Is 215/50R17 bigger than 205/55R16?

215/50R17 is 0.59 inches taller and 10 mm wider. In overall diameter that is +2.36%, which stays inside the ±3% rule of thumb for a substitution.

How much will 215/50R17 throw off my speedometer?

Every reading scales by 1.02358. An indicated 60 mph becomes 61.4 mph, and every 100 miles on the odometer is really 102.4 miles.

How much does 215/50R17 change ground clearance over 205/55R16?

The axle centerline moves by 0.29 inches — half the diameter change, because half the extra height sits below the hub and half above it.

Will 215/50R17 fit where 205/55R16 fits?

Nothing derived from the size code can answer that. Clearance depends on wheel offset, suspension travel and body dimensions that no tire size contains. This page tells you exactly what changes dimensionally, which is the part that can be calculated.

205/55R16 vs 215/50R17

215/50R17 is +0.59″ in overall diameter and +10 mm in section width against 205/55R16 — a diameter change of +2.36%, which stays inside the ±3% substitution rule. An indicated 60 mph would really be 61.4 mph.

Within 3%

Every dimension

Difference between 205/55R16 and 215/50R17
Dimension	205/55R16 → 215/50R17	Change
Overall diameter	24.88″ → 25.46″	+0.59″ (+2.36%)
Section width	205 mm → 215 mm	+10 mm (+4.88%)
Sidewall height	112.8 mm → 107.5 mm	−5.3 mm
Rolling circumference	78.16″ → 80.00″	+1.84″
Revolutions per mile	810.7 → 792.0	−18.7
Axle height / clearance	12.44″ → 12.73″	+0.29″

205/55R16205 mm

215/50R17215 mm

205/55R16 24.88″215/50R17 25.46″

Which is taller, 205/55R16 or 215/50R17?

215/50R17 is the taller of the two, at 25.46″ against 24.88″. The gap is 0.59 inches, or 14.9 mm.

Both are metric sizes, so neither states its height directly. Both figures below are derived from the section width, aspect ratio and wheel diameter in the code. 205/55R16 is 205 mm wide with a 112.8 mm sidewall on a 16″ wheel; 215/50R17 is 215 mm wide with a 107.5 mm sidewall on a 17″ wheel.

What the speedometer will read

Indicated versus actual speed after the size change
Speedometer reads	Actual speed	Error
25 mph	25.6 mph	+0.6 mph
40 mph	40.9 mph	+0.9 mph
55 mph	56.3 mph	+1.3 mph
60 mph	61.4 mph	+1.4 mph
70 mph	71.7 mph	+1.7 mph
80 mph	81.9 mph	+1.9 mph

Fitting 215/50R17 in place of 205/55R16 multiplies every speed and distance reading by 1.02358. Over 10,000 indicated miles the odometer is out by +236 miles.

Effective gearing moves by the same proportion. A vehicle with 3.73 axles running 205/55R16 would need 3.82 to keep the same engine speed on 215/50R17. Work it out for your own axle ratio.

Full specification of each size

205/55R16

Derived dimensions for 205/55R16
Dimension	Metric	Imperial
Section width	205.0 mm	8.07″
Sidewall height	112.8 mm	4.44″
Wheel diameter	406.4 mm	16.0″
Overall diameter	631.9 mm	24.88″
Rolling circumference	1,985.2 mm	78.16″
Revolutions per mile	503.7 / km	810.7 / mile
Measuring rim (estimate)	165 mm	6.5″

215/50R17

Derived dimensions for 215/50R17
Dimension	Metric	Imperial
Section width	215.0 mm	8.46″
Sidewall height	107.5 mm	4.23″
Wheel diameter	431.8 mm	17.0″
Overall diameter	646.8 mm	25.46″
Rolling circumference	2,032.0 mm	80.00″
Revolutions per mile	492.1 / km	792.0 / mile
Measuring rim (estimate)	178 mm	7″

Rim widths differ too: 205/55R16 is designed for 6″–7.5″ and 215/50R17 for 6.5″–8″. Their measuring rims differ, so the same wheel will not be ideal for both.

Can you swap one for the other?

Inside the ±3% rule

The diameter difference of +2.36% is within the ±3% that fitters use as the boundary for a substitution, so the speedometer, odometer and wheel-speed-derived systems stay close enough to calibration. The section width difference of +10 mm is a separate question and is the one that decides whether it rubs.

Neither figure says anything about physical fitment. Whether 215/50R17 clears the strut, the fender liner and the steering stops depends on wheel offset and suspension geometry that a size code does not encode. For maintenance rather than sizing, Car Basics covers tire care.