Changing wheel size 20” to 18”

Hi,

I’m looking at buying a highlander, but note only 20” wheels are available on UK versions whereas 18” is offered on most models in the US.

Big alloys are a bit of a pet hate of mine so would likely want to source some 18s to get a better ride, lower mpg, lower noise, cheaper tyres and better pot hole and kerbing immunity etc. Has anyone made that change? If so were you able to source OEM wheels at a reasonable cost or did you have to go aftermarket?

According to wheel-size.com, the Highlander uses either 235/65R18 tyres fitted to 8Jx18 ET35 5/114.3 60.1 rims or 235/55R20 tyres fitted to 8Jx20 ET30 5/114.3 60.1 rims.

Highlander wheel size

https://www.wheel-size.com/size/toyota/highlander/2023/#region-eudm

However, even if you use the 18" option don't expect a super comfortable ride because an 8J rim is quite wide for a 235/65 tyre, and relatively wide rims make it more difficult for a tyre's sidewalls to flex and absorb road shocks.

For maximum comfort, I suggest you look at 17" and 18" rims from the RAV4.

wheel-size.com shows the RAV4 17" and 18" rims as having a specification of 7Jx17 ET35 5/114.3 60.1 and 7Jx18 ET35 5/114.3 60.1, ie. a full 1" narrower than the 18" Highlander rims.

The below Michelin CrossClimate 2 255/65R17 110H tyre is not an XL tyre which should improve ride comfort compared to an XL tyre due to the softer and more flexible sidewalls. It's also doesn't have an unnecessarily high speed rating, which again should improve ride comfort due to the softer and more flexible sidewalls. Additionally, a 255/65 fitted to a relatively narrow 7J rim will help the tyre's sidewalls flex more easily and again provide an even softer and more comfortable ride.

The reason that Toyota would have chosen such wide sidewalls, ie. 8J for the 235/65R18 option, is because they test their new cars on a smooth racetrack. On bumpy and potholed UK roads, many drivers would benefit from a more comfortable setup.

You might think that a 255 tyre is going to be 20mm wider than a 235 tyre, but a tyre's actual width always depends on the width of the rim that it is fitted to.

As you can see in the below chart, a 255/65R17 tyre fitted to a 7J rim is only about 2mm wider than a 235/65R18 tyre fitted to an 8J rim.

Actual tyre width (measured from sidewall to sidewall of an inflated tyre at the widest point)

235/65R18 fitted to an 8J rim is actually about 252mm wide

255/65R17 fitted to a 7J rim is actually about 254mm wide

Michelin CrossClimate 2 255/65R17 110H (Euro label B B 71dB)

https://www.camskill.co.uk/m140b0s12726p211457/Michelin_Tyres_All_Season_Car_Michelin_Cross_Climate_2_-_255_65_R17_110H_TL_Fuel_Eff_%3A_B_Wet_Grip%3A_B_NoiseClass%3A_B_Noise%3A_71dB

Note that I haven't checked if 17" rims will fit on a Highlander. There's a good chance it would fit, as you don't get many cars that need rims bigger than 17" to clear the front brake calipers.

7Jx18 ET35 5/114.3 60.1 rims from a RAV4 could be a good option on the Highlander, perhaps with the standard 235/65R18 tyre size or a non-standard 255/60R18 tyre size.

Alcar 9997 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4)

https://www.oponeo.pl/felga-stalowa/alcar-kfz-9997#23079978

Alcar 9998 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4)

https://www.mytyres.co.uk/rims/details?vehicleId=1075676964464890994&rimCode=ALCAR9998

Here's a couple of 235/65R18 all-season tyres. The Pirelli seems particularly good value, although I'm not generally a fan of Pirelli due to their rather inconsistent tyre quality over the years. However, the below Pirelli might be ok, because it's made specifically for Jaguar (probably the F-Pace or I-Pace), and I wouldn't have thought Pirelli would want to upset such an important customer as Jaguar by making a sub-standard product. With an A rating for rolling resistance, it looks like it was made with a high emphasis on fuel economy. However, this isn't necessarily a good thing if other criteria have suffered such as grip and wear rate. For example, it's only got a C rating for wet grip.

Goodyear 235/65R18 110V XL (Euro C B 72dB)

https://www.camskill.co.uk/m141b0s12746p211494/Goodyear_Tyres_All_Season_Car_Goodyear_Vector_4_Season_Generation3_SUV_-_235_65_R18_110V_XL_TL_Fuel_Eff_%3A_C_Wet_Grip%3A_B_NoiseClass%3A_B_Noise%3A_72dB

Pirelli 235/65R18 110V XL (Euro A C 71dB) (made for a specific Jaguar model, probably the F-Pace or I-Pace but can be used on other cars)

https://www.camskill.co.uk/m141b0s12747p156066/Pirelli_Tyres_All_Season_Car_Pirelli_Scorpion_Verde_All_Season_-_235_65_R18_110V_XL_(J)_TL_Fuel_Eff_%3A_A_Wet_Grip%3A_C_NoiseClass%3A_2_Noise%3A_71dB

@Aygolite Thanks a lot for the detailed reply. I hadn’t considered RAV4 alloys, I guess they’d be easy to source second hand and keep the OEM look.
 

