Matching tyre size to rim. How?

[rich1068]

I'm toying with the idea of putting some fancy new wheels on my LS 400. I know which wheels I want and to clear the LS brakes with this particular wheel I will have to go from the standard 7Jx16 ET45 wheels with 225/60 R16 tyres to 8Jx17 ET45 wheels. But what size tyre should I go for?

I'll be honest, in all my years I've never put aftermarket wheels on a car so this has never come up. I know I'll lose a little ride quality going from 16s to 17s so ideally I'd like to keep as much sidewall as possible.

Can anyone advise?

[NemesisUK]

Try one of the online calculators like this

https://www.willtheyfit.com/

The bottom line is one must keep the rolling diameter within tolerance or  one can upset all sorts of things, speedometer accuracy being one thing

[rich1068]

Looks like 225/55 17s might fit the bill.

I think I was overthinking this a little. I'm aware of speedo accuracy etc and I'd used willtheyfit and a couple of others but imagined it was all a bit more of a dark art than it actually is. Oponeo has a matching feature that lists dozens of sizes that will fit.

[ColinBarber]

7 hours ago, rich1068 said:

I think I was overthinking this a little.

There is more to it than just the circumference. Rim width and offset may push your wheel outside of the bodywork which is illegal in the uk, or push it into the suspension, and rim width and tyre width need to be compatible with each other.

But you are only going from 16 to 17 inch so I cannot see there being any problem with such a small change, and 225 on an 8" rim is fine.

[ALAW]

On 7/3/2021 at 8:09 PM, rich1068 said:

I'm toying with the idea of putting some fancy new wheels on my LS 400. I know which wheels I want and to clear the LS brakes with this particular wheel I will have to go from the standard 7Jx16 ET45 wheels with 225/60 R16 tyres to 8Jx17 ET45 wheels. But what size tyre should I go for?

I'll be honest, in all my years I've never put aftermarket wheels on a car so this has never come up. I know I'll lose a little ride quality going from 16s to 17s so ideally I'd like to keep as much sidewall as possible.

Can anyone advise?

i think your right there Richie keep a good sidewall and maybe keep away from runflats.

[steve2006]

If you want to fill the arches either 225/55/17 or 235/50/17 tyres with the correct load index and speed ratings, expect to pay in excess of £100.00 per corner for premium brands.

Also check the centre bore size of the wheels, Lexus has 60.1mm anything smaller will not fit the hub and anything larger can be reduced with a set of spigot rings for around a fiver.

Also check the type of wheel nuts required as most aftermarket wheels use tapered nuts whereas Lexus wheels use sleeved nuts. Using the incorrect type could damage the wheels or the wheel could become loose.

[rich1068]

Cheers Steve.

The bore is larger at 73mm so spigot rings would be required.

Good tip with the wheel nuts

 

[paulrnx]

Wheel offset is one of the most important considerations if changing wheels. Having a different offset causes the road contact points to be different to what was intended by the car manufacturer for their specific suspension design which can cause the ride and handling to be completely different and in some cases much worse. I’d always go for wheels with exactly the same offset if possible.