pros and cons of 17 Vs 18

[okla7788]

Hi, I am new to tingering my car.

 

I am considering getting a new set of wheels and tire for my LGT 05.

 

After reading the FAQ on wheel size by Xenonk i am confuse as to the pros and cons of the different size wheels/tires

 

I am hoping to get a bit more grip in corners.

 

It appears that smaller the wheel/tire the faster you can accelerate and more torque. (205/40/17 are described as superfast) So why would anyone want a larger wheels/tires? I must be missing the point here.

 

What about the overall weight of the wheel/tire combo. The weight of the wheels are often listed. How about the weight of the tires. How would the weight of 215/45/17 compare to weight of 225/40/18?

 

Thanks in advance for your help

[froggert]

So why would anyone want a larger wheels/tires? I must be missing the point here.

 

possibly looks, brake clearance or shorter stiffer sidewall.

[krzyss]

Do not forget "bling" effect!

 

If I am not mistaken one car magazine did 17 vs 18 comparo and 18 buys you more expensive tires and heavier wheels.

 

Krzys

 

PS My only reason would be brake clearance but I suspect I would need second set of wheels and brakes for winter (maybe a whole winter car ;-)

[Xenonk]

it's been posted many times before, please read other similar threads about this 17 vs 18 vs 19 vs 20 rim size discussions.

[Shea]

Remember that larger wheels will throw off your speedo. You will possibly increase your top speed a bit with larger wheels, but with larger wheels, comes more weight and more power to turn.

 

Personally, a 17 inch wheel with the 215/45-17 tires are a perfect combination for performance and reliability in all weather. You can still get a really aggressive snow tire or all season tire without selling any organs.

 

If you are in an area where it never snows, then an 18 inch wheel may be best, otherwise, I think the 17s are perfect.

[Xenonk]

Remember that larger wheels will throw off your speedo..

 

 

Not true.. you can use the plus sizing method to retain the same speedo reading.. what you will be sacrificing is the sidewall height of your tires..

 

Total overall tire diameter of a stock GT is 24.8".. so that means 17" of that is the rim, while that leaves 7.8" for the tire sidewall thickness... if you were to go with an 18" and still retain the same speedo rating, then you need a tire that has a sidewall thickness of 6.8".. and 19" rim would make the tire 5.8" and so forth.

[Shea]

Oh, right, I forgot about that part. lol

[robinlsb]

The real issue is contact patch. Given a choice, I would opt for wider 17s unless there were brake clearance issues.

[Xenonk]

^ +1.. wider would be the case for summer tarmac.. but not so for snow use..

 

so the real question comes down to "what do you want to do with your car?"

[Xenonk]

 

I am hoping to get a bit more grip in corners.

 

It appears that smaller the wheel/tire the faster you can accelerate and more torque. (205/40/17 are described as superfast) So why would anyone want a larger wheels/tires? I must be missing the point here.

 

What about the overall weight of the wheel/tire combo. The weight of the wheels are often listed. How about the weight of the tires. How would the weight of 215/45/17 compare to weight of 225/40/18?

 

Thanks in advance for your help

 

 

Taller gearing for taller/bigger tires.. a good example is looking at a stock GT topping out at 58 mph in 2nd gear in stock tire size.. but lets say you want to stay in 2nd (for the sake of being in the power band and not wanting to upshift, happens a lot in autox and tight courses), so you want to get a taller tire to get more mph for every gear.. it can vary as much as 5mph (depending on how big you want)..

 

You could go the other way and run smaller (and actually opt to shift into 3rd instead) and run a smaller tire.. spend more time turning rpms than to turn the tire.. it's something that everyone thinks about. The down side to that is the load capacity of a smaller tire on a bigger car.. if you are cornering THAT hard or carrying that much weight/force, it's possible that you are over working that little tire too much (hence my note saying the smaller tires are only good for autox use rather than street use).

