205/45/16 or 205/50/16

[Carcrazy]

So I've been thinking about this for a while and have come up a list of pros and cons for each size. Both are about the same magnitude off from the original diameter but in opposite directions. In general what are most people running and why? It would be nice to hear the difference from someone who has used both sizes and preferably in the same model tire.

205/45/16:
Pros: Lower effective gearing, ~2 lbs less weight, Quicker turn-in/less sidewall squirm, lower center of gravity.
Cons: More road noise and bump harshness, bigger wheel well gaps

205/50/16:
Pros: Better road isolation, better fender filling for a lower look
Cons: slower acceleration , ~2 lbs heavier (can these be felt?)

I should qualify the fact that I'm thinking of using 7.5" wide wheels. Most will ask why not use the 215/45/16 and my answer is that I want to keep the cost of the tires down on a street car, I don't think I'll utilize the potential of them on the street, they are heavier, they'll net less MPG, and they will hydroplain more easily. Because a 7.5" is quite wide for a 205, the 50 series may look better in that it won't appear so "stretched", so I'm leaning toward the 50 series.

What is your opinion? thanks.

 

[niky]

I feel uniquely qualified to answer this, I just switched from 205/45R16s to 205/50R16s. Same tire type, Neova AD07s.

Yes, you can feel the difference in weight on initial acceleration, and it costs you maybe a horse or two so in the higher reaches. Seems to have an effect on fuel consumption (maybe 1 mpg) versus the 205/45s, but I don't know how much more than stock.

The 45s feel noticeably sharper and firmer in turns unless you put a lot more pressure in the 50s.

I got the 50s specifically to provide better pothole protection than the 45s. They should be more comfortable, but to get the cornering performance I want out of them, (at about 37-38psi) they're almost as stiff anyway. I'm starting to regret the decision.

The performance advantages of the 45s are really quite noticeable versus the 50s. If you don't have a problem with slowing down for potholes, those are the ones I'd get.

 

[Action Jackson]

Depends on the tire's construction as to the comfort level.

On the same wheels I used Fuzion ZRi 205/50/16. These tires are so stiff that the ride is very harsh.

On Hankook RS2's in 205/45/16, these tires are comfy and way, way better than the Fuzion's in performance. I went with the 45's to save weight.

 

[5PADZAM]

my answer is that I want to keep the cost of the tires down on a street car, I don't think I'll utilize the potential of them on the street

I think you answered your own question right here. You are talking about a street car that you don't plan to push the potential on. I can't answer because I never ran the 45's. But I was very happy with my 205/50/16's. The also made the speedometer closer to actual speed than it was with the stock tire size. With the 45's your speedo will be even farther off than with stock tires.

 

[Carcrazy]

super. thanks for the replies! I guess the performance gains of the 45s outweigh the comfort benefits of the 50's, but from my searches here it seemed like most were going with 50's instead of 45's, on stock rims at least. Perhaps that's due to the greater selection of 50's. The 50's sound sluggish compared to the 45's.

Which would you say performs closer to the 195/50's? Which is closer to the 195/50's in terms of comfort?

What width rims are you guys running, BTW? I think the wider rim should help with the side wall stiffness/turn-in, so I might still go with the 50's, but the acceleration and efficiency benefit of the 45's is temping seeing that this car can use every hp it can get.

Anyone find the 205/45's much rougher than the stock size or is the difference in comfort barely noticeable?

 

[khaosman]

50 looks perfect, go with that

Any loss in performance you will just have to fix with upgrades (thumb)

 

[Magus]

i personally have 205/50/16. They might have a slightly higher gearing and weigh a bit more, but it's ok. The tires I got have steel enforced side walls. So with 36psi and the strong side walls it handles great. I was told by others that the tires do a very good job of communicating the road feel. Great if you AutoX. If you are running on a road course, maybe go with the 45's.

 

[NVP5White]

I just bought 45's after only owning stock-sized tires. While I can not directly compare the two, I can say my decision was based on my desire for sharper steering & turn-in. IMO, the P5 will never be "comfortable" on the roads I drive (rt 66 in Northern VA), so why not go for performance.

 

[JoshP5]

I would definitely not use 7.5" rims for 205s. It'll look stretched in 45 or 50 series. Ask me how I know.

