The Best Coilovers For Your BMW Z4 (E85/E86)
Suspension guide
The Z4 is a low two-seat sports car that already handles well, so when owners come in asking about coilovers it is rarely because the chassis is wrong. It is the arch gap, and the soft factory damping on a car that deserves better.
The first thing Cameron asks is which Z4, because the standard roadster and coupe, and the Z4 M, have different kits from Clubracing level up. Garreth's question is what the car is actually for, because a standard Z4 on a sensible budget and a Z4 M going on circuit have very different answers.
Below is what we would fit at each level, cheapest first, with the price, what adjusts, and which Z4 each one covers.
- Standard Z4 (2002–2008) and Z4 M (2006–2008 only) need separate kits from Clubracing level up
- BC Racing only offers BR and RM for this car; there is no ER or ZR for the Z4 on our listings
- MOTON lists the Z4 M only, not the standard Z4
- AST Street kits cover the standard Z4; the Z4 M has no AST Street option
- The Z4 M uses the S54 engine from the E46 M3; different front subframe, different part numbers
Standard Z4 or Z4 M changes everything above entry level
The E85 and E86 cover two different cars on our listings, and which one you have decides the options from Clubracing upwards.
| Your Z4 | Years | Engine | What changes |
|---|---|---|---|
| Z4 Roadster (E85) | 2002–2008 | N52 six-cylinder | Main AST Street kits; Bilstein B12 |
| Z4 Coupe (E86) | 2006–2008 | N52 six-cylinder | Same AST kits as the E85 roadster |
| Z4 M Roadster (E85 M) | 2006–2008 only | S54 (from the E46 M3) | Own BC Racing listing; own AST and MOTON kits |
| Z4 M Coupe (E86 M) | 2006–2008 only | S54 (from the E46 M3) | Same kits as the E85 M |
From the vehicle tables on our listings. Every listing names the exact models it fits.
At Bilstein B12 and BC Racing entry level, the standard Z4 and the Z4 M overlap but are still listed separately: the Bilstein B12 covers only the E85 roadster, and BC Racing lists BCR-I-12 for the standard Z4 and BCR-I-22 for the M.
From Clubracing up, the split is wider. AST builds different part numbers for the Z4 M at every level: the M’s S54 engine and front subframe geometry take their own kits. MOTON lists only the Z4 M. And BC Racing stops at BR and RM for both variants: there is no ER or ZR for the Z4 on our listings. Cameron’s point is straightforward: if you want separate rebound and compression on a Z4, you are in AST or MOTON territory.
The ladder at a glance
Six levels, cheapest first. Prices shown are for the standard Z4 where there is a choice; Z4 M listings appear at each level from Clubracing up.
| Level | Our pick | Price inc VAT | What you can adjust |
|---|---|---|---|
| Lowering springs or matched kit | Bilstein B12 Pro-Kit (E85 roadster) | £1,284 | None, a fixed drop |
| Entry coilover | BC Racing BR (standard Z4) | £1,049 | Height, 30 click damping |
| Fast road coilover | AST 5100 Street Performance (standard Z4) | £3,072 | Height, 12 click rebound |
| Club and trackday 1-way | AST 5100 Clubracing (standard Z4) | £3,480 | Height, 12 click rebound |
| 2-way | AST 5200 2-Way (standard Z4) | £5,064 | Height, rebound, compression on a remote reservoir |
| 3-way | AST 5300 3-Way (standard Z4) | £5,376 | Height, rebound, low and high speed compression |
Prices read from the site on the day this guide was built, inc VAT. The product cards below show prices before VAT, as the rest of the site does; the Inc/Exc VAT switch changes them.
1. Eibach springs and Bilstein B12: lower the Z4 without a coilover
If the car only needs to sit lower and ride better, a matched spring and damper kit is the honest starting point. The Bilstein B12 Pro-Kit puts Bilstein dampers with Eibach springs in one box for the E85 roadster. If your dampers are still fresh and you only want the drop, Eibach Pro-Kit springs fit the E85 roadster, the E86 3.0si coupe, and both Z4 M variants.
Garreth’s caveat: coverage at this level is narrow. The Bilstein B12 covers only the E85 roadster. For an E86 coupe the first stop is Eibach springs or a coilover. For a Z4 M, Eibach has the E10-20-010-04-22 springs for both M body styles.
- Price. £1,284 inc VAT
- Adjustment. None, a fixed drop
- In the box. Bilstein dampers and matched Eibach springs
- Buy it if. The car just needs to sit lower with a better controlled ride, and you never want to touch it again
2. BC Racing BR: the height-adjustable starting point
BR gives you height adjustment and 30 clicks of rebound on rubber top mounts front and rear, at a price that sits close to a spring and damper kit. BC lists BCR-I-12 for the standard Z4 and BCR-I-22 separately for the Z4 M; both ship at 5 kg/mm front and 8 rear. Ride height adjusts independently of spring preload and the dampers are rebuildable.
