The 1986 BMW 635CSi sits squarely in BMW’s grand touring tradition, combining E24 coupe styling with the poised, high-speed character that made the Six Series such a distinctive road car of the era. Tire choice matters on this car because two radial fitments are associated with it: 205/70R14 and the millimetric 220/55R390 TRX-size tire. That gives owners a meaningful decision between a more conventional 14-inch metric radial setup and the specialized Michelin TRX format, along with choices in blackwall, narrow whitewall, redline, dual-redline, and raised white letter styling for 205/70R14. The right selection depends on the wheels actually on the car, the look you want, and how closely you plan to follow its period presentation.
Which Tire Size Is Right for The 1986 BMW 635CSi
The 1986 BMW 635CSi uses two tire sizes, and the first thing to confirm is which wheel setup is on the car. One fitment is the conventional 205/70R14 radial for a 14-inch wheel, while the other is the 220/55R390 radial used with the millimetric TRX wheel system. Once the wheel type is confirmed, the decision shifts to tire style, series, and how closely you want to stay with the car’s period-era presentation.
A 205/70R14 uses a 205-millimeter section width, a 70-series aspect ratio, radial construction, and a 14-inch rim diameter. On a 1986 BMW 635CSi, this is the conventional metric radial fitment and gives access to the broadest visible range of tire choices for this application. Available options include BFGoodrich, Maxxis, and Michelin, with sidewall treatments such as blackwall, narrow whitewall, redline, dual-redline, and RWL across several series. This size is the practical path when the car is on standard 14-inch wheels and you want flexibility in appearance and brand selection.
A 220/55R390 uses a 220-millimeter section width, a 55-series profile, radial construction, and a 390-millimeter rim diameter rather than an inch-based wheel size. On the 1986 BMW 635CSi, this size represents the specialized Michelin TRX fitment, so wheel identification is essential before any purchase decision. The available product here is a Michelin TRX-B blackwall radial, which keeps the tire in its period millimetric system rather than converting to a conventional 14-inch setup. This size is the right one only when the car still has TRX wheels that require a 390-millimeter tire.
Fitment is straightforward here because the covered 1986 BMW 635CSi sub-model shares the same two radial tire-size paths. Checking the exact wheel setup still matters, since the choice is between a 14-inch fitment and a millimetric TRX fitment rather than between different trims.
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1986 BMW 635CSi Base
The 1986 BMW 635CSi Base uses two radial fitment possibilities, depending on whether the car is on conventional 14-inch wheels or on Michelin TRX millimetric wheels. Tire selection starts with confirming the wheels on the car, then narrowing the choice by sidewall style, tire series, and whether you want to retain the TRX presentation.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 1986 BMW 635CSi Tires for Sale
Available 1986 BMW 635CSi tire choices center on 205/70R14 radials from BFGoodrich, Maxxis, and Michelin, with blackwall, narrow whitewall, redline, dual-redline, and RWL styling across several series. The 220/55R390 fitment remains a specialized Michelin TRX-B blackwall option for cars on TRX wheels.
Common 1986 BMW 635CSi tire questions usually come down to confirming whether the car has 14-inch wheels or TRX millimetric wheels, then choosing the right radial tire style, brand, and period-appropriate appearance for road use or restoration-minded ownership.
Tire Size & Fitment
What tire size fits a 1986 BMW 635CSi?
The 1986 BMW 635CSi uses two radial tire sizes: 205/70R14 and 220/55R390. The 205/70R14 is the conventional inch-based metric radial fitment, while 220/55R390 is the millimetric Michelin TRX-type fitment used with a different wheel system.
The important next step is confirming which wheels are actually on the car before choosing tires. A 14-inch wheel requires the 205/70R14 size, while a TRX wheel requires the 220/55R390 size. Many cars have been changed over the years, so a quick wheel and sidewall check is more useful than assuming every 635CSi still carries its original wheel setup.
What size rim does a 1986 BMW 635CSi use?
A 1986 BMW 635CSi can be found with either a 14-inch wheel for 205/70R14 tires or a 390-millimeter wheel for 220/55R390 tires. Those are two different wheel standards, even though both use radial tires and both belong to this exact model year and model.
That distinction matters because tire size follows the wheel, not just the vehicle badge. A 205/70R14 cannot be mounted on a 390-millimeter TRX wheel, and a 220/55R390 cannot be used on a 14-inch wheel. Looking at the wheel itself and reading the tire sidewall already on the car is the safest way to confirm which system your BMW is using.
Does the 1986 BMW 635CSi Base use the same tire size?
The 1986 BMW 635CSi Base is associated with the same two radial fitment possibilities as the model overall: 205/70R14 and 220/55R390. The size does not change because of a different trim name here; it changes according to the wheel system fitted to the car.
That means the Base model still needs the same wheel-first verification as any other 1986 635CSi. Once the wheel type is confirmed, the choice becomes much easier. Cars on 14-inch wheels have several more visible style options, while cars on TRX wheels stay within the specialized millimetric fitment designed for that wheel format.
Choosing the Right Tire
What should I consider when choosing a 205/70R14 tire for a 1986 BMW 635CSi?
