Hey NAM,

Reading an MCS review of the 03 year, someone said that the 16 inch wheels felt like they had faster acceleration AND steering response (must be less gyroscopic mass to turn, my guess) compared to the "hefty" 17's. I understand the logic behind this, but I still love the look of those 17 s-lites. Does anyone know if they are indeed noticeably slower?

 

It seems that most drivers who are really into getting the most performance out of their MINI seem to go with 16'' or even 15'' wheels. I would stick to the 17's if you aren't a performance nut, since you like the look. I'm in that boat!

 

Although there may be some slight weight and resistence parameters, my guess would be that any differences would be more dependent on the particular tire's specific characteristics, more than the 1".

 

For any MINI it is a combination of-
wheel design- size and width along with weight
and
Tires used- size and width along with rubber compound/tread and construction.

For best overall handling and comfort for daily use-
Non runflat tires
16x6.5 if stock
otherwise 16x7 aftermarket
205/50-16 or 205/55-16 size
Ultra High Performance Summer or All Season tires

If handling is more important that comfort then
more aggressive faster wearing tires are possible.

If you budget for wheels is larger then light weight
17x7 or 17x7.5 wheels are possible with
stock 205/45-17 or larger 215/45-17 tires will work.

For stock
16" wheels tend to be lighter weight than 17" and in that year the 16" runflat tended to be a little smoother riding than the 17" runflat.
Current runflats are better than in 2003. For best results a non runflat will be smoother in most cases.

It's not that the 17" wheels are slower but being heavier you will need to use more energy/power to move a heavier rotating mass- at constant speed it's fine. You'll notice the difference speeding up, slowing down and a bit when cornering.

If you drive the speed limit in heavy traffic or are easy on the throttle it doesn't make that much difference. Since the MINI is not overpowered, lighter wheels often are a better match especially for the MC.

 

minihune says " For best overall handling and comfort for daily use-
Non runflat tires
16x6.5 if stock
otherwise 16x7 aftermarket
205/50-16 or 205/55-16 size
Ultra High Performance Summer or All Season tires"

Can I interpret this to mean that I can mount 205/50-16s on my stock 16x6.5 7-fin spoke wheels? Pardon my ignorance.

 

Easily. A lot of people do.

 

Good to know, the look of those 16'' ("crown spoke") is growing on me knowing that theyre actually more maneuverable. I'm not a performance nut, but I would definitely prefer a better handling car over better looking. and if i can mount 205's on there, sounds like I would be all set!

 

205/50-16 fits rims 5.5-7.5" wide and has a tire diameter of 24.1" slightly less than stock.
205/55-16 has better selection of tires but slightly larger tire diameter
and fits rims 5.5-7.5" wide and is 24.9" tall.

Using stock suspension both will fit. Wheel gap is slightly less using 205/55-16 and 55 series sidewall is a little softer for more comfort in street driving.

Note the title of the thread-
16 inchers faster than the 17's?
This only applies to stock wheels and tires- and only as a generalization since you can choose various stock wheels and tires.

In the aftermarket world it doesn't apply because if you spend enough you can get almost any size wheel with decently light weight and very sticky non runflat tires for better performance. On a budget it's easier to accomplish with a 15" or 16" wheel and get decent results for daily use.

 

According to the Miata tire size calculator, 205/50s are smaller diameter than my 195/55s. 215/50s are almost the same. Can I do those on my 16x6.5 wheels? That way I don't change the speedometer vs. actual speed relationship.

 

I'm sure you could, but they wouldn't be a great fit. I had the same concern about spedometer (and odometer) acuracy a while back, but the difference is really not very significant. Someone tried to calculated the odometer variance and came up with a couple thousand miles for every 100,000 miles driven.

 

Yes, for stock 16x6.5" wheels
215/50-16 will fit. Fits rims 6-7.5" wide, perfect fit for 7" wide rim.
Tire diameter slightly taller than stock at 24.5" but very very close.
Usually we think of stock sized as about 24.3 to 24.4" tall.

In 215/50-16 you won't find the larger selection of tires but they are usable and will fit. Tirerack.com has about 6 tires in that size. Three Ultra HP summer and one UHP all season, two HP All Season tires.

 

I agree with most of this except the part about the 17's not being slower. Back when I was in the Nissan SE-R (SR20 powered) crowd, there was a lot of discussion and before/after testimonials about the benefits of lighter wheels. People who went from stock wheels with a weight 17.5lbs to lightweigh wheels in the 10-11lbs range frequently reported a drop of .5 sec on the 1/4 mile. Doesn't sound like much, but that's almost the same impact of 15% reduction pulley.

Although I never took my SE-R to the strip, I too felt a significant difference when I switched from stock to 10.5lb OZ Superleggeras (both with 205/55/15 Yokohama ES-100 tires). Not only was acceleration and braking noticable improved, but so was the overall ride. With less unsprung weight (7lbs per corner) the suspension was MUCH more nimble.

How does translate to the MINI? Well the 17" S-lites are about 24 or 25lbs compared to about 17lbs for the 16" V-spokes, a difference of at least 7lbs per corner. Then factor in that the extra weight is 1/2 inch further from the rotational axis and the change in centrifical (sp?) force when accellerating and braking is very significant. What about the suspension? It's no coincedence that strut tower mushrooming is MUCH more common with 17s. The suspense clearly has a trouble slowing down all the extra weigh and absorbing the bumps.