 

Sometimes you can live and deal with the momentum calculations of the heavier tire setup (sacrifice some acceleration) for the sake of grip due to a wider and heavier tire. You can also go with a lighter rim as well to help that issue but the fact remains that you have to see which is more important for you:

 

Running a lighter tire with less grip capacity VS Running a heavier tire with more grip capactiy.

 

In my preference, I like to run as wide as possible first (weight gained) to maximize grip and the contact patch and worry about the weight later. Then I look into getting a taller tire later.. if I can help it, get a larger rim first and run a lower profile tire (less mass at the edge of the rim to lower the moment calculations.. Praedet has all the info on that to help support my theory). It's also possibly that a lower profile tire is lighter than a taller profile tire, given at the same overall tire diameter, metal is just lighter overall than a steel belts and heavy sidewall construction material located at the very edge of the rolling diameter.

 

Falken Azenis RT-615s is one of the heaviest tires around, but for the amount of grip they offer, I'll take that over a lighter tire with less grip (like the old Toyo T1-S or new Toyo T1-R, a lighter tire by as much as 5 lbs in comparison of the same size).. I can always go in hotter/faster into a corner and use all that grip, rather than spending time slowing down more into a turn and then take advantage of the acceleration due to the lighter weighing tire with less grip. After all, it's grip and time we are comparing.. so spend less time in the turns by not coasting through the turn, get grip to turn the car in, finish the turn quick as possible, get back on the gas ASAP.

 

Go wide, worry about the weight later.

[BigT]

Why are wider tires worse in the snow?

-T

[KartRacerBoy]

Don't forget that a heavier wheel/tire combo will also affect ride and to some extent grip. As you get more unsprung mass that the suspension has to deal with, the suspension will be affected if it has to control too much mass. At the extreme, your ride will suffer just from this effect, as will your handling, espec. in bumpy turns.

[Daedalus]

Why are wider tires worse in the snow?

-T

 

Correct me if I'm wrong but, less of a tire patch or contact area (thinner tire) cuts through the snow better and puts more weight on a smaller area (friction). The wider tires will 'float' and snow-lo-plain (haha i just made that up) easier.

[Paradiso]

Why are wider tires worse in the snow?

-T

 

For the same reason that snowshoes let you walk on snow that you would sink into down to your knees if you were walking in boots.

[BigT]

For the same reason that snowshoes let you walk on snow that you would sink into down to your knees if you were walking in boots.

__________________

 

Wouldn't that principle make the wider, and hence more surface area, tires better?

[lookslikeanevo]

^no cus now your driving on soft powder, instead of the road

[itsme]

Do not forget "bling" effect!

 

If I am not mistaken one car magazine did 17 vs 18 comparo and 18 buys you more expensive tires and heavier wheels.

 

Krzys

 

PS My only reason would be brake clearance but I suspect I would need second set of wheels and brakes for winter (maybe a whole winter car ;-)

 

I think larger wheels may be getting a bad rap. Peolpe say going bigger wheels will make your car slower but, why is the '06 spec. B faster than stock GT? It the same car, motor , and tranny. But it has 18" wheels. If you are not racing I don't think you will notice much if you keep weight and overall dia. close to stock. I went with 19's". I have 225/35/19 on 19"x 7.5(only @20 lbs). I have not noticed any degrade in preformance(Nothing stage 1 won't fix:icon_bigg) The ride is not bad. My wife did not notice a change. I got 19's because I thought they looked good and I got a good price. I think they really make my car stand out.(maybe you would call that bling:) ).

[Xenonk]

Why are wider tires worse in the snow?

-T

 

 

you dont want to mat down the snow.. you want the weight of the car with a skinny tire to cut through the snow and onto the harder pavement to get the grip you need..

[Xenonk]

I think larger wheels may be getting a bad rap. Peolpe say going bigger wheels will make your car slower but, why is the '06 spec. B faster than stock GT? It the same car, motor , and tranny. But it has 18" wheels. If you are not racing I don't think you will notice much if you keep weight and overall dia. close to stock. I went with 19's". I have 225/35/19 on 19"x 7.5(only @20 lbs). I have not noticed any degrade in preformance(Nothing stage 1 won't fix:icon_bigg) The ride is not bad. My wife did not notice a change. I got 19's because I thought they looked good and I got a good price. I think they really make my car stand out.(maybe you would call that bling:) ).

