should not have to be based on potentially misleading information from either side of the debate.