s720, Ksyrium SL's & Reynolds Ouzo fork...



DanP

New Member
Oct 5, 2003
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Hi folks,

Just upgraded my Polar HRM to a 720i, having a really hard time making things work in terms of the speed sensor & magnet:

* The bladed forks on the SL's don't help but the magnet part seemed to attach OK to the very top of the spoke, before the blade expands. But it has to be way up there.

* The supplied tie-wraps for the sensor don't fit around the thick part of this fork, after running around some I found some longer ones but still, the very shape of the fork is just not conducive to having a sensor mounted there, at least not with tie wraps. I managed to make it work for about 10 miles and then it quit.

I assume this would be a common problem with these forks and any brand speedo, any good workarounds for the plastic tie-things?

Other than that the watch is great.

On a side note, did conquer the install of the cadence sensor on a Litespeed Ti downtube, not easy - but first time I ride with cadence-awareness, that was interesting.

Anyway, any tips on how to secure this speed sensor to my fork would be greatly appreciated!
 

lokstah

New Member
Sep 30, 2003
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A few thoughts -- there may be other options than what I've got here.

1) It's not uncommon for the magnet supplied with a computer to be badly suited to the spokes you've got, particularly if you're using a wheel with bladed or oblong spokes. Mavic makes spoke magnets just for their wheels; other wheelmakers do the same. Run by your local shop and ask them what they've got. A quick net search will get the job done, too. Bottom line? Any magnet will work with the computer, so just find one that fits.

2) Bummer about the zip ties. Luckily, if you use a bladed spoke magnet, you should be able to mount the sensor where it fits better.

Good luck!
 

DanP

New Member
Oct 5, 2003
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Thanks Lokstah, it didn't even occur to me to look for 3'rd party magnets (duh! on me), that should do the trick nicely.
 

boudreaux

New Member
Oct 16, 2003
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Originally posted by DanP
Thanks Lokstah, it didn't even occur to me to look for 3'rd party magnets (duh! on me), that should do the trick nicely.
You can make the hole on a magnet bigger and buy longer zip ties too.
 

serenaslu

New Member
Feb 3, 2004
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Originally posted by DanP
Hi folks,

Just upgraded my Polar HRM to a 720i, having a really hard time making things work in terms of the speed sensor & magnet:

* The bladed forks on the SL's don't help but the magnet part seemed to attach OK to the very top of the spoke, before the blade expands. But it has to be way up there.

* The supplied tie-wraps for the sensor don't fit around the thick part of this fork, after running around some I found some longer ones but still, the very shape of the fork is just not conducive to having a sensor mounted there, at least not with tie wraps. I managed to make it work for about 10 miles and then it quit.

I assume this would be a common problem with these forks and any brand speedo, any good workarounds for the plastic tie-things?

Other than that the watch is great.

On a side note, did conquer the install of the cadence sensor on a Litespeed Ti downtube, not easy - but first time I ride with cadence-awareness, that was interesting.

Anyway, any tips on how to secure this speed sensor to my fork would be greatly appreciated!

FWIW, as every mount has its peculiar traits...
I had to use some rubber gasket material under the stock hardware on my Reynolds Ouzo fork to get a satisfactory angle with an older style Cateye mount.

For myself, I always try to mount the sensor on the leading edge of the fork, despite the popular opinion so they tend to get knocked out of the way rather than sucked into the spokes should it get out of kilter.

The one nice thing about tie-wraps is you can always change your mind.
 

DanP

New Member
Oct 5, 2003
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Originally posted by boudreaux
You can make the hole on a magnet bigger and buy longer zip ties too.

Thanks, but that would not work with the metal ones provided by Polar, at least not with my skills & tools. And as mentioned I did get longer ties but the forks are shaped so there is no grip and they slope.

Serenaslu: wow, a big thanks for those pics! Really appreciated.

Between your pics and gasket idea plus lokstah's alternate magnet I should be able to secure this without a problem, particularly if able to get lower on the fork.
 

