By the Suspengo Technical Team · Published 2026-09-04 · Last reviewed 2026-09-04
The part number stamped on your old damper is the fastest route to the right replacement
When a Bilstein damper fails, the most reliable replacement path is the number already stamped on the unit you are removing. Bilstein part numbers encode the product family, the application, and — in some ranges — the fitment position. Once you can read the prefix, you know the range. Once you know the range, you can check whether the replacement should be a like-for-like match or a deliberate upgrade.
This guide explains every prefix group, walks through how to decode the number from your old part, and points you to the index pages where you can search by number directly.
Part number indexes: Full part index A–Z · Bilstein ranges hub · Browse by vehicle
Bilstein part number format
A Bilstein part number follows the structure: XX-XXXXXX
- The two digits before the hyphen identify the product family and series. This is the most important part of the number.
- The six digits after the hyphen encode the specific application — chassis, fitment position, and variant. These do not follow a simple rule; they are looked up in the fitment index.
Prefix groups and what they mean
| Prefix | Range | Type | Intended use | Ride height required |
|---|---|---|---|---|
| 19 | B4 | Monotube replacement damper | OEM-equivalent replacement for everyday road driving | Factory standard |
| 22 | B4 | Complete strut assembly (damper + top mount) | Ready-to-fit strut for applications that require a full assembly | Factory standard |
| 24 | B6 | Sport monotube damper | 30–40% firmer than B4; sport and performance driving at factory height | Factory standard |
| 25 | B8 | Shortened sport monotube damper | Sport driving on a car already lowered 30–40 mm on aftermarket springs | Lowered 30–40 mm |
| 33 | B12 | Complete kit: sport damper + matched spring | Drop-in sport upgrade; lowers 30–40 mm, no height adjustment | Lowers to specification |
| 35 | B14 | Complete kit: sport damper + height-adjustable spring perch | Height-adjustable sport kit; 30–60 mm lower | Adjustable before fitment |
| 46 | B16 | Coilover (rebound-adjustable) | Road and track; continuous ride height and rebound adjustment | Fully adjustable |
| 48 | B16 | Coilover (compression + rebound adjustable) | Performance road and track; full two-way adjustment | Fully adjustable |
How to decode the number from your old part
Step 1: locate the part number. On a Bilstein damper, it is stamped into the aluminium body near the mounting eye, or printed on a label around the reservoir. It reads in the format XX-XXXXXX.
Step 2: read the prefix. The two digits before the hyphen tell you immediately which range you are dealing with. A 24- prefix is a B6; a 25- prefix is a B8. If the prefix is 19 or 22 and you want a firmer result, your upgrade is the same application in a 24-series.
Step 3: decide between replacement and upgrade. If you are replacing a worn damper with the same behaviour, use the same prefix. If you want a performance upgrade, move to the next prefix group: 19 → 24 (B4 to B6) or 24 → 25 if the car has been lowered.
Step 4: search by number. Enter the full part number in the part number index or use the vehicle selector to find the correct number for your car. The index pages below are grouped by series and sorted for fast lookup.
Series index pages
Each index page lists every part number in that series, with fitment notes and links to product pages:
- Bilstein B4 part numbers (19-series and 22-series)
- Bilstein B6 part numbers (24-series)
- Bilstein B8 part numbers (25-series)
- Bilstein B12 part numbers (33-series)
- Bilstein B14 part numbers (35-series)
- Bilstein B16 part numbers (46-series and 48-series)
- Tein Flex Z part numbers
- Tein Street Advance part numbers
- Tein Super Street part numbers
- Full part index A–Z (all brands)
The most common part number lookup scenario: like-for-like replacement
Your B4 (19-series) damper has failed. You want the same behaviour — quiet, factory-compliant, OEM quality — restored. Find the six-digit application code from your old damper. Enter 19-XXXXXX in the B4 index. Order the matching unit. No guesswork.
The upgrade scenario: from B4 to B6 on a standard-height car
Your B4 has failed and you want firmer sport handling without changing ride height. The B6 uses the same external dimensions as the B4 — identical mounting points, identical body length. The application code often differs, so do not assume a 24-series number is the same digits as the 19-series unit you are replacing. Use the vehicle selector or the B6 index to find the correct 24-series number for your car.
When the prefix is not readable
If the stamp is worn or the label damaged, use the vehicle selector — make, model, year, engine — to identify all fitment options for your car. The correct part numbers will be listed by range. Alternatively, contact us via the store with your vehicle details and we will identify the correct number.
Frequently asked questions
- Is the application code (the six digits) the same across ranges for the same car?
- No. Bilstein assigns new application codes when the damper body or valving changes between ranges. A B4 and a B6 for the same car will share the same prefix digits before the hyphen but use different six-digit codes after it. Always confirm fitment using the vehicle selector or the range-specific index page.
- I found two 24-series numbers for my car. Which is correct?
- Multiple part numbers for the same car usually represent different fitment variants — left vs right, front vs rear, or different build-date ranges. Check the fitment notes on the product page or use the vehicle selector with your exact build date to narrow it down.
- My part number starts with something not on this list. What is it?
- Bilstein manufactures OEM-supply parts for vehicle manufacturers with different prefix groups. These are not sold as aftermarket replacements through the standard retail channel. If you see an unfamiliar prefix, use the vehicle selector to find the correct aftermarket replacement number.
- Can I use the part number from one country's distributor in another?
- Bilstein part numbers are global — the same number applies regardless of where you are buying. Regional catalogues sometimes list alternative numbers for the same part; if in doubt, cross-reference using the vehicle selector.
- The index page shows a part as discontinued. What do I do?
- Search the full A–Z part index for a current replacement number, or use the vehicle selector to find the available current fitment. Bilstein occasionally supersedes part numbers when a range is updated.
Find your part number
Full part index A–Z · Bilstein ranges hub · B4 index · B6 index · B8 index · B12 index · B14 index · B16 index · Browse by vehicle
