[Santoshbhat]

Originally Posted by kartikv1

During my last visit to the bmw service to get my tyres checked, noticed 3 bent rims (only slightly albeit). The major reason attributed by the SA was the RFTs - which transfer all impact from potholes directly to rims hence the damage. Once we change to tubeless the rim bending shouldn’t be a problem and also the harsh ride quality will improve.

I seriously detest this trend of 18 inch and upwards tyres - just image driving these on Delhi Jaipur highway and I can guarantee that you will not come out without a bent rim or damaged tyre. Only expressways can be safe places for such tyres.

Completely agree with you about the risk of driving with these big rims + low profile tyres on bad roads. If I look back, most of my driving in the last 2 years with these 19" rims has been up and down on a well known (for me) smooth expressway. Due to the pandemic, I have hardly driven on lesser known state roads. When I bought the 19" rims , I decided to retain the 18" rims + tyres so that I could slap them on to the car whenever we had to tour on leisure to lesser known places. I did do that for one such trip. Will have to remember to do this before planning the next trip

[Thermodynamics]

Quoting from another thread where an R18 of Hyundai Tucson went into trouble with barely 1500 km. 225/55R18 (Hyundai Tucson : Tyre & wheel upgrade thread).

The other trouble with bigger rim sizes is availability of tyres. In a similar instant as the below quote,

Originally Posted by sidhu_hs

... I don't think that particular tyre size is available in the market from any of the well known brands. Your best and cheapest bet is to source one tyre of the same make from Hyundai, even though they might charge quite a premium for that...

when a friend was hunting tyres for his Tucson, he could not find them in whole Bangalore and had to drive all the way till Mysore just because some shop had it available.

Originally Posted by androdev

... the increased power does require larger rims due to larger brakes and wider tires...

Why so, It has to be the load not power, no ?
An underpowered Bolero carrying 1.5 Tonnes of vegetables might need bigger brakes than an overpowered super car. Please correct me if I am wrong.

[androdev]

Originally Posted by Thermodynamics

Why so, It has to be the load not power, no ?
An underpowered Bolero carrying 1.5 Tonnes of vegetables might need bigger brakes than an overpowered super car. Please correct me if I am wrong.

To bring a sports car that is doing 0-100kmph under 4-5 seconds to a complete halt definitely requires larger brakes. Bolero example may come to a complete halt just by taking your foot off the accelerator. I am exaggerating but you get the idea.

I agree looks play a big role but there is definitely some engineering reasoning behind selection of the wheel sizes (brake size, contact patch, unsprung weight, gearing ratio, suspension aspects, steering, etc.). It is just that many engineers don't want to bother about unromantic stuff like bad roads.

[Kosfactor]

Originally Posted by Thermodynamics

Why so, It has to be the load not power, no ?
An underpowered Bolero carrying 1.5 Tonnes of vegetables might need bigger brakes than an overpowered super car. Please correct me if I am wrong.

You are right, mass * velocity at the heart of it.

Bigger wheels are dictated more by style than anything else for normal road vehicles. But supercars need to take into account spirited driving around a track which would need big brakes to dissipate heat quickly a smaller rotor would do this once in one corner and then disappear along with the wheel bearing.

[arighna.dutta]

Originally Posted by manjubp

For exact reason, I am considering to upsize the aspect ratio from 205/55R16 to 205/60R16. The change in sidewall height is nearly 10mm and overall GC will go up by 20mm, with an error of nearly 3.17%, not sure, if this is even advisable to go with..

It will give you a gain of only 10 mm ground clearance and not 20 mm.

Low profile tire + potholes = bent rims unless slowed down to crawling speed.

Factors which can add in more damage maybe:

1. Lesser suspension travel
2. Stiff suspension
3. Lack of tire pressure
4. Softer side walls

Point 1 and 2 is something the German sedans have quite a bit. So maybe BMW alloys might not be weak, but to become the ultimate driving machine, maybe the suspension is also the stiffest among the three.

