Choosing an oil cooler kit for a Harley-Davidson Big Twin starts with fitment, not appearance: the five options here split between newer 2017–2025 Touring models, 2009–2016 Touring bikes, and a universal-style downtube cooler. My leading pick for newer air/oil-cooled Touring models is the FIASRAC Milwaukee-Eight kit, which has stated year and engine compatibility plus included mounting hardware. The HDBUBALUS cooler is a simpler alternative for the same broad model range, while the Billet Proof Designs V-cooler suits riders who want a visible downtube-mounted unit and can verify their frame dimensions.
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The main tradeoff is between model-specific bolt-on fit and broader, more custom mounting. A cooler listed for the right model year may still be wrong for a Twin-Cooled engine or a particular OEM cover, and a universal design demands careful measurement and hose planning. I rank these options by how clearly their fitment is stated, what installation hardware is described, and how well each serves a distinct Big Twin buyer—not by assuming that every cooler will fit every Harley.
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Key Takeaways
- Best defined fit for newer Touring bikes: FIASRAC lists 2017–2025 air/oil-cooled Milwaukee-Eight 107, 114, and 117 engines, but excludes Twin-Cooled models and two named OEM cooler covers.
- Alternative for the same newer fitment window: HDBUBALUS also targets 2017–2025 air/oil-cooled Touring models, though its listing gives less detail about included hardware and exclusions.
- Best for a custom downtube installation: Billet Proof Designs uses 1-1/8-inch downtube mounts; measure the frame and plan for the additional frame clamp before ordering.
- Older Touring owners need a different year range: The FIASRAC kit listed for Street Glide and Road King applications covers 2009–2016, not the 2017–2025 Milwaukee-Eight options.
- Verify engine cooling type, mounting position, and cover clearance: Several kits expressly exclude Twin-Cooled engines, and a product title alone does not prove compatibility with a specific Big Twin.
| FIASRAC Oil Cooler Radiator Kit for Harley-Davidson Touring Models (2017-2025) |  | Best Overall for Specified 2017–2025 Air/Oil-Cooled Touring Models | Brand: FIASRAC | Part number: A05507001231 | Compatible models: 2017–2025 Harley-Davidson Touring, air/oil-cooled Milwaukee-Eight 107/114/117 | VIEW ON AMAZON | See Our Full Breakdown |
| Motorcycle Oil Cooler Radiator for Harley Touring Models 2017-2025 |  | Best Alternative for Newer Touring Fitment | Manufacturer: HDBUBALUS | Model: Oil Cooler | OEM part number: REUSTH015501(1) | VIEW ON AMAZON | See Our Full Breakdown |
| Finned Billet Oil V-Cooler with Downtube Mounts – Fits 1‑1/8″ OD Downtubes – Chrome Finish – for Harley Models |  | Best Custom-Style Downtube Cooler | Manufacturer: Billet Proof Designs | Model number: OIL_COOLR_CHR | Material: Billet aluminum | VIEW ON AMAZON | See Our Full Breakdown |
| Motorcycle Oil Cooler for Harley Touring 2017-2025 |  | Best for a Rear-Positioned Bolt-On Setup | Compatible models: Harley Touring, 2017–2025 | Engine exclusion: Twin-Cooled engines | Material: Aluminum | VIEW ON AMAZON | See Our Full Breakdown |
| Oil Cooler Kit for Harley Touring (Street Glide, Road King) 2009‑2016 |  | Best for 2009–2016 Touring Owners | Manufacturer: FIASRAC | Model: A-01 | Fitment: Harley Touring, including Street Glide and Road King, 2009–2016 | VIEW ON AMAZON | See Our Full Breakdown |
| oil cooler kit for harley davidson big twin | Material | Weight | Package dimensions | Manufacturer |
|---|---|---|---|---|
| FIASRAC Oil Cooler Radiator Ki | Aluminum; TIG-welded construction stated | 12.8 ounces | 8.5 x 7 x 3 inches | — |
| Motorcycle Oil Cooler Radiator | Aluminum | 13 ounces | 8.27 x 6.69 x 3.15 inches | HDBUBALUS |
| Finned Billet Oil V-Cooler wit | Billet aluminum | 3 ounces | — | Billet Proof Designs |
| Motorcycle Oil Cooler for Harl | Aluminum | — | — | — |
| Oil Cooler Kit for Harley Tour | T-6061 aluminum | 1.15 pounds | 8.31 x 4.33 x 3.19 inches | FIASRAC |
More Details on Our Top Picks
FIASRAC Oil Cooler Radiator Kit for Harley-Davidson Touring Models (2017-2025)
This is my first choice for a newer Touring owner because its fitment description is the most specific of the three 2017–2025 options. FIASRAC lists air/oil-cooled Milwaukee-Eight 107, 114, and 117 engines, includes mounting hardware, and describes a direct bolt-on installation. That gives a buyer more to verify than the broader compatibility language on the HDBUBALUS cooler or the shorter listing for the rear-positioned aluminum unit.
