[adasisthefuture]

There is hardly any discussion on this anywhere on the internet.

Every premium car and for that matter every top of the line model of a mid range car comes with alloy wheels. It is well settled now that alloys are much weaker in strength compared to steel wheels. However, how important role the number of spokes in an alloy plays with regard to the strength and durability of the alloy is debatable.

The spokes play an important role with regard to connecting the rim to the plate and therefore it is highly debatable whether more the number of spokes would result in a stronger alloy.

Spokes in an alloy range from three to more than ten. Could it be said that alloy with merely three spokes is as strong as an alloy with 10 spokes in terms of giving overall support to the RIM?

Also, whether an alloy with more spokes better in handling the impacts of pothole ridden Indian roads compared to ones with lesser spokes ?

Further, it would be interesting to study the implications of number of spokes in low vs high profile tyres.

Views and real life experiences of knowledgable members of this forum are requested.

[PaddleShifter]

Strength of an alloy wheel depends on a variety of factors:
1. Forged vs cast wheels- forged are considered better.

2. Design- see this thread/post regarding Mahindra floral design alloys breaking. The post linked below highlights a potential design flaw. The discussion concludes that a particular batch was defective rather than the design.
https://www.team-bhp.com/forum/road-...ml#post3663209 (XUV500 safety issue: Weak alloy wheels. EDIT: Mahindra starts silent recall!)
I have seen SUVs with aftermarket 5 spoke alloys doing fine whereas this Mahindra alloys were breaking off completely.

3. Profile: low profile tyres will put more stress on the alloy wheels.

More spokes will make an alloy heavier that will affect their performance so the spokes on alloys need to be thinner as their number increases. e.g. the horseshoe design alloys from a FIAT Punto weight as much as 1.5 times compared to a steel rim of same size (15”) from Linea (Punto had 14” steel rims so comparing with Linea steel rims).

[SmartCat]

I think it is like slices of Pizza. Whether you have 3 slices or 8 slices, the overall portion remains the same - it is just that the individual slices are smaller/bigger.



Similarly, when it comes to alloys, 5 spoke alloys will have wider spokes and 8 spoke or 12 spoke alloys will have slimmer spokes, but the total amount of metal alloy in the spokes will be near equal (for same manufacturer/wheel size/quality models).

[condor]

in my not educated opinion, I prefer a larger PCD wheel - the spokes will be shorter, and the overall stress on all components will be better distributed.

[turbo]

Originally Posted by SmartCat

Similarly, when it comes to alloys, 5 spoke alloys will have wider spokes and 8 spoke or 12 spoke alloys will have slimmer spokes, but the total amount of metal alloy in the spokes will be near equal (for same manufacturer/wheel size/quality models).

So what you're saying is: All three of the following are as strong as each other.

[SmartCat]

Originally Posted by turbo

So what you're saying is: All three of the following are as strong as each other.

For the pizza logic to hold, all three examples:

- Should be made by the same manufacturer
- Should have the same wheel size
- Should have the exact same alloy composition

The last one is always an unknown. You can't figure this out by looking at the brochure or marketing material. Both can be marketed as "magnesium alloy", but it might have other elements like nickel/aluminum etc and that % might be different for each model.

So the Pizza example just gives a theoretical Material Science point of view

[turbo]

Originally Posted by SmartCat

For the pizza logic to hold, all three examples:

- Should be made by the same manufacturer
- Should have the same wheel size
- Should have the exact same alloy composition (now this is always an unknown, you can't figure this out looking at the pics)

In this case 1 and 2 are a ✅

The third part, if you can't figure it out, what's the point?
AFAIK, no manufacturer mentions their alloy composition, atleast not the affordable ones.

[alexpaul]

I can't figure out the pizza theory mentioned above, but if you look at simpler logic of adding sticks(see spokes) to a tyre made of same manufacturer, tyre with higher number of sticks will have higher weight and have better support to overall circumference than with the tyre with three number of sticks. Guess this is true with metal objects. Yes stick size will vary but support will be higher for higher number of spokes

[dhanushs]

Originally Posted by adasisthefuture

...It is well settled now that alloys are much weaker in strength compared to steel wheels. However, how important role the number of spokes in an alloy plays with regard to the strength and durability of the alloy is debatable.

..

Before commenting on the matter, I would like to understand in what context this question arises. Is this a complaint on some particular design/alloy/steel wheel or is it for general understanding.

One thing I'd like to highlight is that, for a wheel design, aesthetics comes after fulfilling some basic functional requirements. So, whatever be the design, 3 spoke or 10 spoke, the designer needs to make sure it is capable of fulfilling its functional intent.

So, in a way, design will depend on the functional intent of the wheel .

[v1p3r]

Originally Posted by adasisthefuture

It is well settled now that alloys are much weaker in strength compared to steel wheels. However, how important role the number of spokes in an alloy plays with regard to the strength and durability of the alloy is debatable.

How is this well settled? The opposite is true - alloys are far stronger than pressed steel wheels, ceteris paribus.

This whole question is a non issue. There is no relationship between the two that you can empirically state. Each alloy wheel is designed based on use, load factors, and metallurgical composition. Each such design will undergo rigorous FEA, followed by both destructive and non-destructive testing. Without this, there is no DoT or JIL or DIN certification possible. All things being considered, an alloy wheel is ALWAYS going to be better than a pressed steel wheel.

