What, if any, is the performance advantage of having larger wheels/tires on a car? By larger I am referring to taller, such as 20" wheels vs 18" wheels.

Tom

 

Good aluminum wheels should weigh less that a tire, so you reduce unsprung weight and rotational mass, which helps (slightly) in acceleration and braking.

The sidewall has less give, so corner response can improve somewhat and feel more "connected".

They let you have space for larger brakes.

The cost is ride quality. The stiffer sidewall transfers more road imperfections to the chassis and ultimately your bones.

 

I agree with you, Charlie, with some clarification. I've heard conflicting reports about wheel diameter vs. tire diameter. Some claim that there are plenty of "good" aluminum wheels whose incremental weight with increasing diameter actually exceeds the incremental weight savings of an inflated tire with a proportionally increased rim diameter.

I have never taken the time to attempt to prove or disprove this allegation to my own satisfaction, so I decided to do a very small test just to see if the results seemed to lean one way or the other.

Using Tirerack.com and BBS-USA.com to search for tires and wheels of the same exact design and manufacture but with different rim diameters, I found the following:

19 inch set:

BBS RS-GT RS-959-DBPK chrome 19X8.5, weight = 20.8 pounds

Pirelli P Zero Nero 245/45ZR19 8.5” rim, overall rolling diameter 27.7”, weight = 31 pounds

Total weight of 19 inch set: 20.8 + 31 = 51.8 pounds


20 inch set:

BBS RS-GT RS-983-DBPK chrome 20X8.5, weight = 23.6 pounds

Pirelli P Zero Nero 245/40ZR20 8.5” rim, overall diameter 27.7”, weight = 28 pounds

Total weight of 20 inch set: 23.6 + 28 = 51.6 pounds


I noticed that it is important to compare wheels with the same finish because the plating can add 0.5 pounds or more. Comparing a chrome plated wheel with a painted wheel is apples to oranges.

So what can we conclude from the above example? I'm not sure. The 20 inch set weighs 0.2 pounds less, but the weight of its rim is concentrated 0.5 inches further from the axle, presumably increasing its rotational mass compared to the 19 inch wheel. We also don't know the precision of the weights of the wheels and tires listed in the manufacturers' specifications. It's possible that the actual difference in weight is smaller or greater, but presumably within a few tenths of a pound.

I look forward to your thoughts, Charlie, as well as to the input of others!

Cheers,

Don

 

You get a weight saving only if your rims are similarly made, e.g. forged or cast.

I noticed a very different weight for my tyres/rims in 17" (width 7.5")compared to 18" (width 8"). Both rims are Jaguar OEM.

The 18" are the Luxury model, the 17" are 10 spoke forged wheels (Fuchs design, lightweight 8.5 kg per rim).

I can tell you the 17" + 235/55R17 tyre is much lighter (maybe by 20%, don't remember) than the Luxury + 235/50R18 tyre, even though the external dimension of the mounted set is the same!

 

Another issue with larger diameter wheels is the likelihood of damaging a lower aspect ratio tire, at least here on the lousy Michigan roads! My 04 XJR came with 255/35R20 tires and I damaged one when hitting a pot hole. I replaced the rims with 19" in order to go from a 35 to a 40 aspect tire with additional sidewall to absorb the jolts.

 

No, none that you can discern, unless you are putting it on a race track. It is all downside with a rougher ride and wheel damage with any potholes you encounter.

The trend towards larger wheels is just a styling nod to the true track cars and the guys who have 26"s on a Monte Carlo, IMHO.
Vector

 

the 20" wheels are noiser, and more easily buckled. They are very expensive to repair or replace. The tyres are very expensive.


If I was starting again, I would go for 18" Luxury.

 

I changed from the factory 19" on my xjr to aftermarket 20" rims. The bigger rim and tire combo weighed a LOT more than originals. I did notice that i could feel the small cracks and bumps a little more, and that hitting the cracks and bumps also transferred a bit more noise into the cabin. So what some people call a drawback or con, may be what some other people prefer. I preferred the slightly better road feel, especially in high speed corners where the most difference was felt, made the car feel more stable. I live near Chicago and YES, the some roads are horrible, and you have to dodge potholes for fear of not only bending a rim, but ripping out your control arms and tie rod ends. Another benefit I found is that 20" tires are substatially cheaper than 19" tires. So it is all up to you, bigger wheels are easier to damage, not only potholes, but curb rash as well.

