Giant Cadence sensor and frame clearance ?

following my thread last week, cadence sensor installed as per the instructions. Mighty tight to the NDS chainstay though, maybe 2mm clearance… , not helped by my zip ties being a little too wide for the grooves, but pared them down a little 🙂 . I’m guessing there shouldn’t be any rub with decent cranks and a carbon frame…. ?

@iainc

the trick is to split the magnet from the rubber block (its too tall as a package) which is only held on with an adhesive tape – I normally split them using a flat blade screwdriver.

You will then be left with the magnet covered in the rubber outer (you will see the magnet from the inside). I then take one of those rubber strips you use for securing reflectors / light brackets and cut it about 1″ long and use this between the magnet and crank arm – gives the perfect gap for sensor to pick up movement, whilst giving plenty of space for safety, and as you tighten the 2 zip ties the magnet will pull tight against the rubber strip and never shift on the crank arm

I would suggest using a regular sized cadence sensor.

Surely it’ll be fine if it’s going on a giant bike?

Stick a small magnet in the end of the pedal axle. No zip ties required.

@craigw

The ridesense sensor sits inside the chainstay and requires the cadence magnet to sit within a narrow range measured from bb axle centre (magnet end at 128mm).

Photo below shows the typical lack of clearance with the stock magnet/rubber block

Magnet on back of pedal axle is too far for sensor to pickup.

I manage a busy workshop in a giant brand store, we sell a lot of carbon road bikes all fitted with ridesense

@scotroutes…you’d think so! We gets bells that don’t fit, reflector don’t fit, you get the idea. Generic parts

Whoosh! 😆

Get a really powerful magnet, then it will probably work even if its a few centimetres away.
Or just glue it onto the crank in the right place.

@CraigW

no need for glue, zip ties work fine with a rubber strip

The magnet needs to be in the right place because the sensor arm sits inside the chainstay just under the carbon fibre. The forward stub on the sensor in the image below is the part that sits inside the chainstay.

If you get the position of the magnet wrong, you get no signal or an intermittent signal. We tried using other magnets, my first suggested solution of splitting the stock magnet from the thick rubber mounting block works fine.

I’ve just installed one of these on my carbon Defy with 105 cranks. didn’t really think anything about it when I installed the magnet on the crank arm, I thought the clearance was OK. Its similar than the photo above. I can’t really see the problem. Any deflection of the crank arm is likely to bend the arm away from the chainstay and another mm or two clearance will not decrease the risk of anything getting caught in between. I’ll probably be proved wrong next time i’m out on it!

Thanks, some good info. Might try the splitting idea esher, cheers

Ah – my garmin one doesn’t have magnets……. So less of an issue

Would a new 520 fit ? Nobeer can’t get his to work – make him an offer 😉

Oooh, a new 520… Might just ask him 😀

esher_shore – for the new rubber backing, would a small piece of folder inner tube work ? Thanks

I use a bontrager magnet on one bike, a magnet on the pedal spindle on another. The cadence sensor is not in the best place but does work well when set up properly.

Thanks, I sliced the rubber block in half to make it thinner, then mounted with a little bit of double sided tape and zip ties. Clearance now 3-4mm so looks fine. It’s gone out of sync from my fettling so will leave it for a bit to go to sleep and reset.

Balls, it is now too far away to pick up 👿 have tried with clearance down to 2mm with full block and works, so back to cutting up bits of rubber tomorrow. I have the 128mm bit fine so its definitely the thickness of the backing that’s the issue. I guess that’s why Giant make it the way they do, with minimum clearance as per the pic earlier on 😳

need a decent stronger magnet on the pedal spindle

TIRed – will that actually work with the Ridesense positioning ? If so what magnet should I buy ?

I took my magnet out the plastic on put it inside the crevice of the inside of the peddle. Magnet keeps it in place.

Thanks, some of my posts and online stuff suggest that is too far away from the sensor so interesting to know it works

Would a new 520 fit ? Nobeer can’t get his to work – make him an offer

My spidey senses are strong this morning! 520 now working fine, first proper use on the commute this morning, It’s bloody impossible to ignore live segments, even though I just planned an easy pootle in!

Glad it’s working now nobeer 😀

well after much faffing about, including splitting the magnet from it’s base to make it ‘thinner’, I am back with it as supplied. It appears to be hugely sensitive to positioning – if its 2 or 3 mm too far along the crank towards the BB – like 127mm rather than 129 mm (instructions say 128 and a wee bit), it doesn’t pick up, and if it is more than around 2mm clearance from the framestay it also doesn’t pick up. After chopping up the supplied one and faffing about I bought a new magnet and base, and got it working as per the pic above

It appears to be hugely sensitive to positioning

It is. Hence I have a couple of different solutions for each of the three bikes.

I like the Bontrager rubber mount very much though. Looks neat, easy to adjust. Works.

(Come on, you got the sensor free 😉 )

Cheaper here https://www.evanscycles.com/bontrager-crank-cad-cadence-band-magnet-EV166191

ah, that Bontrager one looks clever, will order one now ! (assuming it will pair up with a Garmin Edge 500 ok ?) – is 5mm or 10mm better ?

5mm on my (non disk) Defy SL with plenty of clearance. I also added the old Giant magnet to boost the strength under the rubber. The Propel is currently rocking some electrical tape and inner tube cover. The old Propel has a big magnet on the pedal spindle, but the sensor did not survive the great crash of 2015.

If you can go with 10mm clearance, I’d pick that. Mine came with a sensor for my fixed road bike – that one uses a pedal spindle magnet. If not, 5 plus more magnet strength. It is very neat.

thanks for that, will order a 5 and 10 from Evans and return one of them

No it’s the depth from the back of the crank. Here’s my set up

cheers, I was editing my daft question as you posted !

The standard Giant one is about 12mm deep, so the 10 should be ideal..