New Mid Size Sedan All Comes with Bigger Rims/Wheels?

[louisbosco]

On 11/14/2019 at 2:58 PM, Toeknee_33 said:

Well if you watch slow-mo clips of F1 cars taking corners, actually the tyre wall bounces, flexes and vibrates tremendously, especially when tackling kerbs. Its a nightmare for the chassis engineers to correctly tune the suspension to account for this variable and inconsistent tyre behaviour. 

Anyway, the F1 organisers are keen to change the rim size from 13" to 18" in 2021, but more for the purpose of looks than performance. The F1 engineers would just have to tune the suspension to adapt to the lesser compliance of the thinner tyre walls.

Read this: https://www.racefans.net/2018/08/08/revolutionary-wheels-why-f1-going-18-inch-will-change-everything/

 

to be honest, i'm not keen on f1 switching to bigger rims. it's going to be hard to put the power down with less rubber.. that's what all drag cars have small rims and lots of rubber. but then again, that's a different style of racing..

[Toeknee_33]

21 minutes ago, louisbosco said:

to be honest, i'm not keen on f1 switching to bigger rims. it's going to be hard to put the power down with less rubber.. that's what all drag cars have small rims and lots of rubber. but then again, that's a different style of racing..

Actually I don't quite get that. I had thought that it's the contact patch that puts the power down on the tarmac? How does taller sidewalls increase traction? 

[Didu]

On 11/17/2019 at 5:39 PM, Lala81 said:

I thought pretty universal in american and european car reviews as well.

Malaysia has the Segment A-D and beyond vehicles.

https://www.carbase.my/all-segment

Agree. Remember the Chrysler 300? That's a full size sedan.

[louisbosco]

10 hours ago, Toeknee_33 said:

Actually I don't quite get that. I had thought that it's the contact patch that puts the power down on the tarmac? How does taller sidewalls increase traction? 

the ability to absorb the forces. contact patch is one thing. when putting power down, it's the combination of both. rubber also absorbs and convert energy. when you have a lesser side wall, your potential energy > kinetic energy which is the power sent from the wheels to put it down on the road. hence drag cars run a bigger side wall to absorb the potential energy produce to convert it to kinetic energy to get the cars off from a a standstill. 

that is why normal dragsters run huge rear and very small fronts.. 

don't know if that's a good explanation but it's what i can translate from in my head into words

[Beregond]

11 hours ago, Toeknee_33 said:

Actually I don't quite get that. I had thought that it's the contact patch that puts the power down on the tarmac? How does taller sidewalls increase traction? 

my best guess is the suspension and bumpiness issue. the track is not even and got bump here and there, the high profile tyres help absorb it.

imagine they using low profile tyres and racing in singapore going the hump, maybe the car fly already??

(no expert, i guess only lol)

[Toeknee_33]

1 hour ago, louisbosco said:

the ability to absorb the forces. contact patch is one thing. when putting power down, it's the combination of both. rubber also absorbs and convert energy. when you have a lesser side wall, your potential energy > kinetic energy which is the power sent from the wheels to put it down on the road. hence drag cars run a bigger side wall to absorb the potential energy produce to convert it to kinetic energy to get the cars off from a a standstill. 

that is why normal dragsters run huge rear and very small fronts.. 

don't know if that's a good explanation but it's what i can translate from in my head into words

Wow! I actually get you! Thanks for the explanation! Cheers!

[Toeknee_33]

2 minutes ago, Beregond said:

my best guess is the suspension and bumpiness issue. the track is not even and got bump here and there, the high profile tyres help absorb it.

imagine they using low profile tyres and racing in singapore going the hump, maybe the car fly already??

(no expert, i guess only lol)

That's a good point too, but some of the stiffness can be mitigated by softening the suspension I guess.

[louisbosco]

14 hours ago, Beregond said:

my best guess is the suspension and bumpiness issue. the track is not even and got bump here and there, the high profile tyres help absorb it.

imagine they using low profile tyres and racing in singapore going the hump, maybe the car fly already??

(no expert, i guess only lol)

the tyres are for transfer of energy. potential to kinetic. it absorbs the excess power output by the engine to the tyres.

the unevenness of the road/track is being absorbed by your shock absorbers. your spring rate determines part of the body roll and the rebound of your shock absorbers determine how bumpy the rebound after the hump is.

two completely different specs but working hand in hand

[Beehive3783]

On 11/14/2019 at 5:39 PM, wangxiaodi said:

Anyway, the purpose of this thread is just sharing only. Cos i remember alot of new sedan car in the past come with basic smaller rims like 15inch.

now a lot of the compacted or mid size sedan...already comes with bigger rim like 16 or 17 or even 18. 