 

I found that any price difference is highly dependent on the tire make/model when I bought my 19" tires. Some 19's run higher than 20's, others lower. The top-rated summer tire at Tire Rack is the Michelin Pilot Super Sports (the one you selected ). They have the 19" priced lower than the 20" -- 255/40ZR19 = $294, 255/35ZR20 = $309. In all-season tires, the highly rated Michelin Pilot Sport A/S 3 19" is $27 more than the 20" ($265 vs $238) which is hardly a deal breaker.

As with anything, it pays to shop around!

 

I personally don't see the advantage of larger rims. As mentioned earlier the unsprung weight is higher as well as a greater chance of rim damage occurring. The only upside is cosmetic which IMHO doesn't equal the downsides.

 

No advantage at all, just pure aesthetics.

 

I have Michelin Supersports, they cost me £325 each though small discounts are available.


I looked at Dunlop and Pirelli as well but have found Michelins to be best and give good mileage.


The 18" tyres I looked at were all cheaper than the 20", but perhaps it varies by market and popularity.


p.s.
when I got a dent in a rim, I bought an extra 20" wheel and had it refinished to match so that I don't have to drive around on the spacesaver next time. I keep it at home as it is too big for the boot well. There is a repairer near me that heats up and reshapes bent alloys.

 

I agree with you autoxr1, I ALWAYS shop around for price, I have a Jaguar remember . I am a real cheap skate lol. It runs in the family too, I have a cousin that is one of those extreme coupon people that end up paying only sales tax when she goes shopping and get all the food and merchandise for free. Also don't forget about specials, closeouts, and rebates that may be going on at a particular time!! I only paid $265ea for the Michelin Pilot Super Sports so I got a real good deal then?? The rims I have were only $185ea, now that is CHEAP for a 20in rim. Ohh and tirerack gave me free lug nuts with it, and mounted and balanced them for free also so free valve stems too!! CHA-CHING. Tire prices change dramatically all the time. So yes, ALWAYS shop around, not only for base price but also for rebates, specials, closeouts, free stuff like lug nuts (normally $3.00 ea times 20) and free valve stems I got (normally $2.00 ea times 4), but also for the service. They mounted and balanced the tires for free, and if you search around, EVERYONE charges more for tires with a sidewall ratio of 35 or smaller, so that is another $100. I should mention that my dad owns an auto repair shop and we sell tires so we get discounts from many tire dealers including tirerack. Our discounts are not consistent, some brands, some sizes have different markup on them to the consumer.

Please note that tracking information may not be available immediately.

Item Description Availability Qty. Price Each Item Total 20X8.5 5-108 ET40 AR MAVERICK In Stock 4 $185.00 $740.00

Item Description Availability Qty. Price Each Item Total Required centering ring In Stock 4 N/C N/C Required lugnut for vehicle (nickel plated) In Stock 20 N/C N/C GORILLA LUG EXTENSION 19-19MM In Stock 1 N/C N/C

Item Description Availability Qty. Price Each Item Total 255/35ZR20 Michelin Pilot Super Sport In Stock 4 $265.00 $1,060.00

Item Description Availability Qty. Price Each Item Total Mount and Balance (No Charge) In Stock 4 N/C N/C
Item(s) Total:

$1,800.00 Excise Tax:
$0.00 Shipping:
$90.56

 

This is simply not true. There is an advantage to bigger rims. It is called handling, road feel, vehicle stability, quicker steering response, more feedback, and more confidence in the drive when driven hard.

That is why all performance cars have larger rims and tires. A standard jaguar X350 has 17 or 18 inch rims, and the xjr performance model has either 19 or 20. Guess what, the xjr handles better, but its the same car!!

Take a 2008ish chevy impalla, standard size is 16 inch if you get a base model but if you get the performance packages, you get 18 or 20 in rims, BECAUSE IT HANDLES BETTER, and it is the same car!!

How come when you buy a v6 mustang it comes with 16 in rims, buy a v8 and it gets 18 in rims, you get a supercharged or roush mustang with 675 horsepower and is made to handle better than most cars on the street, it has 20 in rims. SO IT HANDLES BETTER, YOU GET MORE ROAD FEEL, MORE VEHICLE STABILITY, QUICKER STEERING RESPONSE, MORE FEEDBACK THRU THE STEERING WHEEL, HIGHER DRIVER CONFIDENCE, AND THERE IS NO ADVANTAGES???????????????

Ok, now yes there are several disadvantages too like rims get bent easier and get more expensive.

Advantages and disadvantages are many times a personal preference!!!!! One person may look at a high end car like a Jaguar and say that all the fancy options are useless and is just something more to break. They consider it a disadvantage to have those options, and say I would never own that, and instead they buy a Base Impala because less options in there eye is an advantage!!! I look at the options like touchscreen navigation and think it is an advantage.

