I'm downsizing to 16" wheels for winter tires. I'll let you know.
That is What Tire Rack is recommending and I'm close to pulling the trigger.I'm considering 16" DWS tires for our Northwest rain/snow season but is like to locate some 16" Fiesta SES wheels rather than go aftermarket if possible.
Wow. Awesome Explanation. Thank YouOn paper, higher diameter wheels and lower profile tires provide sharper turn in, thus lower diameter wheels and higher profile tires will be "less sharp" at turn in.
As to the 205/40/17, I was totally surprised Ford chose this size as I knew the ride would be extra stiff.
With a 16x7" wheel, you should drop a significant amount of weight per corner vs the stock 17x7. For instance, the 16x7 Team Dynamics Pro Race 1.2
weighs 16.3 lbs, a reduction of 6.2 lbs per corner vs the stock 17x7 wheel's 22.5lbs . Each pound of rotational mass lost provides an equivalent performance gain of a 10 pound reduction in vehicle weight. Using the 16x7 Pro Race 1.2's 6.2lbs decrease in rotational mass, the loss in vehicle weight is 6.2 x 4 x10 = 248lbs. Braking is improved as the amount of heat generated when braking is lowered, and less heat also improves pad/rotor fade/wear.
In general, lighter weight wheels give the suspension more control to keep the wheels planted resulting in better handling. A decrease in wheel diameter will locate the wheel weight closer to the hub, which makes the wheel easier to spin. The ice skater example can be used here as an ice skater spins faster with the weight of his arms close to the body and spins slower with arms extended from the body.
I like to use the 5lb ball example when describing decreases in offset from stock. For example, hold a 5lb ball at your waist, then proceed to extend the 5lb ball horizontally away from your waist. It takes more muscle to hold the ball horizontal the further away from your waist the ball is extended. Because lowering offset moves the wheel weight outward from the stock position, it takes more power to spin the wheel.
I took a quick look at available tires for the equivalent diameter as stock, lower diameter from stock, and higher diameter than stock. Before going any further, a short discussion on tire diameter. The stock tires have a set length of roll out, which is the distance the tire travels to reach one revolution. By lowering the diameter from stock, the shorter the distance the wheel travels to make one revolution compared to stock. Smaller diameters throw off speedometers, resulting in a higher mph readout vs actual. As well, smaller diameter setups affect gearing, resulting in the power band shifting to the lower end and decreasing top end. Conversley, when increasing the tire diameter from stock, the length of rollout increases, speedometer reads a lower speed than actual, and the top end is increased.
With all that in mind, weight typically has the most influence in overall performance. If you are a purist, you can work out the best combination for the driving/performance level to suit your needs. For a daily driver looking for some ride improvement, a taller sidewall and/or smaller diameter wheel and larger sidewall, some performance improvement with lower weight, and a bit of widened stance for appearance if desired is a solid combination. If you auto-x, depending on the class, you will want to lose weight, lower diameter for more power down low, and pinch off a lower offset for a wider stance. For road racing, set ups vary more depending on the design of the circuit.
What is best for most? For a street car wanting increased ride comfort and improve performance, I would recommend a smaller wheel diameter and lower tire/wheel weight, maintain as close to the stock overall diameter as possible, and increase tread width while keeping the offset up to 10mm less than stock. The wider tread width will more than offset the taller sidewall.
Now the tire size...dropping down to a 16x7, while staying as close to stock overall diameter a 205/45/16 will net the same width as stock with a taller sidewall, with many tire options available. 215/45/16 will net a .39" increase in tread width and a taller sidewall, but few tires are available in this size. A 225/45/16 has a taller sidewall yet and an increase of tread width of .79", with few tire choices however.
There are many online calculators to determine fitments. For comparing tire sizes and speedometer error I like to use this one as it is simple and gets the job done. Just put in tire sizes and select compare tire A to tire B. For changes in wheel width and offset, I use this calculator. If you play around with the calculators, you can zero in on what you want and check for availability of size by checking a variety of tire sites. Tire weight is also important to include in your search as well.
If you guys are interested, I can look into a group buy for Team Dynamics 16x7 Pro Race 1.2 wheels. Pm your interest unless the OP is fine with member feedback.
And 205 45 16 DWSs are 18 lbs. Things that make you go Hmm.One other (minor) consideration for going to 16" tires is that all things being equal (height and width) the 16" tire will be slightly heavier than the 17" and thus counteract some of the weight savings on the wheel...for example in Bridgestone RE760 a 205/40-17 is 20 lbs, a 205/45-16 is 21 lbs.
not necessarily true at at. the shorter sidewall needs additional stiffening compared to a taller sidewall tireOne other (minor) consideration for going to 16" tires is that all things being equal (height and width) the 16" tire will be slightly heavier than the 17" and thus counteract some of the weight savings on the wheel...for example in Bridgestone RE760 a 205/40-17 is 20 lbs, a 205/45-16 is 21 lbs.