# Horizon Fitness 7.4AT-02 Treadmill Rear Idler Roller (RP521)

\# Horizon Fitness 7.4AT-02 Treadmill Rear Idler Roller (RP521)

The Horizon Fitness 7.4AT-02 Treadmill Rear Idler Roller is a replacement treadmill roller identified by SKU RP521 and part number 1000503912. It is intended for the rear roller position on a Horizon Fitness 7.4AT-02 treadmill. If the original rear idler roller needs replacement, this preowned component may help restore the correct roller arrangement on the listed treadmill model.

## Product Details and Benefits

This product is a rear idler roller for a treadmill. The rear idler roller forms part of the treadmill’s roller assembly and is located at the back of the running platform. Replacing the original component can help when the existing rear roller is worn, damaged, or no longer suitable for continued use.

The product is listed under the category \*\*Treadmill Rollers\*\* and carries the following identifying information:

\- \*\*Brand:\*\* Horizon Fitness  
\- \*\*Product:\*\* 7.4AT-02 Treadmill Rear Idler Roller  
\- \*\*Product type:\*\* Treadmill rear idler roller  
\- \*\*Part number:\*\* 1000503912  
\- \*\*SKU:\*\* RP521  
\- \*\*Barcode:\*\* RP521  
\- \*\*Condition:\*\* Preowned

The part number and SKU give you two useful ways to compare this roller with the component currently installed on your treadmill. Using these identifiers before ordering can reduce the risk of selecting the wrong replacement part.

## Compatibility and Applications

The Horizon Fitness 7.4AT-02 Treadmill Rear Idler Roller is listed for the \*\*Horizon Fitness 7.4AT-02 treadmill\*\*. It is intended as a replacement rear idler roller for that equipment. The product page does not provide a broader list of compatible Horizon Fitness models, so buyers should not assume that this roller fits other treadmills without confirming compatibility first.

The listing also includes the serial number reference \*\*TM746B2008C03211\*\*. Compare this reference with your treadmill’s records or the identification information on your machine when applicable. If your treadmill has a different model, revision, or serial range, verify the part number before purchase.

## Why Choose This Product

Choosing a replacement roller by its exact model and part number helps simplify treadmill repair and maintenance. This part may suit buyers who need a rear idler roller for a Horizon Fitness 7.4AT-02 and want to match the replacement to the existing equipment rather than purchase an entire treadmill assembly.

Because this is a preowned part, inspect the product information and photographs provided on the listing before ordering. Confirm that the roller’s condition meets your requirements and that the part number matches the component you need to replace.

## Before You Buy

Check the following details before placing your order:

\- Your treadmill is a \*\*Horizon Fitness 7.4AT-02\*\*.  
\- The required part is the \*\*rear idler roller\*\*, not another roller or treadmill component.  
\- The part number is \*\*1000503912\*\* or the SKU is \*\*RP521\*\*.  
\- The listed serial reference, \*\*TM746B2008C03211\*\*, is relevant to your equipment when applicable.  
\- You understand that the item is \*\*preowned\*\*.

The product page does not list dimensions, material, color, warranty details, or installation instructions. Confirm any measurements or fitting requirements needed for your treadmill before buying.

## Details

- **Price:** 99.99 USD
- **Vendor:** Horizon Fitness
- **Type:** Treadmill Rollers
- **Tags:** All

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 99.99 USD | In stock |

## Images

- RP521
- RP521
- RP521
- RP521
- RP521
- RP521

## Additional Information

- **PartNumber:** 1000503912
- **Condition:** PREOWNED

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> Source: [Cardio Equipment Parts](https://www.cardioequipmentparts.com/products/horizon-fitness-7-4at-02-treadmill-rear-idler-roller-rp521)
> Updated: 2026-08-29