I read a post on here earlier where someone was complaining about the auto exit feature an their jag and wanted to know how to turn it off. They are considering it a disadvantage where a 400lbs guy that can barley get in and out of the car might consider it an advantage.

How many times have you heard someone say "they don't build them like they use to" referring to cars? I for one am so glad we have "better" cars today, while someone else says a 1968 challenger is "better" because it is easier to work on. Being easier to work on is an advantage but I see a lot of disadvantages like getting horrible gas mileage, and needing a tune up every 25,000 miles.

How many times have you heard someone say "I wish they made that out of metal instead of plastic!!" Well it was made with plastic to make it cheaper for the consumer to buy, see, the advantage there was price but someone else thought it was weaker and it was a disadvantage!!

OK end of rant, sorry, but I hope is sheds light on what someone considers advantage or disadvantage.

Advantages and disadvantages are many times a personal preference!!!!!

 

pcar hit it there.

...and if you really want to get into it (miata enthusiasts and racers are obsessed with wheel weight/tire combos), different makes of tires weigh differently. Some may be a couple pounds difference.


I think it was said, but rims depend a lot on how they are made; forged are generally always lighter (and stronger and $$$) than cast. Design plays a big part too.

 

Not always. These look pretty short and fat to me, lol!
Vector

 

Hey Vector, well I said performance cars, that's a racecar

 

Also, half of a new car is made of plastic to reduce weight in the interest of better fuel economy, in order to meet government-mandated corporate average fuel economy standards (CAFE), another "improvement" for which we can thank Big Goverment.

 

I would say the new "plastic" cars are doing much better than the old "steel" ones when it comes to both performance and safety.

Vector

 

You are so right. Car manufactures are constantly trying to lightweight their cars to try to meet the crazy CAFE standards. Plastic bumpers now, more plastic interiors, plastic headlights and so on. They use thinner windows than before, and take a look at our cars, x350 changed to an all aluminum body from steel like the x308 to save weight.

HOWEVER, cars are actually heavier than they use to be due to all the massive extra structures they put in to meet the ever stronger crash test ratings!! Crazy right? a 1968 Charger with a 5.2 V8 had a curb weight of just 3330lbs, but 2014 Charger with a 5.7 V8 has a curb weight of 4253lbs, 923lbs more!!! A 1985 V6 Caprice weight 3494lbs and a 2014 V6 Caprice weighs 4043lbs, 459lbs increase.


Look at a 1980 Honda Civic, got 41mpg city, and 55mpg highway and weighted 1700lbs. A brand new 2014 Civic HF model, (going with the HF model because that is the most fuel efficient model besides a hybrid) it gets 31mpg city, 41 highway, and weighs 2749lbs, gaining over 1000lbs and losing 14mpg hwy mpg and losing 10mpg city.

You would think with the 30+ years of technology and innovations (fuel injections, double the amount of transmission gears, engine variable valve timing, cylinder displacement, active fuel management, variable intake runner systems, 4 valves per cyl, double overhead camshafts and so on), cars would be lighter and get better gas mileage but in fact it has been working in reverse for decades. But it is all on order to be safer, and they have more horsepower than ever also.

According to the National Highway Traffic Safety Administration (NHTSA), the average gas mileage for cars sold in the United States during 1980 was 23.1 mpg. In the NHTSA’s Corporate Average Fuel Economy (CAFE) report, it states that the peak gas mileage for cars sold in America was 26.2 mpg and was achieved in 1987. And in 2004. is was DOWN to was 24.7 mpg. And in 2011, the average mpg went DOWN to 22.4mpg !!! Now remember 2011 included the sale of hybrids and electric vehicles so the average mpg should have been magically inflated due to there mpg numbers but it was still down. Remove the sale of hybrids and electric cars from that list the the 2011 average is probably only 22mpg.

Big brother emissions standards are also increasingly stringent, and all this leads to cars getting worse fuel economy!! A friend of mine worked for car companies writing emission software for them and when I asked why many older cars got better gas mileage, he told me it was emission standards. They could make new cars get MUCH better mpgs but the NOx levels would be to high to pass emission. It also cost manufactures more money to get more mpg out of them, so they compare the cost vs. benefit and see where it starts to plateau. Look at diesels, in Europe they get nearly double the mpgs than they do in the US.

Big brother government demands standards on cars that most people dont know about either. The following in in reference to power window switches. Have you noticed they are the same in all new cars?? The federal government made a written contract that all automakers should make the lever switches (as opposed to the rocker and toggle switches) standard on all new vehicles by 1 October 2010.