Wheels, Rims, Tires. I Know Nothing

[tmhtmh]

OK, I did a bunch of searches for rims, wheels and tires and I see it's been talked to death here. great info, but one problem - I am so ignorant on the topic I can't follow much of the discussion. So I have so basic questions I hope some of you can answer.

1. Looking at the window sticker from my 2002 RX300, I see it came with "160 Aluminum Alloy Wheels" and "225/70SR16 Mud and SnowTires". Could someone de-code each of those numbers and tell me what it means?

2. If, as I assume, those are 16" rims, does that mean my tires need a "16" at the end of the code?

3. I see lots of talk of 17,18 and 19" wheels folks have used. WHY? Wouldn't that change the outside diameter of the tire and thus screw up the spedometer and odometer? Or is there just less diameter of tire on those rims?

4. Now, I will be buying a set of rims so I can have my snow tires on a seperate set. That means I can use either the current rims or whatever I buy for the snow tires. Are snow tires "right" on the current rims or is a different rim maybe better? Same question for "summer" touring tires (want smooth, quiet ride) I will be buying?

Thanks again for the help. I've learned a ton here that will help our family enjoy the Lexus even more!

[scoobie]

OK, I did a bunch of searches for rims, wheels and tires and I see it's been talked to death here. great info, but one problem - I am so ignorant on the topic I can't follow much of the discussion. So I have so basic questions I hope some of you can answer.

1. Looking at the window sticker from my 2002 RX300, I see it came with "160 Aluminum Alloy Wheels" and "225/70SR16 Mud and SnowTires". Could someone de-code each of those numbers and tell me what it means?

2. If, as I assume, those are 16" rims, does that mean my tires need a "16" at the end of the code?

3. I see lots of talk of 17,18 and 19" wheels folks have used. WHY? Wouldn't that change the outside diameter of the tire and thus screw up the spedometer and odometer? Or is there just less diameter of tire on those rims?

4. Now, I will be buying a set of rims so I can have my snow tires on a seperate set. That means I can use either the current rims or whatever I buy for the snow tires. Are snow tires "right" on the current rims or is a different rim maybe better? Same question for "summer" touring tires (want smooth, quiet ride) I will be buying?

Thanks again for the help. I've learned a ton here that will help our family enjoy the Lexus even more!

tirerack.com probably has more tire info than you ever want. But here's some short answers to your questions (from a layman),

1) I don't know what the "160" means, but "225" is tire width in millimeters (mm), "70" is the aspect ratio, which gives you the tire height (distance between outside diameter and inside diameter) as a percentage of width, in your case it is 225x0.70 = 157.5 mm, "S" is the tire rating, sort of tells you how fast that tire was designed to go, "R" means radius, "16" is radius of the wheels in inches.

2) yes.

3) When you go to larger rims, you need different size tires as you suspected. You can do the math yourself, tirerack.com has a lookup tool. Idea is to keep the outside diameter of the tire the same (as old setup) but the inside diameter must of course match that of the wheels.

4) I think they make snow tires for many sizes, so that alone should not drive your rim size decision. But if you want comfort, the general consensus, I believe, is for smaller diameter wheels.

edit: under 1) "R" cannot stand for radius, one would have gigantic wheels in that case LOL, it probably stands for radial, a type of tire construction. The "16" is *diameter* in inches.

[tmhtmh]

Thanks. That helps me with the numbers.

I guess I'm still not clear WHY one would use a larger diameter rim. Is it functionally better in some regard or just because some may prefer the "look". Nothing wrong with the "look" reason, just trying to understand the WHY of wheel size.

[scoobie]

Thanks. That helps me with the numbers.

I guess I'm still not clear WHY one would use a larger diameter rim. Is it functionally better in some regard or just because some may prefer the "look". Nothing wrong with the "look" reason, just trying to understand the WHY of wheel size.

Larger wheels => smaller aspect ratio tires => less lean when turning.

