Weekend Tech Tidbits: Karoo 2 Color Cases, 4iiii Crank Buyback, and GoPro Session Labs Update

Here’s a quick round-up of a few items that spilled over from the last week (or so) that I’ve consolidated together for your inner geek to consume.

Hammerhead’s New Karoo 2 Colorful Cases:

Starting off with ‘well, that took longer than I expected’ to launch, are Hammerhead’s Karoo 2 color case shells. I say ‘longer than I expected’ because they quietly teased these in a survey last summer (yes, almost a year ago).  In any event, they’re here now for the Karoo 2. These allow you to replace your black shell with a non-black shell. Obviously, you should choose red.


I suppose if you also have a Garmin Enduro watch, you could choose the lime green color, which roughly matches the accents there. In case you were curious, they followed their survey results exactly. Lime green came in last place of the five colors that made the cut, but it placed well ahead of teal, pink, and army green (in total, 16 colors were considered).

Now, this privilege won’t come cheap – costing $39USD/39EUR…but hey, shipping is free.


Inside the kit is also two screws and a screwdriver. Yes, it actually includes a screwdriver:


I’ve put it in my cart a few times (the red one, obviously), but haven’t quite pulled the trigger on it. Eventually I’ll cross that line. But not yet.

Oh, and in case the last time you checked on the Karoo 2, it’s now available for regular order. No pre-order stuff. Just order and it ships immediately.

4iiii Crank Buyback Program:


Now, are you the owner of an unused Shimano crankset sitting around your garage? Then you can earn enough cash to pay for that lime green Karoo 2 shell, via 4iiii’s Crank Buyback program. This program gives you $30-$45 in straight cash for used Shimano left-arm cranks. Plus, they’ll send you a shipping label. As an alternative to getting cash back, you can have them donate that amount to Trips for Kids, which is a charity that gets bikes into the hands of kids.

So, why is 4iiii doing this? Well, like every other bike-related company in the industry right now, parts are hard to come by. Especially crankset and drivetrain related parts (which is why you see Elite making their Suito trainer offered without a cassette). For companies like 4iiii (and Elite), it’s literally holding back sales, since they don’t have the parts required to sell their products.

Once you send in the crank arm, they’ll inspect it and then ultimately attach a power sensor pod to it for re-sale. The $30-$45 for a crank arm isn’t really that much less than you’d buy a new one for…if you could actually buy a new one. So being able to dig around in a box and grab that used crank-arm to send in for a bit of cash is a decent deal. That’s especially notable if you perhaps took off that very crank-arm to install a pre-attached left-only crank+power meter in the last few years.

In any case, you simply go to their site and choose from the long drop-down list. The screenshot below is only a partial list


And with that…there ya go, all ya need to know. I wonder if we’ll see trainer manufacturers do the same with cassettes soon? Sure, cassettes do get more wear than most crank arms, but, I suspect most cassettes are retired well before reaching even the youth of their years.

GoPro Hero 5 Session Labs Firmware:

This post is apparently all about pulling old things out of the closet. But if you’ve got a GoPro Hero 5 Session sitting around (it launched in 2016!), then you’re the new winner of a bunch of new features. As DroneDJ noticed, this past week it received the option to download the GoPro Labs firmware for it. This joins the GoPro Hero 7, Hero 8, Hero 9, and MAX as being supported GoPro Labs cameras.

(Note: This doesn’t include the GoPro Hero 5, non-session, seen above right – just the Hero 5 session, seen left above.)

If you’re not familiar with GoPro Labs, it was introduced a year ago in May 2020, and allows you to get pretty geeky with configuration of the camera, while also unlocking features not otherwise accessible in the camera. For example, delayed recording (such as to turn on the camera the following morning before sunrise). For the Hero 5 Session, there’s not a simple list that I could find of all the added GoPro Labs features it supports (since some newer cameras support additional features), but looking at the controls QR code creation page, it appears to support:

– Delayed capture start
– Specified capture end
– Setting all the frames/resolutions via QR code
– Setting the time
– Setting all the ProTune controls
– Setting most of the camera preferences

This is especially notable for the Hero 5 Session, as it lacks a normal touchscreen to interact with the menus for the camera itself. If you remember, you had to use this little dual-button system on a tiny calculator-style screen, which was roughly akin to banging your head on a wall (a few weeks ago I went to use this camera for something else and then remembered why I rarely used it).

