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BMW Chassis Reinforcement Kits & Parts

Made in the USAAs much of an "Ultimate Driving Machine" it is, many BMW models unfortunately suffer from weak points in the chassis. Over the years we have uncovered many weak or failure-prone areas in the chassis and have developed our own reinforcing solutions for them. And we continue to be the leading experts on BMW chassis reinforcing. Failures can come from a number, or combination, of causes: improper maintenance, age and mileage, poor design, environmental factors, poor repair work, and over-stressing modifications. The longer you let your car go without repairing or reinforcing these areas, the closer it gets to crumbling apart. Our chassis reinforcement kits are designed to first identify potential weak points and then strengthen and reinforce the existing design.

Most of our kits are not labor intensive although welding is usually required. If you suspect your chassis may have structural problems we recommend taking it to a well-known bodyshop or restoration shop. (find out who your local BMW dealer uses - we sell many of our kits to dealer-authorized repair shops). Making the preventative fix simple and effective is better than a long and complicated repair after the failure. Our kits are not usually used for fixing existing damage (only your body shop can determine the correct course of action). But our kits have been proven under extreme conditions on racetracks around the world to prevent many of the costly - and dangerous - chassis problems.
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E46 Rear Chassis/Subframe Reinforcement Kit
Turner Motorsport - Corporate Logo
T#:91
Part#: TDR4675412
In Stock
Sale - Save 40% $142.95
$85.77
Free Shipping on orders $49 and up
Sale - Save 40% $142.95
$85.77
Free Shipping on orders $49 and up
Updated in 2020 to provide additional reinforcement! The E46 rear driveline and suspension are very similar to that of the E36. An unfortunate side effect of this is that the E46 also shares some of the same problems as the E36. One of these problems is the rear mounting points for the subframe, which can rip out from their spots in the sheet metal. This happens because the rear differential transmits the torsional load from the engine through the subframe, then into the chassis. This constant loading and unloading weakens the sheet metal and causes it to fatigue and separate from the chassis. BMW tried to fix this problem in the E46 by placing a cross member on the front two mounting points of the subframe. This cross member keeps the front mounting points from having problems by placing the bushing and the stud in double-sheer, thus reducing the twisting action on the sheet metal. The unfortunate side effect of this is that the load from the front of the subframe now gets transmitted to the left rear of the subframe. This is where we have seen many failures of the chassis on low mileage street cars and race cars. BMW has also tried to prevent the issue by injecting foam into the open space between the underside of the chassis and the top of the trunk. This seems to work but that does not address the issues of the spot welds failing on the sheetmetal. It can also make any additional work there harder and almost impossible to weld against. Our reinforcement kit has proven over and over again to be effective and the easiest to work with in the long run.

This product reinforces the chassis sheet metal at the subframe mounting points. We do this by thickening the metal and distributing the load over a larger area. This kit will save time when repairing the chassis, and is also strongly recommended as a preventative maintenance item.

Photo Gallery: E46 Subframe Failure / Repair

Click here for installation instructions.

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi M3
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E46 Strut Tower Reinforcement Plates - priced each
Genuine BMW - Corporate Logo
T#:323
Part#: 51717036781
In Stock
19% off MSRP $45.34
$36.95
Free Shipping on orders $49 and up
19% off MSRP $45.34
$36.95
Free Shipping on orders $49 and up
Like the E36 before it, the front strut towers on the E46 are notoriously weak. Under normal driving conditions with a stock, fresh suspension it is unlikely that you will ever have a problem. But with an upgraded street or race suspension with firm springs much of the energy from pounding the road is transmitted to the thin sheet metal in the strut tower. This pounding will cause the tower to deform or even crack. Look for 'mushrooming' or deformity around the holes for the three mounting studs at the top of the strut tower. The sheetmetal around the holes should really be flat and square. Poor shocks or stiff suspensions will actually cause this sheetmetal to pop up.

These factory BMW reinforcement plates will help disperse the energy and save you from costly repairs in the future. A strut brace also helps to prevent this but these plates are designed to reinforce the strut tower from the bottom. The install over your strut mount or camber plate and simply add thickness (strength) to the strut tower. They can be sandwiched in place and do not require welding.

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi
2001-2006 E46 BMW M3*
* - The stock M3 upper strut mount already does a good job of dispersing the loads of the suspension. These reinforcement plates will fit a stock mount for added strength but need to be trimmed to fit inside the strut tower. The are very strongly recommended for all M3s with coil over suspensions because aftermarket coil overs typically have a smaller surface area for their strut mounts.
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E36, E46 Rear Shock Tower Mount Reinforcement Kit
Turner Motorsport - Corporate Logo
T#:3440
Part#: TSU9975100
In Stock
Sale - Save 5% $39.95
$37.95
Free Shipping on orders $49 and up
Sale - Save 5% $39.95
$37.95
Free Shipping on orders $49 and up
Made in the USA A very common weak point on the 3 series BMW is the sheetmetal of the rear shock tower. The sheetmetal here is relatively thin and very susceptible to stress and fatigue. A worn out shock will bottom-out more often and this energy is transferred through the bump stop and into the metal chassis. Stiffer shocks and shock mounts also put more stress on the sheetmetal. Factor in age, mileage, and environmental conditions and it's not a surprise that we see shock tower failures often. BMW addressed this issue with reinforcements of their own but our's are thicker for additional strength. This kit mounts on top of the shock tower and can either be bolted or welded in place. Because of the shape of the rear shock tower, these do not fit cabrio/convertible cars.

This item fits the following BMWs:
1992-1999 E36 BMW 318i 318is 318ti 323is 325i 325is 328i 328is M3 - not for convertibles
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi M3 - not for convertibles
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E46 Front Subframe Reinforcement Kit
Turner Motorsport - Corporate Logo
T#:631
Part#: TDR4675F99
In Stock
Sale - Save 40% $55.95
$33.57
Free Shipping on orders $49 and up
Sale - Save 40% $55.95
$33.57
Free Shipping on orders $49 and up
Made in the USA The motor mount area on a subframe is one of those easily-forgotton areas that may be hiding a serious problem. The subframe on the E46 has a gusset ('ear') welded on for the motor mounts. These gussets take the stress of the motor mount as the engine torques (more upgrades = more torque = more stress). Worn motor mounts only transfer more stress to the subframe. Unfortunately, the sheetmetal will fatigue over time even though the gusset is reinforced from the factory. Check for cracks along the welds and an uneven plane from the subframe to the gusset. A total failure of the guesset will shift your engine to the side and forward, taking out many other components along the way and leading to a very costly repair.

The next time you replace the motor mounts, oil pan gasket, checking your oil pump nut, or any other time you drop the front subframe, you should install these reinforcements. This kit comes with steel reinforcing plates that are welded to the underside of the guesset as well as plates to close off the bottom of the gusset for extra strength. Instructions included.

This item fits the following BMWs:
1999-2005 E46 BMW 323i 323ci 325i 325ci 328i 328ci 330i 330ci M3
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Genuine BMW E36, Z3 Strut Tower Reinforcement Plates (Pair)
Genuine BMW - Corporate Logo
T#:338358
Part#: 31312489795K
In Stock
Starting at $47.34
Free Shipping on orders $49 and up
The shock towers on the E36 and Z3 are notoriously weak. Under normal driving conditions with a stock, fresh suspension it is unlikely that you will ever have a problem. But with an upgraded street or race suspension with firm springs much of the energy from pounding the road is transmitted to the thin sheet metal in the strut tower. This pounding will cause the tower to deform or even crack. Look for 'mushrooming' or deformity around