MMX Performance BMW S55 / N55 One-Piece High HP Crank Hub Upgrade Kit - 4-Pin
- Description
- Fitment
- Refund Policy
The MMX Performance S55 / N55 One-Piece High HP Crank Hub Upgrade Kit addresses one of the best-known failure points on BMW's turbocharged S55 and N55 engines. The factory crank hub is a three-piece assembly that relies on friction to hold its position on the crankshaft. Under high load it can slip rotationally, and once it does the timing moves far enough for piston-to-valve contact. The repair bill after that is substantial.
The MMX hub replaces it with a single-piece design machined from heat-treated billet EN36 steel. Rather than relying on friction, it is mechanically locked to the crankshaft by four aerospace precision-machined dowels. That is the difference: the hub cannot rotate independently of the crank, so the timing relationship holds regardless of load, boost or how hard the engine is being driven. This four-pin version is the one to specify on high-horsepower builds.
Installation requires drilling the crankshaft, so the kit is supplied complete with the drilling jig and drill bit needed to do it accurately. This is not a job for a home garage: the crankshaft is being permanently modified and the alignment has to be right, so professional installation is required.
The kit is available with or without the MMX capture plate. The capture plate is a billet aluminum hat that bolts over the entire head of the crank bolt, making it physically impossible for the bolt to back out under the engine's vibrations and harmonics. Selecting the version with the plate covers both failure modes at once.
Product Details
- One-piece crank hub replacing the factory three-piece assembly
- Machined from heat-treated billet EN36 steel
- Four aerospace precision-machined dowels mechanically lock the hub to the crank
- Eliminates the rotational slip the OE friction-based design allows
- Complete kit including drilling jig and drill bit
- Available with or without the MMX capture plate (MMR20-1002)
- Intended for high-horsepower applications
- MMX part numbers: MMR20-1004 (hub only), MMR20-1004FK (with capture plate)
Related 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.
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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.
