Rim Reader Bracket: Phone Wheel Alignment for Toe and Camber

You may print this bracket and use it in any work, including paid alignments. Selling prints, kits or the files needs our permission: [email protected].

Align it in your driveway

The Rim Reader bracket holds your phone against the wheel, so the Rim Reader app can read toe and camber with the phone's own sensors. You print it, slide your phone in, and the app walks you round the car one wheel at a time.

Get the app: Rim Reader on Google Play · rimreader.com

What you print

One bracket and one wedge. No screws, nuts, magnets, springs, inserts or flexible filament, and no supports.

• Bracket: bracket is the standard bracket, the one to measure with. bracket_camera is the same bracket with the camera channel cut right through, so the phone can photograph the VIN label or a tire without coming out. It's about 30 g lighter and a little less stiff in twist.

• Wedge: one wedge that fits your phone. There are two sets of eight sizes; see Pick your wedge below.

Pick your wedge

1. Pick the set. Hold the phone screen toward you, top up. Buttons on the left side: use a short wedge. No buttons on the left: use a long wedge.

2. Pick the size. Measure the phone's width in its case, at its widest point. Take the wedge whose band covers it:

   • 67–70 mm: wedge_67-70_long or wedge_67-70_short

   • 70–73 mm: wedge_70-73_long or wedge_70-73_short

   • 73–76 mm: wedge_73-76_long or wedge_73-76_short

   • 76–79 mm: wedge_76-79_long or wedge_76-79_short

   • 79–82 mm: wedge_79-82_long or wedge_79-82_short

   • 82–85 mm: wedge_82-85_long or wedge_82-85_short

   • 85–88 mm: wedge_85-88_long or wedge_85-88_short

   • 88–91 mm: wedge_88-91_long or wedge_88-91_short

3. Exactly on a boundary (say 82.0 mm): either fits. For a short wedge, take the narrower one.

The band is engraved on top of each wedge. Phones outside 67–91 mm in their case don't fit this bracket.

Print settings

• Material: PETG for every part.

  • PLA works for a bracket that stays indoors, but it softens at about 55 °C: one left in a hot car or sitting in the sun can take a set you can't see.

• Layers: 8 top, 8 bottom, 4 walls

• Infill: 40% Gyroid

• Supports: None

• Brim: Yes

• Layer Height: 0.2 mm

• Nozzle: 0.40 mm (0.6 with 0.3 mm layers will also work.)

• Bed: everything fits a 220 × 220 mm bed.

Fit your phone

1. Drop the phone in screen up, its top against the end stop at FRONT and its right side against the rail. Right-side buttons sit in the window in the rail.

2. Drop the wedge in beside the phone, thin end toward the end stop. Push it toward FRONT until it's snug, pressing the phone down as you push.

3. To release, pull the wedge's tab.

• A wider phone ends up with the wedge further back. That's normal.

• If a short wedge presses one of the phone's buttons, the phone is narrower than you measured. Use the next size down.

• Push the wedge again once the bracket has come to the outdoor temperature.

• A phone whose camera bump starts at its top edge rests the bump on the ledge and sits slightly nose-up. That's normal; Bracket Calibration takes care of it.

Using it

• Calibrate once: with your phone in the bracket, run Bracket Calibration in the app: a few minutes on a hard floor against a wall. Do it about once a month, and again for a new phone or a new bracket.

• Toe: hold the bracket on top of each wheel the screen lights, flat and screen up, FRONT toward the front of the car, with its prongs on the rim's metal lip. When it's level and still, the phone takes the reading by itself and beeps.

• Camber: the bracket stands upright at the side of the wheel, prongs on the same lip. The app shows which way FRONT points.

• The app's lessons show each step and how to hold the bracket.

What you need

• A phone running with a gyroscope (the app's free Phone Check tells you in two minutes). 

• This bracket and one wedge, printed in PETG.

• Level, firm ground and wheel chocks.

Make your own

Rim Reader also works with a bracket you design yourself if it follows seven rules: see Make your own bracket on our website. Remixes are welcome under the license below.

Liability disclaimer

Rim Reader and this bracket are a consumer measuring tool, not a professional alignment machine. Readings are estimates. Have a qualified alignment shop check the result after suspension or steering work, and before highway driving or carrying heavy loads. You print the bracket yourself, so how well it works depends on your printer, material and settings. Use it at your own risk.