01 · Überblick
Why the 1 Series Convertible didn't get a folding hardtop
When BMW presented the 1 Series Convertible in January 2008, the 3 Series Convertible E93 with its three-piece folding metal roof was already in production within the same group. For the smaller sibling, BMW deliberately decided against this: an electrohydraulic soft top with a heated glass rear window. This means less weight, less installation space and less boot space — 260 litres remain with the top open instead of 305, a loss of only 45 litres.
There is a contradiction regarding the top’s operating speed that continues to haunt the literature to this day. In the preliminary communication from September 2007, BMW stated 40 km/h and 240 or 280 litres of boot space respectively. The final press kit from January 2008 states — in both German and English — 50 km/h and 260/305 litres, and the data sheets of all models confirm this. The German Wikipedia still carries the outdated preliminary figure to this day.
The second thing worth knowing: at 1,392 millimetres, the 135i Convertible is the lowest model in the entire 1 Series model line — even lower than the 135i Coupé at 1,408 millimetres.
02 · Historie
Five and a half years of open-top driving
- 2008 World premiere at the Detroit Motor Show in January, start of production in March. Sales begin in Austria on 29 March; there is no BMW-confirmed German date.
- 2010 In January, BMW announces the N55 for the 135i Convertible, followed by the seven-speed dual-clutch transmission from March.
- 2011 Facelift from March, identical to the Coupé: Air Curtain in the front apron, LED daytime running lights, L-shaped tail lights.
- 2012 In December, BMW presents the Limited Edition Lifestyle — for the Convertible with a brown fabric top with silver-coloured pigmentation, the only brown top colour in the model line.
- 2013 End of production in October.
03 · Modellübersicht
The engines
The engine range corresponds to the Coupé.
Technische Daten anzeigen — komplette Modellmatrix
| Modell | Motor | Hubraum | Leistung | Bauzeit |
|---|---|---|---|---|
| 118i | N43B20 | 1.995 cm³ | 143 PS (105 kW) | 2008–2013 |
| 120i | N43B20 | 1.995 cm³ | 170 PS (125 kW) | 2008–2013 |
| 125i | N52B30 | 2.996 cm³ | 218 PS (160 kW) | 2008–2013 |
| 135i | N54B30, ab 2010 N55B30 | 2.979 cm³ | 306 PS (225 kW) | 2008–2013 |
| 118d | N47D20 | 1.995 cm³ | 143 PS (105 kW) | 2008–2013 |
| 120d | N47D20 | 1.995 cm³ | 177 PS (130 kW) | 2008–2013 |
| 123d | N47D20 with sequential turbocharging | 1.995 cm³ | 204 PS (150 kW) | 2008–2013 |
04 · Karosserievarianten
Karosserievarianten
Two-door Convertible with soft top
4,360 mm long, 1,748 mm wide, 1,411 mm high (135i: 1,392 mm), wheelbase 2,660 mm. Boot space 260 litres open, 305 litres closed. Electrohydraulic soft top with heated glass rear window, deploying roll-over bars behind the rear headrests.
05 · Motoren
The engine that defines the Convertible
N54B30 or N55B30 · 2,979 cm³ · 306 PS — 135i Convertible geprüft
The top model and at the same time the lowest car in the model line. In 2008, BMW advertised that the 135i Convertible was only 115 kilograms heavier than the Coupé. This cannot be cleanly recalculated: according to the data sheets dated 03/2010, it is 135 kilograms compared to the N55 Coupé and 105 compared to the older N54 Coupé. The BMW figure lies exactly in between.
Technische Daten anzeigen
| Hubraum | 2.979 cm³ |
| Leistung | 306 PS (225 kW) at 5,800/min |
| Drehmoment | 400 Nm |
| Leergewicht | 1,590 kg DIN |
| Höhe | 1.392 mm |
| 0–100 km/h | 5,6 s |
BMW press information 01/2008, data sheets 03/2010
06 · Schwachstellen
Known weak points
- High-pressure pump, injectors and wastegates of the N54 (135i up to March 2010). In October 2010, BMW recalled around 130,000 vehicles from model years 2007 to 2010 and extended the warranty on the affected components in the US. The extensions applied explicitly only to the US market.
- Timing chain of the N47 diesels (118d, 120d, 123d). The chain sits on the transmission side, the engine must be removed for replacement. BMW extended goodwill cover to eight years and 200,000 kilometres in early 2014.
07 · Technik
Technik
The soft top
The contradiction regarding top operating speed
Überrollschutz
Sun Reflective Technology
08 · Motorsport
Motorsport
Keiner.
09 · Kaufberatung
What to look out for when buying
The engine issues are the same as with the Coupé. There are no reliable sources regarding the top itself.
There are reports circulating about the top’s hydraulics for which we have not found two independent reliable sources. They are therefore not listed here.
10 · Die Konkurrenz
Die Konkurrenz
Audi A3 Cabriolet (8P)
From 2008 and also with a soft top — but with front-wheel drive and without a six-cylinder.
Volkswagen Eos
With a folding steel roof including an integrated sunroof — the technically more elaborate but heavier solution.
Mini Convertible (R57)
From the same manufacturer, one class below, with front-wheel drive and a significantly smaller interior.
11 · Galerie
Galerie
12 · Quellen