The configuration is referred to as staggered. It focuses on performance and car handling. The tires will stretch if you select 225 for the rears, which will affect your speedometer. The configuration is referred to as staggered.
In This Article...
Why do BMW’s front and rear tires have different sizes?
BMW tire size: To begin with, it is stunning! Since the BMW 318d sedan, the most affordable model of the BMW 3 Series, is the newest model range, wide tires can be chosen in the customization for it.
However, all BMW M vehicles come standard with multi-sized tires in all trim levels, as with emphasized sports versions like the BMW Z4 and BMW 8 Series Coupe. This is true obviously not just for aesthetic reasons.
The dynamic characteristics and controllability are positively impacted by this choice. Furthermore, the rear tires on the most recent X3 M and X4 M super crossovers are only one centimeter wider than the front tires, yet even such tiny differences make sense.
With rapid acceleration, the automobile squats on the rear axle and shifts the majority of its weight to it (the X3 M and X4 M reach a “hundred” in about 4.1–4.2 seconds).
Wider tires enable you to achieve more traction without slipping, tugging, activating traction control, or experiencing other unwanted occurrences. This is especially true if the tires are premium Ultra High Performance (UHP) tires.
It appears to a driver that a car breaks down right away. On BMW rear-wheel drive or all-wheel drive vehicles, when the emphasis of traction is shifted to the rear axle, wide rear tires are useful. The majority of BMW models, that is.
In this situation, narrower front tires are used so that the rear tires’ outer diameter is maintained. It is tougher to make them equally wide.
During maneuvers, the front wheels must be rotated, which necessitates a space in the wheel arches – the broader the tire, the more room required.
Additionally, front tires are more likely to aquaplane. Narrow requires a higher speed to “float” on the water, therefore they are safer. Wide tires can also reduce road stability and steering wheel feedback.
Don’t overlook the handling when making a sharp turn: the tire width ratio was chosen so that the automobile would be enjoyable to drive while maintaining safety.
JPC-BMW
Larger tires in the back will improve grip and traction because this vehicle has a rear wheel drive. Continually use the sizes you have. Make careful to call your insurance company if you want to change the sizes because some of them won’t permit you and some of them won’t mind.
I knew there had to be some reason for it, but I wasn’t sure if that was the regular setup or if someone had previously decided to switch to a broader set. The Mrs F20, which is also rear wheel drive but has the same tire size front and back, is the only other BMW I have to compare it to. However, I agree that the f2* is probably going to be different from the e8*, as was mentioned by another member.
I just realized my car has 225/40 R18 tires up front and 255/35 R18 tires on the back. I’ve only had the car for a few weeks, and since the tires are in decent shape, I didn’t really think about the sizes. any hints?
Dave I appreciate your response. I’ll exchange the xenon lights for your paddles because I’m not sure how I feel about them. The xenons are fantastic, but it’s hard for me to comment on how they perform in the dark because I haven’t driven an E90 without them! …but you look good!
The theory is that because the rears’ “contact patch” is bigger, you receive greater grip from them.
The tendency to oversteer (slide from the rear) is lessened as a result, offering the car more progressive handling and a more neutral stance.
dergside
This is not a concern. BMWs frequently have staggered wheels, also known as wheels with different front and rear widths, especially in larger wheels. The tire sizes you provide are the typical ones for an e46’s 18″ alloy wheels. Although I can’t remember the e90 sizes precisely, I don’t think they differ.
The rolling radius of the tires is practically same between the front and the rear thanks to the difference in the profile on the tyres, which works in conjunction with the width.
Wheel fitment chart for BMW
The information in our guide is based on factory options from BMW and reliable tuning firms; these are the wheel and tire sizes that might have been ordered for your car at the time of manufacturing or that have been tried out by organizations like Alpina, Hartge, and AC Schnitzer. Using these sizes allows you to adapt larger/smaller or different-style wheels while still guaranteeing proper fit and safety, which is crucial. Instead of reproductions or copies, we only offer to our customers authentic BMW wheels created by or for BMW.
When purchasing new BMW wheels, you can use this fitment guide to determine the range of wheel sizes that will fit your vehicle as well as the requirements for proper installation. Although our web configurator offers an automatic way to find the right wheels for your BMW, you should still refer to this chart if you’re looking through our product selection by hand. This table not only aids in determining wheel sizes but also shows tyre sizes for each wheel; this information is helpful when buying a set of replacement tires or adding tyres to an order for new wheels.
The BMW car type (e.g., 1 series, 3 series, 5 series, etc.) and model designation number are listed in this fitment chart; the model designation number is a development code (also known as the Entwicklungscode) that BMW assigns to each vehicle model. The most recent BMWs have been given the letter “F” and a number instead of the traditional “E” and “number” development codes.
For instance, BMW 3 Series vehicles produced between 2006 and 2011 appear on our fitment chart as BMW 3 Series (E90), and BMW 3 Series vehicles produced after 2012 appear as BMW 3 Series (F30).
