Friday 26 October 2012

Cateye Adventure Review: first impressions

Summary


This computer has the same pros and cons as the more common Cateye Strada but with the added feature of an altitude and gradient reading.


Pros


  • Altitude seems to be very accurate and responsive
  • Gradient appears to be good to within +/- 1% (averaged over 50m or so)
  • Batteries last a long time, there is a battery low warning
  • Easy to operate, even in gloves
  • Sensor ID system should reduce or eliminate spurious readings on group rides
  • Good value if bought for the right price (£50)!

Cons


  • There is no way to display both distance and time together or to flick quickly between them.
  • Average speed is shown to only one decimal place which seems mean given that distance is shown to two.
  • Sensor is specific to this model and hard to come by as a spare part.

  • No back light so can't be used at night

  • Selecting mph for speed seems to force the unit to read altitude in feet.

  • Expensive if bought for the recommended retail price (£99.99).

Cateye Strada: My Previous Computer

I recently went looking for an upgrade for my old Cateye computer. I have suffered problems with my old Cateye Strada computer resetting itself, including during this year's (Cambridge to) London to Cambridge ride. The problem was not related to fading batteries (it happens with new ones) but seems to be due to vibration. As the computer gets older it seems to vibrate more and more in the bracket. I tried improving the contact tension on the battery as suggested by one poster on the internet but still had the problem. In the end I used a couple of rubber shims (cut from an old tube) to tighten the fit between computer and bracket. Finally that seemed to resolve the problem but it would have made moving the computer between bikes too fiddly and I'd already resolved to buy a new computer with two sensor kits rather than persevere with the old one. Both solutions are cited in this BikeRadar.com review.

The Adventure Starts

Looking at the latest computer models it seems that the current crop of products falls in to two main categories. Those that are based on GPS and those that are based on the traditional wheel sensor. Clearly some of the GPS-based devices do have support for ANT+ type sensors opening the way for more conventional (and accurate) speed detection. The technology seems attractive and there is surely going to be convergence with mobile phones (some of which already support ANT+) but I've already tried using a phone mount and a GPS-based bike computer app but keeping the screen powered up for more than a couple of hours seems to be a big problem - even with a full charge. Indeed, the downside to all of the GPS type devices is that they need more regular charging and they cost a lot more. So for me, it was back to the traditional design.

The Strada is a pretty basic computer. I've used more sophisticated computers with a cadence sensor in the past but I didn't find that particularly useful past the novelty stage, however I have always been intrigued by the idea of an altimeter integrated into the computer. I imagine that on longer, unfamiliar climbs it might be a useful way of seeing how near the top you are. Curiosity got the better of me and I decided to select the Adventure.

Having resigned myself to the cost of the Adventure I was pleased to see that Amazon were selling it at almost half the price I expected. Unfortunately, I couldn't find anyone who sold the sensor kit for my second bike at anything other than a price higher than the Amazon price for the complete unit so I ended up buying two!

Installation and Set-up

People do complain about the instructions on these computers and I guess they aren't that easy to master. It helps if you've used a simpler Cateye computer before as you'll be familiar the basic way the unit operates. I must admit that I was a bit dismayed to see that the Adventure still uses the hidden button under the unit which you activate by pressing the front of the unit until it clicks. This design seems to require a certain flexibility in the mounting bracket which may be the cause of the vibration that did for my Strada. That said, fitting the bracket and the sensor takes only a few minutes.

Altitude calibration did take a bit or working out. The unit has two altitude figures it uses as a base line, one called 'adjust' and the other 'home'. The idea is that you set the 'home' value to your usual altitude (for me that's 60 feet). The adjust value is there to compensate for the natural variation in atmospheric pressure due to weather. It starts off by displaying the expected altitude (based on a standard model of the atmosphere) but you can adjust it to show the correct altitude at any known point. The computer uses the difference internally to correct the altitude display.

