# Screamin' Eagle Street Tuner vs Spark Plug Reader

The clearest difference is in-app purchases: Screamin' Eagle Street Tuner at none against Spark Plug Reader's 1. Spark Plug Reader's advantage is update cadence (every 2 days vs every 2 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Spark Plug Reader sells 1 one-off in-app purchase. Screamin' Eagle Street Tuner asks for nothing beyond the download.

Screamin' Eagle Street Tuner ships an update every 2 months, Spark Plug Reader every 2 days. The most recent releases landed on October 30, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | Screamin' Eagle Street Tuner | Spark Plug Reader |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.9 (97 ratings)](https://appshunter.io/ios/app/screamin-eagle-street-tuner/id1642944755/reviews)** | — |
| Number of ratings | **97** | — |
| Positive reviews | 16.2% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 days** |
| Monetization | Free | — |
| Size | 180 MB | 37 MB |
| Requires iOS | **15.0** | 16.4 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [Harley-Davidson Motor Company](https://appshunter.io/developer/428393873) | [EVREN YUCEBAS](https://appshunter.io/developer/6782353474) |

## What reviewers say

### Screamin' Eagle Street Tuner

[App page](https://appshunter.io/ios/app/screamin-eagle-street-tuner/id1642944755)

This app simplifies engine parameter management for select Harley-Davidson models when paired with a specific Bluetooth module. It allows users to upload calibrations, perform custom tuning sessions, and monitor vehicle data.

**Highlights:** Upload engine calibrations, Perform Smart Tune sessions, Store run-time data, View performance gauges, View diagnostics

**Features:** Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 🚀 Improved performance
- 👍 Works well when it's working
- 🚀 Fast and crisp tuning

**What reviewers complain about**

- 🐛 Constant crashing and disconnecting issues
- 🐛 Buggy and unstable app
- 🐛 Unreliable Bluetooth connectivity
- 🐛 Fails to save recordings and tunes
- 🐛 Compatibility issues with newer bike models

**Reported bugs**

- App crashes when trying to do smart tune or view data
- Fails to connect to tuner, saying it's paired with another device
- Tuner bricks the motorcycle after flashing a corrupted file
- Voltage error prevents smart tune from starting even with fully charged battery

**Requested features**

- Add ability to turn on oil cooling fan, cool flow fan, and other accessories
- Integrate with Apple CarPlay
- Improve auto-tune functionality and reliability


### Spark Plug Reader

[App page](https://appshunter.io/ios/app/spark-plug-reader/id6805215335)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Version | $4.99 | one-time |


## Frequently asked questions

### Is Screamin' Eagle Street Tuner free?

Screamin' Eagle Street Tuner is free to download, with no in-app purchases.

### Is Spark Plug Reader free?

Spark Plug Reader is free to download, with in-app purchases available.

### Do Screamin' Eagle Street Tuner or Spark Plug Reader have ads?

Neither Screamin' Eagle Street Tuner nor Spark Plug Reader shows ads.

### Which is updated more often, Screamin' Eagle Street Tuner or Spark Plug Reader?

Screamin' Eagle Street Tuner ships an update every 2 months, and Spark Plug Reader every 2 days. Most recently, Screamin' Eagle Street Tuner was updated on October 30, 2026 and Spark Plug Reader on October 6, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*