Direct Answer
The BXT-145 carbon road frameset uses a T47 bottom bracket shell with an 86mm width. Its verified specifications also include a T700 and T800 carbon frame, 12×100mm front and 12×142mm rear axle interfaces, Flat Mount disc brakes, mechanical and Di2 support, and a manufacturer-stated maximum tire designation of 32C. Before ordering, match the frame size, crank, bottom bracket assembly, brakes, wheels and selected package to your build.
Key Takeaways
- The BXT-145 frame uses T700 and T800 carbon; the carbon fork's grade is not specified.
- The manufacturer-reference frame weight is 1050g ±50g for size 54cm.
- The bottom bracket is T47 with an 86mm shell width.
- The hub interfaces are 12×100mm front and 12×142mm rear.
- The frame uses Flat Mount disc brakes and supports mechanical shifting and Di2 at the model level.
- Available sizes are 47, 50, 52, 54, 56 and 58cm.
- The manufacturer lists 700C tires up to a 32C designation; actual inflated width varies with the tire and rim.
BXT-145 Confirmed Specifications
| Specification | Confirmed Information | What It Means |
|---|---|---|
| Frame material | T700 + T800 carbon | This is the manufacturer's material specification for the BXT-145 frame. It is not an independent material or performance test. |
| Fork material | Carbon fiber; grade not specified | Do not assume the fork uses the same T700/T800 layup stated for the frame. |
| Frame weight | 1050g ±50g, size 54cm | Treat this as a manufacturer reference. Paint and included hardware can affect the delivered weight. |
| Bottom bracket | T47, 86mm width | The bottom bracket assembly must match both this frame interface and the crank spindle. |
| Axle interfaces | 12×100mm front; 12×142mm rear | Match the wheel hubs to these interfaces. Confirm axle hardware details before substituting parts. |
| Brake mount | Flat Mount disc, front and rear | Rotor size, caliper and adapter selection still need to be checked for the planned build. |
| Drivetrain support | Mechanical shifting and Di2 at model level | Tell BXT which system you plan to use, especially for a Di2 order. Confirm the exact routing and accessories. |
| Tire designation | 700C; manufacturer-stated maximum 32C | A 32C label is not a guarantee for every tire-and-rim combination because actual tire width varies. |
| Headset | Upper 1-1/2 inch (52mm); lower 1-1/2 inch (52mm) | Confirm bearing angles, headset parts and cockpit integration for the selected configuration. |
| Available sizes | 47/50/52/54/56/58cm | Use current geometry and fit data to choose a size; the size label alone is not a fit recommendation. |
These specifications give you a practical starting point, but they do not define every part required for a complete bicycle. Use the exact component model numbers when checking compatibility.
What Does T47, 86mm Mean for Your Build?
T47 identifies the threaded bottom bracket shell standard. The 86mm measurement is the shell width. Together they describe the frame interface, but they do not identify a complete bottom bracket assembly for every crank.
The crank spindle still matters
Your bottom bracket must connect the T47, 86mm frame shell to the spindle used by your exact crank. Two cranks from the same brand can require different bottom bracket parts, so give the parts supplier or mechanic the full crank model rather than saying only “Shimano crank” or “road crank.”
For a useful compatibility check, provide:
- Frame: BXT-145
- Shell standard: T47
- Shell width: 86mm
- Crank brand and exact model
- Intended drivetrain configuration
Ask whether the matching cups, bearings, seals, spacers and tools are included or need to be purchased separately. This prevents the common mistake of choosing a bottom bracket from the T47 name alone.
Drivetrain and Di2 Compatibility
The BXT-145 supports mechanical shifting and Di2 at the model level. This makes both build directions possible, but the final parts list still depends on the groupset generation and the exact configuration you select.
For a mechanical build, check the required cable-routing parts and confirm that they are included. For a Di2 build, tell BXT before ordering and confirm the routing, battery location, charging access and any small mounting parts for your chosen system. Model-level Di2 support does not mean that every Shimano generation or mixed-component combination has been validated.
The manufacturer product material describes a fully hidden routing design. Confirm that the selected cockpit, routing parts and installation plan match your order. If you want to change the supplied or selected handlebar and stem arrangement, check compatibility and the parts needed to preserve safe cable and hose paths.
Wheels, Brakes and Tires
The verified hub interfaces are 12×100mm at the fork and 12×142mm at the rear. Choose wheels with matching hub spacing and check the supplied axle hardware. The interface dimensions do not establish axle thread pitch, overall length or interchangeability with hardware from another frame.
The BXT-145 uses front and rear Flat Mount disc-brake mounts. Confirm the planned calipers, rotor sizes and any adapters with BXT or your assembler. The available product information does not provide a complete rotor and adapter matrix, so rotor compatibility should be checked for the actual build.
BXT lists 700C tires with a maximum 32C designation. Tire labels are nominal: the same labeled tire can measure differently on different rims. Check the measured tire width, rim specification and safe clearance for the finished wheel-and-tire combination, especially if you plan to use the largest stated size.
Frame Size and Fit
The BXT-145 is offered in 47, 50, 52, 54, 56 and 58cm sizes. Choose among them using the current geometry chart, your body measurements, your riding position and a comparison with a bicycle that already fits you.
Height charts can be a starting point, but they cannot account for proportions, mobility or preferred position. Compare stack and reach, then check how the proposed cockpit and saddle position create the complete fit. If you are between sizes or changing riding position, send BXT your height, inseam, current bike size and intended use, or consult a fitter before ordering.
What Should You Check Before Ordering a BXT-145 Frameset?