[AirbusCapt]

Originally Posted by Hayek

Not had problems with the 18” rims running 245/50 R18 run flats on my X3 so far. Suspect part of the problem with your 530d is the low profile nature with the staggered set up. With 275/40, your sidewall height is just 110 mm VS the 122.5 mm I have on the X3. Guess the 10% difference in sidewall height matters. Of course, even the narrower profile tyre on the 520d at 245/45 has the same sidewall height of 110 that you have.

You are right. It is the sidewall height that matters. I run 235/65 R18 on my discovery sport. Inspite of hammering across all kinds of terrain the alloys, the suspension and the tyres are perfectly fine.

[asit.kulkarni93]

I travelled down south for work in December 2020 and met a few Bhpians in Kerala, Karnataka and Tamil Nadu. I was thrilled looking at their cars with bigger rims. It was a 7k KMs long trip and in my last leg after crossing Hubli, I had decided that I need to put bigger rims on the Laura and then I entered Maharashtra. All my dreams came crashing like that of uday Chopra from Dhoom series. Thanks to the 205/65 R15 setup I have right now, I was able to glide over the potholes without issues but the road conditions are terrible in MH. I am still comfortable with 16 inch rims but anything more and we are inviting trouble especially if you do highway drives in MH. This trend of bigger rims in smaller cars also looks risky. Have seen plenty of citys, Cretas with bent rims and burst tyres on the Outskirts of pune around the NH4. So yeah downsize if you are in Maharashtra is the thumb rule, I would follow.

[ashwinprakas]

Normally for motorcycles as a rule of thumb we blindly replace alloys once the same has received a concerning bend, reason for the same is that Aluminium Alloys loose their durability once mended and are a potential hazzard.

I'm not sure why the same isn't applicable for car alloys, might be a difference in alloy composition, do educate me if I'm missing something.

[vredesbyrd]

Where there is a wheel, there is a way.
I reckon these would look good too with smaller size advantage.

[Celes]

My 2 cents!
Not talking about the high end Germans, it's the same issue with bigger sized rims in lesser cars as well.

I believe the main culprit is the sidewall height. I suffered two tyre bulges and one tyre burst in the first 16000 km with my 205/50 R17 Ford Ecosport. Shifted to 225/50 R17 Contis with stiffened sidewall (XL) since 16,000 km and they ran for almost 75,000 without no issue at all.
Cheers!

[theredliner]

This is a problem even with the 16 inchers of Fiat Linea. The 112.75 mm sidewall of the 205/55 tyres isn't enough for our roads at all. The turbine alloys seem to be particularly soft too as most people I know of with those alloys have managed to bend them. Fiat wants 16k per piece for a new one

Has anyone claimed insurance for wheel bends?

[nkrishnap]

I am on the second set of alloys on my Linea. Though it is 16 inchers, the soft alloys, negative camber and 55 profile tyres dont help it one bit. The front ones bend pretty easily unless you are slow over the ruts and craters. My driving style on my Linea does not help it either . To overcome this, I am running 2 PSI more than the recommended pressure the manufacturer and I slow down a wee bit more now a days to keep the expense on alloys away.

Please note the alloy repair for the alloys on Linea does not help as it gets bent exactly at the same place at the slightest of hits

[gopa99]

Originally Posted by benzinblut

One wheel got slammed in a sudden pothole after a blind downward slope on Ghodbunder Road. That was a nasty one. This happened to 16 inchers. Cant imagine how 18 inchers would have fared here. ]

True, your side profile was much taller than the 18 inches we were discussing. What speed were you in, and what was the vehicle you were driving?

[GeeTee TSI]

A question in order to understand better, how exactly do you repair an Aluminium Alloy wheel which has been bent? Is it a professional job on precision equipment? Do OEMs do this repair and how does it affect (extended) warranties which are still valid?

I had a severely bent alloy in my Polo which the service center promptly demonstrated with a video under the lift. The only option offered was a quote for a brand new set, I lived with the problem for sometime and changed to Momos

[MarutiGuy1977]

An exerpt from the new Range Rover thread.

"The 2022 Range Rover carries forward the clean and minimalistic look from the older model. The SUV gets a new set of sharper-looking LED headlamps, a completely redesigned LED taillight, and newly designed alloy wheels ranging from 20 to 23-inches."

Did someone say 23 inches?