2014-2020 BMW i8 Tire Mobility Kit: Why Your Sealant is Expired and What to Check

Symptoms of a Failed Mobility Kit

Unlike a mechanical car part, the Tire Mobility Kit's failure isn't noticed until you're stranded on the side of the road. A failure means the kit is unable to seal and inflate your tire in an emergency. Symptoms are discovered upon use:

• Compressor Does Not Turn On: You plug the unit into the 12V power outlet, and nothing happens. This could be due to an internal failure of the compressor motor, a bad power cord, or a blown fuse in the vehicle.
• Sealant is Expired: The most common failure is an expired bottle of tire sealant. The sealant has a shelf life of approximately four years, after which it may not effectively plug a puncture. The expiration date is printed on the bottle.
• Compressor Blows Vehicle's Fuse: In some cases, the compressor can draw too much current and blow the fuse for the 12V accessory socket, rendering it useless and potentially disabling other vehicle functions connected to that circuit.
• Sealant Fails to Plug the Leak: Even with a fresh bottle, the sealant may not work if the puncture is too large, located on the sidewall, or has an unusual shape. One user reported the sealant streaming back out of a puncture caused by a large staple.
• Compressor Runs but Doesn't Inflate: The motor might run, but the tire pressure doesn't increase. This can be caused by a poor connection at the tire valve, a leak in the compressor's hose, or an internal failure of the pump mechanism.

Vehicle-Specific Known Issues & Variants

The Tire Mobility Kit in the BMW i8 has several model-specific details and issues that owners must be aware of.

Crucial: Expired Tire Sealant

The single most important issue is the tire sealant's expiration date. The liquid inside the canister degrades over time and loses its ability to seal punctures. Most BMW sealant bottles have a shelf life of about four years. An i8 from 2014 or 2015 is almost certain to have expired sealant unless it has already been replaced. Using expired sealant will likely result in a failed repair, leaving you stranded.

Compressor Blowing Fuses

Some BMW owners have reported that using the included air compressor blew the fuse for their 12V power outlets. This immediately disables the kit. While this issue was reported on other BMW models, the compressor unit is often shared across the lineup. If you find yourself with a flat, you may face the choice of risking a blown fuse or calling for roadside assistance without attempting a repair.

Two Different Kits for the i8 (Pre- and Post-10/2015)

The BMW i8 used two different, non-interchangeable mobility kits depending on its production date.

• Vehicles built up to October 2015: Use a specific compressor and sealant bottle design. The sealant refill part number for this version is 71106888308.
• Vehicles built from October 2015 onward: Use a newer, different style of kit. The sealant refill part number for this version is 71106850379.

Buying a Used 2014-2020 i8 Tire Mobility Kit

A used OEM mobility kit can be a cost-effective replacement, but careful inspection is essential to ensure it will work when you need it most. Here’s what to check before buying:

1. Check the Sealant Expiration Date: This is the most critical step. Do not buy a kit with an expired or soon-to-be-expired sealant bottle. If the sealant is expired, you will need to purchase a new bottle separately, adding to the total cost.
2. Test the Compressor: If possible, plug the compressor into a 12V outlet to confirm it powers on. Listen for any unusual grinding or weak motor sounds.
3. Inspect for Completeness: A full kit includes the compressor, sealant bottle, hoses, various valve adapters (for balls or bicycles), nylon gloves, and the carrying case. Ensure all original components are present.
4. Verify Compatibility: Check that the kit is the correct style for your i8's production year (pre- or post-October 2015). While the universal compressor may work, the integrated sealant bottle might not fit correctly if it's from the wrong version.
5. Examine Physical Condition: Look for cracks in the plastic housing of the compressor, cuts or cracks in the air hose, and damage to the 12V plug. Avoid units that look heavily worn or damaged.

Cost Comparison

Since the i8 relies on this kit, having a functional one is not optional. Here are the typical costs to repair or replace components:

Replacement and Location

Accessing and replacing the mobility kit components is very simple.

• Location: The Tire Mobility Kit is stored in the trunk of the BMW i8. It is located behind a removable access panel on the left-hand (driver's side) wall of the trunk.
• Replacement: The entire kit lifts out of its compartment. To replace just the sealant, the old bottle typically slides or unclips from the compressor unit, and the new one is secured in its place. The process requires no tools.

Frequently Asked Questions (FAQ)