Build one written specification for the complete bike. It gives BXT, your parts supplier and your assembler the same information and makes different quotes easier to compare.
Items to Confirm Before Ordering
| Item | What to Check | Why It Matters |
|---|---|---|
| Frame size | Current geometry, fit targets and cockpit dimensions | A frame-size label cannot determine the final riding position by itself. |
| Crank and bottom bracket | Exact crank model and the matching assembly for T47, 86mm | T47 and shell width identify the frame side, while spindle requirements identify the crank side. |
| Drivetrain | Mechanical or Di2 system, generation, routing and small parts | Prevents missing guides, plugs, mounts or battery-related hardware. |
| Cockpit and headset | Handlebar/stem configuration, headset details and internal routing | Integrated routing can limit which parts work together without additional hardware. |
| Wheels and axles | 12×100mm front and 12×142mm rear hubs; supplied axle hardware | Hub spacing must match, while axle length and thread details still require checking. |
| Brakes and rotors | Flat Mount calipers, intended rotors and required adapters | The mount standard alone does not define the complete brake setup. |
| Tires and rims | Intended 700C tire, actual inflated width and safe clearance | A manufacturer-stated 32C maximum is a nominal designation, not a measured result for every rim. |
| Package contents | Exact included components, finish, sizes and optional parts | Product images can show a package configuration that differs from the option you select. |
| Assembly | Tools, torque information and professional work required | Helps you budget for a safe finished build rather than only the frame purchase. |
Confirm the selected package
Manufacturer images show a package with the frame, fork and several build parts, but included items can vary by option or production revision. Ask for an itemized list tied to your order. Confirm the fork, cockpit, seatpost, headset, axles, bottom bracket parts, routing pieces, seat clamp and small hardware rather than relying on a product photograph.
The product material also shows multiple cockpit dimensions and finish options. Treat the size you select and the contents BXT confirms for your order as the purchasing record.
BXT-145 Frameset vs Complete Bike
A frameset is the better starting point when you want to choose each component, already own compatible parts or plan to work with a trusted assembler. It gives you more control, but you must confirm every interface and account for missing parts, tools and labor.
A complete bike is easier to evaluate as one specified package. It may suit buyers who prefer fewer component decisions, although you should still verify size, final specification, assembly state and after-delivery work.
| Your Situation | Frameset Approach | Complete-Bike Approach |
|---|---|---|
| You already own components | Check each part against the BXT-145 interfaces and price the remaining items. | Compare the supplied build with the parts you would otherwise reuse. |
| You want a specific drivetrain | Build an itemized compatibility list before purchase. | Check whether the offered configuration already matches your preference. |
| You need assembly support | Get a workshop quote based on the final parts list. | Confirm what arrives assembled and what a local shop must finish. |
| You have a fixed budget | Include components, shipping, applicable charges and labor. | Compare the total delivered and ride-ready cost. |
Who Is the BXT-145 Best Suited For?
The BXT-145 suits a buyer planning a carbon disc-road build around a T47, 86mm bottom bracket, 12×100/142mm wheels and Flat Mount brakes. It also fits buyers who want a mechanical or Di2 build and are comfortable confirming exact component details before ordering.
Its six listed frame sizes give buyers several fit options, while the 32C maximum tire designation can support a road build that uses more tire volume than a narrow race setup. Base the final tire choice on measured clearance with the selected rim.
Who Should Choose Another Option?
Consider another frameset or a complete bike if you need a different axle, brake or bottom-bracket standard; require tire capacity beyond the stated 32C designation; or prefer a purchase that includes a fully specified and assembled component package. You may also want another option if your fitter cannot reach the intended position with the available BXT-145 sizes and compatible cockpit arrangement.
FAQ
What bottom bracket does the BXT-145 use?
The BXT-145 uses a T47 threaded bottom bracket shell with an 86mm width. Choose the bottom bracket assembly by matching that frame interface to your exact crank spindle.
How much does the BXT-145 frame weigh?
BXT's manufacturer reference is 1050g ±50g for a size 54cm frame. Finish and included hardware are not specified in that reference, so ask for the weight of your selected configuration if it is a critical buying factor.
What axle standards does the BXT-145 use?
The verified hub interfaces are 12×100mm front and 12×142mm rear. Confirm the included thru-axle hardware and do not assume axles from another frame are interchangeable.
Does the BXT-145 support Shimano Di2?
Yes, the BXT-145 supports mechanical shifting and Di2 at the model level. Tell BXT your exact Di2 system before ordering and confirm the routing, battery arrangement and required accessories.
What tire clearance does the BXT-145 support?
The manufacturer states 700C with a maximum 32C tire designation. Actual inflated tire width varies by tire and rim, so verify safe clearance for the complete wheel-and-tire setup.
What sizes are available?
The verified available sizes are 47, 50, 52, 54, 56 and 58cm. Use current geometry and fit information rather than selecting from height alone.
Are the handlebar, seatpost and bottom bracket included?
Product images show a package containing several build components, but contents can vary with the selected option or production revision. Ask BXT for an itemized list for your exact order before assuming any component is included.
Is the BXT-145 UCI certified?
This guide does not claim UCI certification for the BXT-145. If UCI approval is required for your intended event, check the current official UCI equipment list for the exact model and confirm with BXT before ordering.
Related BXT Products and Guides
- View the BXT-145 product page and select your configuration
- Compare the BXT-145 and BXT-155 EVO
- Plan a Shimano Di2 or mechanical BXT build
- Explore BXT disc-brake road frames
Specifications can vary by configuration or production revision; confirm the current specification and package contents before ordering.