Tire Size

[tommygunn]

I just switched over to winter tires; I purchased a set of OEM 18 wheels off eBay for a excellent price. They were a little scratched up, but these will be used in the winter with road salt and such, and i didn't want to ruin the original set.

I purchased a set of 245/60/18 Continental ContiTrac LX. I bought them used as I couldn't justify spending $900 on a set of tires that would be used for 4 - 5 months of the year. The DOT number is 2006, so they are fine with regards to age.

I know the OEM size is 235/55/18. To me the always seemed a little wimpy. I won't go into how I hate the Goodyear RS-A performance, but until they wear out......

The larger tires are great, the car seems to ride truer, with no noticable ride difference. If anything, they ride quieter. But I read on TireRack.com the the Contitrac is a great tire.

What do you think of going with a larger tire??? I have a 10 day try and buy. If they don't work out, or I hear a great reason not to run a larger tire, I can get a set of 235/55/18 Goodyear Assurance. Also ranked very well by TireRack.com.

[RX400h]

Your larger replacement tires are, in fact, almost 1.5 inches taller - not good in my book. You should always try to retain the same diameter, not only to ensure that there is no interference between the tire and suspension components, but also to avoid problems with ride control/active handling features. Some RX owners here have gone with larger/wider tires, but I am not a fan of this practice unless the overall diameter of the tire remains the same or close to the same.

[Jim Clark]

The car doesn't know it's riding on different size tires, it just thinks it's going a little slower than it actually is. With the larger diameter, when the speedo shows 60 mph, you're actually doing 63 mph.

At 1010Tires.com, they warn against going more than 3% larger but cite possible brake failure as the problem, probably due to the heavier weight and greater centrifugal force generated by the larger tire.

[mrc88dal]

Since you mentioned Tire Rack, I thought I'd quote what they say about choosing the right snow tire size. Here it is:

A wide, low profile or large tire has to "plow" a wide path through snow which causes more resistance. The narrower the tire, the easier you can get through snow. We'll help verify sufficient load capacity and the appropriate diameter for your vehicle when you speak with one of our sales specialists or use Winter Shop by Vehicle.

Winter tire sizes should be based on one of the following:

The Optional Tire and Wheel Size from Your Vehicle's Base Model

This is often the easiest way to select an appropriate narrow tire for your car or truck. For example, a 2003 Lexus IS300 would store its original 215/45R17 tires in favor of optional 205/55R16 tires on 16" wheels.

A Minus Size Tire and Wheel

Minus Sizing is simply traditional Plus Sizing techniques used backwards. For example, a 2003 Volkswagen Jetta GLX VR6 would store its original 205/55R16 (or optional 225/45HR17) tires in favor of Minus One or Minus Two size 195/65R15 tires on 15" wheels.

In both of these examples, not only would snow traction be enhanced, but the cost of a Base Model or Minus Size winter tire & wheel package is usually lower than a package maintaining your vehicle's original size tires and wheels.

I have Bridgestone Blizzaks, size 235/65R17, mounted on dedicated alloys for winter driving. For summer, Bridgestone Alenzas mounted on the OE alloys, size 235/55/R18.

[tommygunn]

I took the advice of this forum, and had the tires swapped for a set of 235/55/18 Goodyear Assurance. The Assurance is very quiet; and rides well. But I would recommend the ContiTrac in a heartbeat.

[singeroi]

Since you mentioned Tire Rack, I thought I'd quote what they say about choosing the right snow tire size. Here it is:

A wide, low profile or large tire has to "plow" a wide path through snow which causes more resistance. The narrower the tire, the easier you can get through snow. We'll help verify sufficient load capacity and the appropriate diameter for your vehicle when you speak with one of our sales specialists or use Winter Shop by Vehicle.

Winter tire sizes should be based on one of the following:

The Optional Tire and Wheel Size from Your Vehicle's Base Model

This is often the easiest way to select an appropriate narrow tire for your car or truck. For example, a 2003 Lexus IS300 would store its original 215/45R17 tires in favor of optional 205/55R16 tires on 16" wheels.

