Hello everyone.
My current car’s engine makes a mere 115 HP.
Current (Factory spec) tires/rims are 195 65 with 15" rims.
Considering (same brand) 205 55 tires with 16" rims.
I would expect a handling improvement with this tire/rim upgrade but am concerned that with only 115 hp to work with, that acceleration may noticeably decrease.
Any help on this issue would be greatly appreciated
Your acceleration will change only if the new tires are heavier than the old ones. (For normal city driving )
Your tread diameter is pretty much the same either way, so there shouldn’t be any significant change in acceleration.
Tires + wheels. Some after market wheels are pretty heavy.
I think the handling may improve somewhat. A lot of handling characteristics are down to the suspension as well as tire type. For example, Continental tires tend to have a more compliant sidewall construction compared to Michelin or Bridgestone (IME).
With a larger contact patch, stopping distance may improve slightly as well.
The tire diameter is the only factor to consider w/regard to acceleration. The diameter of your current tire is 24.98. " your suggested replacement 24.88. " Theoretically, your acceleration rate will increase, but it will not be noticeable.
right, wot they said. you’re staying within the same overall tire diameter so there shouldn’t be any appreciable difference.
Changing the tire diameter is effectively changing the car’s final drive ratio; a smaller diameter tire will lower the effective final drive, improving acceleration a bit. vice versa for a larger diameter tire. But your speedometer will also be off.
What model car is it? At 115HP I don’t imagine addressing handling issue through tires would make much difference.
115 HP would be something like a Hyundai Accent, Fiat 500 or an entry level VW Golf. I doubt tires could possibly make a noticeable difference. It’s like a novice golfer buying expensive golf balls; it’s pointless to worry about that.
I agree with this, but…
The weight of the tire and wheel package makes a big difference. Wheels and tires are both unsprung mass that has to be managed by the suspension and rotational mass that has to be accelerated by the engine and decelerated by the brakes.
If you are going from 15" aluminum wheels to bigger (and almost undoubtedly heavier) 16" wheels, the extra mass will hurt acceleration. However, if you are going from a 15" steel wheel package to a lightweight aluminum alloy wheel, your acceleration, braking, and turning should all improve a bit (again, depending on the specific tires chosen). .
The size of the contact patch for a particular car is mostly determined by the air pressure. It doesn’t meaningfully change when you change tires. The shape of the contact patch does change, however, and it can noticeably affect turning, braking, and stopping. Generally though, the change in the tire compound to newer and potentially sportier tires will have a bigger influence.
Or an early Miata or Volkswagen GTi or Porsche 914, or early air-cooled Porsche 911, or Lotus Elise (Euro spec) or a Honda CRX Si. There are plenty of classic performance cars that could benefit handily from a tire upgrade. Even a Fiat 500 would make it through a set of cones noticeably faster with better tires.
I don’t know the empirical data on this but non-skid stopping distance depends on static friction, which is based on the coefficient of friction between the tire and the road, plus the downward force on the contact patch, i.e., weight of vehicle. The formula does not take into account the contact area; a larger contact area will have more units of area (i.e., sq. in.) but less pressure per unit of area, so it’s a wash. In an idealized “physics textbook” situation varying the size of the contact patch while leaving the weight and cf constant will not change stopping distance.
I hadn’t considered that. Ignorance fought.
air pressure + weight of the car