Review - Bike Computer

[WRT]

I've looked around a bit over the last few months at various options on putting a speedo on my CR250. Having hunted around, you can start from around $20 for a cheap bike computer designed for a push bike, all the way up to around ten times that for a reasonable computer designed specifically for motorbikes. The "proper" ones are loaded with features, have a huge, easy to read screen on them, and can include the ability to switch between bikes, which is quite handy for those with more than one dirt bike in their stable.

With me having some Dutch in my ancestry, I went for the el-cheapo option. I went around a few of the cycle retailers (Bike Barn, Pack and Pedal, Hedgehog, etc), and settled for a Vetta RT33, which is available from iBike for $30. This has the five main features I was looking for, which are:

• Vehicle speed
• Trip meter
• Odometer
• Service Timer (in hours)
• Clock

There are cheaper models that have less features (for example, no service timer), and more expensive models with more features (such as average speed / max speed, etc) without having to resort to a $200 unit specifically designed for motor bikes. I figured that I'm just wanting the basic features, and given the amount of punishment it will receive offroad and the vibration on a two stroke bike, the unit should be as "disposable" as possible. You also have the option of having a wireless system, but I went for a wired one, which in hindsight might not have been the best idea.

Basically what your $30 buys you is a handlebar mounted display, a magnet to clip onto your spokes, and a pickup that mounts on your forks so that it gets "tripped" each time the magnet passes. Included with the pack are some cable ties, different thickness mounts for the handlebars and forks, some stickers and a set of instructions. The display itself has a quick release from the handlebar mount so that you can pull it off the bike easily between uses. It also goes into a powersave mode if no input from the wheel or the buttons are received for five minutes to help conserve the battery.

The actual configuration of the unit is quite simple. There are only two buttons on it, one used for cycling (excuse the pun) through values and one that acts as an Enter/Tab button. You are asked to enter the time, clock format (12/24 hour), whether you wish to have the readout in kilometers or miles, the circumference of your tyre, and what the service intervals are. The tyre's circumference is worked out by marking a spot on the floor, rolling your bike forward for one revolution of the wheel, and then measuring the distance in mm.

Mounting the unit seems relatively straight forward, and I would imagine on a pushbike it most probably is. However, adapting it to fit a motorcross bike took a little bit of work. First issue is that the spokes on a MX bike are significantly thicker than on a push bike, hence the pickup doesnt really fit on them. Second issue was the distance from the spokes to the fork - far to great for the pickup to register the passing of the magnet. Third issue was the distance from handle bars to wheel - with the forks fully extended the supplied cable was far too short.

The cable is a simple fix, I merely added a extra lengh of speaker wire to it. Five minutes with a soldering iron, a bit of heat shrink, and you're good to go.

The problem of where to mount the magnet and pick up was more problematic. Nowhere do the forks and spokes come close enough together. Realistically, you need to have the magnet pass with a couple of mm of the pickup, and given the punishment the front wheel of a MX bike takes the mounting points need to be pretty inflexible.

How I got around it was by mounting the pickup on the front axle spacer (which doesnt rotate), and making a small bracket to mount the magnet onto the disk bolts. Effectively the magnet is inside the disk, passing underneath the calipers as the wheel rotates. Fortunately there is sufficent room for this without anything being in jeopardy of getting snagged on the brakes - which would have disasterous results, as I'm sure you can imagine.

This actually works quite well, as from here its easy to run the cable up the front brake line, resovling the problem of getting it up past the suspension. Also there is a cover which goes over the whole brake assembly and protects the lot from damage.

First test ride was on Saturday, in the pouring rain up at Woodhill. A quick blat down the beach confirmed two things, the speed takes a little while to update, and that at pace the small screen can be hard to read. By the end of the day, the unit had been well and truly soaked and abused, but it came through with no sign of deterioration. The display is hard to read if you are blasting along, but normally you wouldnt bother with that as all your attention should be focused on the terrain ahead.