 

 

actually, it's faster because of the different gear ratios (Spec B uses a taller tire.. it's actually transmitting the rotations of the motor into more distance covered over the same period of time).

 

Lighter wheels are better.. that's the idea.. not heavier rims.. size matters when WEIGHT becomes an issue.. the next issue is momentum calculations and rotational mass.. run a lighter rim, then you'll feel in response from steering, accelerating, and braking.. it's really noticable.. racing or not. Just cuz you have lighter rims doesnt mean you have lighter tires.. it all makes a difference.. tell me which is easier for you to swing in your hand a 5 lbs weight or a 20 lbs weight? It could be a weight or a huge box, it's just going to be akward for you to control a bigger box at the end too (think of your suspension parts).

[Hiroki]

Well, theres also the thing about rotational inertia.

 

An 18lb 17" wheel will effectively be lighter than an 18lb 18" wheel. Sure, on a static frame of reference an 18" wheel may seem to be the better deal. But remember when they're spinning, rolling mass is much more of a problem. Since most of the weight of a wheel is by the rim, that 18" wheel will have most of its weight half an inch further outwards than that 17" wheel.

 

But then again, a stiffer sidewall will also increase handling performance. Regardless of what manufacturers say about their sidewall stiffness, a 35 profile tire will be stiffer than a 45 profile provided their widths are the same and the only difference is wheel diameter.

 

Its a balancing act really, and for street performance, something I think will yield un-appreciable differences. So buy your wheels for whatever reason makes you feel good.

 

Besides, if you get that anal about performance, you'd probably be the ones that track their car and would have a second set of track-only tires.

 

<-- Ran BBS RK's 17x7 (17-ish lbs) with 215/45/17 FS SZ50EP's on track with BBS LM F1's 18x7.5 (18.3) on 225/40/18 FK RT 615's on street.

[Xenonk]

An 18lb 17" wheel will effectively be lighter than an 18lb 18" wheel. Sure, on a static frame of reference an 18" wheel may seem to be the better deal. But remember when they're spinning, rolling mass is much more of a problem. Since most of the weight of a wheel is by the rim, that 18" wheel will have most of its weight half an inch further outwards than that 17" wheel.

 

But then again, a stiffer sidewall will also increase handling performance. Regardless of what manufacturers say about their sidewall stiffness, a 35 profile tire will be stiffer than a 45 profile provided their widths are the same and the only difference is wheel diameter.

 

Its a balancing act really, and for street performance, something I think will yield un-appreciable differences. So buy your wheels for whatever reason makes you feel good.

 

Besides, if you get that anal about performance, you'd probably be the ones that track their car and would have a second set of track-only tires.

 

 

you totally forgot the tire and its weight and the affects of the tire compound in terms of grip that it can offer..

 

and being anal about weight? it's more about being able to get better control out of the car.. I am not going to dump money into the car if it's not going to either make it run faster or more effiecent..

[Hiroki]

I wasnt talking about the tire dude... "affects of the tire compound in terms of grip?" que? what are you talking about? we're discussing wheel sizes right now.... besides if you want to discuss tire grip then you'd want the widest size possible with as stiff of a sidewall as possible all the while balancing with tire/wheel weight.

 

Well you maybe a special case considering you're really heavy into motorsports. The average guy may not give a crap about the weight and just go for looks instead of shelling out thousands for lightweight 16's, R comps that he'll only enjoy every other sunday in an auto-x setup for 5-6 runs.

 

Im still going to stand by my thoughts that effects an un-appreciable on street applications. Thats unless you buy 20" spinnArz that weight 40-50lbs standing and are comparing it to 17" SSR Integrals (16-ish lbs?).