I guess my only concern would be if the narrower rims would be ok given the extra 450KG weight of the highlander vs the RAV4. I can imagine the lateral forces on the tyres when cornering would be higher with the extra weight and I guess the 8J was possibly chosen to prevent the tyre rolling off the rim under cornering. 
 

Will do a bit more research and see what other similarly heavy 7 seaters use.

Good point about the weight carrying capacity of the rims.

I would check the gross axle weights of the Highlander. The rear axle probably has a higher gross axle weight than the front axle. To find the minimum weight bearing capacity of the rims, divide the gross axle weight by two. For example, if the maximum gross axle weight of the rear axle (assuming this is more than the front axle) is 1,500kg, then you would need rims that can support at least 750kg each.

The maximum weight bearing capacity of all new rims sold should be in the manufacturer's technical documentation, so that you don't fit rims that are too weak for the weight of the car.

Tyres don't roll off rims that are fitted to ETRTO approved rim widths. See the ETRTO chart below. All new cars sold have to follow ETRTO's guidelines. Even the big car companies and tyre brands such as Toyota and Michelin have to follow ETRTO's guidelines. As you can see in the chart below, a 235/65R18 tyre has to be fitted to a rim between 6.5" and 8.5" wide, with 7.0" being the standard rim width for this tyre size, and hence highlighted in bold.

There's no need to consider the rim diameter when looking at ETRTO's approved rim widths chart, because rim diameter doesn't effect the approved range of rim widths. It's just the nominal tyre width and the aspect ratio that need to be considered to find the range of ETRTO approved rim widths.

The reason for wide rims is to improve steering response and handling, at the expense of ride comfort. When you fit tyres to relatively narrow rims the rims move about more inside the tyres when the car is subjected to lateral forces, eg. cornering. You will often find Audi and BMW cars using relatively wide rims for this very reason. The Aygo used relatively narrow 4.5J rims for its 165/65R14 and 165/60R15 tyre sizes to prioritise comfort over ultimate handling and steering precision. I expect most Aygo owners appreciated the improved comfort over the slight reduction in steering precision.

One easily overlooked point, is how much weight you can save by choosing a smaller rim. A 20" alloy rim will often be over 50% heavier than a 17" steel rim. A steel rim is usually lighter than the equivalent sized alloy rim, but even a 17" alloy rim is going to be a lot lighter than a 20" alloy rim.

ETRTO approved rim widths

235/70 6.0-7.0-8.0

235/65 6.5-7.0-8.5
245/65 7.0-7.0-8.5
255/65 7.0-7.5-9.0

235/60 6.5-7.0-8.5
245/60 7.0-7.0-8.5
255/60 7.0-7.5-9.0

An oversize tyre option for the standard Highlander 8Jx18 ET35 rims could be 255/60R18. Notice in the ETRTO chart above, that an 8J rim is still relatively wide for this tyre size but not as relatively wide for the standard 235/65R18 tyre size. This should help the wider 255/60R18 tyre's sidewalls to flex more easily than the narrower 235/65R18, and thereby provide more comfort.

Michelin CrossClimate 2 255/60R18 112H XL (Euro label B B 71dB)

https://www.blackcircles.com/catalogue/michelin/crossclimate-2-suv/255/60/R18/H/112/m?tyre=43651819

Thanks, great information!

Just to add to the above, I've noticed that the Audi Q7 also uses a 255/60R18 tyre size fitted to an 8J rim as its entry level tyre size.

On 4/11/2023 at 6:09 PM, Aygolite said:

According to wheel-size.com, the Highlander uses either 235/65R18 tyres fitted to 8Jx18 ET35 5/114.3 60.1 rims or 235/55R20 tyres fitted to 8Jx20 ET30 5/114.3 60.1 rims.

Highlander wheel size

https://www.wheel-size.com/size/toyota/highlander/2023/#region-eudm

However, even if you use the 18" option don't expect a super comfortable ride because an 8J rim is quite wide for a 235/65 tyre, and relatively wide rims make it more difficult for a tyre's sidewalls to flex and absorb road shocks.

For maximum comfort, I suggest you look at 17" and 18" rims from the RAV4.

wheel-size.com shows the RAV4 17" and 18" rims as having a specification of 7Jx17 ET35 5/114.3 60.1 and 7Jx18 ET35 5/114.3 60.1, ie. a full 1" narrower than the 18" Highlander rims.

The below Michelin CrossClimate 2 255/65R17 110H tyre is not an XL tyre which should improve ride comfort compared to an XL tyre due to the softer and more flexible sidewalls. It's also doesn't have an unnecessarily high speed rating, which again should improve ride comfort due to the softer and more flexible sidewalls. Additionally, a 255/65 fitted to a relatively narrow 7J rim will help the tyre's sidewalls flex more easily and again provide an even softer and more comfortable ride.

