Bicycle Mechanics - Rear mount a Cyclocomputer?

Hi all,

First time post here, hope this forum is the right one.
My Question> Can a Cyclocomputer be mounted on the rear for trainer use?

Just getting into riding and a buddy kind of laughed at my vintage Puegoet that i was riding at a "Coffe ride" (almost killed me) and offered his Cinelli to try. So i thought i would put mine on a trainer and was wondering if i can rear mount it.

thanks,
DD

Yeah you just have to get longer cables. I know Sigma makes a specific Rear wheel mount.

Long cable as mentioned or wireless that has the range, I use VDO CD3 DS on our tandem rear wheel running 2 computers with no problems the VDO wireless has a 15' range so no problem from any rear wheel.

Cat Eye's Astrale is a wired cyclometer with a rear wheel pickup and cadence so it is particularly suited for trainer use.

Cat Eye's Astrale is a wired cyclometer with a rear wheel pickup and cadence so it is particularly suited for trainer use.

I've been using the Astrale for several years and it's always been mounted to the rear tire. Back when I first got it I had read somewhere that cyclometers were supposed to be mounted to the rear wheel. I've learned since then that this is not as important as I once thought.

One low cost possibility is to use a regular "front wheel pickup" cyclometer and mount the handlebar bracket on the top tube a few inches ahead of the saddle. That way, a regular length wire will reach the rear wheel and the pickup switch can be mounted on the chainstay or seatstay.

Yes, you will have to read it sideways and, yes, you will have to look straight down to see it but, on a trainer, so what?

Um...just for the record, I spliced in some extra wire, soldered connections with heat shrink over them, to reach the rear wheel for my wife's recumbent. No problems.

If your "friend" laughs at your bike again, push his Cinelli in front of a moving SUV.

Um...just for the record, I spliced in some extra wire, soldered connections with heat shrink over them, to reach the rear wheel for my wife's recumbent. No problems.
This can be done but the splices have to be carefully made and very well sealed against dirt and moisture. The pickup "signal" is very weak and any additional resistance will cause faulty or erratic readings.

Most wireless do not have the range to mount on the rear wheel. Cayeye and Blackburn have models that rear mount with cadence which is nice for indoor work.

Thanks everyone! i'll give it a shot this weekend, I put a wireless on the Cinelli and my buddy gave me another computer that has a long enough wire so i can mount it in the rear.
:beer:

So, if you aren't using your bike in a trainer, what are the advantages to mounting the pickup on the rear wheel? Just curious.

Caruso

I am putting it on a trainer.....read the first post:D

Wireless > Cinelli
rear wired > Puegoet

DD

I am putting it on a trainer.....read the first post:D

Wireless > Cinelli
rear wired > Puegoet

DD

I read the first post and each one that followed. Read my question: If you ARE NOT using a trainer, what would be the advantage, if any, to a rear mount. I asked the question out of curiosity . . . that's all.

Caruso

I read the first post and each one that followed. Read my question: If you ARE NOT using a trainer, what would be the advantage, if any, to a rear mount. I asked the question out of curiosity . . . that's all.

Caruso

If you want cadence, rear pickup cyclometers are more common since the wires are going there anyway. Other than that, you are right, there is no advantage and it makes the wires more vulnerable.

Last winter I mounted a $9.99 Target bike computer on the rear wheel of my trainer-bike. I cut the wire between the pickup and the computer, spliced in a 4 foot section and installed the 'puter on the bars. The hardest part was getting the correct spacing from the chainstay to the spoke-mounted magnet. I put a section of hose over the chainstay and zip-tied my pickup to that. Super easy to do and everything worked just great first time.

If your "friend" laughs at your bike again, push his Cinelli in front of a moving SUV.:roflmao:

I just put a Cateye Astrale on my road bike, mainly because my olde Sigma 500 was showing some anomalies, and partly because it was time to spend some money on cycling :). The Astrale has the wheel pickup on the rear, the SIgma on the front.

Today I rode with both computers. For the most part the speeds were identical, occasionally + or - 1 kph. What I found interesting was that the distance was off by .50 km: 30.36km from the front/Sigma and 29.86km from the rear/Astrale. Both computers are set to values published in their respective manuals for my tire size (same front and rear). I can see where, when turning, particularly when turning tight, the rear wheel would track a shorter distance than the front, but I don't know that it would amount to 0.5km over that distance on this course.

Could it be just a calibration issue? Or maybe it's the way my front wheel spins when I come off the ground at the top of the hills :).

I just put a Cateye Astrale on my road bike, mainly because my olde Sigma 500 was showing some anomalies, and partly because it was time to spend some money on cycling :). The Astrale has the wheel pickup on the rear, the SIgma on the front.

Today I rode with both computers. For the most part the speeds were identical, occasionally + or - 1 kph. What I found interesting was that the distance was off by .50 km: 30.36km from the front/Sigma and 29.86km from the rear/Astrale. Both computers are set to values published in their respective manuals for my tire size (same front and rear). I can see where, when turning, particularly when turning tight, the rear wheel would track a shorter distance than the front, but I don't know that it would amount to 0.5km over that distance on this course.

Could it be just a calibration issue? Or maybe it's the way my front wheel spins when I come off the ground at the top of the hills :).

You'd really have to measure your rollout to get a more accurate setting for each computer.

I have a 1985 Schwinn Sprint on my trainer. No trick at all to mount the pickup for a cheap Schwinn cyclocomputer on the chain stay. Wires were long enough.
Incidentally, if you do have to lengthen the wire, don't worry about signal strenght. It is not some magical, mysterious electronic signal, it is simply an on/off switch on the sensor.

