If you are involved in car repair, you have probably encountered bolts under SPLINE - these unusual “stars” with 6, 12 or even 16 rays are increasingly found in modern cars. They are especially often used Volkswagen Group (Audi, VW, Skoda), BMW, Mercedes-Benz and Porsche for attaching brake discs, hubs, suspension and even interior elements. Regular hexagons or Torx will not work here - you need a specialized tool.

The problem is that SPLINE bit sets not as widespread as Torx or Hex. They are more difficult to find in stores, and prices can vary greatly - from budget Chinese sets to professional ones Hazet or Wera. In this article, we will look at what types of SPLINE bits there are, what to look for when purchasing, where it is more profitable to order them, and how not to run into a fake. We’ll also tell you why cheap analogues can ruin a bolt in a couple of turns.

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What is SPLINE and where is it used in a car?

SPLINE (or spline profile) is a type of fastening joint where radial grooves are used instead of traditional edges (like a hexagon). Externally, the bat looks like a “star” with evenly spaced rays. The main sizes found in cars: M5–M14 (internal SPLINE) and E4–E24 (external SPLINE, often for brake systems).

Where exactly can you encounter such bolts?

  • 🔧 Brake system: attaching brake discs to the hub (especially with Audi, VW Golf 7/8, BMW F-series).
  • 🚗 Suspension: levers, silent blocks, shock absorbers (for example, Mercedes W205 or Porsche 911).
  • ⚙️ Engine and gearbox: covers, oil pans, turbine mounts (found in Volvo and Jaguar).
  • 🪑 Salon: seat mounts, steering column (less common, but happens with premium brands).

It is important to understand that SPLINE is not a universal standard. For example, a bat E14 from Bosch may not fit the bolt E14 from Audi due to the different angle of rounding of the rays. Therefore, before purchasing, check compatibility with a specific car model.

📊 Which SPLINE bolt do you most often encounter?
Brake discs
Suspension
Engine/gearbox
Salon/interior
Haven't worked with SPLINE yet

Internal vs external SPLINE: what is the difference

This is a key point that many people miss. Internal SPLINE (Female) - when the grooves are inside bolt (like Torx), and external SPLINE (Male) - when the “star” appears outward (like some nuts). They require different bits:

Type SPLINEApplication exampleSizes (popular)Bit shape
Internal (Female)Brake disc mounting (Audi A4 B9), hub nutsM8, M10, M12, M14Bit with lugs
External (Male)Suspension nuts (BMW E60), shock absorber mountingsE10, E12, E14, E18Slotted bit
Double-sidedUniversal kits for servicesM8/E8, M12/E12Combined

⚠️ Attention: If you see only type designations in the kit description M12 or E14, specify whether it is an internal SPLINE or an external one. For example, for brake discs VW Tiguan needed internal M12, and for levers BMW 5-series — external E14.

Another nuance: some manufacturers (for example, Hazet) mark bits by the number of rays - 6-Spline, 12-Spline. It's not the size, it's profile shape. Make sure the kit contains exactly the option you need for your car.

Top 5 SPLINE bit manufacturers: comparison of quality and prices

The SPLINE tool market can be divided into three categories: premium (for professional service stations), middle segment (for car owners) and budget (risky choice). Here's who deserves attention:

  • 💎 Hazet (Germany): standard of quality, bits made of chrome vanadium steel Cr-V, covering Hazet-Protect against corrosion. Set price (5 bits) – from 8 000 ₽.
  • 🔧 Wera (Germany): series Wera Kraftform with ergonomic handles, suitable for frequent use. A set of 6 bits will cost 6 500–7 500 ₽.
  • 🛠️ Facom (France): professional tool, often used in dealerships. Bits are sold individually (from 1 200 ₽ per piece).
  • 💰 Nussbaum (Germany): budget premium, quality close to Hazet, but 20–30% cheaper. Set of 4 bits - approx. 4 500 ₽.
  • ⚠️ No-Name (China): bits without markings or branded type Jonnesway, Stayer. Attractive price (from 800 ₽ per set), but there is a risk of “licking off” the edges of the bolt - 50%.
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Before purchasing, check if the manufacturer has a certificate DIN 3122 or ISO 1173. This is a guarantee that the bat will not break at the first effort.

📌 Key Takeaway: If you plan to use SPLINE bits regularly (for example, to work in a service), it is better to overpay for Hazet or Wera. For one-time repairs you can take Nussbaum. Cheap Chinese kits are only suitable for “soft” bolts (for example, in the interior), but not for brake systems!

Where to buy SPLINE bits: review of sites and tips for choosing

In regular auto parts stores (such as AutoMag or Chip and Dip) SPLINE bits are rare. Here's where professionals look for them:

  1. Specialized tool stores:
    • 🛒 Hazet Russia - official website, 2 year warranty.
    • 🛒 Wera Tools — there are sets for specific car brands.
    • 🛒 Facom — sold individually, suitable for rare sizes.
  2. Foreign sites:
    • 🌍 Amazon Germany — large selection, but delivery is required (from 2 000 ₽).
    • 🌍 eBay - you can find rare sizes (for example, E20 for trucks).
  • Russian-language marketplaces:
    • 🛒 Wildberries — there are budget sets (but check the reviews!).
    • 🛒 Ozon - sometimes you come across original ones Hazet on promotion.

    ⚠️ Attention: On AliExpress and similar sites sell “clones” of famous brands. For example, under the guise Wera may sell low quality soft metal bits. How to spot a fake:

    • 🔍 The original bits have a laser engraving of the logo and size.
    • 🔍 Packaging must be branded (from Hazet - blue box with a hologram).
    • 🔍 Lower price 3 000 ₽ for a set of 5 bits - a reason to doubt.

