Re: Wheels and Tyres (or 'Tires' if you prefer...)

[FB]

To quote myself in the ASk the Apex thread:

One reason for F1 using 13" wheels is because the rim is heavier than rubber so a smaller wheel makes lighter wheel/tyre combo. This would help the designers with their weight distribution and, I would presume, allow them to make the suspension units lighter as they have to support less weight. A heavier wheel/tyre would also increase the stress on the drive shafts & gear box. I found a thread which estimated the increase in weight of going to 18" rims as being as much as 33KG - about 5% of the weight of an F1 car.

 

[RickD]

Would there also be a higher chance of failures with low profiles? It seems that in all other formulas that do use low profiles, there seems to be a high chance of failure in the walls of the tyres, especially on the faster circuits. Could this be a reason for not going with them as a failure of the rim around somewhere like Turn 8 wouldn't be a good thing for the 'sport'.

 

[Brogan]

Well with higher sidewalls there is much more flex and therefore much more chance of a tyre coming off the rim.

I would have thought a lower profile would handle this a lot better.

 

[sportsman]

Brogan.You have actually hit the nail on the head.The flex in the sidewalls amounts to 80% of an F1 cars suspension movement.
Low profile tyres would provide far greater stability and better cornering speeds
To use them would require a complete suspension redesign as the the suspension movement would need to less rigid than at present.
There is also the matter of F1 cars bouncing over the curbs as a matter of course.Low profile tyres would not take kindly to that sort of treatment so that would need addressing by the drivers.
Then of course you will get the "dinosaurs" complaining that "they don't look right".

 

[Chad Stewarthill]

There is also the matter of F1 cars bouncing over the curbs as a matter of course.Low profile tyres would not take kindly to that sort of treatment so that would need addressing by the drivers.

A major benefit to fitting them, perhaps. Then the drivers might be more inclined to keep within the track limits.

 

[Brogan]

Then of course you will get the "dinosaurs" complaining that "they don't look right".

They would definitely take some getting used to

 

[Tacitus]

"a plan to increase wheel diameter from 13 inches to 18 inches has been delayed until at least 2014"
Looks like we'll have to wait a little while longer
news.bbc.co.uk/sport1/hi/formula_one/13412925.stm

 

[RevMaxPower]

I guess we'll have to wait for the "Big Wheels" in F1 to make their minds up...

 

[sportsman]

I guess we'll have to wait for the "Big Wheels" in F1 to make their minds up...

I like that.
Seriously though I can see them going to 15 inch as an interim measure.

 

[Fenderman]

Couple of points re. the technical issues of low profile vs fat spludgy things.

As well as the weight advantage the conventional F1 tyre supplements the suspension systems as an additional shock absorber and enables the race engineer to tweak the softness/stiffness of the car via changes in tyre pressures.

The weight difference of the two types of wheel and tyre is not a factor on the load on a cars suspension, since wheels, tyres and brake assemblies are unsprung parts of the car (unlike chassis, engine, running gear and body). However, it is a relevant factor in terms of the overall distribution of weight throughout the car.

Therefore the advantage of going to low profile tyres is that parts of the car (located above a reference plane drawn across the top of the tyres) could be lightened whilst the extra weight of the low profile tyre/wheel arrangement could be used to lower the centre of gravity of the car - thus improving road holding. There would also be an effect from spreading mass across the overall width of the car, although I'm not sure if that's a good or bad thing (I'll have to think about that).

The downside is the need to compensate for the lack of suspension provided by the low profile tyre. This would need redesign of suspension components such as torsion bars and dampers to compensate for the need to increase suspension travel and adjustability.

The other loss would be the lateral suspension effects conferred by the tyres ability to deform on cornering, which as Sportsman notes helps deal with shocks from clipping kerbs.

As in all things F1, it's a case of weighing up (excuse the pun) the pro's and con's and probably making some compromises along the way.

 

[snowy]

Pimp my F1.

 

[Chad Stewarthill]

To be honest, it's not just Formula 1 anyway that we're talking about. It's also GP2, GP3, F3, F2, Formula Renault 3.5, Formula Renault 2.0, Formula Ford, etc. etc. that use 13" rims, presumably for all the above quoted reasons of weight distribution, use as secondary 'suspension' etc. (as well as out of habit). Even Indy cars, the only single seater series I can currently think of that have larger wheels only use 15" rims, not 18". It would seem to me that it's only the closed-wheel formulae that use really low profile tyres. So does anyone know of any open wheel single-seater series where they currently use wheels with a rim diameter larger than 15"?

 

[sportsman]

As far as I am aware the only open wheels series that use 15 inch wheels is as you say Indycar.
But the reason for that is all of the other series you mention are FIA specifications.Indycar isn't.
The logic in this is that all of the other series are tailored to acclimatise the drivers who progress to F1 do not have to adapt to a very different type of tyre characteristic.