Spubgas

Hi,

I've searched for the answer to this but can't seem to find one anywhere on the forums.

I had a 2009 UK spec RX400h. This came with 18 inch wheels. I purchased a spare set of 18 inch wheels which have winter tyres on them.

I recently traded in the RX400h for a 2010 UK spec RX450h. This comes with 19 inch wheels, although, I do know some of these vehicles came with 18 inch ones as standard.

My question is, can I do a straight swap of the 19 inch wheels and tyres for my 18 inch wheels (from my previous RX) and winter tyres, or will I need to purchase a new set of 19 inch wheels and new winter tyres?

I'm hoping it's a straight swap, but wanted to ask first. I see from a number of websites the 18 and 19 inche wheel dimensions are slightly different (eg offsets etc.)

Many thanks in advance



Guy

MellonC00

do you have 235 tires or 225 tires?

Spubgas

MellonC00

Your 19 inch wheel will stick out 3 mm (0.1'') farther. this is perfectly fine. but the new wheel set will fill out the wheelwell by extra 13 mm. You may or may not have enough room. but the bigger problem is that your speedometer will read 60mph (96.6km/h) when your actual speed will be 62.2mph (100.1km/h).

Here are some reference values: your 18 inch wheels have 38mm offset and your 19 inch wheels has 35mm offset. keeping this in mind go to this website and compare the wheel sizes and see how it fits.

https://rimsntires.com/specspro.jsp

Spubgas

That's really helpful thank you.

I'm not too concerned about the speedo being out as it's only a few mph.

Would you suggest the best thing to do is to actually try and fit the wheels and check for enough clearance around the tyres?

Once again, thank you for taking time to help me with this.

Guy

RickC5

Yes, by all means do a trial fit--just on one front wheel will suffice. Jack up the RX; swap the wheels; spin to make sure no rubbing on the brake caliper; Lower the car, remove the jack and start the engine. Leaving the car in park, turn the steering wheel lock-to-lock, ensuring that there is no contact/rubbing on any of the steering mechanism or the wheel wells on either side at full lock--you may need to crawl under with a flashlight/torch to verify. OTOH, I believe you should have NO problems with this swap, as most Gen 3 RXs sold in North America come with 18" wheels. But, no harm in making sure.

Spubgas

Ok, will do.

I was concerned about suspension travel and the tyre hitting the wheel arch.

I don't go off roading, but the roads in the UK are full of bumps and holes!

Appreciate all the help so far received. Thank you.

Guy

kezgao

IMO, you can probably get away with it.
However if you were to look at the diameter difference, the current tires are 26 mm (3.6%) bigger. The tire shops here will not install anything more than +/-3%. You're just slightly above that 3% margin. I am not sure if there any local laws that would consider 3.6% unsafe and list you liable for any accidents.
Just my two cents, stay safe.

MellonC00

I just realized that I did this backwards (going from RX450 wheels to RX400). but instead, you are fitting an RX 400 wheels into RX450h. Sorry.

so the calculation is backwards.

Suspension clearance: the new wheel is 3 mm (0.1'') closer to suspension/brakes components. Acceptable for most cars.
Fenders clearance: 100% clear (leaves even more room than OEM)
Wheelwells clearance: 100% clear (leaves even more room than OEM)
SPEEDOMETER: When speedometer reads 60mph (96.6km/h) actual speed will be 57.9mph (93.2km/h): 3.5% slower.

Spubgas

RickC5

Here's a link to a Tire Size Calculator, where you can figure out the differences yourself. Hope this helps.

https://www.tacomaworld.com/tirecalc...0r18-275-65r18

Spubgas