Ethirteen
Product Description
e*thirteen Helix Race e*spec Direct Mount Chainring for Bosch CX/SX - 36T, 13mm Offset, Black
The e*thirteen Helix Race e*spec Direct Mount Chainring merges cutting-edge engineering with a refined technical aesthetic, delivering the ultimate drivetrain performance upgrade for modern electric mountain bikes (e-MTBs). Forged and precision CNC-machined from premium 7075-T6 aluminum, this one-piece direct mount chainring is purpose-built to handle the high-torque loads of aggressive e-bike riding. When paired with Helix Race Alloy e*spec crank arms, it creates a clean, fully integrated look that significantly enhances both the strength and style of your motor system assembly.
This Bosch-specific version features a 13mm offset, meticulously calculated to deliver precise, friction-free chainline optimization depending on your specific Bosch motor generation. For Bosch CX Gen 4 and lightweight Bosch SX motor systems, it yields an agile 53mm chainline. When mounted to the latest high-performance Bosch CX Gen 5 motors, it transitions perfectly to a wider 55mm chainline. This accurate offset prevents premature drivetrain wear, minimizes friction, and guarantees smooth shifting performance across the entire gear range of wide-ratio cassettes.
Drivetrain security is managed by e*thirteen's updated M4 narrow-wide tooth profile. This advanced long-wearing shape features enhanced tooth geometry that locks the chain securely in place over punishing, high-speed trail chatter, eliminating the absolute need for a heavy chain guide. Furthermore, the M4 profile offers comprehensive cross-compatibility with Shimano, SRAM, and TRP 11 and 12-speed drivetrains—including seamless operation on premium SRAM T-Type Transmission systems, allowing you to run your preferred shifter and cassette setup without compromise.
Weighing 127g, this 36T chainring is the largest size in the lineup, making it ideal for aggressive trail riders and high-speed e-bike applications where maximizing top-end speed on fire roads and fast singletrack descents is a priority. The one-piece design balances weight-saving performance with structural stiffness to prevent flexing under hard, out-of-the-saddle efforts. Finished in a durable, stealthy black anodized coating that protects the alloy against rock-strike abrasions and elements, it delivers maximum wear life and long-term reliability. The Helix Race e*spec chainring is compatible with all matching Bosch direct mount motor systems and is backed by e*thirteen's dependable 5-year manufacturer warranty.
Key Features
- Forged & CNC-Machined 7075-T6 Aluminum: One-piece construction delivers maximum structural stiffness, high wear life, and premium impact resistance
- M4 Narrow-Wide Profile: Advanced tooth geometry offers bulletproof chain retention across brutal trail chatter and eliminates chain drop
- Universal Drivetrain Compatibility: Engineered to run seamlessly with Shimano, SRAM, and TRP 11/12-speed systems, including SRAM T-Type Transmission
- Bosch Direct Mount Integration: Designed specifically for clean integration with Bosch CX Gen 4, Bosch CX Gen 5, and Bosch SX motor splines
- Optimized Drivetrain Chainline: 13mm offset achieves a 53mm chainline on CX Gen 4 / SX systems, and a 55mm chainline on CX Gen 5 platforms
- Maximum Speed Output: High-gear 36T profile provides a significant top-end push for high-velocity trail segments and open forest tracks
Specifications
- Model: e*thirteen Helix Race e*spec Direct Mount Chainring
- Tooth Count: 36T
- Motor Compatibility: Bosch CX Gen 4, Bosch CX Gen 5, Bosch SX
- Offset: 13mm
- Chainline Realization: CX Gen 4 / SX: 53mm | CX Gen 5: 55mm
- Drivetrain Compatibility: Shimano / SRAM / TRP 11-Speed & 12-Speed (Including SRAM T-Type)
- Tooth Profile: M4 Narrow-Wide
- Material: Forged and CNC-Machined AL-7075-T6 Aluminum
- Weight: 127g
- Color: Black
- Warranty: 5 Years
A premium, high-stiffness direct mount chainring built for aggressive e-MTB riders who demand zero chain drops, maximum high-speed efficiency, and long-term gear durability on high-torque Bosch motor systems.
Shipping Policy
We pay shipping on orders over $150 to Nationwide addresses, excluding Rural addresses and some Bulky items.
Orders under $150 cost $7.99
Rural order fee $4.99
Aerosol and Dangerous Goods fee $9.99
For a specific delivery ETA based on the exact item(s) you want to purchase, please call us at 0800 793 593 or message us via Chat before placing an order.
We understand that when you make an order, you want your parts as quickly as possible and we will do our best to make that happen! Most of the items we sell will ship quickly and be at your door fast. If urgent freight is required, we work closely with our vendors in order to have the product shipped directly to you from their warehouse if that means you will get the product faster.
Items will have an availability status shown once a size/color is selected on the product page; this availability status will also be shown on the shopping cart page and in your order confirmation email. Most products will be marked "In Stock". These products will ship within 1-2 business days.
While we will do our best to ship from the distribution center closest to you, not all items will always be in stock in every location at all times. In some cases we will split the order and ship each package out to you individually and in other cases we may need to consolidate the items in one location to ship out as one package. We utilize our best judgment in an attempt to get the products to you as quickly as possible.
A shipping confirmation email including courier specific tracking information will be sent the same day as the item ships.
RETURNS POLICY
Returns
Our policy lasts 90 days. If 90 days have gone by since your purchase, unfortunately we can’t offer you a refund or exchange.
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.
Several types of goods are exempt from being returned. Perishable goods such as food, flowers, newspapers or magazines cannot be returned. We also do not accept products that are intimate or sanitary goods, hazardous materials, or flammable liquids or gases.
Additional non-returnable items:
- Gift cards
- Downloadable software products
- Some health and personal care items
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)
- Any item not in its original condition, is damaged or missing parts for reasons not due to our error
- Any item that is returned more than 90 days after delivery
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.
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 sales@moto1.nz.
Sale items (if applicable)
Only regular priced items may be refunded, unfortunately sale items cannot be refunded.
Exchanges (if applicable)
We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at sales@moto1.nz
Gifts
If the item was marked as a gift when purchased and shipped directly to you, you’ll receive a gift credit for the value of your return. Once the returned item is received, a gift certificate will be mailed to you.
If the item wasn’t marked as a gift when purchased, or the gift giver had the order shipped to themselves to give to you later, we will send a refund to the gift giver and he will find out about your return.
Shipping
To return your product, please email us to receive instructions.
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 return shipping will be deducted from your refund.
Depending on where you live, the time it may take for your exchanged product to reach you, may vary.
If you are shipping an item over $75, you should consider using a trackable shipping service or purchasing shipping insurance. We don’t guarantee that we will receive your returned item.
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