Source: automotive and motorsport engineer with real world experience.

[adasisthefuture]

Originally Posted by dhanushs

Before commenting on the matter, I would like to understand in what context this question arises. Is this a complaint on some particular design/alloy/steel wheel or is it for general understanding .

This is for general understanding.

[TN13Sleeper]

Originally Posted by dhanushs

So, whatever be the design, 3 spoke or 10 spoke, the designer needs to make sure it is capable of fulfilling its functional intent.

Originally Posted by v1p3r

This whole question is a non issue. There is no relationship between the two that you can empirically state. Each alloy wheel is designed based on use, load factors, and metallurgical composition. Each such design will undergo rigorous FEA, followed by both destructive and non-destructive testing. Without this, there is no DoT or JIL or DIN certification possible.

Source: automotive and motorsport engineer with real world experience.

Most people are quite aware that irrespective of alloy design, they have to meet the minimum functional requirements.

I would suggest the original poster to include the term "Factor of Safety" in his initial post/question.

I assume that he wants to know whether an alloy with more dense spokes would have a higher "Factor of Safety" vis a vis an alloy with fewer dense spoke design. (While arbitrarily assuming metallurgy to be nearly similar)

[Raghu M]

But isn't the pizza theory not applicable to the old story about breaking sticks one by one rather than a bundle together? The more the spokes, the weaker the wheel, the lesser (with the right weight proportions around), the stronger. This is not by any chance an educated guess, but just a theory drawn from the moral of that story!

[Dr.AD]

Originally Posted by adasisthefuture

There is hardly any discussion on this anywhere on the internet.

For a good reason that merely the number of spokes in an alloy wheels has no direct bearing on the strength of the wheels. The strength of the wheels is a complex function of many parameters, and the number of wheels is not the primary one. So there is really nothing to discuss here.

It is well settled now that alloys are much weaker in strength compared to steel wheels.

I do not think this is true. In fact, the opposite is true. Alloy wheels can be designed to be very strong. Not necessarily every alloy wheel ever made is always very strong, but in theory, by use of right material composition, right design and right manufacturing techniques, the alloy wheels can be made much stronger than steel wheels. That is in fact the whole point of alloy wheels. The aesthetics is secondary.

The spokes play an important role with regard to connecting the rim to the plate and therefore it is highly debatable whether more the number of spokes would result in a stronger alloy.

Again not true. The number of spokes in the alloy wheel would dictate the strength of the wheel only if every spoke was exactly identical (of identical size, identical material composition, and identical manufacturing technique) and other than the spoke, every other aspect of the wheel (design, dimensions, material properties, manufacturing techniques etc) was identical. If all of these things were exactly identical, then more number of spokes could mean more strength (even this needs to be checked with more detailed analysis, especial dynamics and related simulations, and can not merely be judged without a deeper calculation; optimal strength of an element comes form a fine balance between the amount of material, its rigidity or flexibility, dimensions, load patterns and load frequencies, and the combined dynamics of all these factors). Maybe in your mind you are assuming this oversimplified wheel design. But this is not the case in any real wheel design.

Could it be said that alloy with merely three spokes is as strong as an alloy with 10 spokes in terms of giving overall support to the RIM?

No, one can not say anything about the strength of wheel merely by the number of spokes. 3 spokes is not better than 10 spokes and 10 spokes is not better than 3 spokes. There is just no correlation. The entire alloy wheel design matters and not just the number of spokes.

One can design an alloy wheel with 3 very strong and big spokes which overall hold more strength than 10 tiny and poorly designed spokes. And vice versa. The strength of a mechanical element is a complex function of many factors including the dimensions, the volumes, the material properties, the manufacturing processes, the surface finish etc. There is absolutely no correlation between just the number of spokes in a wheel with the strength of the wheel, because all these factors come into play.

[adasisthefuture]

Originally Posted by Dr.AD

I do not think this is true. In fact, the opposite is true. Alloy wheels can be designed to be very strong. Not necessarily every alloy wheel ever made is always very strong, but in theory, by use of right material composition, right design and right manufacturing techniques, the alloy wheels can be made much stronger than steel wheels. That is in fact the whole point of alloy wheels. The aesthetics is secondary.

Originally Posted by v1p3r

How is this well settled? The opposite is true - alloys are far stronger than pressed steel wheels, ceteris paribus.


Source: automotive and motorsport engineer with real world experience.

There are a lot of articles on the Internet from reliable sources which have stated that Steel Wheels are stronger than Alloys. A few links are given below for ready reference. Contents of the articles cited are Self Explanatory.

https://www.thedrive.com/cars-101/41...heel-materials

https://www.tyremarket.com/tyremantr...-steel-wheels/

https://tyres.cardekho.com/news/allo...hich-is-better

https://carorbis.com/blog/steel-whee...f-alloy-wheels

https://gomechanic.in/blog/alloy-wheel-vs-steel-wheel/

There are many more such articles concluding that Steel Rims are stronger than Alloys but I do not want to burden the record by citing all of them. Accordingly, I reiterate that this aspect is well settled. I would however like to see an article which argues to the contrary and I request learned members to post one.