Some people prefer less lean for better "feel".

[tmhtmh]

Thanks, scoobie. My 2002 RX300 does really lean on turns. That's the worst part of the "ride" of this vehicle I'd say. So a larger wheel size would help that, which makes sense based on the physics of it (smaller rim, more rubber to "give", larger rim, less rubber profile).

Now, does the smaller rim give a smoother overall ride? (more rubber and air to ride on)?

Thanks again.

[Topshelf]

Yes guys, make sure you know what you want before upsizing your rims. Going to a larger 18/19/20" rim will have a considerable negative effect on the smoothness of your ride. Also remember that there's a lot more to body roll than just rim size, so don't think that throwing some 20's on there is going to give you a perfectly flat cornering experience. Most likely you'll notice the harsher ride more than the slight decrease in roll. These are vehicles designed for a nice smooth highway ride, not sporty cornering. So moving up to a 17, maybe an 18 would be a good compromise if body roll is that much of a problem, but I'd find someone with a similar mod first since it isn't cheap if you don't like it. Personally, I'll stick with my 16's and enjoy the quiet comfort of my B-Stone Alenza's.:)

[Grumpa72]

Thanks. That helps me with the numbers.

I guess I'm still not clear WHY one would use a larger diameter rim. Is it functionally better in some regard or just because some may prefer the "look". Nothing wrong with the "look" reason, just trying to understand the WHY of wheel size.

Larger wheels => smaller aspect ratio tires => less lean when turning.

Some people prefer less lean for better "feel".

The down size to bigger wheels and tires, of course, keeping the outside diameter approximately the same, is that the ride typically suffers. The reduced sidewall from a bigger tire gives less flexibility and therefore reduced ride comfort. Like the saying goes, there ain't no free lunch.

Gary

[RX in NC]

Tmhtmh mentioned in another post that he was "cheap". If cost is indeed a factor, you'll be better off to stay with your 16-inch rims not only for a better overall ride, but also for the fact that your future replacement tires will be considerably less expensive than those for larger rims with a lower profile.

[tmhtmh]

Tmhtmh mentioned in another post that he was "cheap".

HEY!!! I resent that! DID I say I was CHEAP?!?!

uh...oh yeah.....that's right, I am cheap. Thanks for the reminder, RX/NX.

I think I'll stick with the 16" rims and buy a second set for my snow tires. Also, my research points to the Michelin Cross Terain or the Yokohama Geolander as good choices for all-weather tires when the snows aren't on. I only put the snow tires on for the "meat" of the winter, so i want decent traction in crappy weather with my "normal" tires. However, I value comfort/smooth ride for the Lexus (that's why I bought it, after all) and the reviews I read say these two tires provide that also. It's also why, after all the good advice here, I'll likely stick with the 16" wheel.

Yeah, I know those are expensive tires, sometimes even us cheapos splurge a bit. (Of course, i'll shop around for the best deal I can get!).

[tmhtmh]

Oh, one more question on the topic of rims/wheels.

If I'm looking on eBay for a set (I'm in no hurry) what other vehicles use the same OEM size wheel? Is it 16" x 7.5" rim? I see lots of Highlander wheels that are 16" x 6.5" . I assume I don't want those, right?

I have also looked at tirerack.cm and tires.com to see what's out there. I'd prefer used from eBay for my snow tires if I can get a great deal.

[Topshelf]

Don't overlook the Bridgestone Dueler H/L Alenza. It is not the same crappy OEM tire that came on these trucks. The RX I purchased had these mounted on them and I am incredibly impressed with the comfort, quietness, traction and superb handling these tires provide. The guy I bought the RX from used these to get out of an insanely steep driveway and some twisty roads during the past winter with no problems at all. Right now they are listed as #1 on tireracks chart, but they only have about 1/8 the miles as the Yokohamas and 1/26 as much as the Michelins. If you actually read the Lexus reviews on tirerack for the Yoko's you might change you mind...I did. I was fully prepared to drop the coin on the Michelins, but am so impressed with these tires, I have no thoughts about changing and $650 back in my pocket. I just thought I'd share since you are asking for opinons.;)

[tmhtmh]

great, Topshelf, complicate my decision with experience and research..... Just what I needed.

