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  1. #1
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    lefty fork and polar 720I

    is there any way to use a polar 720I on a lefty fork?
    Ive tried mounting the sensor to the very top of the fork but that didnt work out very well.

    any ideas would be appreciated

  2. #2
    LA CHΘVRE
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    Have you checked the FAQ containing 4 threads about computer mounts? If not, take a look in there: thread 1, thread 2, thread 3 and thread 4.

    Good thing I went with a Garmin Edge, it doesn't need a magnet, I can use it with all my bikes without any setup to do, just turn it on and go. I can even leave it in my Camelbak if I just want it to record the ride and review it when I get home.

    DAN.GEROUS.NET : MOUNTAIN BIKING : CYCLOCROSS : ROAD :

  3. #3
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    Thanks.Ive seen those that allow cat eye type computers to be mounted .I was looking for something specifically for a 720I.The mounts made for regular type computers mount too far down for the polar to pick up the signal.

    I also have a garmin but really like my polar better.

  4. #4
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    You need an extender

    I do not think you can make it work without the extender thing. I have a s625x and CS600. They have different sensors, but both require an extender. I have this one http://www.bikeparts.com/search_resu...p?ID=BPC115842 which works well with the older polar speed sensors like on the 720i.
    .It is a little but too small, but works with the newer style polar sensors(WIND). FYI I think the S720i and S625x are exceptional. I have had a 625x for 3+ years and(other then having to send it in 3 times for new batteries) it has been great. For mountain biking I think the watch versions of the polar computers are much more durable when bar mounted like the CS600.

  5. #5
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    had to figure out what you have...yours is wireless and the manual says maximum distance between computer and sensor is 1 foot 8 inches...so now i see you predicament since the best place to attach anything on the lefty is down at the base of the fork

    where did you try to mount your pickup and sensor...at the top of the fork boot? i was feeling under the boot right at the top, there seems to be another inch worth of fork tube...where one could wrap zip tyes around and not affect the fork motion
    "He can make even a global summit meeting seem like a kegger." M. Dowd, NY Times, 19 July 2006

  6. #6
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    Quote Originally Posted by adamantane
    had to figure out what you have...yours is wireless and the manual says maximum distance between computer and sensor is 1 foot 8 inches...so now i see you predicament since the best place to attach anything on the lefty is down at the base of the fork

    where did you try to mount your pickup and sensor...at the top of the fork boot? i was feeling under the boot right at the top, there seems to be another inch worth of fork tube...where one could wrap zip tyes around and not affect the fork motion

    yep...tried it up top and the sensor mounts nice and snug up there.The only problem is when the fork "bobs" the sensor also "bobs"causing it(the sensor)to get out of line with the magnet.This kinda skews the data that is being transmitted. .

  7. #7
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    Quote Originally Posted by sheppardk
    I do not think you can make it work without the extender thing. I have a s625x and CS600. They have different sensors, but both require an extender. I have this one http://www.bikeparts.com/search_resu...p?ID=BPC115842 which works well with the older polar speed sensors like on the 720i.
    .It is a little but too small, but works with the newer style polar sensors(WIND). FYI I think the S720i and S625x are exceptional. I have had a 625x for 3+ years and(other then having to send it in 3 times for new batteries) it has been great. For mountain biking I think the watch versions of the polar computers are much more durable when bar mounted like the CS600.

    you mount your sensor at the bottom of the fork?During the cohutta100 yesterday I used that same thing but had to mount my watch/reciever to the side of my fork so it could get a signal from the sensor.

  8. #8
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    Hi Mark.
    I had the same problem as you, but fixed it with lefty computer mount mentioned in a previous post AND by boosting the signal from the speed sensor. Having done that you can just place the 720 on the bars.............
    I will try to paste the guidelines....... - btw it was not difficult to do, i.e. the fixing

    "If you observe either the speed or cadence readings drop out while riding, and the sensors and receiver have been mounted as per the factory instructions, the problem could be caused by obsorbtion of the sensor output signal by the bike frame. If the sensor has been in use previously with no problems, it could be an indication of a low battery voltage.

    It is always recommended to send any Polar unit which is malfunctioning back to an authorised Polar repair centre for checking.
    However, by following the below proceedure, the problem may be overcome. If you don't have the correct small philips head screwdriver or are not confident, don't attempt the adjustment and return to an authorised Polar repair centre.

    Please first try and position the sensor as close as possible to 90 degrees to the wheel to get the best transmission lobe to the receiver. If this does not help, the sensor range can be increased as follows:

    To increase the transmission range on the S510/S520/S710/S710i/S720 s-series speed/cadence sensors only:
    • Remove sensor from the bike.
    • Undo 2 small screws holding the two halves of the sensor together with a small philips screwdriver.
    • Carefully remove one section of the housing (end with cable ties).
    • Carefully slide the exposed printed circuit board a little way out.
    • Remove the jumper plug from the inner most pin and insert it over the two pins closest to the edge of the circuit board. This will give the maximum range. Shorting out the inner two pins with the jumper plug gives the medium range.
    • Re-assemble carefully in the reverse order.
    • Becareful not to over-tighten the two screws which can either distort or crack the case leaving the unit not water resistant.
    • Further information can be found on Page G82 of the S510 user's manual or Page G90 of the S710i/S720i user's manual.
    TO ENSURE SENSOR WATER RESISTANCE IS MAINTAINED, PLEASE BECAREFUL DURING RE-ASSEMBLY THAT THE FINE RUBBER SEALING RING AND CASING ARE NOT DAMAGED.

    After reassembly, if the sealing ring or casing appear to be damaged, please immediately return to a Polar service centre to be replaced before re-fitting to the bike.

    Note. Increasing the transmission range may interfere with other bike riders with the similar Polar setup and will also shorten the battery life of the speed/cadence sensor."

  9. #9
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    I ended up mounting my computer sensor on my rear wheel. I dont know if yours has the range, mine does.
    Lead by my Lefty............... right down the trail, no brakes.

  10. #10
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    It works for me

    Quote Originally Posted by Mark D.
    you mount your sensor at the bottom of the fork?During the cohutta100 yesterday I used that same thing but had to mount my watch/reciever to the side of my fork so it could get a signal from the sensor.
    Yes.I use a S625X bar mounted and recently the CS600 bar mounted and they both work well. I ride 3 or 4 days a week year round rain or shine so they have been well tested. On the lefty it is mounted as high as I can but below the boot. I also had the magnet mounted to disc brake roter. This worked but was fragile. I have used the 625X and CS600 on my AL Scalpel and AL Rush both large with carbon leftys and carbon bars using the polar mounting hardware.

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