Mazda uses 6.5" for 205/50s and 7" for 205/45s. I'd stick to those guidelines if possible.

 

[Carcrazy]

I would definitely not use 7.5" rims for 205s. It'll look stretched in 45 or 50 series. Ask me how I know.

Mazda uses 6.5" for 205/50s and 7" for 205/45s. I'd stick to those guidelines if possible.

Thanks. I'm fine with the stretched look. I've had that size in a different car before. What is your experience and why do you not recommended it?

FWIW, my 01 Miata Sport came with 205/45/16 on a 6.5" rim.

 

[JoshP5]

I mentioned Mazda's sizes based on the current Miata and the Protege MP3, which use 16x6.5, 205/50; and 17x7, 205/45 respectively.

I'm running 16x7 and 205/50 and the tires (Falken 512) look stretched. It bugs me. But the "stretch factor" does have a lot to do with the type of tire you get, not just the size. Some look better than others. My Miata had 15x7 rims and I ran Pirelli (and later Kumho) 195/50s and it looked fine.

 

[khaosman]

Yeah, certain tires run wider. Higher performance tires will run wider, like Azenis. Hell, my new Bridgestone Potenza RE01R 205 series tires are damn near as wide as my 225 Kumho V700 race tires.

 

[rickrock]

For the important relation of weight on your wheels and tires, I catched this really interesting article on JTuned:

Specificly for the thread:

Unsprung Weight The weight from the Suspension apparatus which includes the Tire and Wheel combination is called “Unsprung Weight”, and reducing the weight of this section is crucial to the performance of the vehicle. If 1kg of weight is saved from the suspension system, the value of a 15kg weight loss from the vehicle’s overall weight can be saved. This means if an aluminum wheel which is 1kg lighter than a stock steel wheel is installed, 60kg of total of body weight can be saved.

The entire article: http://www.jtuned.com/content/templates/tune.aspx?articleid=288&zoneid=16

 

[Carcrazy]

Yeah, certain tires run wider. Higher performance tires will run wider, like Azenis. Hell, my new Bridgestone Potenza RE01R 205 series tires are damn near as wide as my 225 Kumho V700 race tires.

agreed, and the degree of stretch is subjective. Are we all concerned about appearance? I assume that stretching a tire only stiffens it's side wall and that is desireable.

interestingly, on at least one model of tire on the Tirerack, the specs listed indicates that the 45 has a narrower section width and that's when measure on a 0.5" wider wheel, 7". Both indicate a max wheel width of 7.5", but the 45 has a 1" wider minimum width of 6.5". I guess you need more side wall to fold in toward the wheel, but both 45 and 50s can be stretched to the same width.

 

[niky]

I guess it depends on the tire. With extreme performance rubber like AD07s or Falken Azenis RTs, 7 - 7.5" of width seems just right. My friends run AD07s and Azenis RT215s on 15x7 rims, and they look really fat on them.

My spare is still my stock 16x6, and I got a 5th tire (kinda stupid thing to do... so sue me... ), and it looks like it's falling off the wheel... it's so wide. on 16x7, it's still a bit fat. On my previous set of AD07s, the 45s, it's just perfect.

It's really up to you. Good luck!

 

[JoshP5]

Are we all concerned about appearance?

Yes.

I assume that stretching a tire only stiffens it's side wall

No.

 

[Carcrazy]

Josh, can you please elaborate on why you don't think stretching a tire on a wider rim stiffens the side wall or is at least beneficial?

 

[JoshP5]

Sure. Since the sidewall does not change structurally depending on how wide the rim is, mounting on a wider rim does nothing to stiffen it. Its orientation, however, changes slightly. This may affect how the tire responds to loads, which may be beneficial or malign.

Which is better from a performance standpoint, this |___| or this \___/? Since manufacturers do their research, development, and testing on the former, I'll stick with that.

Do you have an argument for stretching?

 

[Carcrazy]

Thanks for your personal rational.

I personally can imagine the sidewalls being tighter and stiffer when stretched. As such, there is less potential for lateral movement of the side walls when they are pulled with more tensile force, but maybe there isn't any more tensile force on the sidewall...I'm not sure.