 

So to answer the question of this thread, YES 16's ARE FASTER THAN 17's.

As a planning note, however, you will frequently see race prep'ed MINI's with 17's. This is so that they can fit a big brake kit (BBK) as there are not as many BBK options for 16" & 15" wheels.

 

Other than the " butt dyno", does anyone, not a friend, yourself, have any machine recorded data where they ran 0-60, 1/4 mile, 70 -0, track lap with 16 vs 17 inch wheels and tires, tires beind same brand, series, model,speed rating, just 16 versus 17 inch only difference? It easy to say "I know", "here's why" "these are the stats", but I would like to see factual numbers. Anyone

 

Going from 215/45/17 to 205/50/16 I can tell a huge difference in acceleration. The tires are the same brand and the 17" wheels weigh 16lbs where the 16" weigh in at 18lbs. The 17"s do seem to grip better in the turns.

Looking at 1010's calculator the 16"s are 0.79% faster than stock and the 17"s are 1.44% slower than stock. Stock being 205/45/17.

 

Meaning that if you have the 17" tires and switch to the 16" tires, the car will actually be going 60.4 mph when the speedometer reads 60. Four tenths (.4) of a mph is not a huge difference. The chart does not take into effect rpm, torque, hp, as the axle has to turn 864 times to go a mile for the 16" and only 857 times for the 17". One would think the motor is running easier with the 17" but I have no test to prove my 'think'.

However, thanks for the 1010 tire comparison calculator, it is a good one!

 

You don't need to test, it's simply physics. At a constant speed (i.e. 60mph) the additional weight of the 17's have more momentum, thus the engine wouldn't have to work as hard. Even if the 17's were the same weight as 16's, the 17's put the weight an extra 1/2 inch from the rotational axis, which also produces more momentum. HOWEVER, as soon as you accelerate/decelerate the engine/brakes have to work harder to manage that momentum.

The principle is the same with flywheels. Your Grandpa's Cady has a heavy flywheel which helps make it a great interstate cruiser. For cars with sporting intentions that not ideal. The weight needs to be drastically reduced b/c it impacts the freeness with which the engine revs and, by extension, acceleration.

 

Allow me to interject here:
I have seen this claimed made before many times but since we are talking Physics here we need to be accurate.

What makes a difference in the engine power by consumed by the accelerating/decelerating wheel (and by that -- the vehicle) is the Polar Moment Of Inertia (Some people call it Principle Moment Of Inertia) of the wheel -- tire mounted on the rim -- not the rim weight. Rim weight can give you some indication but not something I would base my tire/rim swap on. Weight comparison between to rims definitely can not give you a performance comparison. I can go into the math but I am sure nobody wants to see that.

I have not seen this data published anywhere, tire or rim manufacturer.

Just thought I bring this up.

 

Can you explain why this is the case?

But I'm sure if you asked anyone involved in racing, they'd choose lightweight wheels over heavier ones.

 

What? How do you figure? Ceteris paribus, going to a lighter rim will give you an acceleration and deceleration improvement. Also, ceteris paribus, going from a larger rim to a smaller rim will give you an acceleration and deceleration improvement, since you are moving the mass towards the rotational axis (rim metal weighs more than tire rubber). If I remember correctly, the effect of moving mass inward (reducing r) gives you an exponential improvement in polar moment, versus a linear improvement by simply reducing mass. Thus, even a small reduction in radius can give you a relatively significant improvement in acceleration. Soooo, before I moved from S-lite to X-lite, I knew I would achieve better acceleration and deceleration. I dropped over 30 pounds, and moved the mass towards the center.

 

What I meant to say that it cannot give you quantitative comparison. In other words you do not know how much performance gain you will get with, say, 2 lb lighter rim. This because you do not know what is the difference between the PMI of the 2 wheels (rims + tires) and the PMI of the wheel -- mounted tire on the rim -- is what gives you the performance gain.

True, in general a lighter rim will result in a smaller PMI RIM. Yes 20% weight saving per rim seems a lot but does it mean 20% saving in the PMI of the mounted wheel. I don't know -- this is what I am saying

As far as smaller diameter wheel, it will result in a higher mechanical advantage but you still need to conceder how does it play with the gearbox ratios and the way the engine vary its torque production with respect to RPM change. I am sure there is bunch of data out there that support the fact that a small reduction in contact radius (i.e. wheel diameter) will result in better accel, to what point I don't know.

Sorry for the long post...

 

NP, makes sense now.

 

I can tell you that when I go from my 17" S-lites in the spring/summer/fall to my 15" Blizzak Snow Tires on alloy rims in winter, my zero to 60 is much quicker - though I've never timed it. The wheels/tires are much lighter.

Always a pleasant surprise at that time of the year.

 

Agreed, and the colder air helps make power. That's why I decided to go with PERFORMANCE winter rubber and went with the Dunlop SP Winter Sport M3's...

http://www.tirerack.com/tires/tires....inter+Sport+M3

 

16's faster than 17's? If the overall diameter of the tires are the same then i would assume the 16's would be due to less weight. However if the same height side wall is used on both rims (same distance from the edge of the rim to the tread of the tire) Than the overall size of the 17 would be larger, and thus effect your gearing.

I tired to explian the differences here in this thread a while back. I Hope it doesnt confuse you. I talk about the overall sizes of rim and tire.

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