I'll have a look at 'em. Especially if I see them on sale around here! They are an "all-weather" correct? What size do you have on yours?

[Topshelf]

Haha, sorry to use my exhaustive research and experience on you.

Yeah, they are a Highway All-Season in the stock 225/70-R16 size. You can check them out here. I don't think you can go wrong with either these or the Michelin CT's, and the guy at BJ's Wholesale Club said they are going to have a sale right around mid April....tax refund money. Anyway, I know they carry the Michelins and I'm not sure about the Stones. But they have really good prices and an excellent deal with the mounting/balancing/roadside plan. Good luck with your choice, but I don't think you can make a bad one at this point.

[TunedRX300]

Oh, one more question on the topic of rims/wheels.

If I'm looking on eBay for a set (I'm in no hurry) what other vehicles use the same OEM size wheel? Is it 16" x 7.5" rim? I see lots of Highlander wheels that are 16" x 6.5" . I assume I don't want those, right?

I have also looked at tirerack.cm and tires.com to see what's out there. I'd prefer used from eBay for my snow tires if I can get a great deal.

One of the most overlooked aspect of tire/wheel is rotational mass. Every pound you save at the wheels translate into two pounds in static weight during acceleration and braking. Remember the car needs not only moves tires/wheels forward (like other static weight of the car) but also keeps them rotating. This means lighter lug nuts, rims, and tires will save you a lot of gas and brake pad.

Have you ever wonder why RX came with alloy rims instead steel rims? One of main reasons is to reduce unsprung weight. OEM rims weight 26 lbs per, made of cast alloy, if you can finds a set of forged alloy rims, you will save >10lbs per rim. It is even more importance to be careful with tire weight because it is mounted at least 16" moment arm from the axel. Ever swing a old tennis racket that is made of aluminun instead of titanium? Now image how much harder you have to swing if all of weight added is at the top of the racket.

[Topshelf]

Hold on there cowboy! Yes, unsprung weight is always something you want to minimize. However, on a truck like ours, you would spend a whole lot of money to gain almost nothing in return. Yes, the truck will accelerate a little quicker, but that would be almost imperceptible under normal driving conditions. As far as braking goes..your still stopping a 3700lb vehicle, so the brakes still have to do their job. If this was a race car, there would be absolutely no question about going with the lightest rims possible. Hell, I raced motorcycles for 5 years and even the weight of the tires were a factor in which brand to buy, and they only varied by 1 or 2lbs. But you're also talking about 400lb machines where every ounce was huge. tmhtmh seems to me like he's just looking for a nice riding and reliable luxury SUV. If that's the case, his best bet would be to put new tires on the factory rims and find some cheap steelies for his dedicated winters. That gives him the perfect setup for what Lexus had in mind. If he, or anyone else is worried about 0-60 times and lateral g's, then some 20" low profile high performance summer tires on carbon fiber rims is the way to go. Everyone needs to make that decision based on their wants out of their vehicle. I just don't want anyone thinking that dumping $2500 into tires and rims is going to drop their 0-60 times by 2 seconds, make their brake pads last 3 times as long and give them 27mpg. But if .2 seconds, 3 months longer and maybe .5mpg is what's important, by all means spend the money and enjoy your new bling. ;)

[tmhtmh]

Guys, thanks again for getting me straight on this. I still have one issue to better understand on this.

What is the width of the OEM rims? Is it 6.5", 7", or 7.5 "? AND do I need the exact width in a new set to fit well? Also, is the "offset" I see mentioned on rims fairly uniform or do I need to duplicate the OEMs on this?