The TIG-welded aluminum construction and fin design are sensible features for a component exposed to heat, road debris, and weather. Still, those details do not establish a measured cooling advantage over the other aluminum kits. The real strength here is the clearer fitment boundary and stated hardware inclusion, not a performance claim I cannot substantiate from the provided information.
There are firm exclusions: it does not fit Twin-Cooled engines or OEM oil cooler covers P/N 25700633 and 25700634. Those exceptions matter more than the general “Touring” label, so I would check the engine and existing cover before ordering. Compared with the HDBUBALUS option, FIASRAC gives more explicit caveats; compared with the older 2009–2016 FIASRAC kit, it serves a different generation entirely. Its one-year warranty is also stated, though installation may still call for a mechanic if oil-line work is outside your comfort zone.
Pros:- Specific 2017–2025 air/oil-cooled Milwaukee-Eight fitment is listed.
- Includes mounting hardware for a bolt-on installation.
- TIG-welded aluminum construction with a corrosion-resistant finish.
- One-year warranty is specified.
Cons:- Excludes Twin-Cooled engines and two named OEM cooler covers.
- Professional installation may suit owners unfamiliar with oil-system work.
- No comparative temperature-reduction figures are supplied.
Best for: Owners of 2017–2025 Harley Touring models with air/oil-cooled Milwaukee-Eight 107, 114, or 117 engines who want a model-specific bolt-on kit and can confirm the cover exclusions.
Not ideal for: Twin-Cooled Touring owners, bikes using OEM cover P/N 25700633 or 25700634, and riders who need a cooler for a non-Touring Big Twin.
- Brand:FIASRAC
- Part number:A05507001231
- Compatible models:2017–2025 Harley-Davidson Touring, air/oil-cooled Milwaukee-Eight 107/114/117
- Incompatibility:Twin-Cooled engines; OEM oil cooler cover P/N 25700633 or 25700634
- Material:Aluminum; TIG-welded construction stated
- Weight:12.8 ounces
- Package dimensions:8.5 x 7 x 3 inches
- Warranty:1 year
Our verdict“I rank this first for newer air/oil-cooled Touring bikes because it pairs stated engine fitment with included hardware, provided its cover and Twin-Cooled exclusions match your bike.”
Motorcycle Oil Cooler Radiator for Harley Touring Models 2017-2025
HDBUBALUS targets the same broad bike range as the FIASRAC kit: 2017–2025 air/oil-cooled Milwaukee-Eight Touring models. That makes it a reasonable comparison rather than a universal substitute. Its aluminum core and described bolt-on installation may appeal to an owner seeking a straightforward replacement-style cooler, and the listing also calls out waterproof construction for all-weather use.
Where it falls behind my first-place pick is fitment and package detail. FIASRAC names engine sizes and specific OEM cover exclusions, while this listing does not provide equivalent cover-clearance information or a detailed inventory of included mounting parts. Its stated OEM part number may help with cross-checking, but I would confirm it against the bike and seller documentation rather than treating the broad year range as a guarantee.