But now, come to think of it, if rim diameter is large, 17 and above, but the width is too narrow, like 205 and below.....doesn't look good.

just personal superficial opinion.

Because long long ago, cars were smaller and lighter, therefore brake discs were smaller, therefore wheels were smaller.

You can't expect them to use the same brake disc meant for 13" or 14" wheel if the car has already grown in size and weight right?

[GTO-1]

On 11/14/2019 at 10:49 AM, Beehive3783 said:

Renault Scenic wheels are big because the rotors are huge.

And the tyre size is also extremely unique. 195/55R20. Pretty hard to find in SG I suppose.

Spoke to an SE about the scenic and grand scenic having 20" rims and a weird width.  He said that the thinner wheel helps with fuel economy (which is true) and the bigger diameter makes the car look in proportion (maybe true), and also 195/55R20's are stocked quite commonly (not true). 

If I recall it's 20x6.5, which is really disproportionate. Weirdly it also uses a 114.3x5 PCD, which is more common in Asian cars and not consistent across the Renault range. 

[inlinesix]

3 minutes ago, GTO-1 said:

Spoke to an SE about the scenic and grand scenic having 20" rims and a weird width.  He said that the thinner wheel helps with fuel economy (which is true) and the bigger diameter makes the car look in proportion (maybe true), and also 195/55R20's are stocked quite commonly (not true). 

If I recall it's 20x6.5, which is really disproportionate. Weirdly it also uses a 114.3x5 PCD, which is more common in Asian cars and not consistent across the Renault range. 

Reduction of unspring weight improves FC.

Edited November 20, 2019 by Davidtch

[GTO-1]

10 hours ago, Davidtch said:

Reduction of unspring weight improves FC.

True, and so does reducing rolling resistance of the tyre. By reducing the width of the tyre, the rolling resistance decreases, which also decreases FC. 

 

[SZ_ford]

10 hours ago, GTO-1 said:

Spoke to an SE about the scenic and grand scenic having 20" rims and a weird width.  He said that the thinner wheel helps with fuel economy (which is true) and the bigger diameter makes the car look in proportion (maybe true), and also 195/55R20's are stocked quite commonly (not true). 

If I recall it's 20x6.5, which is really disproportionate. Weirdly it also uses a 114.3x5 PCD, which is more common in Asian cars and not consistent across the Renault range. 

ask the SE, name another car that use 195/55/20, haha

I'm guessing they don't build a wide wheel well in Grand scenic, so chose a narrow rim as stock

[SZ_ford]

15 hours ago, Beehive3783 said:

Because long long ago, cars were smaller and lighter, therefore brake discs were smaller, therefore wheels were smaller.

You can't expect them to use the same brake disc meant for 13" or 14" wheel if the car has already grown in size and weight right?

speaking of big rims, 23" from Audi RSQ8  with 18" disc rotor

 

[Cheefarn]

1 hour ago, SZ_ford said:

ask the SE, name another car that use 195/55/20, haha

I'm guessing they don't build a wide wheel well in Grand scenic, so chose a narrow rim as stock

Its not that difficult to find actually. 

There are only 2 brands/models that offers this size, Goodyear EfficentGrip Performance and Michelin Premacy 4

The rest no need to see. And don't bother going to Bolehland to change  

[t0y0ta]

Famous Youtube "Engineering Explains" broke 2 of his Tesla 20" wheels driving over pothole roads. He spent something like 5k to replace them. Eventually changed to 18" to save his wallet.

The interesting part is that he subsequently did a bake-off between the same car with large wheels and small wheels (same overall tyre diameter). The small wheels setup beats the large wheels setup hands down in terms of acceleration.

[Beregond]

12 hours ago, GTO-1 said:

Spoke to an SE about the scenic and grand scenic having 20" 195/55R20's are stocked quite commonly (not true). 

 

ask him pick up the phone and randomly call 10 tyres shop, see how many stock this tyres.🤣

 

[SZ_ford]

23 minutes ago, Cheefarn said:

Its not that difficult to find actually. 

There are only 2 brands/models that offers this size, Goodyear EfficentGrip Performance and Michelin Premacy 4

The rest no need to see. And don't bother going to Bolehland to change  

that tells u how ''common'' this tyre is, haha