As design fashions change, one criterion of car aesthetics does not change – beautiful light alloy rims are necessary for a good-looking new model. As the enthusiasts of still-refined cars joke, the car is not a shopping cart, so it only looks good with large-diameter wheels. This usually has a negative impact on ride comfort, but the engineers managed to overcome this challenge.
The offer is big
True, the ideal combination of large wheels, the highest level of comfort and impeccable handling characteristics is still not a cheap pleasure.
It is no longer necessary to look for original design rims in car decoration stores. The manufacturers themselves equip new models with wheels of various styles and sizes, and their wide range meets the needs of buyers.
The new-generation Volkswagen Golf comes with 16-inch rims as standard, but 18-inch wheels are also available. The basic equipment of the new Kia Sportage includes 17-inch rims, but you can also choose 19-inch diameter wheels. In the segment of large city SUVs, this is not the limit. Let’s say that even 22-inch wheels can be chosen for the Volvo XC90 model without sparing an additional two thousand euros.
There are already solutions
Do large diameter wheels really have a negative impact on ride comfort? Car suspension engineer Domas Zinkevičius emphasizes that it depends a lot on what tires are installed. Large rims are usually equipped with stiff low-profile tires, which will transfer more impact force through the rim to the suspension over the same bump than a combination of smaller-diameter rims and high-profile tires.
“If high-profile tires were installed on a larger diameter rim, the level of comfort might even increase. They are soft, and considering the fact that large wheels weigh more, it would take more force to move them. Unfortunately, with low-profile tires, everything is the other way around – a stiffer tire transmits even greater force to the suspension through a heavier rim,” the specialist teaches.
D. Zinkevičius points out that, when improving the smallest city cars, it is not economically appropriate to seek comfort with larger diameter wheels. Without paying too much attention to all the options, in most cases the wheels that buyers choose most often have the best performance.
According to the interlocutor, starting with compact models, more advanced solutions are applied. Electronically controlled suspensions, which are also installed in urban SUVs, such as the new generation Kia Sportage, are particularly useful.
“The options for reducing the negative impact on comfort can be diverse. One of the best examples is the hydrodynamic rubber used in the old Mercedes-Benz E-Class sedans. These oil-filled parts act not only as springs, but also as shock absorbers. An important achievement in terms of the entire automotive industry is the significantly increased rigidity of the bodies. This not only improves handling, but also increases comfort, because the stiffer body does not resonate as much after a strong impact,” the engineer shares.
Technology is extremely expensive
Another simple solution is applied in the design of urban SUVs. In order to increase comfort, regardless of the size of the installed wheels, the suspensions are adjusted to operate more softly.
According to D. Zinkevičius, this is not the best idea, because driving through potholes while driving some models can still be extremely unpleasant, and due to the soft suspension, the car’s handling characteristics are obviously reduced.
“A good way to check if the car you have with larger wheels will maintain the desired handling characteristics is to drive on those stretches of road or streets that have pit covers recessed into the road surface unevenly.” As you drive faster, the wheels bouncing over bumps will lose traction and start to pull the car to one side. And the wheels jump just because of the soft suspension,” explains the interviewer.
D. Zinkevičius adds that it is almost impossible to maintain good handling characteristics and at the same time ensure the highest level of comfort in an average car. According to the engineer, this requires complex technological solutions, which are applied only in extremely expensive, more than 100 thousand. in cars costing euros.
“In these cases, particularly technologically complex parts are used. And simpler models can be equipped with shock absorbers with variable characteristics, but their stiffness changes slowly. The suspension can react to sudden changes only by using fast-acting electronically controlled shock absorbers, which is already a very expensive pleasure,” the interviewer names the essential difference.
Suspension design is important
Multi-link suspension is a necessary attribute of a car that drives comfortably with large-diameter wheels and low-profile tires. D. Zinkevičius notes that such a modern design is comprehensively superior to analogues: it softens the impact transmitted to the body and at the same time ensures relatively good handling characteristics.
The engineer confirms that, regardless of the size of the car, the installation of 20-inch alloy wheels without too much sacrifice of ride comfort and steering precision is only possible on models whose rear wheels are not connected by a one-piece bridge.
Such a design not only helps to better absorb shocks when overcoming road irregularities, but also reduces noise and vibrations.
Speaking about the maximum size wheels he would recommend for, for example, a C-segment hatchback or a medium-sized city SUV, D. Zinkevičius jokes that people will still ignore it and find a way to justify the desired purchase.
“I understand what the consequences of one or another choice are, so I look at cars a little differently. The same can be said for large diameter rims with low profile tires. Since I know what qualities they have, it’s not the best combination for me. You can say that I also convince myself to think this way simply because I have more experience”, – the interviewer talks about the psychological aspect.