A Minus Size Tire and Wheel

Minus Sizing is simply traditional Plus Sizing techniques used backwards. For example, a 2003 Volkswagen Jetta GLX VR6 would store its original 205/55R16 (or optional 225/45HR17) tires in favor of Minus One or Minus Two size 195/65R15 tires on 15" wheels.

In both of these examples, not only would snow traction be enhanced, but the cost of a Base Model or Minus Size winter tire & wheel package is usually lower than a package maintaining your vehicle's original size tires and wheels.

I have Bridgestone Blizzaks, size 235/65R17, mounted on dedicated alloys for winter driving. For summer, Bridgestone Alenzas mounted on the OE alloys, size 235/55/R18.

thanks for the post it helped a lot.. its my first time with snows. :)

simulation

assurance vie

[sontom]

Thank you so much for the post. It's really useful. :D

fiscalite assurance vie

[NeoN]

ive stretched the limits of what the rx400h can fit, i run a 255/50/18 Pirelli Scorpion Ice/Snow in the Winter, Absolutely Love that tire. Great in the Snow, Ice, Dry, Rain, amazing all around tire, just a bit noisy on the highway.

I run a 275/40/20 on my summer wheels, this is probably the max size you can do on the RX400h, maybe .5" taller but I wouldn't push it. Anything wider is tough since it rubs the inner sidewalls, I run a 5mm spacer / extended lugs (from an is300). you could probably get away with running a 10mm wheel adapter and your wheels won't stick out past the fender. I can probably bump my wheels out another 5-10 mm without any issues, running a 15mm wheel adapter would be probably the max I would run on a +25 offset wheel. I want to widen these wheels or get wider ones, but that's really not necessary now, 20x8.5 is fine but 20x9.5 would be sweet.

[katzjamr]

2010 rx runs 19's now, nEOn, imagine what you could do with that...

[chand3]

ive stretched the limits of what the rx400h can fit, i run a 255/50/18 Pirelli Scorpion Ice/Snow in the Winter, Absolutely Love that tire. Great in the Snow, Ice, Dry, Rain, amazing all around tire, just a bit noisy on the highway.

I run a 275/40/20 on my summer wheels, this is probably the max size you can do on the RX400h, maybe .5" taller but I wouldn't push it. Anything wider is tough since it rubs the inner sidewalls, I run a 5mm spacer / extended lugs (from an is300). you could probably get away with running a 10mm wheel adapter and your wheels won't stick out past the fender. I can probably bump my wheels out another 5-10 mm without any issues, running a 15mm wheel adapter would be probably the max I would run on a +25 offset wheel. I want to widen these wheels or get wider ones, but that's really not necessary now, 20x8.5 is fine but 20x9.5 would be sweet.

Neon,

Do you require a spacer for the 255/50/18 winter tire? I also want to put wider tires on the OEM rim, but would rather not have to use spacers. Also, how do the Pirelli's compare to the OEM all seasons (handling, braking etc), if you can remember how they felt seeing as you have upgraded your summers.

I'm not too happy with the handling of the OEM 235 Michelins, so I'm hoping to at least improve my winter ride by getting wider tires. I'll upgrade the summers when the Michelins wear out in a couple years.

[Agosin]

I just switched over to winter tires; I purchased a set of OEM 18 wheels off eBay for a excellent price. They were a little scratched up, but these will be used in the winter with road salt and such, and i didn't want to ruin the original set.

I purchased a set of 245/60/18 Continental ContiTrac LX. I bought them used as I couldn't justify spending $900 on a set of tires that would be used for 4 - 5 months of the year. The DOT number is 2006, so they are fine with regards to age.

I know the OEM size is 235/55/18. To me the always seemed a little wimpy. I won't go into how I hate the Goodyear RS-A performance, but until they wear out......

The larger tires are great, the car seems to ride truer, with no noticable ride difference. If anything, they ride quieter. But I read on TireRack.com the the Contitrac is a great tire.

What do you think of going with a larger tire??? I have a 10 day try and buy. If they don't work out, or I hear a great reason not to run a larger tire, I can get a set of 235/55/18 Goodyear Assurance. Also ranked very well by TireRack.com.

I ride these tires: Nokian 275/40 R20 106 Y XL to my entire satisfaction since June and just switched to the regular 235 snow tires, I got as an all in option from toyota on car purchase.