Cameron notes what the listing makes clear: BC only offers BR and RM for the Z4. RM adds an inverted front strut if that suits your build; it is on the same listing. There is no ER or ZR for this car, so the next meaningful step up is AST or MOTON. If you have a Z4 M and want to confirm BCR-I-22 is the right kit, drop us an email or click to open a chat before ordering.
- Price. £1,049 inc VAT, BR
- Adjustment. Height, 30 click damping
- In the box. Coilovers with springs; the top mount options are on the listing
- Buy it if. You want the car sitting right with a damping dial, on a sensible starting budget
3. AST 5100 Street Performance: the road car step up (standard Z4)
The AST Street kits are for the standard Z4 only. There is no AST Street option for the Z4 M; the M goes from BC Racing straight to Clubracing.
The Street Performance is a monotube with 12 clicks of rebound, a front coilover with an OEM-style divorced rear and camber-adjustable front top mounts included. That last point matters on a lowered Z4: the standard Street kit (ACS-B1101SD) comes without the camber mounts and costs a bit less; the Street Performance is the better choice if the car is going to sit lower than factory.
Cameron would fit the Street Performance on a standard Z4 that gets used properly on the road. Garreth would step up to Clubracing the moment the car sees a track. If you want to confirm whether ACS or ACT suits your setup, drop us an email or click to open a chat and we will help you decide.
- Price. £3,072 inc VAT
- Adjustment. Height, 12 click rebound
- In the box. Springs and camber-adjustable front top mounts
- Buy it if. It is a standard Z4, driven hard on the road, and you want the camber sorted at the front
4. AST 5100 Clubracing or MOTON 1-Way: the trackday Z4
Both are full coilovers front and rear with camber-adjustable front and solid rear top mounts. The AST Clubracing has 12 clicks of rebound; the MOTON 1-Way has 15. The standard Z4 gets the ACC-B1106SD. The Z4 M has its own ACC-B2203SD, and the MOTON 1-Way only lists the M.
Garreth would point a Z4 M doing regular trackdays to the MOTON 1-Way. It is the MOTON damper without a reservoir to package, and for most Z4 M trackday owners one dial is enough to work with between sessions. Cameron thinks the AST Clubracing is the right choice for a standard Z4 that sees the odd track day, because it costs less and the 12-click rebound gives you enough range to work with. Both are rebuildable through an authorised AST x MOTON service centre.
- Price. £3,480 inc VAT
- Adjustment. Height, 12 click rebound
- In the box. Coilover rear, camber front and solid rear top mounts
- Buy it if. The car goes on track and you want the rear spring rate and camber under your control
5. Two way: AST 5200 or MOTON 2-Way
Separate rebound and compression is where a track car gets tuned. The standard Z4 gets the AST 5200 RIV-B1101SD; the Z4 M gets its own RIV-B1010SD and the MOTON 2-Way. Both AST kits are coilover suspension with remote reservoirs. The MOTON 2-Way carries MOTON’s blow-off valve system in the reservoir for kerbs and rough surfaces, and the reservoirs sit on hoses so they can go wherever there is room.
Cameron’s rule: buy this rung when somebody is going to change the settings between sessions and write them down. Garreth’s is that AST and MOTON both build to the car, offer custom spring rates and have a UK rebuild centre, and that is what the extra money over BC Racing buys on a car that races.
- Price. £5,064 inc VAT
- Adjustment. Height, rebound, compression on a remote reservoir
- In the box. Springs, reservoirs, top mounts where applicable
- Buy it if. You set the car up at the circuit and want both adjusters
6. Three way: AST 5300 or MOTON 3-Way
The top rung splits compression into slow and fast movements. The standard Z4 gets the RAC-B1101SD. The Z4 M gets the RAC-B1010SD and the MOTON 3-Way, which splits compression into 15 high speed and 6 low speed positions on top of 15 clicks of rebound. A MOTON triple adjustable won the European Touring Car Championship in 2004.
Buy one when somebody is going to write the settings down.
- Price. £5,376 inc VAT
- Adjustment. Height, rebound, low and high speed compression
- In the box. Springs, reservoirs, top mounts where applicable
- Buy it if. It is a race car, or a trackday car with somebody setting it up properly
Anti-roll bars to go with them
Anti-roll bars change the balance in corners; coilovers change how the car sits and controls body movement over bumps. H&R list uprated bars for the Z4 in one kit covering both the E85 roadster and E86 coupe.