[Xenonk]

I wasnt talking about the tire dude... "affects of the tire compound in terms of grip?" que? what are you talking about? we're discussing wheel sizes right now.... besides if you want to discuss tire grip then you'd want the widest size possible with as stiff of a sidewall as possible all the while balancing with tire/wheel weight.

 

Well you maybe a special case considering you're really heavy into motorsports. The average guy may not give a crap about the weight and just go for looks instead of shelling out thousands for lightweight 16's, R comps that he'll only enjoy every other sunday in an auto-x setup for 5-6 runs.

 

Im still going to stand by my thoughts that effects an un-appreciable on street applications. Thats unless you buy 20" spinnArz that weight 40-50lbs standing and are comparing it to 17" SSR Integrals (16-ish lbs?).

 

 

you cant run a wheel without a tire last time I checked.. so the tire has to be part of the equation when you are working into this discussion.. and last time I checked, most tires are heavier than the rims.. rims/tires have the same principles as if you were swinging a sledge hammer.. sure, you can have a lighter and longer handle, but you are putting the weight of the head further out away from the center, thus making it harder to control (it's torque 101).

 

What I was trying to say is that based on tire construction differences, there's weight differences and different compounds yield different grip levels (you can go as wide of an all-season tire, but it's not going to have the same grip as a narrower race-compound or even a summer tire). A wider tire can add weight (especially when using the plus sizing method).. eventually, you'll also need stronger sidewalls in the process to maintain the similar load capacities of the stock tire (unless people here want to run a lower load capacity which I dont know why), but all that just adds up more weight to the overall package.

 

What the guy may spend on looks on heavy weight rim can cause other potential wear and tear that some of us are overlooking such as:

 

excessive wear in brake pads

higher temps in rotors which may lead to warping

wear on the wheel bearings (if the offset is also too far out)

wear on suspension components from shocks to springs and all the bushings in between..

or better yet, a possible difference in gas mileage as one would potentially feel a difference if one is a spirited driver (doesnt even have to be a weekend racer, some of the people out there drive their cars as IF it was a race to work everyday).

 

We are dealing with a smaller range of a scale when it comes to wheels.. of the rims I have gone through (from 27 lbs 18" rims down to 17" 12.5 lbs rims) theres a dramatic difference, even for street applications as you say. IF you look at the difference, that's a 14.5 to 15 lb gain per corner.. it may not seem like much, but I would like to see you carry 15 lbs on your arms every day and swing them around like wheels and tell me if you get some burning in your shoulders.. even like the human body and cars, we go through wear and tear.. problem is, the only thing that repairs the car is the owner making the decision to repair the car or not.

 

And to go back on tires, here's a pro to a 17" rim, the 17" tires are usually cheaper as well.. if you want to factor in the price, it can go both ways.. you can spend very little money on a heavy rim, or you can spend more to get a lightweight rim.. ride quality is dependent on the tire selection you choose so either case for a 17" or an 18" application comes down to a wash. As for looks, here's a pro and con for an 18".. a con would be something like making your stock brakes look small.. on the other hand, an 18" rim could accomodate a larger rotor and possibly bigger calipers for a really nice street look.. (dont forget to fill in your wheels after you fill in your wheel gap).

 

This discussion of 16" vs 17" vs 18" vs 19" vs 20"s have more than 12930532905875 threads on this topic. It's getting old to even think of arguing about which is better.. the fact is that I can't argue someone about looks vs performance.. it's the same thing that goes with people that make their cars for show and some for racing.. it's your own preference of which you want your car to do..

[thatwouldbegreat]

17" wheels are a good choice, there are lots of inexpensive wheels and tires that are high quality and perform quite well.

 

I upgraded our 2005 OB from the factory 225/60-16 sucky RE-92's to 225/55-17 Michelin Hydroedge on Tire Rack's $75 Sport Edition wheels.

 

Big improvement in handling and a better look, IMHO.

 

There are lots of well reviewed high performance all season 17" tires that are around $80 to $150.