    Specify the type (internal/external)|Check the size with the vehicle documentation|Check for DIN/ISO certificate|Evaluate reviews of the seller|Compare prices on 2–3 sites-->

    How to use SPLINE bits: step-by-step instructions

    Even with the right bat, you can ruin a bolt if you don't follow the proper technique. Here's how to work with SPLINE fasteners:

    1. Preparation:

      Clean the bolt from dirt and rust (use a wire brush or WD-40). If the grooves are clogged, the bit will not fit tightly and will tear off the edges.

    2. Tool selection:

      Suitable for internal SPLINE extension cord with ratchet, for external - spanner or socket. Avoid open-end wrenches - they can “loose” the edges.

    3. Fixation:

      The bit must fit into the bolt tight, no play. If you feel it is loose, try a different size or brand.

    4. Application of force:

      Do not press the key at an angle! The effort must be strictly along the axis of the bolt. If the bolt does not budge, use penetrating lubricant (for example, Liqui Moly MoS2) and wait 10–15 minutes.

    What to do if the SPLINE bit is scrolled?

    If the bit rotates in the bolt, do not apply more force - this will cause you to finally “lick” the edges. Try:

    1. Use extractor (for example, Hazet 1840-1).

    2. Weld a nut onto the bolt and unscrew it.

    3. Apply left hand drill (only for non-critical fastenings!).

    In services for such cases they use special cutters, but it's expensive (from 3 000 ₽ for work).

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    Never use SPLINE bits with impact wrench! The vibration quickly destroys both the bit and the bolt. For tight connections it is better to use lever with extension or hydraulic wrench.

    Prices for SPLINE bits in 2026: what affects the cost

    The cost of the set depends on four factors: brand, material, equipment and appointment. Here are the current prices for June 2026:

    Brand/TypeEquipmentPrice, ₽Where to buy
    Hazet 675SPL/55 bits (M8–M14), ratchet8 200–9 500Official website, Amazon DE
    Wera Kraftform Spline6 bits (E8–E18), holder6 500–7 800Wildberries (official seller)
    Nussbaum 124504 bits (M10, M12, E12, E14)4 300–5 000Ozon, auto tool stores
    Jonnesway (China)10 bits + ratchet1 200–1 800AliExpress, local markets
    Unnamed set6 bits, plastic case800–1 500Wildberries, Ozon (risk of counterfeiting)

    Important: in 2026, due to sanctions, official dealers Hazet and Wera raised prices by 15–20%. If you see a set cheaper 6 000 ₽, most likely it is not original or old stock.

    Tip: If you only need one bit (eg. E14 for Audi A6), it is more profitable to buy it piece by piece at Facom or KUKKO. This will cost 1 500–2 500 ₽, while the whole set may not be useful.

    Common mistakes when working with SPLINE and how to avoid them

    Even experienced craftsmen sometimes make mistakes that lead to edges breaking or the bat breaking. That's what it's impossible do:

    • 🔨 Use the wrong size bat. For example, trying to unscrew M12 bat M11. The result is a breakdown of the edges.
    • 🔧 Use extension cords without fixation. If the bit is not secured in the holder, it will spin.
    • 💥 Hit the key with a hammer. SPLINE bolts are often made of hardened steel - impact will only “jam” them.
    • 🛠️ Ignore corrosion. Rusty bolt needs to be treated lubricant (for example, PB Blaster) and wait.

    ⚠️ Attention: If you are working with brake discs Volkswagen or Audi, remember: their SPLINE bolts often have reverse thread (left)! Before unscrewing, check the direction of the thread, otherwise you risk tightening the bolt even more.

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    For stuck SPLINE bolts, use heating. Warm up the bolt with a hair dryer (up to 200–250°C), then try to unscrew it. Thermal expansion will weaken corrosion.

    FAQ: Answers to frequently asked questions about SPLINE bits

    Can Torx be used instead of SPLINE?

    No! Despite the external similarity, the profiles Torx (T) and SPLINE (M/E) have different beam angles and groove depths. Torx bit T55 not suitable for bolt M12 SPLINE - it either won’t sit down or will tear off the edges.

    Which set of SPLINE bits is needed for VW Golf 7?

    For VW Golf 7 (and most models Volkswagen Group on the platform MQB) you will need:

    • Internal SPLINE: M12 (brake discs), M10 (stepped suspension bolts).
    • External SPLINE: E14 (levers, silent blocks).

    The best choice is a set Hazet 675SPL/5 or Wera Spline-Set.

    How is SPLINE different from Hex (hexagon)?

    Hex (hexagon) has 6 straight edges, and SPLINE - 6, 12 or 16 rounded rays. This allows SPLINE to withstand more torque without breaking edges. For example, brake disc bolts BMW often go under SPLINE, because Hex does not provide the required reliability.

    Is it possible to make a SPLINE bit yourself from a hexagon?

    Theoretically, yes, if you grind the edges to the desired angle. But in practice this extremely unreliable:

    • A homemade bit will not fit accurately into the grooves.
    • The risk of bolt edges breaking increases with 3–5 times.
    • For hardened bolts (for example, in the brake system) this is not an option at all.

    It's better to buy an inexpensive set Nussbaum or rent a bat from a car service center.

    Where in Moscow/St. Petersburg to buy SPLINE bits with a guarantee?

    In Moscow:

    • Shop "Tool Profi" (m. Tulskaya) - official dealer Hazet.
    • "AutoSpetsInstrument" (metro station Begovaya) - large selection Wera and Facom.

    In St. Petersburg:

    • "Tools and Technology" (Optikov St., 4) - check availability by phone.
    • "AvtoMaster" (Engelsa Ave., 134) - sets available Nussbaum.

    In all cases, ask warranty card - official dealers have it.