I guess what I'm wondering is how specific the rims are to the vehicle. Do similar vehicles use the same )Highlander) or is it even more broad tha that? Would MANY makes/models of vehicles have rims that fit my 2002 RX300? I know many are sold used fairly cheap but I don't know how I know if a set will fit like I want.

[TunedRX300]

Hold on there cowboy! Yes, unsprung weight is always something you want to minimize. However, on a truck like ours, you would spend a whole lot of money to gain almost nothing in return. Yes, the truck will accelerate a little quicker, but that would be almost imperceptible under normal driving conditions. As far as braking goes..your still stopping a 3700lb vehicle, so the brakes still have to do their job. If this was a race car, there would be absolutely no question about going with the lightest rims possible. Hell, I raced motorcycles for 5 years and even the weight of the tires were a factor in which brand to buy, and they only varied by 1 or 2lbs. But you're also talking about 400lb machines where every ounce was huge. tmhtmh seems to me like he's just looking for a nice riding and reliable luxury SUV. If that's the case, his best bet would be to put new tires on the factory rims and find some cheap steelies for his dedicated winters. That gives him the perfect setup for what Lexus had in mind. If he, or anyone else is worried about 0-60 times and lateral g's, then some 20" low profile high performance summer tires on carbon fiber rims is the way to go. Everyone needs to make that decision based on their wants out of their vehicle. I just don't want anyone thinking that dumping $2500 into tires and rims is going to drop their 0-60 times by 2 seconds, make their brake pads last 3 times as long and give them 27mpg. But if .2 seconds, 3 months longer and maybe .5mpg is what's important, by all means spend the money and enjoy your new bling. ;)

There is no magic here, conservation of energy. Energy the car used to push 40-50 lbs of additional rotational mass either can be saved or used for propell the car forward. We are talking about ROTATIONAL mass mounted at a MOMENT ARM, not just static weight on other parts of the car.

Again, a wooden or aluminum tennis racket does not weight much, but titantium and carbon alloy design allow tennis player to hit the ball harder for the same amount of force. No one is using wooden racket anymore, just like no luxury car is using steel rims anymore.

Benefits for both acceleration and deccelarate last for the life of the car. It also gives the owner to customize the look. How many item can you claim three tangible long lasting benefits?

If one has to replace wore out OEM tires, it is not $2500. Plus there should be a high residual value of rims that are well designed with superior material. $2500 out of pocket cost is a well inflated cost.

Find one tire 2-3lbs heavier than the other, mount them on the drive axel of a car, you will immediately see the effect of torque steer, the car will pull to the heavier side because more torque is delivered to the light side.

Have you realized that both OEM tires, Goodyear Integrity (25lbs) and Bridgestone Dueler (28lbs) are two lightest tires on the market for 225/70/16 tires? They perform poorly in snow and wears quickly, but Lexus know most people do not complain about wear until 2-3 years later and snow traction until the first heavy snow fall, but they will check the mpg at the first fill-up or first glance at the fuel computer display.

[TunedRX300]

Guys, thanks again for getting me straight on this. I still have one issue to better understand on this.

What is the width of the OEM rims? Is it 6.5", 7", or 7.5 "? AND do I need the exact width in a new set to fit well? Also, is the "offset" I see mentioned on rims fairly uniform or do I need to duplicate the OEMs on this?

I guess what I'm wondering is how specific the rims are to the vehicle. Do similar vehicles use the same )Highlander) or is it even more broad tha that? Would MANY makes/models of vehicles have rims that fit my 2002 RX300? I know many are sold used fairly cheap but I don't know how I know if a set will fit like I want.

OEM is 16x6.5, +35 offset. There is only 12mm clearance between the OEM tire and the rear strut, if you go for wider rim/tire you need a spacer for lower (less positive) offset to push them out.