| Part number | Fits | Price inc VAT |
|---|---|---|
| 33276-1 | Z4 Roadster (E85) and Z4 Coupe (E86) | £572 |
Every option we list for the Z4
| Range | Part number | Listed for | Price inc VAT |
|---|---|---|---|
| Eibach Pro-Kit | E10-20-010-04-22 | BMW Z4 M Coupe (E86) / Z4 M Roadster (E85) - 855 kg Front Axle | £340 |
| Eibach Pro-Kit | E10-20-010-01-22 | BMW Z4 Roadster (E85) - 790 kg Front Axle | £340 |
| Eibach Pro-Kit | E10-20-010-05-22 | BMW Z4 3.0si Coupe (E86) | £340 |
| BC Racing | BCR-I-22 | BMW Z4 M (06-08) [E85] | RM £1,239, BR £1,049 |
| BC Racing | BCR-I-12 | BMW Z4 (02-08) [E85/E86] | RM £1,239, BR £1,049 |
| Bilstein B12 Pro-Kit | 46-181237 | BMW Z4 Roadster (E85) | £1,284 |
| AST 5100 Street | ACS-B1101SD | BMW E46 / E85 / E86 | £2,568 |
| AST 5100 Street | ACU-B1101SD | BMW E46 / E85 / E86 | £2,604 |
| AST 5100 Street Performance | ACT-B1101SD | BMW E46 / E85 / E86 | £3,072 |
| AST 5100 Clubracing | ACC-B2203SD | BMW E85 / E86 | £3,480 |
| AST 5100 Clubracing | ACC-B1106SD | BMW E46 / E85 / E86 | £3,480 |
| MOTON 1-Way Clubracer | M 505 178SD | BMW E85 / E86 | £3,600 |
| MOTON 2-Way Motorsport | M 505 112SD | BMW E85 / E86 | £5,016 |
| AST 5200 2-Way Motorsport | RIV-B1101SD | BMW E46 / E85 / E86 | £5,064 |
| AST 5200 2-Way Motorsport | RIV-B1010SD | BMW E85 / E86 | £5,064 |
| AST 5300 3-Way Motorsport | RAC-B1101SD | BMW E46 / E85 / E86 | £5,376 |
| AST 5300 3-Way Motorsport | RAC-B1010SD | BMW E85 / E86 | £5,376 |
| MOTON 3-Way Motorsport | M 505 110SD | BMW E85 / E86 | £5,796 |
Every coilover and spring listing that names the Z4 today. BC Racing prices are per series.
Before you order
- Which Z4. Standard roadster or coupe, or Z4 M: separate BC listings, and different AST and MOTON kits from Clubracing up
- AST Street kits. ACS and Street Performance (ACT) fit the standard Z4 only; there is no AST Street for the Z4 M
- BC RM. Available as a series option on the same BC listing as BR: an inverted front strut is the difference
- Alignment. Lowering changes camber and toe; book the alignment as part of the job
Common questions
What are the best coilovers for a standard Z4 on a budget?
BC Racing BR, at a little over a thousand pounds, with height and 30 click damping adjustment and 5 kg/mm front and 8 rear springs matched to the car.
Does the Z4 M need different coilovers to the standard Z4?
At Clubracing level and above, yes. AST writes separate kits for the M from Clubracing upwards, and MOTON only lists the Z4 M. BC Racing also has a separate listing: BCR-I-22 for the M and BCR-I-12 for the standard Z4.
Is there a budget 2-way option for the Z4?
No. BC Racing only offers BR and RM for both the standard Z4 and the Z4 M on our listings. There is no ER or ZR for this car, so if you want separate rebound and compression the options are the AST 5200 or MOTON 2-Way.
Does the standard Z4 have MOTON coilovers?
No. MOTON only lists the Z4 M. The standard Z4 goes as far as the AST 5300 3-Way at the top of our ladder.
Can I fit AST 5100 Street coilovers on a Z4 M?
No. The AST Street and Street Performance kits fit the standard Z4 Convertible and Coupe; the Z4 M has its own ACC-B2203SD Clubracing kit. If you want to confirm the right part number before ordering, drop us an email or click to open a chat.
What we would fit
For a standard Z4, Cameron fits BC Racing BR and spends what is left on a proper alignment. The stance is sorted, the damping dial is there, and the kit is rebuildable. Garreth would go to the AST 5100 Street Performance if the car is driven hard, because the camber-adjustable mounts are worth having once the car sits lower than factory.
For a Z4 M, they split. Cameron thinks BC BR is the honest answer for a road car: it does the job for a fraction of the AST price and the extra money is better spent on tyres. Garreth disagrees. The Z4 M is already set up as a sports car, and fitting a trackday kit means MOTON 1-Way, because the non-inverted endurance damper handles the mileage better. Where they agree is the 2-way: buy it when the car has a proper setup programme, not just a day out.
Our AST guide and MOTON guide go deeper on those ranges, and the BC Racing BMW guide covers every BC fitment for the brand.
Send us the registration and what the car is used for. We will find the right part number and check the listing notes with you before you order.
Tell us the model, the year and what the car is for. We will confirm the right part number and check the notes on the listing with you before anything is ordered.