I just put a Cateye Astrale on my road bike, mainly because my olde Sigma 500 was showing some anomalies, and partly because it was time to spend some money on cycling :). The Astrale has the wheel pickup on the rear, the SIgma on the front.

Today I rode with both computers. For the most part the speeds were identical, occasionally + or - 1 kph. What I found interesting was that the distance was off by .50 km: 30.36km from the front/Sigma and 29.86km from the rear/Astrale. Both computers are set to values published in their respective manuals for my tire size (same front and rear). I can see where, when turning, particularly when turning tight, the rear wheel would track a shorter distance than the front, but I don't know that it would amount to 0.5km over that distance on this course.

Could it be just a calibration issue? Or maybe it's the way my front wheel spins when I come off the ground at the top of the hills :).

The rear wheel carries more weight, the effective radius is less than for the front wheel.

Al

If your "friend" laughs at your bike again, push his Cinelli in front of a moving SUV.

Yes, people who laugh at vintage Peugeots usually come to a sticky end. :p

Yes, people who laugh at vintage Peugeots usually come to a sticky end. :p
Unless the Peugeot is an automobile. Then everyone laughs. :)

The rear wheel carries more weight, the effective radius is less than for the front wheel.


Wouldn't that tend to make the rear computer OVER estimate distance, since the rear wheel, being smaller, would have to go round and round more times to cover the same distance? That would be just the opposite of what I observed.

I know I am replying late to this thread, but I too have a front mount sensor that i want to mount to the rear wheel so that i can get a speed readout while on my wind trainer. I followed the advice above, but to no avail...splicing the wires did not work. After a few hours a swearing and cursing I went to the local Cyclepath shop for help. Apparently, for some cyclecomputers, there is an invisible coating on the copper wires that must be burned off prior to splicing. If you peel away the protective plastic casing, then hit the wires with a cirgarette lighter you will be able to splice in an extension wire no problemo. They also said that old headphone wire works the best. Hope this helps you and saves you some aggrivation. I wish this solution had been posted somewhere before I wasted a few hours "discovering" it the hard way. To think, I almost went out and spent $100 on a new rear mount speedo...
Cheers.

Have a look in the tandem bike sub-forum. Lot's of people have solved this in lots of different ways to allow their stoker to have a bike computer.

Yes, you can mount a cycle computer's sensor and magnet at the rear wheel and traingle. I have it set up that way on my Vitus Carbone 7:

http://i2.photobucket.com/albums/y44/BeckVFR/DSC00159.jpg

See the magnet on the spoke on the rear wheel at the 10:30 position in the pic above? The magnet sensor for the VDO wireless computer is mounted on the left, non-drive side chainstay, just a few inches aft of the bottom bracket You can just see a a small black box hanging down from the left chainstay in the pic. I now also have a cadence sensor mounted next to it with a magnet on the left side crankarm too. Both had been working flawlessly since I mounted the computer on the bike early this year.
Being a French classic bike fan, I take offense to your friend laughing at your vintage/classic Peugeot:mad:. Please smack him on the back of the head for us C&V fans the next time you see him, and also please realize that just because the bike is old, it does not mean you have to "put it to pasture" to a life on a trainer. Some of the best riding bikes out there are 20 years and older. Keep her on the road and just ignore dolts that think C&V bikes are funny.

Chombi

Yes, they can, and some cyclocomputers are made to be mounted that way. I bought my vintage Trek 520 from a guy here in town, and it came with a Cateye Astrale (also a vintage piece) already installed; it has a magnet on the left crank with a sensor on the front part of the chainstay for measuring cadence, and a magnet on the inner rear wheel with sensor on the rear part of the chainstay for measuring speed. It, however, was made to be hooked up this way. Other cyclocomputers can be Jerry-rigged to similarly work on the rear wheel. I took a $10 Bell (-gasp- Wal-Mart brand!) cyclocomputer and routed the cable up over the toptube and down the chainstay about as far as it would go (it wasn't very far, but it was far enough to reach the spokes of the rear wheel), and I chipped the corner off a piece of foam insulation that just happened to have an elliptical edge that would be just perfect for fitting itself to the seatstay; this provided the extra space buffer I needed, since the magnet needed to be a lot closer to the spoke/sensor (it was made to be on the front wheel). Then I simply zip-tied the sensor and the small piece of insulation to the seatstay, put the magnet at the appropriate spot on a corresponding spoke, adjusted the distance between them, and voila, it worked! I actually used that setup all of last winter to keep my cycling fitness up to a bare minimum...I've found I ride a lot harder if I have something to tell me how hard I'm actually riding.

oops...sorry for helping resurrect this thread; I just realized it was three years old 8P

Today I rode with both computers. For the most part the speeds were identical, occasionally + or - 1 kph. What I found interesting was that the distance was off by .50 km: 30.36km from the front/Sigma and 29.86km from the rear/Astrale.
You have what is know as; "The Two Watch Problem". It goes; "The man with one watch knows what time it is. The man with two watches is never sure."

I have Cat-Eye Enduros on two road bikes and also have a Garmin Forerunner 305 GPS running/bicycling watch. I'm amazed on how closely the Garmin and the Cat-Eyes agree as they read within 0.1 mile of each other on 35 mile rides. However, I do set my Cat Eyes slightly lower than the recommended calibration number. For a 700x23 tire they recommend a calibration number of 210 and I use 209.