The product is expressly limited to air/oil-cooled models and excludes Twin-Cooled engines, so it does not solve that common compatibility problem. The listing also describes only one finish, offering less choice than a style-focused custom cooler such as Billet Proof Designs. I would place this second among the newer Touring choices when the FIASRAC exclusions or part details do not fit your situation—but only after confirming the exact application and installation hardware.
Pros:- Listed for 2017–2025 air/oil-cooled Milwaukee-Eight Touring models.
- Aluminum core and bolt-on installation are specified.
- Waterproof construction is described for varied riding conditions.
Cons:- Does not fit Twin-Cooled engine models.
- Included hardware and cover exclusions are not detailed as clearly as on the FIASRAC listing.
- Only one finish is stated.
Best for: Owners of 2017–2025 air/oil-cooled Harley Touring models who want an aluminum bolt-on cooler and can independently verify part-number and mounting compatibility.
Not ideal for: Twin-Cooled owners, buyers who need clearly documented included brackets and fittings, or anyone seeking a finish choice or custom downtube mount.
- Manufacturer:HDBUBALUS
- Model:Oil Cooler
- OEM part number:REUSTH015501(1)
- Fitment:2017–2025 Harley Touring, air/oil-cooled Milwaukee-Eight
- Engine exclusion:Twin-Cooled models
- Material:Aluminum
- Weight:13 ounces
- Package dimensions:8.27 x 6.69 x 3.15 inches
Our verdict“This is a plausible newer-Touring alternative, but I would choose it over FIASRAC only after confirming its part number, cover clearance, and supplied mounting pieces for the exact bike.”
Finned Billet Oil V-Cooler with Downtube Mounts – Fits 1‑1/8″ OD Downtubes – Chrome Finish – for Harley Models
Billet Proof Designs takes a different route from the model-specific Touring radiators: this is a downtube-mounted V-cooler sized for 1-1/8-inch outside-diameter tubes. Twin vertical tubes follow the front frame downtubes, making the unit a visible styling choice as well as an oil-cooling component. Its billet aluminum construction, chrome finish, barbed fittings, and vibration-resistant top mount give the listing more mounting and finish detail than the newer bolt-on kits.
This design makes sense when a rider wants a compact, exposed installation and has a compatible frame. The listed weight is only three ounces, and the product measures 10-1/8 inches long, but those numbers do not make it universally compatible. The tube diameter is a hard constraint: measure the actual downtubes before buying, and account for the additional frame clamp noted in the listing. That extra part and any oil-line routing needs make this a more involved choice than FIASRAC’s stated bolt-on Touring kit.
Unlike the year-specific Touring products, the listing says it fits most Harley models with the specified downtube size, but does not establish a model-by-model Big Twin application. I would not treat “most Harley models” as proof of fit for a particular bike. Compared with the rear-positioned 2017–2025 cooler, this one prioritizes custom placement and appearance over direct model-year matching. Choose it for a measured, planned installation—not as the simplest replacement.
Pros:- CNC-machined billet aluminum with a stated chrome finish and optional anodized black.
- Includes two 5/16-inch barbed fittings, a top mount, and downtube clamps.
- Compact listed dimensions and three-ounce weight.
- Provides a distinct visible mounting style compared with hidden or rear-positioned Touring coolers.
Cons:- Fit is limited to 1-1/8-inch OD downtubes.
- An additional frame clamp is required.
- The listing does not give a specific model-year fitment chart.
Best for: Harley owners building a custom or exposed downtube installation who have 1-1/8-inch OD downtubes and are prepared to confirm hose routing and the extra clamp requirement.
Not ideal for: Riders seeking a model-year-specific Touring bolt-on kit, owners with differently sized downtubes, or anyone unwilling to source additional mounting hardware.
- Manufacturer:Billet Proof Designs
- Model number:OIL_COOLR_CHR
- Material:Billet aluminum
- Finish:Chrome; optional anodized gloss black stated
- Downtube fit:1-1/8-inch outside diameter
- Dimensions:10-1/8 inches long; 4-1/8-inch top width; 6-1/2-inch bottom width
- Weight:3 ounces
- Included fittings and mount:Two 5/16-inch barbed fittings, vibration-resistant top mount, downtube clamps
Our verdict“I recommend this only for a custom-minded buyer who measures the frame first; it offers the most distinctive mounting style but the least direct model-specific fit guidance.”
