Description
BMW E46 M3 Convertible inverted (00-06) BC Racing HM coilover kit 6/9 kg/mm
The BC Racing HM coilover kit E46 M3 Convertible (part number I-121-HM) is a coilover kit adjustable in height and damping, also simply called a coilover, for the BMW E46 M3 Convertible, model years 2000 to 2006. The spring rate is 6 kg/mm front and 9 kg/mm rear.
It is the inverted reservoir kit from BC Racing. The HM series brings two worlds together: the inverted design of the RM and the dual piston with external reservoir of the ER.
On MacPherson struts the HM uses an inverted monotube with dual piston. The external reservoir is connected with PTFE-coated, braided steel lines and contains the second piston. You adjust compression and rebound independently of each other, each in 30 clicks.
The spring rate is 6/9 kg/mm front/rear. The damping is digressive, the dampers are filled with synthetic oil and the ride height is infinitely adjustable via the damper body.
Key benefits
- Inverted design with reservoir: the RM and ER in one kit.
- 2-way adjustment: compression and rebound 30 clicks each.
- PTFE-coated braided steel lines: with the second piston in the reservoir.
- Dual piston: more adjustment range than a 1-way kit.
- Digressive damping: tight during weight transfer.
- Synthetic oil: stable during heavy sessions.
- Camber plates on suitable kits: rubber top mounts optional.
- Spring rate 6/9 kg/mm: specific to the M3 Convertible.
Suitable for
BMW M3 E46 Convertible, model years 2000 to 2006
- Serious track use
- Track days with high cornering loads
- Drivers who want stiff inverted struts with 2-way adjustment
Technical specifications
- Manufacturer: BC Racing
- Part number: I-121-HM
- Series: HM, inverted with external reservoir
- Spring rate front/rear: 6/9 kg/mm
- Damper design: inverted monotube with dual piston on MacPherson struts, external reservoir with PTFE-coated braided steel lines, digressive, synthetic oil
- Damping: 2-way, 30 clicks compression and 30 clicks rebound, independent of each other
- Ride height: infinitely adjustable via the damper body
- Top mounts: camber plates on suitable kits, rubber top mounts optional
- Contents: dampers and springs front and rear, lower mounts, top mounts where applicable, adjustment spanners and warranty card with serial number
- Warranty: 1 year on manufacturing defects. Noise from track-focused series is not covered by the warranty
Fitting and delivery
When fitting, take the time to position the reservoirs and the braided steel lines neatly, so that they stay clear during steering and suspension travel. Then set the ride height and have a wheel alignment done on the M3 Convertible. BC Racing advises periodic greasing of the HM 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 the manufacturer is temporarily sold out, you can still order and we will keep you informed.
Inverted dampers with a reservoir on braided steel lines: the HM gives an open-top M3 the design of a serious track kit.
Why choose this HM coilover kit E46 M3 Convertible?
Because you get the stiffness of inverted struts while being able to adjust compression and rebound separately. Where the RM offers simplicity and the ER adjustment range, the HM combines both. For an M3 Convertible that is driven often and hard on the circuit, the HM is the 2-way kit with inverted struts and an external reservoir.
BC Racing coilover kits for the BMW E46 M3 Convertible
Overview of the BC Racing series for the BMW E46 M3 Convertible 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-121-BR-RA | 6/9 | 30 clicks, linear | Road with the occasional track day |
| DS | I-121-DS-DA | 6/9 | 30 clicks, digressive | Track-focused, sporty road use |
| RM | I-121-RM-MA | 6/9 | 30 clicks, digressive, synthetic oil | Track days, hill climbs, tarmac rally |
| ER | I-121-ER | 6/9 | 2-way, 30 clicks per direction, external reservoir | Serious track and competition use |
| HM (this kit) | I-121-HM | 6/9 | 2-way, 30 clicks per direction, external reservoir | Serious track use |
| ZX | I-121-ZX | 6/9 | 3-way (20/12/30 clicks), external reservoir | Competition, long sessions, drift |
| ZR | I-121-ZR | 6/9 | 3-way (20/12/30 clicks), external reservoir | Competitive motorsport |
Frequently asked questions
What is the difference between the BC Racing HM and RM for the E46 M3 Convertible?
The HM coilover kit E46 M3 Convertible has a dual piston, an external reservoir and 2-way adjustment; the RM is 1-way without a reservoir. Both are inverted.
What is the difference between the BC Racing HM and ER for the E46 M3 Convertible?
The ER also has a reservoir and 2-way adjustment, but the HM uses an inverted damper with the second piston in the reservoir, connected via PTFE-coated braided steel lines.
What is the delivery time of this BC Racing HM coilover kit?
The delivery time is 1 to 2 weeks as long as the manufacturer has stock. Without stock you can still order; we will let you know when the kit arrives.
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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