My original RFs have finally run their course, so I am looking at some new non-RF summer rubber for my Clubman. I am looking at the Continental ExtremeContact DW and was originally just considering the 205/45-R17 size. From the time I bought my R53 in 2003, I have always just run the stock tire size, but I'm curious about the benefits/drawbacks of going to a 215/45-R17 size.

When comparing the specs of the two tires sizes, obviously the 215/45-R17s are going to be slightly larger.

Diameter
205/45-R17: 24.26"
215/45-R17: 24.62"

Section Width
205/45-R17: 8.07"
215/45-R17: 8.46"

Sidewall Height
205/45-R17: 3.63"
215/45-R17: 3.81"

Circumference
205/45-R17: 76.23"
215/45-R17: 77.34"

With those numbers in mind, what differences am I going to see in the real world between a 205/45-R17 and the 215/45-R17 tire? Logic would tell me the following...

A larger diameter tire should result in less gap space between the tire and the wheel arch...a bit less than 1/2". The wider section width means a larger contact patch, and should mean better grip. However, turn-in will probably feel a bit less crisp. A slightly larger sidewall should equate to a bit of a more comfortable ride, especially on crappy Chicago-area roads. However, more sidewall also means more lateral movement of the tire, so I guess they could feel a bit more squirmy under heavy cornering. The larger circumference will affect the speedometer accuracy, probably bringing it closer to showing the actual speed (instead of reading high). It seems like 215/45-R17s can be installed without fear of rubbing with a stock suspension setup.

So what are some pros/cons that I may be missing or not even thinking of?

 

Only half of the difference in diameter will affect the wheel gap. Wider tread (which you don't list) will result in a wider and shorter contact patch with the same area as before. Better cornering, worse acceleration and braking. Half of the wider section will be an increase in protection against curb rash. Speedometer will be more accurate. Odometer will record fewer miles. Load rating is higher on the 215. 215 is 0.5 to 1.5 lb heavier. 205 fits a 7" wide wheel better which aids handling. 215 still fits though.

Now, after digesting and calculating all of these morsels of information, I promise you that in a blind taste test you won't know the difference between these tire sizes. And they are only $3 different in price at TireRack. You will be gob smacked happy you bought either size after torturing your MINI and you on runflats.

 

A few more things to add to the list. If you went from 16x195 to 17x215 you would have felt the difference. I do notice the difference going from our winter 16x195 to summer 17x205. The added width and grip makes the steering heavier. Wider tires also means more drag which in turn will result in worsened mpg. But like every thing else it's somewhat promotional so you may not realize the fraction of difference added. Weight Will go up slightly and larger diameter will add to mpg as well as through a slightly slower acceleration. This is affecting mostly city driving with a lot of stop and go. On the highway = better mpg. Again all incremental.
It will also affect the alignment. It could help or hurt depending on the tire used. I'm having issues of excessive corner wear with the type summer tires I have and mini alignment spec which don't create any issues with my winter tires.
If you were in a snowy zone l would add less grip in snow. Thinner tire is actually better in the snow.
Most likely it will be just fine. But it's a good question.

 

I definitely felt a difference on my old R53 going between my summer 205/45R17s and winter 195/55R16s...turn in felt much crisper, even on the winter rubber.

I guess these responses pretty much sumsup my expectation...that most people probably cannot tell the difference between the same 205/45 and a 215/45 tire.

I'm looking at the Continental ExtremeContact DW...so I guess my question now becomes, why would I go with 215/45 instead of the original equipment 205/45 size?

 

I have three sets of wheels one with oem size 205/45/17 which is good looks good and rides well. The other set is 215/40/17 with direzza star spec really good handling and looks good too but will better when lowered and sometimes harsh with stock suspension. And other set is 215/45/17 with extreme re-11. And those are my favorites with perfect handling and soft on potholes and are quite responsive even tho are taller. I used to run dws with same size and it was very good comfort tire I have them for sale with less than 1000 miles... I went with 215 because I thought it will improve grip. But my tires still spin in second gear and sometimes in third.