Motorcycle Oil Cooler for Harley Touring 2017-2025
This listing’s clearest distinction is its stated rear position and black finish. It covers Harley Touring models from 2017 through 2025, excluding Twin-Cooled engines, and describes an aluminum bolt-on cooler without rewiring. For an owner comparing newer Touring options, that position detail may be useful if it matches the bike’s intended mounting arrangement; it is a feature to verify against the service instructions and existing components, not a guarantee of clearance.
Compared with FIASRAC, this product gives less engine-specific fitment detail and does not mention included brackets, oil lines, or other cooling accessories. Compared with HDBUBALUS, it does at least state the mounting position and color, but offers little additional information about the kit contents. That makes it harder to judge how complete the installation package will be before purchase.
The aluminum construction and bolt-on description make it relevant to riders who want a simple Touring application, but its broad model-year claim still has a meaningful exception: Twin-Cooled bikes are excluded. The listing also provides no stated warranty, part number, or measured cooling results. I rank it below the other newer Touring options because it offers less information for checking fit and planning installation, not because the available details establish inferior cooling.
Pros:- Lists 2017–2025 Harley Touring fitment with a Twin-Cooled exclusion.
- Aluminum construction and bolt-on installation are stated.
- Rear position and black color are specified.
- No rewiring is described as necessary.
Cons:- Does not specify additional mounting or cooling accessories in the package.
- Provides less detailed fitment guidance than the FIASRAC kit.
- No warranty or part number is supplied in the provided details.
Best for: A 2017–2025 Touring owner whose bike is not Twin-Cooled and who specifically wants to evaluate a black, rear-positioned bolt-on cooler.
Not ideal for: Twin-Cooled models, owners who require a detailed included-parts list, or buyers who need an explicit engine-size and OEM-cover compatibility check.
- Compatible models:Harley Touring, 2017–2025
- Engine exclusion:Twin-Cooled engines
- Material:Aluminum
- Position:Rear
- Color:Black
- Installation type:Bolt-on
- Included components:Oil cooler
Our verdict“This cooler is worth checking for a compatible newer Touring bike when rear positioning matters, but the sparse package and fitment details keep it behind the clearer FIASRAC option.”
Oil Cooler Kit for Harley Touring (Street Glide, Road King) 2009‑2016
This FIASRAC kit fills the lineup’s older-bike gap: it is listed for 2009–2016 Touring applications, including Street Glide and Road King, rather than the 2017–2025 Milwaukee-Eight range covered by the newer kits. That year split is the deciding point. A rider with an older Touring Big Twin should not substitute one of the newer coolers just because both listings use the Harley Touring name.
The kit uses T-6061 aluminum and is described as a front-mounted, passive cooler with brackets and hardware included. Passive operation avoids a fan and its wiring, which can keep the installation simpler than an active system, but the listing itself cautions that passive cooling may not be enough under extreme heat or heavy load. That limitation matters to riders who spend long periods in severe conditions; a cooler alone should not be treated as a fix for every temperature concern.
Compared with the 2017–2025 FIASRAC option, this one suits a different generation and has a more clearly stated front position. Its year range is also narrower than the Billet Proof cooler’s broad downtube language, but it offers a more direct Touring-kit format with brackets and hardware. The available details do not identify engine sub-variants or exclusions, so I would verify the exact model and oil-line arrangement before ordering. Its role is straightforward: an older Touring-specific choice, not a general Big Twin solution.
Pros:- Targets 2009–2016 Harley Touring models, including Street Glide and Road King.
- T-6061 aluminum construction is stated.
- Front-mounted, passive design avoids fan wiring.
- Mounting brackets and hardware are described as included.
Cons:- Fitment is limited to the 2009–2016 range.
- Passive cooling may be insufficient under extreme heat or heavy load.
