Rinehart HP45 XL: Engineered for the Modern Stretched Bagger

The Rinehart 4 1/2″ HP45 XL Slip-On Mufflers are the definitive answer for 2017-2026 Harley-Davidson Touring riders who demand both peak performance and flawless visual proportions. As Harley-Davidson moved toward “Special,” “ST,” and “CVO” models with factory-stretched saddlebags, standard mufflers often appeared “sunken” or too short, leaving an awkward gap at the rear of the bike. The HP45 XL features an extended muffler body designed to sit flush with the end of the bags, providing a seamless, custom-shop silhouette. Compatible with the Road Glide, Street Glide, and Road King, these mufflers are built to handle the massive air-flow requirements of the 107, 114, 117, and 121 cubic inch Milwaukee-Eight engines, ensuring your bike looks as powerful as it performs.

Internal Volume and the DBX Performance Advantage

The “XL” in the name doesn’t just refer to the length; it also signifies an increase in internal resonance volume. By utilizing a 4.5-inch diameter body and an extended length, Rinehart has created more space for exhaust gases to expand. This extra volume, paired with the legendary DBX performance baffle, produces a sound that is noticeably deeper and “thumpier” than standard slip-ons. The DBX baffle is specifically tuned to eliminate the “tinny” or raspy high-pitched sounds that can plague high-flow M8 exhausts. Instead, it delivers a crisp, mechanical bark under load and a smooth, rhythmic low-frequency rumble at idle. This engineering ensures that while you get an aggressive sound, you maintain the necessary backpressure to keep your mid-range torque curve climbing.

Expert Tuning & Installation Advice

As V-Twin performance specialists, we’ve found the HP45 XL to be a favorite for those performing Stage II cam upgrades. Pro Tip: Because the XL body and DBX baffle significantly increase exhaust flow, your Milwaukee-Eight engine will require more fuel to stay within a safe operating temperature. We highly recommend a Vance & Hines Fuelpak FP4 or Dynojet Power Vision to properly calibrate your ECM. This prevents the “lean-burn” that causes headers to glow and chrome to blue. Installation Note: When mounting the HP45 XL, ensure your rubber muffler hangers are in good condition; the extra length of the XL body places slightly more leverage on the rear mounts. Always wipe the pipes down with denatured alcohol before the first start to prevent fingerprints from being permanently etched into the finish during the first heat cycle.

The Signature Rinehart Craftsmanship

Every Rinehart exhaust system is 100% Made in the USA and backed by their industry-leading reputation for quality. The HP45 XL is finished with CNC-machined billet aluminum end caps that add a premium, high-velocity look to your Bagger’s rear profile. Whether you are building a “Blacked-Out” ST-style performance bike or a classic “Chrome-and-Stretched” cruiser, the Rinehart HP45 XL provides the perfect blend of high-end aesthetics, massive sound depth, and dyno-proven results. It is the definitive choice for the rider who refuses to compromise on style or soul.

Fitment Note: Fits all 2017-2026 Touring models. Highly recommended for models with stretched saddlebags. Not compatible with Trike models.

Rinehart 4 1/2″ HP45XL Full Length Slip-Ons For Harley Touring

A striking, bold addition to the Rinehart Racing catalog of performance products, the HP45XL brings a fresh style and finish paired with race-inspired performance and power you’ve come to expect from Rinehart. Mufflers provide free-flowing exhaust while maintaining the perfect amount of back pressure, unlocking both horsepower and torque. Contrasting end caps are color-matched to pair perfectly with paints used by Harley Davidson on ST and Anniversary Touring models.

Similar in many ways to the 4.5″ HP45 Mufflers from Rinehart, HP45XL Slip-On Mufflers feature a longer silencer body that extends the end caps beyond the back of bike – as shown in product images.

Features:

• Extended length slip-on performance muffler
• 4.5″ muffler body diameter
• Works with factory head pipes
• Constructed with Rinehart DBX performance baffles
• Race caliber performance and awesome sound
• Chrome/Black and Chrome/Bourbon models feature PVD finished end caps
• End caps accents are color-matched to OEM HD paint used on FLTRXST Road Glide ST and Anniversary models
• Midnight Edition is a perfect match to your ST Touring bike
• Iconic Rinehart rumble included