I bought a set of used 18x7.5 SSR Competition off ebay for $830, each weight 15.5lbs, 10 lbs lighter than OEM rim despite 2" larger in diameter and 1" wider. Pirelli Scorpion Zero 235/60/18 is just $10 more than OEM sized Michelin Cross Terrain. Since my OEM tires wore out, real tire cost to me is just $40.

SSR are forged alloy made in Japan, not cheap and heavy cast steel (who still provide OEM rims in steel anyway ), or run-in-the-mill cast alloy. 20 Muteki cold forged lug nuts M12x1.5 cost $33 shipped off ebay. Each weight 29g each, OEM lug nut is about 70g per.

BTW, OEM alloy rims do not like the combination of winter road salt and brake dust. My RX had two winters in upstate NY and I washed my car every 2-3 weeks during winters, still have aluminum bubbles formed under the clear coat.

[tmhtmh]

Thanks, Tuned. I appreciate the wheel/tire education.

Why did you go 235 vs. 225 OEM ? How does that effect ride comfort and handling? Or is it just a better "look" for you?

Also, I still can't get soemthing here. Can the wider tire (235) be put on the same 6.5" rim? I know you don't have OEM rims now, but can it be done on the OEM 16" x 6.5" rims.

Lastly, you mentioned the offset is +35 OEM. OK, then would I use that or a more-posative (say, 50 ofset) or do I go more negative (20 offset)? Or doesn't it matter much. Obviously, if I buy new from a wheel shop they can hook me up with what i need. But if I buy from aBay or the newspaper I need to know what to get.

Thanks again.

[Topshelf]

Yes, I do understand the benefits of lighter wheels and tires. It is proven and true. But I still say it's not worth the cost unless you are mainly interested in bling. Do you have any records of mpg or 1/4 mile times before and after changing out the rims/tires to show the improvement gained? And ofcourse putting a heavier combo on one side will cause the vehicle to pull in that direction, might as well put a smaller tire on one side and see what happens. I'm not telling anyone not to do it. I'm simply saying that unless your goal is to put some fancy looking rims on you car, there's no point in spending the extra money expecially since going to a larger rim size is most likely going to decrease the comfort of the ride. I personally prefer the factory look over these ill proportioned giant rims, but my opinions shouldn't make anyones decision. You seem happy with your purchase which is great, and I'm happy with my stock setup. Just want to make sure that tmh has both sides of the story before running out and spending all his money on something he may or may not be happy with. ;)

[TunedRX300]

Thanks, Tuned. I appreciate the wheel/tire education.

Why did you go 235 vs. 225 OEM ? How does that effect ride comfort and handling? Or is it just a better "look" for you?

Also, I still can't get soemthing here. Can the wider tire (235) be put on the same 6.5" rim? I know you don't have OEM rims now, but can it be done on the OEM 16" x 6.5" rims.

Lastly, you mentioned the offset is +35 OEM. OK, then would I use that or a more-posative (say, 50 ofset) or do I go more negative (20 offset)? Or doesn't it matter much. Obviously, if I buy new from a wheel shop they can hook me up with what i need. But if I buy from aBay or the newspaper I need to know what to get.

Thanks again.

Lexus offers 235/55/18 and 18" rim as RX330's optional equipment. Yes there is a handling and comfort tradeoff but 18" setup is good enough for Lexus offer to RX's owners.

I went to 235/60/18 because I wants a little more rubber height, it is only 0.65" shorter than RX300's OEM setup. Icing on the cake is my odometer records 2.46% fewer miles than actual, which gives me more actual miles under warranty and better resale value. Pirelli Scorpion Zero is the OEM tire for Porsche Cayenne and VW Touareg. Tirerack has pretty good owner feedback rating on wet and dry traction ratings on this tire.

