Can you replace 20" rims on lowered suspension with smaller rims and bigger profile tyres if so how do i calculate the numbers to find the right size

[vc commodore]

So an update, looking at getting 18 inch calais rims with 245/45/18s for the time being from wreckers. In good condition for a very reasonable price.
Next stop is suspension town.
Thank you everyone for your input its refreshing to see how helpful this world can be especially commy heads you guys are the dons

See how you go with the 18" rims...The tyre size will help prevent rims buckling and cracking to start with

 

[lmoengnr]

Suspension is a small portion of the cause....The sidewall of a tyre acts like a shock absorber....The more sidewall, the more absorbtion, the less chance of rims buckling or cracking....Add in, the modern day rim has bugger all support on the inner edge, so this compounds the issue

Just take a step back to the days before 17" and above became the norm....You very rarely heard of buckled or cracked rims due to pot holes when a 15" rims were the bees knees for your ride....And to lower the car, you grabbed the makita and had it riding on the bumpstops

Crappy chinese cast alloy wheels don't help either.

 

[vc commodore]

Crappy chinese cast alloy wheels don't help either.

I started striking cracked and buckled rims back in 2000ish, with factory Ford and Commodore rims, when 17" rims started to become really popular....So it wasn't just crappy chinese alloys...It was factory alloys doing it

 

[lmoengnr]

I started striking cracked and buckled rims back in 2000ish, with factory Ford and Commodore rims, when 17" rims started to become really popular....So it wasn't just crappy chinese alloys...It was factory alloys doing it

So you mean the crappy Asian cast alloy wheels then?

 

[vc commodore]

So you mean the crappy Asian cast alloy wheels then?

I think Holden had them made in Australia...Not sure about Ford.....Would have to double check where they were made...

 

[J_D 2.0]

I think Holden had them made in Australia...Not sure about Ford.....Would have to double check where they were made...

Pretty sure both Ford and Holden used ROH to make their wheels until the mid 2000s.

 

[vc commodore]

Pretty sure both Ford and Holden used ROH to make their wheels until the mid 2000s.

Which shows the lack of tyre sidewall is the cause of rims cracking and buckling

 

[Mitchward234]

Feels great on the 18s with much larger sidewalls.
It's not going to fix the fact that this suspension is way to low but also to soft for my roads and in my opinion sssl is just over the top if you expect any drivabilty from your ride, backed up with Munro's its all going to be the same. Any body got any suggestions on suspension so far I'm thinking of finding some fe3s out of a redline if I can line one up for the time being but also just tempted to bite the bullet and sink 2 or 3 grand into suspension I could call a finished product.

 

[vc commodore]

Suspension height is a personal choice.....You could try FE3 and see how it feels.....Me personally prefer FE2....

 

[VS 5.0]

I'm thinking of finding some fe3s out of a redline

Mine has FE3.

Firm ride but not harsh.....and that is with 20s.