- The supplied details do not specify engine sub-variants or exclusions.
Best for: Street Glide and Road King owners with a 2009–2016 Touring model seeking a passive, front-positioned kit with brackets and mounting hardware.
Not ideal for: 2017-and-newer Touring owners, non-Touring Big Twin riders, or bikes used under extreme heat and heavy load where a passive cooler may not meet the need.
- Manufacturer:FIASRAC
- Model:A-01
- Fitment:Harley Touring, including Street Glide and Road King, 2009–2016
- Material:T-6061 aluminum
- Position:Front
- Operation:Passive; no fan
- Weight:1.15 pounds
- Package dimensions:8.31 x 4.33 x 3.19 inches
Our verdict“For a 2009–2016 Street Glide or Road King, this is the relevant year-specific option here, but confirm the exact engine application and keep its passive-cooling limits in mind.”
How We Picked
I ranked these five options around the question a Harley Big Twin owner has to answer first: will this cooler fit my exact bike and cooling configuration? The supplied product details identify two different Touring year ranges, one downtube-mounted design, and several kits that exclude Twin-Cooled engines. I gave more weight to explicit compatibility information than to broad claims about cooling performance, since no comparative test data is provided.
Next, I compared the installation approach and included parts. The newer FIASRAC listing specifies mounting hardware, while the Billet Proof design describes its fittings and downtube clamps but also calls for an additional frame clamp. The other listings describe bolt-on installation, yet provide less detail about what arrives in the box. I treat that difference as a practical buying consideration, not proof that one cooler performs better.
Finally, I considered material, mounting position, and the limits that could rule out a purchase. Aluminum construction is common across the options, but mounting geometry and year coverage differ sharply. I do not infer oil-temperature reductions, service life, or universal fit from promotional wording. My order favors useful fitment detail and a clear buyer role; riders should still confirm the part against their exact model, engine, cover, and frame before installation.
| oil cooler kit for harley davidson big twin | Material | Manufacturer |
|---|---|---|
| FIASRAC Oil Cooler Radiator Ki | Aluminum; TIG-welded construction stated | — |
| Motorcycle Oil Cooler Radiator | Aluminum | HDBUBALUS |
| Finned Billet Oil V-Cooler wit | Billet aluminum | Billet Proof Designs |
| Motorcycle Oil Cooler for Harl | Aluminum | — |
| Oil Cooler Kit for Harley Tour | T-6061 aluminum | FIASRAC |
Factors to Consider When Choosing Oil Cooler Kit For Harley Davidson Big Twin
Before comparing cooler construction, I would pin down the motorcycle’s exact year, model, engine, cooling system, and current cooler or cover. The listings here are not interchangeable: three address newer Touring bikes, one is for 2009–2016 Touring models, and one depends on downtube diameter.
Match the model year and engine first
Start with the year range in the product details, then check the engine configuration. The FIASRAC and HDBUBALUS choices listed for 2017–2025 specify air/oil-cooled Milwaukee-Eight Touring models; the FIASRAC kit also identifies 107, 114, and 117 engines. Both exclude Twin-Cooled bikes. The 2009–2016 FIASRAC kit belongs to a separate application window, so it is not a replacement for a newer-model kit. If a listing omits your exact engine or model, confirm fit using the manufacturer or seller before purchase.
Check cover clearance and package contents
Even a matching year range may not settle fitment. FIASRAC names two incompatible OEM oil cooler covers, P/N 25700633 and 25700634, making those part numbers essential checks for affected bikes. Other listings provide less cover information, which increases the need to compare part numbers and mounting points directly. Also confirm what is included: one listing specifically states brackets and hardware, another names fittings and clamps but requires an additional frame clamp, while the rear-positioned cooler lists only the cooler as included. Do not assume hoses, clamps, or every needed fastener are in the box unless the listing confirms it.
