- Description
- Fitment
- Refund Policy
The MMX Performance BMW N55 / S55 One-Piece Crank Hub Upgrade Kit is engineered to address the factory three-piece crank hub design found on BMW N55 and S55 engines. The factory assembly relies on friction surfaces between multiple components to maintain crankshaft timing, creating the potential for rotational slip under load.
The MMX one-piece crank hub replaces the factory multi-piece assembly with a single, integrated billet component. By eliminating the separate friction-based sections of the original hub, the MMX design removes the possibility of the hub components slipping independently of one another and provides a more robust foundation for maintaining crankshaft timing.
At the center of the upgrade is a CNC-machined crank hub manufactured from billet EN36 steel. The component is heat-treated with a 0.75mm case hardening to provide the surface hardness, strength, and wear resistance required for a critical engine timing component. A new crank bolt is also supplied with the kit for installation.
This unpinned one-piece configuration provides an important advantage for street-driven and moderately tuned BMW applications: installation does not require precision drilling of the crankshaft for locating dowels. MMX recommends this version for standard through Stage 1 tuned N55 and S55 engines, providing a significant upgrade over the factory three-piece design without the additional installation requirements of a pinned crank hub.
For additional crank bolt security, the system can be paired with the MMX Crank Hub Capture Plate. The billet aluminum capture plate mechanically secures the crank bolt head to help prevent loosening caused by engine vibration and harmonics.
For higher-output builds requiring an additional mechanical connection between the hub and crankshaft, MMX also offers a 4-pin version. The 4-pin system uses four precision-machined dowels to mechanically locate the hub to the crankshaft and is recommended by MMX for applications operating beyond the intended range of the standard one-piece upgrade.
Product Details
- MMX Performance one-piece crank hub upgrade for BMW N55 and S55 engines
- Replaces the factory three-piece crank hub assembly
- Single-piece construction eliminates internal friction-plate slip
- CNC-machined from billet EN36 steel
- 0.75mm case-hardened heat treatment
- Engineered for increased strength, wear resistance, and durability
- Includes new crank bolt
- Unpinned design does not require drilling the crankshaft for locating dowels
- Recommended by MMX for stock through Stage 1 tuned N55 and S55 applications
- Compatible with the MMX Crank Hub Capture Plate
- Professional installation required
Recommended Products
Returns
Our policy lasts 14 days. If 14 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange. All items are subject to 15% restocking fee from the manufacturer.
To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.
Additional non-returnable items:
Gift cards
Downloadable software products
To complete your return, we require a receipt or proof of purchase.
Please do not send your purchase back to the manufacturer.
There are certain situations where only partial refunds are granted (if applicable)
You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the cost of shipping to you will be deducted from your refund. If your original order qualified for free shipping, the actual cost of shipping the item to you will still be deducted from your refund.
If you would like to start a return please click here
Refunds (if applicable)
Once your return is received and inspected, we will send you an email to notify you that we have received your returned item. We will also notify you of the approval or rejection of your refund.
If you are approved, then your refund will be processed, and a credit will automatically be applied to your credit card or original method of payment, within a certain amount of days.
You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the cost of shipping to you will be deducted from your refund. If your original order qualified for free shipping, the actual cost of shipping the item to you will still be deducted from your refund.
Late or missing refunds (if applicable)
If you haven’t received a refund yet, first check your bank account again. Then contact your credit card company, it may take some time before your refund is officially posted. Next contact your bank. There is often some processing time before a refund is posted. If you’ve done all of this and you still have not received your refund yet, please contact us at info@amtuning.ca.
Sale items (if applicable)
Only regular priced items may be refunded, unfortunately sale items cannot be refunded.
Labor Fees (if applicable)
AM Tuning Canada is not responsible for, and shall not be liable for, any labor fees, installation charges, removal charges, diagnostic fees, or other service-related costs incurred by the customer or any third party in connection with the installation, removal, modification, servicing, or use of any products purchased from AM Tuning Canada. Unless expressly agreed to in writing by AM Tuning Canada, all such labor and service costs are the sole responsibility of the customer.
Exchanges (if applicable)
To start an exchange, click here
Non-refundable items
The following items are non-refundable and non-returnable once purchased: oils, fuel or oil additives, filters, tuning cables, OBDeleven products, Braum seats, spark plugs, coil packs, and similar consumable, wheel spacers, wheels bolts, license plate brackets, electronic tuning components and any other product subject to discretion of AM Tuning Canada.
Other products from brands such as MHD, Bootmod3, Ecutek, Braum racing, Novitec are also non-refundable and non-returnable.
All sales of these items are final and are subject to the policies and discretion of AM Tuning. By completing a purchase, the customer acknowledges and agrees to these terms.
