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Sun Company makes a clip-on bike thermometer that looks nice. Even the good reviews say it's hard to read tho.

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Does anyone have one? Are you able to read it without stopping?

I thought about attaching a keychain thermometer somehow but that would probably be hard to read too.

Anyone know of a better product? All could find was this one and a chinese motorcycle version that looks chintzy.

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    Personally, I would not trust more the reading of a thermometer that is exposed to the sunlight and to the elements than what I could get by looking at a weather app on the phone/watch.
    – Rеnаud
    Commented Jan 24 at 22:11
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    I'm in the middle of nowhere and app-reported temperatures are usually wrong. That's the only reason I'm finally buying a thermometer. I finally wondered "what's the actual temp?" too many times.
    – user66598
    Commented Jan 25 at 1:43
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    @user66598 physics says they can't possibly design a thermometer that reads a sensible air temperature in direct sunlight (the power of which varies with time, date, and latitude) le alone one that also works in shade. The black casing says they didn't even try to minimise solar heating. A thermometer placed in a light-coloured bag udder the top-tube would probably be best, then you'd have to get it out to read it
    – Chris H
    Commented Jan 25 at 11:02
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    This thing will just get hot in the sunlight. I would not trust it at all. Commented Jan 25 at 13:31
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    @user66598 if you fancy riding around with a Stevenson screen on your bike you could get something approaching decent. Even they get some solar gain (white paint being no more than about 90% reflective). The constraint of practicality was implied (with you the engineer and me the physicist, that feels like the wrong way round).
    – Chris H
    Commented Jan 25 at 16:59

3 Answers 3

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Probably worth noting, some bike computers (can) have temperature sensors, even if it is not advertised on the product pages or listed among the available sensors. Based on the comments of DoNuT and Vladimir F, the presence of a barometer is a serious hint of the presence of a thermometer (necessary to correct barometric measures).

On the existing products:

  • Some "basic" computers offer temperature readings (Sigma seems to include temperature quite fast — even on 30€ wired computers, Cateye reserves it to the top of the range).
  • looks like all Wahoo have one (the most basic has one, so I'm assuming others have one as well).
  • Garmin Edge Explore 2, Edge 510 upwards have one (and probably the higher models as well) — thanks to the commenters for the info.
  • Garmin sells an external temperature sensor — wireless (which allows to place it on a better location than the handlebar).

If you already have a bike computer, it may be worth investing the available fields that can be displayed, and if there's a temperature sensor, temperature should be listed among the data to be displayed.

It can be the case of other brands as well, I haven't done an extensive research.

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    Garmin definitely has internal sensors, I think the external one is mostly used as addon for devices that have none or of which you don't get realistic readings from, for example because you carry your GPS tracker in the backpack and still want to pair it with the external sensor somewhere exposed on the outside.
    – DoNuT
    Commented Jan 25 at 10:43
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    Also the Explore 2 does have a temperature sensor. These days the (often Bosch, e.g. BMP 280) miniature sensors used to measure the air pressure usually also measure the air temperature and/or air humidity. Commented Jan 25 at 13:28
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    @user66598 it's indeed a totally different question, and it depends obviously on the bike computer. This question may interest you: bicycles.stackexchange.com/questions/62502/… (but it's mostly about advanced bike computers, not the basic ones)
    – Rеnаud
    Commented Jan 25 at 15:55
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    Most microcontrollers have temperature reading built in, chargeable devices often have a second one in power management IC, and air pressure sensors typically have another one. So it's just a question whether to show the temperature in UI.
    – ojs
    Commented Jan 25 at 20:25
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    @ojs Yeah but on a bike computer, you would expect temperature readings to be from a purpose-built sensor and not just some sensor that shows an internal value impacted by factors like charging or warming circuits. It is a design decision to show values and in the end, users somewhat rely on the readings and it should at least be in the right ballpark. My feeling is that at least while riding, Garmin computers do a decent job but you have to take readings with a grain of salt initially (lets say the first 5 minutes in cold conditions) or after you stopped in sunlight....
    – DoNuT
    Commented Jan 26 at 9:25
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I do not think it would be hard to read as there are many readings on E bike display that have very comparable size and you only need to spot where the arrow is. Gear indicator, if present, is also about of this size and easily readable.

In any case it is not something you would look at very often, but if very hot or very cold, may be interesting to talk about later.

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  • Thanks for a 2nd opinion. We agree! On my ride earlier I decided that I'd probably only look at the thermometer once or twice per hour, and even if I have to duck my head a few inches to read it that won't be a big deal.
    – user66598
    Commented Jan 25 at 1:40
2

I took this thing and my most accurate thermometer on a ride to compare readings. Even in winter the mid-day sun caused the clip-on thermometer to read more than 10 degrees above the actual temperature. Twisting the thermometer so the handlebar shades it and then flipping it up to read solved that problem and the thermometers were within a degree or two of each other after that.

Having to flip it up like that means it's not really readable while riding (cables are in the way so it takes two hands) but having to stop makes the fact that it's a bit tiny less of a problem.

A bigger concern might be that it's made for bars of 1" diameter or less. My gravel bike's bares are 1" on the ends but larger in the center. The thermometer barely fits on the bar right where the tape starts.

Ultimately it's a usable product and I think will be more or less worth the price (˜$13 I think).

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    it broke. i got about 3.75 rides out of it for $13. The first ride it read 10 degrees high due to being in the sun. The 2nd ride I used an accurate thermometer to determine that this thermometer was accurate if kept in the shade by twisting it. 3/4 thru the 3rd ride it broke from catching on the brake cable when I twisted it. I have drop bars on this gravel bike and the thermometer barely fit between the end of the bar tape and where the bar increases in size. It might last longer on flat bars with nothing in the way.
    – user66598
    Commented Mar 16 at 15:26

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