[lemon]

Since you mentioned Tire Rack, I thought I'd quote what they say about choosing the right snow tire size. Here it is:

A wide, low profile or large tire has to "plow" a wide path through snow which causes more resistance. The narrower the tire, the easier you can get through snow. We'll help verify sufficient load capacity and the appropriate diameter for your vehicle when you speak with one of our sales specialists or use Winter Shop by Vehicle.

Winter tire sizes should be based on one of the following:

The Optional Tire and Wheel Size from Your Vehicle's Base Model

This is often the easiest way to select an appropriate narrow tire for your car or truck. For example, a 2003 Lexus IS300 would store its original 215/45R17 tires in favor of optional 205/55R16 tires on 16" wheels.

A Minus Size Tire and Wheel

Minus Sizing is simply traditional Plus Sizing techniques used backwards. For example, a 2003 Volkswagen Jetta GLX VR6 would store its original 205/55R16 (or optional 225/45HR17) tires in favor of Minus One or Minus Two size 195/65R15 tires on 15" wheels.

In both of these examples, not only would snow traction be enhanced, but the cost of a Base Model or Minus Size winter tire & wheel package is usually lower than a package maintaining your vehicle's original size tires and wheels.

I have Bridgestone Blizzaks, size 235/65R17, mounted on dedicated alloys for winter driving. For summer, Bridgestone Alenzas mounted on the OE alloys, size 235/55/R18.

While the 235/65/17 works for winter (and is in fact what I have on my RX - not by choice - bought used Lexus rims with Pilot Alpins) a better size for winter would in fact be 225/65/17.

Good tire calculator here

http://www.miata.net/garage/tirecalc.html

where you can see that the stock 235/55/18 has a diameter of 28.2 and the 225/65/17 has a diameter of 28.5 vs the 235/65/17 with a diameter of 29. Not a huge difference, but the closer the replacement diameter is to the original, the better.

[Calvin@Canada]

I also have a question on tire size.

My wife has a 2006 Rx400h which currently has 235/55V/18's and are 5 x 4.5 (or 5 x 114.3 in mm)

I have a fellow trying to sell me a set of rims and tires that are 18" Motegi racing rims (FF7) they are 5 x 4.5 with an offset of 45 and the tires are 225/40/18's.

I know if I use these tires they will be smaller and that will offset the speedometer by 10% or so but I"m thinking I could just buy the rims and then just put new tires on the rims as they are a decent price even without using the rubber. Would there be any problems with using the right size rubber on these rims (sorry I don't know a lot about tires)

Thoughts?

Thanks

Calvin

[lemon]

The offset on the Lexus rims is +35 (or maybe +32 - I forget). I'm no tire expert either, but I don't think I'd go with a +45 offset on those rims. I definitely (absolutely, positively) wouldn't use those tires - the difference in overall diameter is too great (3 inches).

[Calvin@Canada]

The offset on the Lexus rims is +35 (or maybe +32 - I forget). I'm no tire expert either, but I don't think I'd go with a +45 offset on those rims. I definitely (absolutely, positively) wouldn't use those tires - the difference in overall diameter is too great (3 inches).

I was thinking the same thing on the tires but the rims should be ok with the right tires correct?

Thanks

Calvin

[lemon]

I'm no expert on wheels, so I don't know if a +45 offset vs a +35 offset is a huge deal or not. Maybe ask at at a dedicated wheel/tire shop.

[Calvin@Canada]

I'm no expert on wheels, so I don't know if a +45 offset vs a +35 offset is a huge deal or not. Maybe ask at at a dedicated wheel/tire shop.

Lemon,

Good call - I ended up calling my Lexus dealer and they told me that the range is 35 to 42 for offset. I could go more but I'd void my warranty (and as I paid for the extra warranty to 160,000 km's that is a no go). Should have called first I guess but I thought I might get lucky on the forums.

Cheers

Calvin

[RXREY]

Right now I have 255/55 18' and they are great, about 1/2" bigger than the stock 235/55s. I want to get Michelin Primacy Mxv4s but they don't have our size but after I looked at the tire calculator, their 225/60 18s are really, really close. They are in between the stock and the 255/55s...a wee bit closer to the latter. so...225/60 18" works just fine for us. Rey in L.A.