TUSITA Seat Post Quarter Turn Mount Compatible with Garmin Varia RTL510 RTL515 RVR315, RearVue 820 Rearview
Quick take
The TUSITA quarter turn seat post mount is designed to help you keep a compatible Garmin Varia rear radar or RearVue 820 rearview device securely positioned while riding. It clamps to seat posts in three common diameters (27.2, 30.9, and 31.6 mm) using included spacers and is intended for quick, tool-assisted install and adjustment. The biggest deciding factor is whether your bike’s seat post fits those sizes and whether the fixed mounting angle matches how you want the device aimed.
Pros and cons
Pros
- Designed for specific Garmin Varia models (RTL510, RTL515, RVR315) and RearVue 820 rearview.
- Includes spacers for seat-post diameters 27.2 mm, 30.9 mm, and 31.6 mm.
- Quick adjustment and secure locking via a quarter-turn style mechanism.
- Lightweight mount build (listed at 0.13 lb) using polycarbonate co-polymer materials.
- Tool-free installation is emphasized for under-60-second mounting and disassembly.
Cons
- Fit depends on having a standard seat post diameter in the supported range, and a compatible mounting geometry.
- Mount angle may not suit every bike setup, especially non-standard headrest or upright bar placements.
What buyers think
Buyer-review evidence is broadly positive, with recurring themes around secure clamping and confident positioning for Garmin Varia setups. Multiple reviews mention that the mount holds firmly once installed, and several highlight the practical value of the included shims/spacers for achieving a correct fit on their seat post diameter. Ease of use comes up frequently too, with comments describing straightforward installation and adjustment without fuss. Review evidence is more limited regarding long-term durability beyond typical “ride after ride” impressions, but overall feedback centers on stability and day-to-day usability.
What this mount is for
This is a seat post mounting option intended to keep compatible Garmin Varia Rearview bike radar or tail light devices securely attached to the rear of your bike. It is built around a quarter-turn style clamp, so you can dial in the aiming and lock it down for riding conditions where you want consistent performance from a rear visibility device.
Compatibility and fit: the details that matter
Which devices it’s meant to work with
The mount is intended for Garmin Varia models including RTL510, RTL515, and RVR315, plus the Garmin Varia RearVue 820 rearview. It is also positioned as compatible with Varia smart bike lights in general, which makes it a reasonable choice if your setup uses the same family of mounting interface.
Seat post sizes it supports
Mounting is for seat posts in three diameters: 27.2 mm, 30.9 mm, and 31.6 mm. It includes three spacers specifically for those sizes, which is a major part of getting a snug, secure clamp without relying on improvised adapters.
Adjustability and mounting angle
The mechanism supports rotation and aiming adjustments, and reviews suggest the mount can be adjusted with a few turns before locking. Keep in mind that the mount’s geometry is still tied to a seat-post location, so if you ride with a non-standard rear mount area, you may need to look at an alternative mounting style.
Installation experience
The mount is designed for quick setup, with tool-free installation emphasized and a small hex key included for the lock nut. In practice, the install flow is typically centered on selecting the correct spacer for your seat-post diameter, aligning the mount, and locking it down. That setup process matters most for avoiding tilt or looseness, and the included spacers are commonly described as useful for achieving a proper fit.
Pros and cons recap
Best for
- Riders using a compatible Garmin Varia rear radar or RearVue 820 who want a seat-post mounting solution.
- People with seat posts in 27.2, 30.9, or 31.6 mm who prefer a snug clamp with simple adjustment.
- Bike owners who want an easier way to mount and remove the device without redoing the setup each ride.
Who should avoid it
- Riders whose bike does not use a standard seat-post diameter in the supported range.
- Anyone expecting the mount to work seamlessly with upright or non-seat-post mounting points (for example, some recumbent headrest bar arrangements), since seat-post geometry is the intended fit.
Price and availability
At the time of writing, this mount is positioned as an affordable accessory in the vehicle mount category. If you want a simple seat-post attachment for a compatible Garmin Varia device, the value will largely depend on whether your seat post matches one of the supported diameters and whether the aiming angle works for your frame and riding position.
Alternatives to consider
If the seat-post clamp does not match your bike, you can narrow alternatives by feature priorities:
- Different mounting location: If your setup does not accommodate a traditional seat post, look for alternative Garmin Varia mounting styles designed for other bike areas.
- Angle flexibility: If you need more vertical rise or different aiming range, choose a mount whose adjustment range better fits your frame geometry.
- Device family compatibility: Ensure the mount is made for your exact Garmin Varia model so the connection and alignment are correct.
Verdict
The TUSITA seat post quarter turn mount is a solid, practical choice if you run a compatible Garmin Varia RTL510/RTL515/RVR315 or RearVue 820 and your seat post matches 27.2, 30.9, or 31.6 mm. Reviews consistently point to secure locking and straightforward installation. The key caution is fit, especially if your bike requires a different mounting location or if the mount’s angle does not line up with your preferred placement.
FAQ
Is this mount compatible with Garmin Varia RTL510 and RTL515?
Yes. It is intended for Garmin Varia RTL510 and RTL515, along with RTL515, RVR315, and the RearVue 820 rearview.
What seat post diameters does it fit?
It supports 27.2 mm, 30.9 mm, and 31.6 mm seat posts. Spacers for those sizes are included.
How difficult is it to install?
The mount is designed for quick installation with tool-free setup emphasized, plus a small hex key for the lock nut. In typical use, installation is mainly about choosing the correct spacer and locking the clamp in place.
Does it lock securely once adjusted?
The intended design is a quarter-turn style lock for keeping the device positioned. Review feedback commonly highlights that it holds securely after tightening.
Will it work on a bike without a standard seat post?
This mount is made for seat posts. If your bike uses a different mounting point or a non-standard bar arrangement, compatibility may be limited, so it’s important to confirm it can clamp to your actual seat post diameter and placement area.
Specifications
| Product Title | TUSITA Seat Post Quarter Turn Mount Compatible with Garmin Varia RTL510 RTL515 RVR315, RearVue 820 Rearview - Fit 27.2mm 30.9mm 31.6mm Bars Seatpost |
|---|---|
| Category | Electronics > GPS, Finders & Accessories > GPS System Accessories > Vehicle Mounts |
| Brand | TUSITA |
| Manufacturer | TUSITA |
| Model Name | TUSITA Seat Post Quarter Turn Mount |
| Model Number | Seat Post Quarter Turn Mount |
| Color | Black |
| Item Weight | 0.13 Pounds |
| Compatible Devices | Diameter 27.2mm 30.9mm 31.6mm Seatpost, Garmin Varia Rearview Bike Radar RTL510 RTL515 RVR315, Varia RearVue 820 |
| Compatible Phone Models | Varia RTL510 RTL515 RVR315, Varia RearVue 820, Varia Rearview Radar |
| Mounting Type | Seat Post |
| Additional Features | Rotatable |
| Compatible with Vehicle Type | Bicycle |
| Enclosure Material | Polycarbonate |
| Warranty Description | 18 months |
| Built-In Media | 1 x TUSITA Seat Post Quarter Turn Mount |
Available variants
Size
- AirTag & Varia Mount
- Varia Mount
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