Description
BC Racing ZR coilover kit BMW 3 Series E46 True Rear Sedan/Coupe/Touring (98-06) 7/6 kg/mm
The BC Racing ZR coilover kit E46 True Rear (part number I-31-ZR) is a coilover kit adjustable in height and damping, also simply called a coilover, for the BMW 3 Series E46 Sedan, Coupe and Touring with rear-wheel drive, model years 1998 to 2006, in True Rear version. The spring rate is 7 kg/mm front and 6 kg/mm rear.
This motorsport kit has a complete strut on the rear axle. The ZR is a 3-way series with external reservoir that BC Racing makes for competitive motorsport.
True Rear means that the separate spring and the separate damper the E46 has at the rear from the factory make way for one coilover with the spring around the damper. You then set height and spring travel in the same way at the front and rear. The standard ZR without True Rear (I-02) keeps the original rear layout.
On MacPherson struts an inverted monotube is used, on double wishbones an upright monotube, in each case with dual piston and an external reservoir connected via steel-braided lines, which can be mounted on the chassis or on the damper body. The ZR is 3-way: 20 clicks low-speed compression, 12 clicks high-speed compression and 30 clicks rebound. The ride height is fully adjustable independently of the spring preload and the spring rate is 7/6 kg/mm.
Key benefits
- Complete strut at the rear: the True Rear layout with the spring around the damper.
- 3-way damping: slow compression, fast compression and rebound each separately.
- Ride height fully independent of preload: height and spring travel adjustable independently.
- Flexible reservoir placement: on the chassis or on the damper body.
- Inverted monotube on MacPherson: stiff front struts under high loads.
- Steel-braided lines: durable and resistant to track use.
- Synthetic oil and digressive tuning: predictable, even when things get hot.
- Spring rate 7/6 kg/mm: stiffer than the 6/5 kg/mm of the other E46 True Rear kits.
- Rebuildable: made to keep going season after season.
Suitable for
BMW 3 Series E46 Sedan, Coupe and Touring, model years 1998 to 2006, with rear-wheel drive, in True Rear version (BC Racing part number I-31; not for the M3 and the Convertible)
- Competitive motorsport and club championships
- Teams that use their own setup for each circuit
- E46 race cars where every damping phase must be separately adjustable
Technical specifications
- Manufacturer: BC Racing
- Part number: I-31-ZR
- Series: ZR, 3-way motorsport with external reservoir
- Version: True Rear, a complete strut at the rear with the spring around the damper
- Spring rate front/rear: 7/6 kg/mm
- Damper design: inverted monotube on MacPherson, upright monotube on double wishbones, dual piston, external reservoir, digressive
- Damping: 3-way, 20 clicks low-speed compression, 12 clicks high-speed compression, 30 clicks rebound
- Ride height: fully adjustable, independent of the spring preload
- Top mounts: camber plates on suitable kits, rubber top mounts optional
- Contents: 4 struts with dampers and springs, lower mounts, top mounts where applicable, adjustment spanners and warranty card with serial number
- Warranty: 1 year on manufacturing defects. With this track-focused series, noise is not covered by the warranty
Fitting and delivery
Before fitting, decide where the reservoirs fit best, on the chassis or on the damper body, and route the lines so that they stay clear at full suspension travel. At the rear the coilovers replace the separate spring and damper. Please note: BC Racing specifies that the body shell must be reinforced before fitting a True Rear kit. After setting the ride height, have a wheel alignment done on the E46 and preferably have it corner weighted on scales. BC Racing advises periodic greasing of the ZR series and recommends it less for road use than the BR, DS, ER or ZX. The delivery time is 1 to 2 weeks as long as the manufacturer has stock. If it is out of stock, you can still order and we will keep you informed.
The ZR with True Rear is the kit that takes an E46 Sedan, Coupe or Touring from track day car to real race car.
Why choose this ZR coilover kit E46 True Rear?
Because every phase of the damping can be adjusted separately, height and spring travel are independent of each other and the rear has complete struts as well. On top of that the kit remains rebuildable, so your investment lasts for years.
BC Racing coilover kits for the BMW E46 Sedan, Coupe and Touring in True Rear version
Overview of the BC Racing series for the BMW E46 Sedan, Coupe and Touring in True Rear version supplied by Race4DriftParts, with the BC Racing part number. Spring rates in kg/mm, front/rear.
| Series | Part number | Springs f/r | Damping | Intended for |
|---|---|---|---|---|
| BR | I-31-BR-RH | 6/5 | 30 clicks, linear | Road with the occasional track day |
| DS | I-31-DS-DH | 6/5 | 30 clicks, digressive | Track-focused, sporty road use |
| RM | I-31-RM-MA | 6/5 | 30 clicks, digressive, synthetic oil | Track days, hill climbs, tarmac rally |
| ER | I-31-ER | 6/5 | 2-way, 30 clicks per direction, external reservoir | Serious track and competition use |
| HM | I-31-HM | 6/5 | 2-way, 30 clicks per direction, external reservoir | Serious track use |
| ZX | I-31-ZX | 6/5 | 3-way (20/12/30 clicks), external reservoir | Competition, long sessions, drift |
| ZR (this kit) | I-31-ZR | 7/6 | 3-way (20/12/30 clicks), external reservoir | Competitive motorsport |
For the standard version without True Rear, BC Racing has separate kits for the E46 Sedan, Coupe, Touring and Compact. Their part numbers start with I-02. For the E46 Convertible, BC Racing has its own kit under part number I-90.
Frequently asked questions
What is the difference between the BC Racing ZR True Rear and the standard ZR for the E46?
The ZR coilover kit E46 True Rear (I-31) has a complete strut at the rear with the spring around the damper and 7/6 kg/mm. The standard ZR (I-02) keeps the separate spring and damper at the rear and has 8/10 kg/mm.
What is the difference between the BC Racing ZR and ZX for the E46 True Rear?
The ZR uses an inverted monotube on MacPherson struts and lets you mount the reservoir on the chassis or on the damper body; the ZX has an upright monotube. Both are 3-way with the same click distribution.
Does this BC Racing ZR coilover kit E46 True Rear fit an E46 Touring or Convertible?
Yes for the Touring: BC Racing releases this True Rear kit for the rear-wheel drive E46 Sedan, Coupe and Touring, except the M3. For the Convertible, BC Racing has no True Rear kit, but its own standard kit under part number I-90.
What is the delivery time of this BC Racing ZR coilover kit?
The delivery time is usually 1 to 2 weeks as long as the manufacturer has stock. If the kit is temporarily sold out, you can still order and we will let you know when it comes in.
Delivery outside the European Union: different shipping costs may apply. Don’t worry: we will email you as soon as possible after your order and agree the shipping with you. You are not committed to anything without your consent.
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