Mongoose MGX DXR Dual Suspension Mountain Bike Rear Rim Parts Guide

If you own a Mongoose MGX DXR dual suspension mountain bike and need to replace the rear rim, you're not alone. This budget-friendly full-suspension bike delivers decent trail performance, but its wheels often take a beating, especially the rear. Whether yours is bent, cracked, or simply worn out, finding a suitable replacement rear rim can be tricky without the right information. This guide covers stock specs, compatibility factors, and practical buying advice to get you back on the trail.

Understanding the Mongoose MGX DXR Rear Wheel Setup

The MGX DXR is a 26-inch wheel mountain bike (check your specific year; most are 26-inch, though some later models may use 27.5-inch). The rear wheel uses a 6-bolt disc brake rotor and a threaded freewheel (not a cassette hub). The stock rim is typically a single-wall alloy rim, 36-spoke, with a 14-gauge spoke count. The rear hub spacing is 135mm, standard for quick-release axles. The rim width is around 21-23mm internal, suitable for tires up to 2.1-2.3 inches.

Key specifications to note:

• Rim diameter: 26 inches
• Spoke count: 36 holes
• Brake interface: 6-bolt disc (rotor not included with the rim)
• Freewheel type: threaded (usually a 7-speed freewheel)
• Axle: quick-release, 135mm spacing
• Rim profile: single-wall, non-eyeleted

These details matter when hunting for a replacement. Most budget aftermarket rims will work if they match the spoke count and diameter.

Finding a Compatible Rear Rim

Compatibility boils down to a few critical measurements. Ignoring one can lead to a wheel that simply won't fit or function properly.

Rim Diameter and Width

Stick with 26-inch rims. While 27.5-inch wheels might clear the frame on some MGX DXR models, they alter geometry and may not work with the suspension. The stock rim width is narrow (21-23mm internal). For better tire support, you can go up to 25mm internal width, but avoid going too wide as it can affect handling and tire fit.

Spoke Count and Holes

Your hub and rim must both have the same number of spoke holes. The MGX DXR rear hub has 36 holes. Therefore, you need a 36-hole rim. Using a 32-hole rim would require a new hub or relacing, which is not recommended unless you rebuild the entire wheel.

Brake Compatibility

The rear brake is a 160mm or 180mm disc rotor attached via 6 bolts. The rim itself doesn't need any brake surface, but you must ensure the rim's spoke bed doesn't interfere with the rotor. That's rarely an issue with disc-specific rims.

Freewheel Type

This is a common sticking point. Many modern rear wheels come with a cassette hub. The MGX DXR uses a threaded freewheel, meaning the freewheel screws onto the hub. If you buy a complete wheel with a cassette hub, you'll also need a new cassette and possibly a different derailleur. The simplest route is to keep your existing hub and replace only the rim. However, if you find a complete wheel with a threaded hub, make sure it's 135mm quick-release and 36-spoke.

Axle and Spacing

The MGX DXR uses a 135mm quick-release rear axle, not a thru-axle. All replacement rims or wheels must be for 135mm QR spacing. Thru-axle wheels won't fit without adapters, which can compromise safety.

Replacement Options: OEM vs Aftermarket

You have two main paths: source an original equipment manufacturer (OEM) rim from Mongoose or buy an aftermarket rim.

OEM Rim from Mongoose

Contact Mongoose customer support or a licensed dealer (not naming stores) to order a stock replacement rim. The part number is typically something like "MGX DXR rear rim 26x1.95" but vary by year. OEM rims are inexpensive and match exactly, but they are often low-quality and may dent easily again. However, for a quick fix, they work.

Aftermarket Rims

Many aftermarket rims in 26-inch, 36-hole, disc-specific fit. Brands like Alex Rims (DH19, DM24), Sun Ringle (MTX 33), or WTB (SX25) offer affordable options. You'll need to lace them to your existing hub, or buy a pre-built wheel with a compatible hub. Pre-built wheels from brands like Jalco or Weimann often use threaded hubs.

Note: Avoid overspending. A $100 rim is overkill for this bike; a $30-50 rim is plenty.

Step-by-Step Considerations for Installing a New Rear Rim

If you plan to rebuild the wheel using your existing hub, here's what's involved.

Tools Required

• Spoke wrench (size 14g)
• Truing stand or zip ties on frame
• Nipple driver
• Grease for spoke threads

Process Overview

1. Remove tire, tube, and disc rotor from the old wheel.
2. Deflate tire and remove it, then remove the disc rotor (T25 Torx bolts).
3. Unthread the freewheel using a freewheel remover tool and a large wrench.
4. Remove all spokes from the hub and rim, taking care to note the lacing pattern (usually 3-cross).
5. Clean the hub and inspect for wear. Replace bearings if needed.
6. Set up the new rim and begin lacing: start with the right-side flanges, leading spokes. Follow the original pattern.
7. Tighten spokes evenly to achieve true and centered rim.
8. Reinstall freewheel, rotor, tire, and tube.
9. Mount the wheel on the bike and check for clearance.

If you're not handy with wheel building, buying a complete wheel is far easier. Just confirm it matches the specs above.

Where to Look for Parts

OEM parts can be ordered directly from Mongoose's website or through authorized bike dealers. For aftermarket rims, check local bike shops or online retailers that specialize in bicycle components (avoiding mega-marketplaces). Many small bike parts websites carry 26-inch wheels with threaded freewheel hubs. Look for "26-inch rear wheel 36h 135mm QR disc brake". Ask the seller specifically if the hub is threaded (freewheel type).

Final Recommendation

For most MGX DXR owners, the easiest and most cost-effective solution is to buy a complete aftermarket rear wheel that matches all specifications: 26-inch, 36 holes, 135mm quick-release, disc brake, threaded freewheel hub. This avoids wheel building and ensures compatibility. Expect to pay $40 to $80 for a decent quality wheel. If you're mechanically inclined and want a stronger rim, rebuild your existing hub with an aftermarket rim like the Alex DM24. Either way, taking the time to verify specs will save you headaches.