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Everyday fixes
Clip-on rear fender for seatpost
A seatpost fender stops road spray soaking your back on wet commutes and clips on without tools. The fender blade is 300 mm long, 70 mm wide with a 60 mm radius curve to shadow a 700c tyre, 2.5 mm thick, and joins a snap clamp for a 27.2 or 31.6 mm seatpost with a 1.5 mm gap so it flexes open. Printing the blade at a slight angle across the bed keeps it in one piece, and PETG or ASA keep it from going brittle in the cold. Open the ready-made model free, resize it on your phone or computer, then download a print-ready STL, 3MF or G-code sliced for your printer, free.Opening the ready-made model and downloading it as STL or 3MF are free, no card; AI changes use credits, from Maker at $7.99 a month.No printer? We print this part and ship it to your door. See its priceUpdated
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Adjust
Change its numbers in the viewer for free, or ask the AI in the chat: wall thickness, hole size, the thing it clips onto. AI changes use 2 credits per request (1 for a quick edit, 3 for a redesign), paid with a plan from Maker at $7.99 a month.3Print
Download a watertight STL or 3MF free, with your numbers and hand edits, or G-code sliced for your printer at the same price. After an AI change the download is included in every plan (4 credits without one).
Dimensions of the ready-made model (editable)
| Parameter | Value |
|---|---|
| along the curve, mm | 300 mm |
| mm | 70 mm |
| mm | 2.5 mm |
| cross-section curve radius, mm | 60 mm |
| seatpost diameter | 27.2 mm |
| mm | 3 mm |
| opening gap width | 1.5 mm |
| mm | 20 mm |
| connects clamp to blade | 25 mm |
| mm | 20 mm |
| mm | 3 mm |
Example prompt
Make a clip-on rear bike fender with a 300 mm long blade, 70 mm wide, 2.5 mm thick, curved to a 60 mm cross-section radius, and a snap-on clamp for a 27.2 mm seatpost with 3 mm walls, a 1.5 mm opening gap and a 25 mm stem connecting them.
Fit notes
With SpeakCAD you generate a fender for your seatpost diameter and tyre width in one go and adjust the length or the clamp tightness through the chat. Open the ready-made model free, change its numbers in the viewer and download the STL or 3MF free; AI changes use credits.
Questions people ask about a clip-on rear fender for seatpost
A seatpost fender stops road spray soaking your back on wet commutes and clips on without tools. The fender blade is 300 mm long, 70 mm wide with a 60 mm radius curve to shadow a 700c tyre, 2.5 mm thick, and joins a snap clamp for a 27.2 or 31.6 mm seatpost with a 1.5 mm gap so it flexes open. Printing the blade at a slight angle across the bed keeps it in one piece, and PETG or ASA keep it from going brittle in the cold.
Click Open it free on this page and create a free account (no card): the ready-made model opens in your browser, on your phone or computer, nothing to install. Change its numbers in the viewer for free and download a watertight STL or 3MF free, or G-code sliced for your printer at the same price. An AI change in the chat uses 2 credits per request (3 for a redesign), and the download after it is included in every plan (4 credits without one). Start with Maker: 50 credits a month for $7.99, cancel anytime.
On this page: open the ready-made model free in a SpeakCAD account (no card), change any dimension in the viewer, then download the STL or 3MF free, or G-code sliced for your printer at the same price.
A shared STL is modelled for someone else's measurements. Here you open the ready-made model free, change it to your measurements in the viewer, then download a file sized for the part you actually own, free as STL or 3MF.
Yes. SpeakCAD slices the part on its servers with OrcaSlicer and your printer's official profile (380+ printers, including Bambu Lab, Prusa, Creality and Elegoo), and you download the G-code (a sliced .gcode.3mf for Bambu Lab printers). G-code sliced for your printer costs the same as the STL: included in every plan, free for a part you shaped by hand, 4 credits without a plan for a part with AI work in it. Pick your printer on the printers page to see its profile.
No. SpeakCAD runs in the browser on your phone or computer: the chat, the 3D engine and the live viewer load in the tab. The only file you download is the finished STL, 3MF or sliced G-code.
Print it your way
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