Wider tires would be unsafe to fit into rims that are too narrow. Tirerack has a good article on rim width guideline matched up with tire width.

http://www.tirerack.com/tires/tiretech/tir...sp#measrimwidth

If you go with bigger rims/tires, the offset should be less positive. You can play with this handy calculator to figure out the effect of different offset and rim width.

http://marksink.com/tire_wheel_offset/offset.html

For me, it is a no brainer as I need to replace worn out OEM tires and damaged OEM rims, no way I will spend more $ on OEM products when I can get better combo for the same cost. Honda S2000 JDM and Subaru WRX STI supply BBS's forged rims as OEM standard equipment. JDM S2000's OEM is 16" and weight 13.3lbs, about 50% of RX's OEM rims. If a mere 2-3 lbs difference in tire weight on the SAME drive axel can pull my 3483 lbs Acura TL consistantly to one side, one can see how much 13lbs PER wheel can do for acceleration. This is NOT due to tire diameter change, but mainly power DELIVERED to each tire. A mere 2.5% (0.5mpg on 20mpg) translates to about $218 fuel saving per 70K miles, assuming one fills up with $2.50 per gallon.

As I first posted, wheel/rim weight is one of the (most overlooked) factors you should consider. By no means, it is THE factor. Research and decide for yourself.

[Topshelf]

A mere 2.5% (0.5mpg on 20mpg) translates to about $218 fuel saving per 70K miles, assuming one fills up with $2.50 per gallon.

Ahh, that's all I was trying to say. It's going to take 70,000 miles to save $218 on gas!!! I think I'll be just fine spending the extra $36 per year over the next 6 years in gas to keep my current setup. Again, if it's your thing please enjoy. Facts are all I'm concerned with.

Oh, and usually when a larger wheel size is offered from the factory, it comes with chages to the suspension to compensate. And most go for a larger tire when choosing a sport package where the comfort trade-off is a given.

[TunedRX300]

A mere 2.5% (0.5mpg on 20mpg) translates to about $218 fuel saving per 70K miles, assuming one fills up with $2.50 per gallon.

Ahh, that's all I was trying to say. It's going to take 70,000 miles to save $218 on gas!!! I think I'll be just fine spending the extra $36 per year over the next 6 years in gas to keep my current setup. Again, if it's your thing please enjoy. Facts are all I'm concerned with.

Oh, and usually when a larger wheel size is offered from the factory, it comes with chages to the suspension to compensate. And most go for a larger tire when choosing a sport package where the comfort trade-off is a given.

LOL, that is just a small part. You are making it sounds like this is everything. Didn't I say there are THREE main beneifts plus other "icing on the cake". I am not here to debate with anyone, just trying to help the guy who starts the thread with all information before he consider buying tire/wheel combo.

Here is a fact for you. KYB, RX300's OEM strut supplier, lists same strut part #s as soon as one selects FWD or AWD. Front ones are 235905 (left) and 235904 (right), regardless of performance package.

[Topshelf]

Hahaha, I'm not looking to argue either. Just wanted to put the THREE main benefits in perspective since it's easy to lose sight of what's important or how great the effects truly are. I think there's more than enough information and facts presented in this thread fro tmh and anyone else who is interested in upgrading their rims. So let's just leave it at "to each his own" and enjoy our RX's. B)

[bassholic]

A mere 2.5% (0.5mpg on 20mpg) translates to about $218 fuel saving per 70K miles, assuming one fills up with $2.50 per gallon.

Ahh, that's all I was trying to say. It's going to take 70,000 miles to save $218 on gas!!! I think I'll be just fine spending the extra $36 per year over the next 6 years in gas to keep my current setup. Again, if it's your thing please enjoy. Facts are all I'm concerned with.

Oh, and usually when a larger wheel size is offered from the factory, it comes with chages to the suspension to compensate. And most go for a larger tire when choosing a sport package where the comfort trade-off is a given.

hmmm gas use to be $2.50 ??

The only reason this was brought back to the top was i found the gas comment funny and i am looking for rim options and this thread popped up in the search