The clock is very handy to have, and the odometer/trip meter give usefull info as well. Once you know the distance you can get from a tank it will make it a lot easier to gauge on the fly how long you can keep riding for. The service interval timer should help out considerably as well, seeing as I dont currently have a motominder fitted to the bike.

In the mean time, I'll still be counting my hours until I come to fully trust the unit, but after the hard time it was given on Saturday it looks like the unit will work just as planned.

Final thoughts: I think that it might have been easier with the wireless option, however it would pay to check how far and how reliable the "connection" between the display and the pickup would be. Also, the magnets are a replaceable component - so perhaps it would pay to put two in place at opposite locations on the wheel. Then you could halve the circumference value you enter into the unit and theoretically also halve the time it takes the display to pick up speed changes.

All in all however, I'm quite happy with the unit and for $30 its a bargain.

Pictures below, please excuse the quality as they were taken with my phone. I'll take some with the camera if anyone is interested in better res images.

[TLDV8]

That was a ace report

I have been thinking about one of these units for some time.
Is there a Auckland retailer who stocks the slightly higher spec MC version's ?.
Anyone think of a reason the pick up couldn't be mounted on the rear wheel of a road bike.

[WRT]

Cheers mate

Dunno about an Auckland Retailer, but the best computer I have seen is probably this one:
http://www.dirtbike.co.nz/default.asp?pageid=12

I looked at doing the rear wheel, but the cable would need to be quite a bit longer, so I was little nervous about signal loss, plus I couldnt protect it as well from mud and stones on the rear. Not to mention that my back wheel doesnt give too accurate a reading, as its normally spinning faster than the front one . . . I really gotta replace that tyre sometime soon.

One advantage of using the rear wheel however is that the suspension only pivots, rather than shortening/lenghtening like the front does, so should be easier to cable. Running the cable down the front brake line does seem to work a treat however.

[McJim]

What is the maximum speed the Vetta cycle computer can cope with?

[WRT]

I think it's 299kph, or 199mph, whichever is applicable for the display setting (kph/mph) you selected during setup. Either way, it's a little more than the CR is ever going to get up to!

[McJim]

I think it's 299kph, or 199mph, whichever is applicable for the display setting (kph/mph) you selected during setup. Either way, it's a little more than the CR is ever going to get up to!

It's a shedload more than any pushy is gonna do too! Nice idea for the motorbike though.

[Pixie]

I have these on my bike and car ( I like to have an exact speedo )
The one on the car has an extended cable,signal loss won't be a problem.
I put the magnet in one of the disc rivets on the bike.
Some computers go to 99 km/h and some go to 199 km/h.However,they begin to count from zero again when you exceed the display limit,so you can still read your speed,eg 23 km/h would be 123 km/h
The maximum speed achieved reading on mine goes above 300 km/h.
The brand I have is Echowell

[Tim 39]

I have a topeak one on my RS125, is perfect for keeping track of maintenance etc, ive had it to 202kph and it was stil going, so all good

[steved]

One question I have with bike computers is the refresh rate. I rode a ZZR600 with a bike computer and wasn't overly impressed with how often the speed updated.

Is this something I can check in the spec sheets before I make a purchase?

[WRT]

Dunno, but the update time on the Vetta is a bit slow for my liking too, to be honest. Really only noticed it on more open land where you are gunning it hard, so didnt find it such a problem on my first ride out.

[ArcherWC]

i have had one of the trailtech ones lying around in my garage for a couple of years (i only ride mx now), will sell cheep (say $50 +postage) to a fellow KB member.

It will probably need a new battery, and if i cant find the pickup, i believe you can get these seperatly as well

[cheese]

I was going to get one of the ones like you WRT, but you can buy just eh magnet from www.dirtbike.co.nz for $9 I think.

Brain interested in your computer. Let me know if you have the cable. Don't know if it will be too much of a mission to for to teh RM.

[ArcherWC]

Yep, got the cable and everything, all you will need is the pickup magnet, and possibly a battery

[XP@]

I ran with a cycle 'puter on my F650 for years excellent value.
I also fitted a Dick Smith speedo as the only speedo on my XT400 and managed to get a wof!
http://faq.f650.com/FAQs/Aftermarket...Computer%20FAQ

Hi,

I have just installed a cycle computer, done 1300kms (mostly in the rain) with it and plan to use it for an Iron Butt event next weekend.