If you are unclear of your vehicle’s development code, please consult your owner’s manual. You may also find more information by taking a look at our list of BMW models and codenames.
The dimensions and offsets for BMW wheels and tires are provided in our fitment guide below. For your information, our primary fitment guide includes a page with an explanation of each of these measures.
Why are the tire sizes on my automobile different?
The basic definition of differential is the ability to have various speeds between your wheels. This is crucial because, when you spin your car, the inside wheel, which has less distance to travel, rolls more slowly than the outside wheel.
Can my BMW have wider tires?
When making tight turns or when the suspension bottoms out, the tires may rub against the fender well if the new wheels and tires are larger than the stock ones. Speedometer readings can be erroneous because they measure speed by measuring the distance covered with each wheel rotation. Both the factory diameter and breadth of the wheels and tires must be preserved in order to keep the suspension and speedometer operating properly.
On the original rim, it is generally safe to install a tire that is up to 20 millimeters wider than stock. Depending on the rim’s width, the tire’s actual width will change: For every half inch (12.5 millimeters) increase in rim width, the tire will enlarge by 5 millimeters.
Because tire sizes are a combination of metric and percentage measurements while wheel sizes are in Imperial measurements, switching to a different rim becomes a little more challenging.
For instance, the car’s current tires are 225/45R15. This is what it indicates:
- Tire width in millimeters is 225.
- Sidewall height expressed as a percentage of tire width is 45.
- Rim diameter in inches, 15.
Multiply the wheel size by 25.4 to get the millimeter equivalent:
1.5 times 25.4 equals 381 millimeters.
Next, multiply the tire width by the height percentage to determine the sidewall height:
101.25 millimeters is equal to 225 millimeters times 0.45.
To determine the combined height of the wheel and tire, add the two figures together:
482.25 millimeters (381-201 = 381.25)
The new tire and wheel should be within 3% of the height of the original combination in order to maintain speedometer accuracy. A tire with a height of 75.85 millimeters, or 34 percent of the 220 millimeter width, or 220/34R16, would be needed to move to a 16 inch (406.4 millimeter) rim. The closest size produced, 220/30R16, is well within the size tolerance of 3%.
Why are the diameters of my front and rear tires different?
Is there a cause? I went to view an automobile that had differing front and rear tire profiles: 40 at the front and 35 at the back.
A BMW, perhaps? Many were manufactured with various front-to-rear profiles. Wider rears frequently have a lower profile, resulting in nearly the same sidewall depth overall.
To maintain the same height of the sidewall, anything with varied width tires would likely also have varying profiles (who had the brilliant idea to quantify profile as a percentage of width, anyway?).
(Who had the brilliant idea to measure profile as a percentage of width, anyhow?)
I’ve thought about that previously. I believe it dates back to a time when tires lacked a selection of profiles, though I can’t say for sure. You could simply get a 145 14R, and as the profile was the usual 80%, it wasn’t indicated. Then we acquired this method because someone wanted to utilize “low profile” tires.
Why measure the width in mm, the profile in %, and the rim in inches? is the obvious next query.
Because the car was built by experienced engineers, it doesn’t matter if the front and back tires are different sizes. Perhaps the bigger issue will arise when Barry puts different size tires on each end of his car because his friend had a pair of them for sale.
In the many instances where the manufacturer’s engineers specified Michelin Sport Cups on the front and Wanli Bakelite Specials on the back, I’m confident that everything will be alright.
That one, in my opinion, is due to history. The first major producers of radial ply tires and wheels were from regions where both measurements were measured in inches. Then a particular Mr. Michelin from France created a cross-ply tire that was commercially successful; being French, he didn’t like inches but had no choice but to support existing rims, so he simply produced tyres for inch-based rims with the other dimensions in metric measurements.
Although that’s undoubtedly incorrect, I don’t think it will cause too many issues. A minor amount of aerodynamic lift will result from the front riding around 1 cm higher than the back, but I highly doubt you’ll feel it while driving. Your speedometer will also be out by a few percent if the rears are off.
Do all of my tires need to be the same size?
You will find important information regarding combining tires on your car in this area. You should, first and foremost, refrain from combining various tread patterns and tire brands. Manufacturers generally do not advise tyre mixing at all, while there are a few unusual exceptions for certified mixed-tyre fits.
The same brand, size, tread pattern, load index, and speed rating should be used for both the front and rear tires of your car in order to provide maximum safety and performance.
Tyres must, at the very least, adhere to the manufacturer’s guidelines for size, load index, and speed rating. In many nations, it is a requirement of the law.
Driving a car with a set of tires that are mismatched in terms of size, structure, load index, or speed rating puts you and other drivers in danger. Always adhere to the recommendations of the vehicle’s manufacturer or get advice from a certified tire expert.