This all sounds a bit fiddly until you realise that you don't need to play with the adjust setting unless you are away from home. If you are starting your ride from your home you only need to press and hold the unit until the adjust screen appears, then press once more to switch to the 'home' setting and finally press and hold again until you are returned to the normal screen showing speed etc. This rather unintuitive sequence of actions sets the 'adjust' value to match your home altitude and can be done without removing the computer from the bracket. This is all you need to do to compensate for changing weather.

Altitude and Gradient in Operation

If you've ever sealed up a plastic bottle during a plane flight and watched it slowly get crushed during your descent you'll know that changes in atmospheric pressure can be quite significant. Although the cabin is pressurised during flight it is not kept at sea-level pressure. Boeing have a nice article on this, apparently the pressure is kept no lower than you'd experience at 8,000 feet. I've noticed the same effect at lower altitudes too. A plastic water bottle closed at 2,500 feet will still appear slightly squashed if you descend to, say, 500 feet.

If you want to know how pressure changes as your altitude changes there are various formulas to help you work it out. There is a handy little calculator at aviation.ch from which you can see that pressure drops by about 1 millibar for each 30ft of ascent at low altitudes. I have a wall-mounted barometer in my house and I can easily detect changes of 0.5 millibars with that (which would translate to an accuracy of 15 feet) but I had no experience of the type of pressure sensors that fit in to small cycle computers until I used the Adventure.

On my first ride I took my bike over some low hills near my home (max height 223 feet according to my survey map). The altitude seemed to be fairly responsive and it briefly read just over 220 feet as I went over the top). The gradient, shown as a percentage, lags the altitude a little. As far as I can tell it is calculated using an averaging process over the last 50 or perhaps 100 meters. As a result you tend to be at the end of a steep section before the gradient starts reading a realistic percentage. You may also find that it keeps reading positive values even though you've started the descent. I still find it useful even though I haven't tried it anywhere with really long or steep climbs yet. When I got back to my house the altimeter was reading 47 feet, a drop of 13ft. This type of inaccuracy is typical with this type of altimeter of course. In this case the pressure was rising at a rate of about 1 millibar every 90 mins so my 45 minute ride coincided with about 0.5 millibars of increased pressure so the altimeter should have read about 15 feet lower - again, I was impressed with the accuracy.

My second ride was longer (about 70 miles) but much flatter. According to the survey map my route touched the 0 contour a couple of times, at those points the reading flipped between 4ft and 8ft. Even bridges with relatively short approaches registered a gradient and a brief increase in altitude up to a realistic looking 20 or perhaps 30ft.

Overall, I'm very impressed with the accuracy of the pressure/altitude reading, it is easily responsive enough and results in a much more accurate altitude reading than the typical GPS-only capability of my phone.

Perhaps the only issue I have had is that the reading on the unit can be a little too reactive. On very flat roads (we have a lot of those near my home) the altitude reading might flip between two adjacent readings sometimes generating brief but spurious sections of 1% gradient. You won't notice this sort of error so much when going uphill but on longer flat rides you may want to be mindful of this when interpreting the total ascent reading.

Other Functions

The Adventure is basically all about adding altitude to the basic Strada computer. With more functions you find yourself having to press the button more times to scroll right through the various display modes. For example, if you are looking at distance and want to change to view elapsed time you have to press 7 times! If you are timing yourself over a fixed distance you'll have to compensate for that in your head.

As a side effect of the altitude function you also get a temperature reading (which I assume is required to accurately calculate altitude from the pressure sensor). In itself the temperature reading is only likely to be useful for spotting icing conditions but as it only shows in the clock mode you are unlikely to see it routinely.

The additional altitude and temperature readings are given in the centre of the display making the overall unit size larger than the Strada. I found the display a bit tricky to read at first (the digit 4 is rendered a bit oddly) but I soon got used to it. There is no back light so forget using this unit at night or in low-light conditions.

Further Reading

You may be interested in the brief review on Bike Radar or this longer review on road.cc.