235/45R18 vs 275/40R18
275/40R18 is 1.3% taller (+0.33 in) and 1.57 in wider than 235/45R18.
275/40R18 is 1.3% taller than 235/45R18. That is inside the ±3% most shops treat as a straight swap.
Real speed on 275/40R18.
Change in height under the axle.
On the same wheel, split inboard and outboard.
Shop 275/40R18 tires
Opens the store’s own searchPrices and stock change often, so check a few stores. We don’t earn anything from these links.
235/45R18 or 275/40R18?
Can I use 275/40R18 instead of 235/45R18?
275/40R18 is 1.3% taller than 235/45R18. That is inside the ±3% most shops treat as a straight swap. Also match or beat the original load index and speed rating, and check that the wheel width suits the new tire.
Will my speedometer be off?
At an indicated 60 mph on 275/40R18 you are really doing 60.8 mph if the speedometer was set up for 235/45R18. Going the other way, 235/45R18 would make it read 59.2 mph at a real 60.
How much ground clearance does it change?
Half the diameter difference: +0.17 in (+4 mm) under the axle.