Start by confirming that the car is actually on 14-inch wheels, because 205/70R14 is only correct for that setup. From there, compare construction, series character, sidewall appearance, and wheel-width compatibility. In this size, the 1986 BMW 635CSi has choices from BFGoodrich, Maxxis, and Michelin.
The visible differences matter on an E24 because tire appearance can strongly influence the car’s overall presentation. Blackwall keeps the look understated, while whitewall, redline, dual-redline, or raised white letter options create a more stylized period feel. Rim-width range is also worth checking so the selected tire matches the wheel already on the car without creating an avoidable fitment mismatch.
What sidewall styles are available for 1986 BMW 635CSi tires?
For the 1986 BMW 635CSi, the 205/70R14 fitment is available in several sidewall styles, including blackwall, narrow whitewall, redline, dual-redline, and RWL. The 220/55R390 TRX fitment is offered as a blackwall, which keeps that millimetric setup more specialized and less varied in appearance.
Sidewall choice affects the visual tone of the car at least as much as the brand name does. A blackwall tends to preserve a clean touring look, while redline, dual-redline, or raised white letter styling shifts the car toward a more overt period presentation. Selecting the sidewall should match both the wheel setup and the kind of restoration or driver character you want.
What brands offer tires for the 1986 BMW 635CSi?
The 1986 BMW 635CSi is served by Maxxis, BFGoodrich, and Michelin in the applicable sizes. Brand choice depends partly on which wheel system the car has, since the conventional 205/70R14 fitment opens up multiple brands, while the 220/55R390 TRX fitment stays within a Michelin TRX-series offering.
That brand spread makes the 14-inch setup more flexible for buyers comparing appearance and product character. BFGoodrich covers several visual treatments in 205/70R14, Maxxis adds a classic whitewall option, and Michelin offers both the XWX in 14-inch form and the specialized TRX tire for millimetric wheels. The best comparison point is not the badge alone, but brand plus size plus sidewall style.
Restoration & Appearance
Which tire should I choose for a period-style 1986 BMW 635CSi?
A period-style choice starts with the wheel setup on the car. A 635CSi still wearing TRX wheels naturally points toward the 220/55R390 Michelin TRX-B, while a car on conventional 14-inch wheels can use 205/70R14 in several period-minded radial presentations, including Michelin XWX, blackwall, redline, or whitewall-oriented options.
The right answer depends on whether the goal is preserving the car’s specialized wheel-era character or creating a broader restoration-style look around standard 14-inch wheels. Appearance details should be checked against photos, marque-club references, and the car’s own history if exact originality matters. Tire size and wheel format come first, then sidewall styling becomes the finishing detail.
How does tire construction affect the appearance of a restored 1986 BMW 635CSi?
On a 1986 BMW 635CSi, construction is less of a visual dividing line than wheel system and sidewall treatment because both primary fitments are radial. The larger appearance difference comes from whether the car remains on the TRX millimetric setup or uses a conventional 14-inch wheel with 205/70R14 tires.
Within the 14-inch fitment, sidewall choice becomes the main styling tool. Blackwall gives the car a restrained grand touring look, while redline, dual-redline, narrow whitewall, or raised white letter styling changes the overall tone without changing the vehicle itself. On a restoration-minded BMW, tire construction stays consistent, but wheel type and sidewall design heavily influence how authentic or personalized the finished car feels.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1986 BMW 635CSi?
Yes, modifications can affect tire fitment on a 1986 BMW 635CSi, especially if the car has aftermarket wheels, altered suspension height, or non-original wheel widths. Those changes can influence which tire size is practical, how much clearance is available, and whether the car should stay with a 14-inch setup or a TRX wheel system.
Even when the tire size itself is correct, wheel width and offset still matter. A lowered car or one with replacement wheels can create steering or fender-clearance issues that would not exist on a stock setup. Measuring the wheels on the car and checking clearance at full steering lock is a smart step before mounting new tires on any modified E24.
What should I inspect before driving a 1986 BMW 635CSi on new tires?
Before driving a 1986 BMW 635CSi on new tires, inspect the wheels for damage, confirm the actual wheel diameter, and make sure the tire size matches the wheel system on the car. Tire pressure, valve stems, and basic suspension condition also deserve attention, especially on a collector-era coupe that may not see daily use.
A short check for rubbing or interference after installation is just as important as the tire choice itself. Turn the steering from lock to lock, look for fender or suspension contact, and watch for any unusual vibration once the car is on the road. Catching those issues early helps protect both the new tires and the driving character the 635CSi is known for.
How should 205/70R14 tires on a collector 1986 BMW 635CSi be maintained?
205/70R14 tires on a collector 1986 BMW 635CSi should be maintained with regular pressure checks, visual inspections, and attention to age-related condition even when tread still looks good. Collector cars often spend long periods parked, so sidewall cracking, flat spotting, and gradual air loss can become just as important as normal tread wear.
Storage conditions make a real difference on a low-use car like this. Keeping the BMW away from prolonged sunlight, excess heat, moisture, and ozone sources helps preserve the tires between drives. It also helps to inspect for cuts, bulges, or uneven wear before longer outings, since a car that sees limited mileage can still develop tire problems while standing still.