I bought a VDO C10 for $75 NZD. This was my second computer because, on closer inspection, the first one would not register > 99kmph, ok for a cycle but not really cool for a real bike.

Buying Tips:

* Double check the max speed before you buy! it should be min 200 kph
* Don't buy a wireless computer because it will not work, they need line of sight.
* Check for a durable magnet that you will be able to fix to the brake disk ( the spokes will be too far away). unless you plan to replace the magnet.
* You should be able to set the wheel diameter accurately, some only give you pre-determined sizes.

My Experiences so far:
* Having a second trip meter allows you to record distance accurately and still know how much petrol is in your tank.
* Once the wheel size is set up it is as accurate as the big dial on the dash.
* Once you know where it is, it is easy to read during the day. At night it can be read if you are going at the speed limit past street lights.
* Make sure you clip it in properly, they do bounce but not too often.
* They are waterproof (900+kms in driving rain)
* I guess it would be a bad idea to let a cop see it who has just pulled you over for speeding (it records max speed, they may just know how to use one)
* After about 300kms (in the rain) it stopped registering for about 10 mins then started working again. I don't know why ... it could have been my dodgy soldering.

Features for the VDO C10 are:

* Large (ish) KMPH / MPH display
*
2* Trip Counter up to 999.99 km or miles - the second is great for road book instructions
* Ride Time - The amount of time you have been moving (up to 10 hours)
* Stop Watch - Up to 10 hours
* Average speed
* Max Speed
* Clock
* Two wheel sizes
* Small durable magnet, with chromed case (many are plastic).

Fitting to a Classic F:

1. Remove the LHS front fender.
2. Work out where you are going to place both the magnet and receiver. I used the bottom bracket on the LHS mudguard. For the magnet, there are holes in the brake disk, you will need to attach the magnet to one of these. work out which is closest to the future location of the receiver.
3. I used a couple of large washers, some blue LocTite and just screwed the Magnet assembly together as tight as I dared in to one of the holes near the centre of the disk. (don't use the holes in the outside of the disk, the magnet will not get past the brake pads)
4. Before I attached the receiver I had to extend the cable, I did this by soldering another length of thicker wire in the region where it passes the steering head. ( any suggestions on how to attach, in a waterproof manner, a thick and thin wire are welcome, my fix was trashy).
5. Measure the front wheel diameter. Test by raising the front wheel and spinning as fast as you can. ( I manages 20kmph)
6. The wire at the right length I used cable ties and duct tape to secure the computer cable up through the steering head and on to the LHS handle bar. The lower half followed the brake cable.
7. Test again, and re-do the bad soldering you did earlier.
8. Test ride to make sure nothing falls off.

On Board Computer Comments/Feedback:

* Sigma Sport BC1400): Buying tips:
- If you are going to use it in a rally, check how many seconds it needs to reset the trip-meter. You do not want to spend to much time resetting it.
- Brands to look at: Sigma Sport, Topek Panoram and VDO. Fitting to a classic F: About the soldering (nr4):
- Replace the shitty thin wires with some decent sized wire (1.5 or so). Change the length to 130 cm. Solder it together and use Plastic Shrink Tubing for protection against water.
- If needed get a new rare earth (= neodym) magnet and epoxy it to the brake disc (recommended by Harl #380). Spakur in Sweden.
* Sigma Sport Bike Computer. I have a bum basic Sigma on one of my Hawks as there's no speedo drive with the F3 fork and Marchi rim combo . It works great; my only gripes being the lag on hard acceleration ( really only a concern when The Man is sighted : P ) and that it isn't backlit . The higher end models are though I'm pretty sure , but I'm a tightwad and it doesn't have legal headlights anyway so I just got the cheapest option the bike shop had . Aerostich sells a neat looking unit that is back lit and also seems to be a bit easier to operate the avg speed/fastest speed/odometer functions. Joel.