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Changing the section width also changes the section height and tire diameter. So you will change speedo readings and decrease braking and acceleration. Please review the plus sizing rules to make sure that you are doing the right thing. You can go for wider section and lower profile to preserve the tire diameter to be same as old, or go for the tire diameter of the Aero tires.
Why not go with 17" wheels and use the tire sizes used on the Aero's. These will fit and the ECU can be used to adjust the speedo ratio to accomodate that size.
There are tires with built in shoulder features which help protect the wheels.
At tire rack:
original tire size: 215/55-16
optional (Aero) 225/45-17
For Michelin Pilot Sport A/S (you need to review all of this for a different tire choice, there are such variations.)
215/55-16 818 revs per mile <- original size
225/55-16 806 revs per mile <- biggest diameter of this group
225/45-17 829 revs per mile <- Aero 17" optional size, smallest diameter
225/50-16 824 revs per mile <- best match in 16" rim of this group
Based on the above, a 225/50-16 at 824 would also be a good alternative.
These are all relatively the same diameter, so no problem with that as far as tire clearances go, and the same vehicle clears a 225 tire section with the 17" wheel options, so no problem there either. So all of these would fit.
Your orginal tire size is a 7" nominal rim width with a range of 6.0 to 7.5"
All of the 225/5[0|5] section tires are a 7" nominal rim, range 6 to 8", 225/45-17 is 7.5" 7-8.5"
So your 16x7.5 rims will be fine for any of these tires. If the 'new' wheels are not from Saab, make sure the bolt circles, hub centering diameter and offset are correct. If you order wheels from a place like tirerack, they will make sure that those things are right and you can get the new tires mounted and balanced for free, no taxes for many destinatons and ready to mount.
If you go to a larger tire, smaller revs per mile, if your tire is around 3 to 4% bigger (less revs per mile), then the effect will be mostly a reduction of typical speedo error and your reading will be closer to true. In that case, acceleration would decrease by 3 or 4 % as well.
posted by 66.139.12...
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