Choose the mounting style that suits the bike
The newer Touring kits are presented as bolt-on options, while Billet Proof Designs mounts along the front downtubes. The latter needs 1-1/8-inch OD downtubes and additional frame-clamp planning; it is better suited to custom builds than a buyer looking for a clearly model-specific replacement. The older FIASRAC kit is listed as front-positioned, and another newer option specifies a rear position. Check available space, nearby components, and the recommended oil-line route before selecting a position. If installation calls for work beyond your skills, have a qualified motorcycle technician inspect the setup.
Read material and cooling claims with care
Several choices use aluminum, with the listings describing TIG-welded construction, billet machining, or T-6061 alloy. These details help distinguish construction and style, but they do not provide directly comparable temperature results. Finned designs are intended to expose surface area to airflow, while passive kits avoid fan wiring; neither description proves a specific reduction in oil temperature. Match the design to your riding and installation needs, and treat claims about heat dissipation as product descriptions rather than measured comparisons.
Plan installation and service checks
A bolt-on description can still involve oil lines, fasteners, clearance checks, and a careful inspection for leaks after installation. Look for clear instructions and confirm whether the kit includes the brackets, fittings, and clamps needed for your bike. The FIASRAC 2017–2025 kit lists mounting hardware; the 2009–2016 kit describes brackets and hardware; Billet Proof lists fittings and downtube clamps but calls for another frame clamp. Verify the complete parts list before starting, use the proper service procedure, and check for leaks and secure mounting before riding.
Frequently Asked Questions
Will these oil cooler kits fit every Harley-Davidson Big Twin?
No. The products have different year ranges, mounting styles, and engine exclusions. Three listings focus on 2017–2025 Touring models, one covers 2009–2016 Touring applications, and the Billet Proof V-cooler depends on 1-1/8-inch downtubes. Check the exact motorcycle model, engine, cooling type, mounting points, and part number before ordering.
Can I install a 2017–2025 Touring cooler on a Twin-Cooled model?
The supplied details expressly exclude Twin-Cooled engines for the FIASRAC and HDBUBALUS 2017–2025 listings, and the rear-positioned cooler also states that it does not fit Twin-Cooled models. I would not assume that a similar-looking part will work. Confirm the engine’s cooling configuration and choose only a kit whose fitment documentation names that application.
Which option suits a 2009–2016 Street Glide or Road King?
The FIASRAC kit listed for 2009–2016 Touring models is the relevant choice among these five, and its description specifically names Street Glide and Road King. The newer Touring coolers cover a later year range, while the Billet Proof design requires a downtube-based custom fit. Verify the precise model and engine application before buying, since the supplied listing does not detail every engine sub-variant.
Is the Billet Proof downtube V-cooler a direct bolt-on replacement?
It is not presented as a model-specific Touring replacement. The listing says it fits 1-1/8-inch outside-diameter downtubes and includes fittings, a top mount, and downtube clamps, but also calls for an additional frame clamp. Measure the bike and plan oil-line routing and clearance; confirm the complete mounting requirements before treating it as a fit.
Does an oil cooler kit guarantee lower engine or oil temperatures?
No guaranteed temperature reduction can be drawn from the supplied product descriptions, which do not provide comparable test figures. The kits are described as aids to heat dissipation, but results depend on the motorcycle, installation, airflow, riding conditions, and overall engine condition. A cooler should not replace diagnosis of an overheating problem or the manufacturer’s service guidance.
Conclusion
For a 2017–2025 air/oil-cooled Touring owner, I would start with the FIASRAC kit because its engine fitment, included hardware, and specific cover exclusions are stated most clearly. HDBUBALUS is a reasonable alternative for the same broad range when its part number checks out, while the rear-positioned aluminum cooler is best treated as a more lightly documented option. Owners of 2009–2016 Street Glides or Road Kings should focus on the older FIASRAC kit rather than trying to adapt a newer application.
If your priority is a custom downtube-mounted look, the Billet Proof V-cooler offers a distinct layout, but only after measuring the frame and accounting for its extra clamp. Whichever direction you choose, verify the exact bike, cooling type, existing cover, mounting clearance, and complete package contents. That fitment check is more valuable than choosing by broad claims about cooling performance alone.
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