F1 question for you

[Tony]

Road going supercars have ultra-low sidewall tyres for improved handling etc, so why is it F1 cars run tyres with high sidewalls

[parthiban]

They're totally custom made tyres though so the tyre walls will be the same stiffness if not more.

 

There was talk earlier this year with the change of tyre manufacturer for next year and in the interests of saving costs to change to 18" wheels - that way the tyres would be closer to road and other race tyres and would make them easier and cheaper to develop.

 

That's been scrapped though so they're sticking with 13".

[liner33]

To generate heat i thought

 

I guess the fact they only weigh a fraction of a road going car comes into it as well , i always knew they were light but didnt know they were only 620kgs including driver and fuel

 

The cars on their own weigh little more than 400kgs

[Tony]

Heat is generated by rubber compound, the inflation used in F1 is a very complicated nitrogen ( secrete ) mix, this still doesn't explain the sidewall aspect ratio..... I have my own ideas, but i wonder what you peeps think?

[liner33]

Heat is generated by friction higher sidewalls = more flex= more friction = more heat

 

I agree the compound is key but the heat isnt created due to construction it needs the car to generate the friction

 

Nitrogen is used (AS i understand it )

 

1) Its a dry gas so no moisture is present and moisture reacts with temperature and will increase the tyre pressure unpredictably

2) Its inert so safer than using oxygen which would do the same

3) Its hold pressure longer than air

[parthiban]

There may actually be no reason for it whatsoever except that it's in the rules! If there was one though I'd imagine weight would be a key factor?

 

Also the tyre does constitute the majority of the suspension travel on an F1 car - although not sure if that's the cause or effect of having such high sidewalls.

[hms]

Also the tyre does constitute the majority of the suspension travel on an F1 car - although not sure if that's the cause or effect of having such high sidewalls.

 

Thats my guess (uninformed) as well.

h

[dazz33]

I would say its to do with "unsprung weight" also the cars run virtually no movement in the springs on F1 cars so the tyres sidewall takes care of the flex over kerbs and bumps/compressed surfaces..?

[liner33]

If the tyres were designed to flex that much they would be totally flat at 200mph on a straight due to downforce the suspension is hard but does move to absorb bumps , kerbs etc , it doesnt compare to road cars of course but circuits are much much smoother

[hms]

At the speed F1 goes at the tyres enlarge due to centripetal force.

h

[liner33]

Dragsters do but they have soft sidewalls the cars are set to exploit this growth as an extra gear

 

If F1 cars did grow significantly at say 200mph then the ground effects would alter unpredictably as this happened making the cars unstable ie higher speed would mean less downforce it would be impossible to set a car up

[Tony]

Some great offerings coming to this topic.... keep em coming because i don't think we have hit the nail yet.

[hms]

Some great offerings coming to this topic.... keep em coming because i don't think we have hit the nail yet.

 

Is that a cue for a run flat joke?

h

[CIH]

F1 cars have very small brakes too. IIRC they fit under 13" wheels.

[parthiban]

This is an interesting topic, do you know the answer Tony or is this to find it?

 

At the end of the day the wheels are this size because that's what the regulations dictate, it would be interesting to know whether the regulations have just stayed from a time when wheels this size were normal or whether there is a reason for them being this size.

[liner33]

This is an interesting topic, do you know the answer Tony or is this to find it?

 

At the end of the day the wheels are this size because that's what the regulations dictate, it would be interesting to know whether the regulations have just stayed from a time when wheels this size were normal or whether there is a reason for them being this size.

 

 

CIH covered the reason for 13" wheels above , ie to limit the braking given the choice F1 teams would not run 13" wheels and tyres for sure but its in the rules and thats that

[CIH]

This is an interesting topic, do you know the answer Tony or is this to find it?

 

At the end of the day the wheels are this size because that's what the regulations dictate, it would be interesting to know whether the regulations have just stayed from a time when wheels this size were normal or whether there is a reason for them being this size.

 

 

CIH covered the reason for 13" wheels above , ie to limit the braking given the choice F1 teams would not run 13" wheels and tyres for sure but its in the rules and thats that

 

it is ? lol I didn't know that.

[Tony]

This is an interesting topic, do you know the answer Tony or is this to find it?

 

At the end of the day the wheels are this size because that's what the regulations dictate, it would be interesting to know whether the regulations have just stayed from a time when wheels this size were normal or whether there is a reason for them being this size.

 

Conclusivally i don't know the answer, i have some logical ideas but these are just my thoughts.

 

I'm aware the tyre width/ aspect ratio and compound are regulated within the rules but.... and that was the question, why is the aspect ratio so detached from the modern cars super low profile tyres?

[parthiban]

CIH covered the reason for 13" wheels above

Errr, where exactly?

 

 

Been reading around this a bit and it doesn't seem there is any actual reason. In fact I've read in a few places that lower profile tyres would actually provide more grip than they currently have (which isn't necessarily a bad thing, more mechanical grip could mean more overtaking)

 

I think the main reason for not changing things is that the cars would need a technical overhaul - more weight means more strain on the gearbox. Less tyre means the suspension will need to be redesigned to allow more travel. And the list goes on........

[liner33]

Post above yours

"F1 cars have very small brakes too. IIRC they fit under 13" wheels."

 

There is an interview with Mike Gascoyne on the net where he discusses the wheel sizes and the fact the 13" rule limits brake disc sizes and that given the choice they would run larger wheels and lower profile tyres

[parthiban]

Post above yours

"F1 cars have very small brakes too. IIRC they fit under 13" wheels."

 

There is an interview with Mike Gascoyne on the net where he discusses the wheel sizes and the fact the 13" rule limits brake disc sizes and that given the choice they would run larger wheels and lower profile tyres

That doesn't explain why though, just states the fact. If you have 13" wheels then the brakes obviously have to be smaller than that.

 

There is no information as to "why" relating to either of those dimensions though. If anything having larger wheels with lower profile tyres would provide a greater advantage than larger brakes.

[liner33]

Post above yours

"F1 cars have very small brakes too. IIRC they fit under 13" wheels."

 

There is an interview with Mike Gascoyne on the net where he discusses the wheel sizes and the fact the 13" rule limits brake disc sizes and that given the choice they would run larger wheels and lower profile tyres

That doesn't explain why though, just states the fact. If you have 13" wheels then the brakes obviously have to be smaller than that.

 

There is no information as to "why" relating to either of those dimensions though. If anything having larger wheels with lower profile tyres would provide a greater advantage than larger brakes.

 

 

You mean why do they have 13" wheels ?? Thats already mentioned because thats what size they are allowed in the technical regs , the reason behind it is to limit the size of the brakes.

 

I'm certainly not convinced that larger brakes is less of an advantage then stiffer sidewalls , the larger sidewalls they currently have maximises the tyres footprint under load.

 

Weight is another thing as again unlike normal cars the wheels are magnesium and super light (mate had a 10x15" ex-indy car wheel on his dragbike and it was amazingly light you could hang it from your little finger) if a lower profile tyre was used the wheel would have to be made stronger and almost certainly heavier