The reason that Toyota would have chosen such wide sidewalls, ie. 8J for the 235/65R18 option, is because they test their new cars on a smooth racetrack. On bumpy and potholed UK roads, many drivers would benefit from a more comfortable setup.

You might think that a 255 tyre is going to be 20mm wider than a 235 tyre, but a tyre's actual width always depends on the width of the rim that it is fitted to.

As you can see in the below chart, a 255/65R17 tyre fitted to a 7J rim is only about 2mm wider than a 235/65R18 tyre fitted to an 8J rim.

Actual tyre width (measured from sidewall to sidewall of an inflated tyre at the widest point)

235/65R18 fitted to an 8J rim is actually about 252mm wide

255/65R17 fitted to a 7J rim is actually about 254mm wide

Michelin CrossClimate 2 255/65R17 110H (Euro label B B 71dB)

https://www.camskill.co.uk/m140b0s12726p211457/Michelin_Tyres_All_Season_Car_Michelin_Cross_Climate_2_-_255_65_R17_110H_TL_Fuel_Eff_%3A_B_Wet_Grip%3A_B_NoiseClass%3A_B_Noise%3A_71dB

Note that I haven't checked if 17" rims will fit on a Highlander. There's a good chance it would fit, as you don't get many cars that need rims bigger than 17" to clear the front brake calipers.

7Jx18 ET35 5/114.3 60.1 rims from a RAV4 could be a good option on the Highlander, perhaps with the standard 235/65R18 tyre size or a non-standard 255/60R18 tyre size.

Alcar 9997 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4)

https://www.oponeo.pl/felga-stalowa/alcar-kfz-9997#23079978

Alcar 9998 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4)

https://www.mytyres.co.uk/rims/details?vehicleId=1075676964464890994&rimCode=ALCAR9998

Here's a couple of 235/65R18 all-season tyres. The Pirelli seems particularly good value, although I'm not generally a fan of Pirelli due to their rather inconsistent tyre quality over the years. However, the below Pirelli might be ok, because it's made specifically for Jaguar (probably the F-Pace or I-Pace), and I wouldn't have thought Pirelli would want to upset such an important customer as Jaguar by making a sub-standard product. With an A rating for rolling resistance, it looks like it was made with a high emphasis on fuel economy. However, this isn't necessarily a good thing if other criteria have suffered such as grip and wear rate. For example, it's only got a C rating for wet grip.

Goodyear 235/65R18 110V XL (Euro C B 72dB)

https://www.camskill.co.uk/m141b0s12746p211494/Goodyear_Tyres_All_Season_Car_Goodyear_Vector_4_Season_Generation3_SUV_-_235_65_R18_110V_XL_TL_Fuel_Eff_%3A_C_Wet_Grip%3A_B_NoiseClass%3A_B_Noise%3A_72dB

Pirelli 235/65R18 110V XL (Euro A C 71dB) (made for a specific Jaguar model, probably the F-Pace or I-Pace but can be used on other cars)

https://www.camskill.co.uk/m141b0s12747p156066/Pirelli_Tyres_All_Season_Car_Pirelli_Scorpion_Verde_All_Season_-_235_65_R18_110V_XL_(J)_TL_Fuel_Eff_%3A_A_Wet_Grip%3A_C_NoiseClass%3A_2_Noise%3A_71dB

Here are the maximum wheel loads and the maximum rolling circumferences of the Alcar 9997 and 9998 steel rims.

Not surprisingly, these limits correspond with the limits of the Toyota RAV4 2019-present (Gen V), as this is the car that these rims are made to fit.

Alcar 9997 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4 2019-present Gen V)

Maximum wheel load 610kg

Maximum rolling circumference 2208mm

Alcar 9998 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4 2019-present Gen V)

Maximum wheel load 610kg

Maximum rolling circumference 2210mm

I've added the weight (as claimed by Alcar) to the specification of the below two 7Jx17 ET35 5/114.3 60.2 Alcar steel rims.

If the weight claimed by Alcar for these two rims is correct, the stylized Alcar 9997 rims are a massive 34% heavier than the Alcar 9998 rims. That's a lot of weight to add to unsprung weight and rolling weight for style.

Clearly, the stylized steel rim needs to have much thicker steel in order to maintain its strength compared to the standard steel rim design.

Alcar 9997 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4 2019-present Gen V)

Maximum wheel load 610kg

Maximum rolling circumference 2208mm

Weight 13.4kg

https://www.oponeo.pl/felga-stalowa/alcar-kfz-9997#23079978

Alcar 9998 7Jx17 ET35 5/114.3 60.1 steel rim (from RAV4 2019-present Gen V)

Maximum wheel load 610kg

Maximum rolling circumference 2210mm

Weight 10kg

https://www.mytyres.co.uk/rims/details?vehicleId=1075676964464890994&rimCode=ALCAR9998