 

I just bit the bullet, and went with the Continental ExtremeContact DWs in the 215/45-R17 size. I don't think the size change is drastic enough that there is going to be a noticeable difference between the 205/45 and 215/45. Either way, they're going to be better than my current RFs.

 

I'm betting you will notice the difference, either choice is good.

 

I'll definitely notice a difference between runflats and non-runflats...back in the day, when I got my R53 off runflats, it was a revelation.

I'm just curious how much difference I'd really feel between the 205/45R17 and 215/45R17 Continental ExtremeContact DWs. I think the most noticeable difference would be the crispness/responsiveness upon turn-in, due to the extra width.

But I'd guess most people could not tell the difference between identical 205/45 and 215/45 tires mounted on their MINI.

 

Allowing for rounding measurements to the nearest tenth of an inch (which Continental does in their specifications), the differences in size are:

tread width: 0 - 1.3%; actual reported: 7.0 and 7.0"
section width: 0.1 - 2.3%; actual reported: 8.4 and 8.5"
sidewall height: 1.5 - 5.3%; actual reported (diameter) 24.3 and 24.6"
weight: 6.3 - 7.4%; actual reported 17.5 and 18.7 lbs.

I'd say the 205 DW would turn in faster (faster response to steering input).
I would also say that anyone who says they can tell the difference in these sizes on the street is likely comparing a worn out tire to a brand new full-tread-depth tire.

 

So I ended up going with the 215/45-R17 Continental ExtremeContact DWs, and got them mounted last week. After week and ~400 miles, I am still "breaking in" the tires, so I cannot comment positively or poorly on the performance aspect yet.

As for the size change however...the only daily driving difference I can tell at this point is that turn in is a bit less "crisp". It's barely noticeable, but it's there. However, I'm still figuring out tire pressures, so perhaps that could aid that feeling somewhat (though I don't expect it to completely go away). Outside of that, it just feels like I went from a runflat to a non-runflat tire...much more comfortable and they soak up the bumps in the road a hell of a lot better.

 

Curious, what were your tire specs before? Assuming you had 205/45-17 with run flats?

Please keep us updated!

 

The slower steering response is due to no longer having super stiff sidewalls in the runflats. In trade you will have better compliance, better foot print, better grip, and better ride.

 

sdiver,

You're doing fine, for the Conti ExtremeContact DW for each tire size you mentioned the prices are very close and both offer XL sidewalls which means the sidewall is a little more reinforced and a little stiffer which helps with responsiveness/handling.

On stock suspension both tire sizes are fine, if you care about wheel gap then 215/45-17 is a good choice. If you had not selected an exact tire then there is better tire selection in 215/45-17 for many tire classes.

Realize that the exact tire you choose plays a big role in how it will perform for you whether for street comfort, better handling or more grip. This is due to the rubber compound, tread design, etc. and can be a bigger factor than just tire size alone.

This means the DW in either size will feel very close, minor for street driving.
But if you changed to Michelin Pilot super sport, either 205/45-17 or 215/45-17 will feel more comfortable and perform better both dry and wet. However it costs significantly more.

You can appreciate this from the owners survey for Max Summer tires in 215/45-17:
http://www.tirerack.com/tires/survey...=true&filter=y

But the final test is how does it work for you.

 

+1. I seriously doubt anyone outside of being a professional driver will be able to tell the difference.

Its all what we THINK we are feeling based on a fuzzy memory of what we used to have.

 

 

How do you think 215/45-17 tires are going to protect rims on bad roads any differently than 205/45-17 tires would? Just because the sidewall is 10mm x 45% taller?

Answer is tire size difference is not as big a factor. Bad roads are bad and potentially trouble no matter what tire.

However some summer tires will ride more harshly and be more jarring. Look for a tire that has more ride comfort, lower noise, a little more sidewall softness vs stiffness either due to SL vs XL load rating or sidewall construction.

16" rims allow for tire sizes that are much taller- 195/55-16, 205/55-16 or 225/50-16 but tire selection may be different than in 17" sizes. Better performance tires come in 17" while more All season and street tires come in 16".