Still, while I appreciated the theory of the size, the practicality of it for most people wasn’t all that different, once you had it mounted, than a regular GoPro. I do suspect these days though they could launch a legit tiny GoPro competitor to the Insta360 Go2, but perhaps super-lightweight that’d also be useful for the DIY FPV drone community (with a removable micro-SD card, and power connectors). Perhaps something hardware-wise stripped down to save weight, but without having to make a so-called ‘naked GoPro’ yourself.

In any case (get it?), with that – thanks for reading!


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  1. David

    Another tidbit for you : my Garmin Forerunner 245 updated to v7.10, which added these features:

    Changes made from 6.20 to 7.10
    – Added Daily Suggested Workouts (limited) for Run activities. Go to Training > Workouts > Today’s Suggestion for options.
    – Added the ability to rate the perceived effort and feel of a Run, Bike, or Swim activity. The prompts appear during activity save. Go to [Activity] Settings > Self Evaluation for options.
    – Added VO2 Max for Trail Run activities.
    – Improved results for daily Body Battery calculations.
    – Updated Intensity Minutes determinations to align with guidance from CDC.
    – Updated workout audio prompts for hundredths distance precision.
    – Improved feedback on stress level readings.
    – Improvements to swimming activities.
    – Fixed some metronome interference with wrist-based cadence.
    – Other minor improvements and bug fixes.


  2. Arno Smit

    The crank buy back program is only for US and Canada 🙁 I have a 172,5 6800 + 175 R8000 crank lying here gathering dust….

  3. Jd

    I don’t want to send my unused crank arm to 4iiii because what if I need to send the one with a power meter on it back to 4iiii again? Then I have a useless bike.

  4. Greg

    The 4iiii deal is good on the other end too. After they take the used crank and put a power meter on it they sell them as low as $280 CDN (Shimano 5800), which is getting close to 200US for single sided power. I’m not aware of an other reputable DF power meter at this price.

    • Robert

      Greg, I agree with your comments. I bought a 105 left crank for CAN $280 a couple of weeks ago and am very pleased with the 4iiii product. My groupset is Tiagra, but since it is Hollowtech II, the 105 crank is compatible. This product is a great value.

      (Note to Ray, thanks for providing such consistently helpful posts and videos).

  5. Tom

    Bring back the week in review (monthly if necessary).
    It’s the thing that drives me to visit your site, to view software updates. Yeah I could bookmark that page, but it allows me to peruse your site at the same time.

  6. Adam

    Good news about the Session 5 now being configurable by Labs, cos they removed some setting from the unit’s menu recently. This will hopefully bring them back.

    Oh and I love the session size. I use it to record my rides when in traffic and it’s a small unit, with a one button on/off.

    I’d love them to bring it back.

  7. David Horn

    So you send 4iiii a crank arm, they donate $35 to a kids charity, stick a cheap* plastic pod onto it and take the profit? 4iiii, if you’re reading this, the option should be “$40 cash or SUBSTANTIALLY MORE to the charity”.

    *cheap to produce, not cheap to design…

    • ShermanO

      I genuinely don’t understand your point. 4iiii isn’t a charity itself. If it economically makes sense for them to send out $35 for a crank arm, why would you expect them to send out more if it goes to the charity? You’re upset that they are not making a matching contribution? Are you upset every other bike related company that doesn’t send a contribution? And what does it matter what they sell the end product for in this scenario? If you think it’s too much, don’t buy it. If you don’t think you’re getting enough in return, don’t send in your used crank arm.

    • David

      4iiii can (will) offset the charity donations against their tax as an expense, so society loses out compared to just selling the part on eBay and donating directly (OK, it’s a tiny amount in the big scheme of things but it’s the principle).

      I think you raise a really good point though simply because I wrote the original comment with a nagging feeling of not really understanding why it annoying me so much, but a sense that it was wrong. I guess that doesn’t make sense either.

  8. ccj

    Karoo 2 has limited availability and unable to send to many parts of the world… be quick and get it done before 1040!

  9. Martijn

    Some other Garmin tidbit in addition: it seems that garmin silently improved their account protection. You can protect your garmin connect account with two factor authentication:

    link to support.garmin.com

    I think it is introduced recently. This old forum topic got updated 5 days ago:


    I think this is a good step in protecting your personal data stored at garmin connect.