wanted to get a list of pros and cons together of these two tires sizes (of the same tire).205/55/16 -stock size-more slection-fills wheel well better-proper speedo and odo
205/45/16-smaller diameter = slightly better accel-slightly lighter- shorter/stiffer sidewall for more quick response.
what else to add?
how much do you guys think there will be a difference is there in the shape of the footprint between these 2 sizes?
Ive also heard that since 205/55 is a very common stock size, this size isnt as high performance as other rarer sizes. anybody have anything to back this up?
205/55/16 vs 205/45/16
-
Shift_Kouki
- Posts: 692
- Joined: Mon Sep 11, 2006 2:34 am
- Car: 95 Nissan 240SX SE
Im running the 205/50/r16 version of the Khumo ECSTA SPT
Just like the 45's I think there is a lower load index on the tire. Hence why tire rack called me about my order telling me a higher minimum inflation pressure than what was listed for the tire under nominal circumstances.
Its not that big a deal for me on street driving as I hardly ever keep my tires under 40psi... But when I go autocrossing now... Lets just say I miss that wider pressure adjustment range.
I think all your guesses about the pros and cons of the tire are correct, but if I were to do a smaller tire again, I'd want other areas of suspension adjustment because you are loosing some of the tire pressure adjustment.
Just like the 45's I think there is a lower load index on the tire. Hence why tire rack called me about my order telling me a higher minimum inflation pressure than what was listed for the tire under nominal circumstances.
Its not that big a deal for me on street driving as I hardly ever keep my tires under 40psi... But when I go autocrossing now... Lets just say I miss that wider pressure adjustment range.
I think all your guesses about the pros and cons of the tire are correct, but if I were to do a smaller tire again, I'd want other areas of suspension adjustment because you are loosing some of the tire pressure adjustment.
Re: (Shift_Kouki)
Can you explain a little bit more detail on what you expereinced with the tire pressure adjustment range?
I know with my experimenting with different size tires, I was running some 45's in the rear and experienced excessive wheel spin at 42psi, little bit better at 38psi, and final at least reasonalbe at 35psi.
Granted I didnt have the same exact tire to compare the affects of different sizes.
I know with my experimenting with different size tires, I was running some 45's in the rear and experienced excessive wheel spin at 42psi, little bit better at 38psi, and final at least reasonalbe at 35psi.
Granted I didnt have the same exact tire to compare the affects of different sizes.
205/45/16 has a load index of 83.
A Standard Load tire reaches it's maximum load carrying capacity at 35psi. The maximum load carrying capacity is engineered at 35psi even if the max pressure may say 51 or something on the tire. Here is a load index chart of load indexes and max load carrying capacities.http://www.discounttire.com/dtcs/infoLoadIndex.dos
205/55/R16 89V= S14 SE oe tire. OE pressue= 29psi.(89 max load = 1279)
205/45/R16 83 = your tire in questionnew pressure= ???(83 max load = 1074)
With some algebra you can determine the intended oe load each tire is to carry at 29psi.
(maxpress)/(maxload)=(oepress)/(intended load)X=intended load35/1279=29/XX=(1279*29)/35X=~1060lbs
Now the new pressure of the new tire can be found in a similar fashion.
(maxpress)/(maxloadnew)=(newpres)/1060Y=newpress.35/1074=Y/1060Y=(35*1060)/1074Y=34.5psi
You have to put 35psi in that tire to just match the oe s14 tire at 29psi. Putting 29 in that tire would be under inflating by 6psi.
On that same note, with a higher load index you could put less air than oe to have same load carrying capacity.
Hope it's not to confusing.
A Standard Load tire reaches it's maximum load carrying capacity at 35psi. The maximum load carrying capacity is engineered at 35psi even if the max pressure may say 51 or something on the tire. Here is a load index chart of load indexes and max load carrying capacities.http://www.discounttire.com/dtcs/infoLoadIndex.dos
205/55/R16 89V= S14 SE oe tire. OE pressue= 29psi.(89 max load = 1279)
205/45/R16 83 = your tire in questionnew pressure= ???(83 max load = 1074)
With some algebra you can determine the intended oe load each tire is to carry at 29psi.
(maxpress)/(maxload)=(oepress)/(intended load)X=intended load35/1279=29/XX=(1279*29)/35X=~1060lbs
Now the new pressure of the new tire can be found in a similar fashion.
(maxpress)/(maxloadnew)=(newpres)/1060Y=newpress.35/1074=Y/1060Y=(35*1060)/1074Y=34.5psi
You have to put 35psi in that tire to just match the oe s14 tire at 29psi. Putting 29 in that tire would be under inflating by 6psi.
On that same note, with a higher load index you could put less air than oe to have same load carrying capacity.
Hope it's not to confusing.
-
Shift_Kouki
- Posts: 692
- Joined: Mon Sep 11, 2006 2:34 am
- Car: 95 Nissan 240SX SE
Basically, Eddie explained it in a properly technical manner that I would be hard pressed to match. So I'm not going to touch why the max loads for tires are the way they are.
All I'm going to say is that because I don't want to go under my min inflation pressure of 36 or so... I have 7psi less pressure to play with compared to an OE size of the same tire with the same max pressure.
Honestly, it's only ever been an issue when Auto Crossing and I want to set my pressures to make the car oversteer a little for a better slip angle.
If I didn't have stock suspension I'd be adjusting other things as well... But with the stock hardware, tire pressure is just about all I have to play with on the track.
All I'm going to say is that because I don't want to go under my min inflation pressure of 36 or so... I have 7psi less pressure to play with compared to an OE size of the same tire with the same max pressure.
Honestly, it's only ever been an issue when Auto Crossing and I want to set my pressures to make the car oversteer a little for a better slip angle.
If I didn't have stock suspension I'd be adjusting other things as well... But with the stock hardware, tire pressure is just about all I have to play with on the track.