Do low-profile tires improve handling?
 

I just bought a 2005 LS430 with 147k miles. My first mod was to replace the brand new low-profile tires and 20" rims the previous owner had installed with the stock wheels and new Firestone tires. My question is, do these low-profile tires improve handling, or is it just about looking cool? If it's the latter, I'll just sell them; if it's the former, I'll hang on to them and perhaps use them in the summer.

When you think about it, this would equate to putting racing strips on the Titanic...

The car was designed to offer a smooth, quiet ride by eliminating as many bumps as possible via the suspension/tires. The lower profile tires do offer some improved grip, but without improving the suspension to utilize the softer, wider compound of the low profile tire, the car could actually feel worse.

So, to answer your question, they, for the most part are supposed to look "cool".

That being said, 20's do fill out the wheel well very nicely!

The local Goodyear dealer says the ultra low profile tires often flat. You'll probably be able to get lots of $$$ if you sell.

In general, rim weighs more than tire, and larger rims add unsprung weight. Now why would Porsche and other exotics have 20-22" rim OEM then, dunno.

I do remember a wheel test where C&D tested stock to +3 on a BMW, this was years and years ago. 17" was optimal. imho the worst offenders are when the rim gets larger, the width stays the same, and the profile is lower. If optional puts 255's on the rear instead of 225's, I'm all for it. But if going +1 does not add width, I'm against, who needs to scrape and dent....

I do care about looks and did a -1 on the LS snows dropping to skinny 225's and 17". Sometimes one has to let function prevail.

It's all about the cosmetics now with the really big rims. Personally I think it's a real ugly look, but each to their own.

Decades ago, having a larger rim with a lower profile tire did help handling as there was less sidewall flex and was usually for sports cars like Porsche. But that was when we were talking about going from a 15" rim to a 17" rim.

Now in the era of 20" plus rims, it means slower acceleration, worse fuel economy, more road noise, horrible ride quality, expensive tires etc and can also even have worse handling as the weight starts to become a drag on the car.

Car and Driver had a pretty good shootout where they would experiment with different rim sizes and see what sort of handling improvements were made from upgrading stock rims, and after about 17" or 18", it started to become detrimental to the handling and performance of the car. And the handling improvements even in the era of smaller rims was pretty menial unless you liked taking your car to the track on the weekends.

I personally would never upsize my rims for a handling improvement.

Thanks for the input. I think I'll just sell them. I never did care for that low-slung, big-wheel skinny-tire look.

I don't care for the look either and hopefully it's just a passing fad just like wearing your pants down below your butt and goes away soon.

Well my BMW has 35's and I like the look, esp when it had runflats. they suit a purpose because it puts 255's on the rear and 225's on the front, and came with the sport package. The stock is square 225's.

Why 255's? Seems like 6/10 folks will say so the car will understeer. WHAT?? The other 4 will say it's for traction. At any rate, they suit a purpose. But not on a LS430. Although I would go with the 245's on 18's, over the 225's on 17's. That has a limited purpose.

Wheels & Tires
 

Wheels and tires can be a can of worms. I'll tell you what I know. Mostly tires and wheels on a street car are for looks.

However:
1. Low profile tires do help handling.
2. Standard profile tires can also be very good for handling, but with modern suspension systems on sporty cars a hard corner, taken very fast, can cause the tire to actually roll off of the rim. I've done it several times and it bothered me. Low profile tires help prevent that.
3. An expert on wheels will probably tell you that a wheel over 19 inches is foolish. 19 is supposed to be the limit although one never really knows. Steel wheels are generally the best wheels and are often lighter than an aluminum wheel because you need more aluminum to make the wheel as strong as steel. NASCAR uses steel and money means nothing to them.
4. Tires change all the time. Temperature, weather, road surfaces, comfort, tire speed and wear ratings are all variables.
5. If you are going to obey highway speeds and not go over 100 MPH, just get a good tire. Price sometimes has little to do with it.

I bought one of my LS 430's from the neighbor lady and she said she was sorry that she went for cheap tires. Thing is, they are Z rated, have never lost a pound of air, handle great and are wearing like iron. Go figure.

Loren

Sounds like the Rydanz that came on my LS. I'm not gonna throw tires into the garbage, just because they were made in China. I would have in the past, but now that I actually own such tires, I won't. Even a Lexus dealer that was selling a LS for top dollar, emailed me a work order showing 4 new Dunlops that listed for $248. When I saw the car in person, they were made in China no names. dEalers really lie. One thing we can always count on in addition to the sun coming up.

Be cautious buying after-market cheap, junk wheels. You don't want to experience this:

In my experience ride quality suffers a lot with low profile tires. On a car I had in the past I went from stock 225/55/16 to 245/45/17 so it was not a drastic change. The bumps and vibrations in the car were brutal. Over the years I just got used to it but during the first week I worried about breaking something in the suspension because the tires were not as cushy. Steering response was improved with larger wheels.

Overall; I would say it is about looks. The LS' stock 18s impress me because the ride is surprisingly nice even on urban streets with really bad surfaces.

who cares whether they handle, those wheels look hideous

Smaller diameter wider thicker rubber lighter wheels better handling.

You might get $600-700 for those wheels with the tires $800 if you wait till spring when everyone wants to keep up with the Jones'

I would think that if the rims are purchased from a reputable dealer, such as an eTailer, they should be fine. For example, I paid $112 for MSW's for my snow tires. The low price does not mean it's junk, as a matter of fact, my buddy has the same rims on his Accord for snows, and the rims are sold out for the season, meaning others have bought them too.

But I know what you mean, there are substandard auto parts floating around on eBay etc....like say a lower radiator support for a Maxima costing 1/4 of OEM. forums have said these can fail as quickly as 12 mos., stick with OEM esp. given the welding needed to install....