Chaim

New Member
Jan 24, 2004
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Originally posted by DanP
Thanks, but that would not work with the metal ones provided by Polar, at least not with my skills & tools. And as mentioned I did get longer ties but the forks are shaped so there is no grip and they slope.

Serenaslu: wow, a big thanks for those pics! Really appreciated.

Between your pics and gasket idea plus lokstah's alternate magnet I should be able to secure this without a problem, particularly if able to get lower on the fork.

I connected my sensot to the REAR wheel. The signal is strong and this way I can use the HRM on my trainer in the winter. I also have the Cadence install and the singnal is reaching the HRM with no problems.
 

RC2

New Member
May 21, 2004
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FWIW I have a wireless S520, and there were two different spoke magnets included with it; one was for conventional spokes (a light-weight dual cylindrilical contraption, one cylinder compresses onto the spoke, the other is the magnet), and one was for misc. spokes (the older style heavier magnet with a hole through it and a screw to clamp down onto the spoke). The latter works w/bladed spokes, the former doesn't.

At any rate, love the Polar. Just shy of a year and thus far it's the most reliable HRM/computer I've used.
 

buffedupboy

New Member
Feb 28, 2004
39
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I have a S720i as well and mine came with two magnets as well. Before you head out and buy yourself another magnet, for some reason, my HRM does not work with other magnets. For instance, I previously had a Sigma magnet on my wheel and tried using that without any success.

Ciao,
Sean
 

DanP

New Member
Oct 5, 2003
104
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Hmm, I had tried the flat-magnet first but it wouldn't fit, so I went for the old-style cylinder one.

But I can probably just bend the metal sleeve a tad to make it fit, nothing to lose by trying that route.

Good to hear that the range is good enough for the rear wheel, that will make things easier.

P.s.: still nothing was easier than the GPS-based ForeRunner I've been using... just slap on any bike and go, then to your wrist for a run.
 

veloci

New Member
May 1, 2004
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I had the same fork amd rims. Just attach the magnet high up on the spoke, get longer ties and you will have no issues. But, with the Mavic rims and Reynold fork, you have to have the sensor way up the fork. so, the only and better looking solution is to get longer ties. do not try to bend the magnet bracket, it will not work, take it from me. i tried and is not worth it.
 

Whitney

New Member
Feb 13, 2004
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I used a grinder with a metal cut-off blade to carefully widen the slot on the metal spoke magnet. Worked like a charm.

Usually the Polar comes with some rubber pads with stick-um on the back to mount the sensors. If you didn't get any, cut a small piece of rubber, like an old inner tube for instance, a little bit wider than the sensor itself, put a piece of double-stick tape on the back, wrap it around the fork, and zip-tie the sensor on top. The rubber won't move and the sensor won't move.

As far as the zip-ties go, if the ones supplied are too short, like they always are on carbon forks, then you can always hook two together to make a longer one. Just insert the pointy end of one into the square end of another one, push it a few clicks up and then run it around the fork and stick the other two ends together. Voila!

As far as the cadence sensor goes and magnet goes, I had a terrible time getting the magnet to stick on the crank and not hit the front der. Finally removed the little rod magnet from it's plastic case and epoxied it directly to the crank in the right location. Works GREAT and weighs almost nothing.

wonder if I could epoxy a magnet to a spoke?

Oh, also, I have found that mounting the wheel magnet and sensor absolutely as far up the fork and directly under the polar mount as possible does wonders to stop mis-reads and lost data.


Whit
 

maxxevv

New Member
May 31, 2004
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Actually, I use the same SL wheels with the S710i with no problems at all. Polar supplies extra cable ties. Just attach 2 together and you get a longer piece. No issues what so ever.

In fact, I frequently swap my wheels between wheels while having auxiliary sensors mounted on the 2 bikes. Again no issues at all. Just mount your magnet as provided by the wheels high up near the rims. And likewise for you Polar Speed sensor.

Works like a gem. I've done over 5000km on them swapping between 2 bikes set up identically with no issues at all. Just need careful alignment on setting up. Patience will go a long way.