TUSITA Bike Seat Post Mount Compatible with Garmin Varia RTL510 RTL515 RVR315, RearVue 820
Quick take
The TUSITA seat post quarter-turn mount is built to secure Garmin Varia rearview radar units (RTL510, RTL515, RVR315) and the RearVue 820 tail light to a variety of seat post shapes.
Pros and cons
Pros
- Compatible with Garmin Varia RTL510, RTL515, RVR315 and RearVue 820 tail light.
- Quarter-turn mounting design with included shims for seat post variation.
- Injection-molded high-strength composite construction for a sturdy hold.
- Works across round seat posts (25.4 mm to 35.0 mm) and also supports aero and D-shaped profiles.
Cons
- Uses rubber bands, and one review suggested the band may become brittle in cold.
- Exact aero and D-shaped compatibility can vary by bike model, so fit may depend on your seat post shape.
- Not a hard-mount clamp, so some riders may prefer a more rigid mounting approach if they dislike band-based systems.
What buyers think
Buyer-review evidence is generally positive on usability and stability. Multiple riders describe the mount as solid and secure for holding a Varia unit during normal riding, and several specifically call out the mount as fitting well and being easy to move between bikes. Reviewers also tend to like the thinner mounting profile, noting it does not protrude as much as some alternative styles that can rub a leg during pedaling.
Where feedback becomes more cautious is around the rubber band element. One review mentioned the band starting to feel weak or brittle in cold conditions. That suggests this mount can be a good day-to-day option for many riders, but weather and temperature may matter if you frequently ride in freezing or consistently cold environments.
What this mount is (and what it fits)
This is a seat post quarter-turn mount intended for Garmin Varia rearview radar models RTL510, RTL515, and RVR315, plus the Garmin RearVue 820 tail light. The goal is to attach your Varia or RearVue to the seat post area while keeping the unit positioned behind you for visibility and awareness.
Fitment details you should check before buying
- Seat post diameter (round profiles): Compatible with round seat posts from 25.4 mm to 35.0 mm.
- Aero and D-shaped posts: The mount includes shims intended to adapt to these shapes, but compatibility can vary by bike model. If your seat post is not round, measure carefully and plan to choose the correct shim and band placement.
- Mount style: It uses a quarter-turn approach and includes two rubber bands plus three fitting shims. The bands are part of the clamping system.
Build and design, in plain terms
The mount is made from high-strength composite materials using injection-molded co-polymer construction. It’s paired with rubber components (bands) and shims so the mount can sit correctly on different seat post geometries. At about 60 g, it’s not meant to be bulky on your bike, and some riders also like that it stays relatively low profile where it mounts near the seat tube.
Pros and cons for different types of riders
Best for riders who want a low-profile, seat-post based setup
If you’re using a Varia RTL510/RTL515/RVR315 or RearVue 820 and you want a mount that’s relatively thin and easy to reposition between bikes, this quarter-turn, band-and-shim system is a strong match for the use case.
Who should be more cautious
- Cold-weather riders: If you ride in freezing temperatures often, pay attention to the fact that rubber bands can change feel over time. Limited review evidence suggests the band may become brittle in cold.
- Non-standard seat post shapes: Aero and D-shaped compatibility can vary by bike model, so double-check your seat post geometry and plan on trying the correct shim configuration.
- People who dislike band-based clamping: If you strongly prefer metal-only clamp mounts, you may find a band system less reassuring than a rigid bracket.
Price and availability
This mount is positioned as an accessible replacement or extra seat-post option for Varia users, and it’s available in the United States at the time of writing. If you want to compare it with higher-cost alternatives, focus on fitment confidence for your exact seat post shape and how you feel about rubber-band tension versus a more rigid mounting design.
Alternatives (how to choose instead of just comparing brands)
You can shop in a few directions depending on what matters most to you:
- If your top priority is exact fitment for an aero or D-shaped post: look for mounts that explicitly list your seat post geometry and include enough adaptation hardware (shims, bands, or adjustable clamps).
- If your top priority is extreme weather durability: consider designs that use more rigid clamping components or offer better protection for rubber parts.
- If your top priority is preventing leg rub: favor mounts with a thinner profile or shorter protrusion compared to bolt-on styles.
- If you frequently swap between bikes: choose systems that are quick to attach and remove without complicated tools.
Verdict
The TUSITA seat post quarter-turn mount is a practical choice for Garmin Varia RTL510/RTL515/RVR315 and RearVue 820 owners who want a sturdy, relatively low-profile mount and like the convenience of a shims-and-bands system. Fitment is the key variable for aero and D-shaped seat posts, and cold-weather riders should consider the rubber band as the potential weak point based on limited feedback.
FAQs
Is this mount compatible with Garmin Varia RTL510, RTL515, and RVR315?
Yes, it’s designed for Garmin Varia rearview radar units including RTL510, RTL515, and RVR315.
Will it work with the Garmin RearVue 820?
Yes, it’s also intended for the RearVue 820 tail light.
What seat post sizes does it fit?
For round seat posts, it’s compatible with diameters from 25.4 mm to 35.0 mm. It also supports aero and D-shaped seat posts using included shims, but compatibility can vary by bike model.
How does the mounting hold the device in place?
The mount uses a quarter-turn mechanism, along with two rubber bands and three fitting shims to secure the mount to the seat post and help match different seat post shapes.
Does it stay secure on rough rides?
Reviewers commonly describe the mount as solid and holding the Varia effectively during rides. The main caution is that rubber band feel may change in cold weather, which could matter if you frequently ride in freezing temperatures.
Is it easy to move between bikes?
Many buyers mention it’s quick and easy to move to another bike, which is helpful if you swap your Varia setup across different frames.
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Specifications
| Product Title | TUSITA Bike Seat Post Mount Compatible with Garmin Varia RTL510 RTL515 RVR315, RearVue 820, Rearview Radar - Round,D Shaped,Aero Seat Post Compatibility |
|---|---|
| Category | Electronics > GPS, Finders & Accessories > GPS System Accessories > Vehicle Mounts |
| Brand | TUSITA |
| Manufacturer | TUSITA |
| Model Number | T00194 |
| Color | Black |
| Material | High strength composite |
| Item Weight | 0.09 Kilograms |
| Brand Name | TUSITA |
| Set Name | Seat Post Mount Set (5 Piece) |
| Manufacturer Part Number | T00194 |
| Manufacturer Warranty Description | 18 Months Warranty |
| Included Components | 1 x TUSITA Seat Post Quarter Turn Mount, 2 x Rubber bands, 3 x Fitting shims |
| Item Type Name | AA |
| Item Dimensions | 3 x 3 x 3 inches |
| Unit Count | 1.0 Count |
| Item Depth | 3 inches |
| Material Type | High strength composite |
| Mounting Type | Seat Post |
| Finish Types | Unfinished |
| Item dimensions L x W x H | 3 x 3 x 3 inches |
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