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  1. #1
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    I-Drive Pivot maintenance/repair

    Here's a quick run down of how you can fix or maintain the pivots on an I-Drive bike. These pivots might be creaking or knocking on you (making you think it's the bottom bracket....mine were knocking on out-of-the-saddle pedaling). However, after this, I think it's good to do this sort of maintenance once or twice a year depending on the mileage whether they are making noise or not. This little tool that John at Performance in Laguna Hills told me to make cost about $30. Happy wrenching!


    Here are the parts you will need. Two bottom bracket tools, some threaded rod, and some nuts and fender washers to hold them in place. You could also use a quick release skewer! Personally I think in the future I'll be using a spring from an RC car to create pressure rather than having to tighten and loosen as you remove the pivots. (you'll see what I mean below.


    The Assembled Tool.


    Remove your crankset


    This will expose both the main pivots.


    If you're running a chain guide, then you'll have to remove the bottom bracket to get to the pivot.


    Using a 4 and 5mm allen, undo the shock to allow the arm to swing down.


    Using a 5 and 6mm allen, take out the securing bolts and the washer.





    The bolts and washers removed allowing removal of the pivot.


    Using your special tool, insert the treaded rod through both sides to keep the BB tools from falling out and stripping the splines.


    Now loosen the left side while holding the right side. NOTE, when loosening, you will be threading out the pivot, putting pressure on the nuts on the outside. Turn the wrench, then loosen the nut, turn the wrench, loosen the nut, and so on until you can turn the BB tool by hand. Then, take out the rod and loosen the left side until it comes out.


    The right side of the pivot needs some help. Using a spark socket, or something similar, take a rubber mallet and tap the pivot out from the left side.


    This is what it will look like as it starts coming out.


    Remove the split beveled washer (Not shown) to expose the bearing. That's a years worth of dirt and I was shocked to see so much in there!


    I'm glad they are sealed! Now take a cloth and gently wipe the dirt off the sides and clean up. Do not press down! Even though they are 'sealed' dirt can still be forced in.


    Once you're finished cleaning everything, make sure to grease the pivot threads with grease (I use poly 1000). Reassemble the upper pivot until hand tight. DO NOT TIGHTEN FULLY YET.


    Proceed to use the same process on the lower pivot. You'll have to move it around to dislodge it and get to the pivot. Look! More dirt!

    Clean and replace bearings and hand tighten. Make sure the swingarm moves freely and there is no binding.

    Tighten both the upper and lower pivots using the tool. Here you'll have to turn and tighten the outer nuts as you screw in the pivot.


    When installing the pinch bolts and washers, please use loc-tite!

    If this doesn't solve the creaking problem, please refer to other posts in the GT Sanction Force Reference thread for lubing the rear dropouts.

  2. #2
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    Great work!

    My first time servicing the i-drive pivots was really intimidating, but in hindsight it's really quite simple. Hopefully this guide with encourage others to do their own service.

  3. #3
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    Any advice on servicing the single main pivot and self-lubing bearings from my old 2001 i-Drive 1.0? It's got the truly old-school Eccentric bottom bracket design, with the dogbone through from the lower end of the downtube, through eccentric shell. There was alot of wobble in the Main Pivot area, and I'd like to remove the pivot, the two sets of bearings left and right sides, get replacements for them and put them back together again with my handy-dandy bench vise. I tried tapping the main pivot out last night with an appropriately sized spark plug box wrench and a hammer, and it only moved out of the end by 1/16." Is there a better way to do this? GT/Pacific are useless. The only GT "dealer" in my area took one look at it, called GT, then told me I was out of luck, but, oh, by the way, we have a sweet new Specialized for $2800 to sell you! I am sure that this is not a difficult fix, but I'd like some advice from someone who may have done this before. I know I can get replacement bearings and even a new main pivot from several suppliers in the UK. Now I just need to get these stubborn things out of the frame.



    Chris

  4. #4
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    I posted a bunch of pics on the yahoo GT I-Drive Team forum that I took of my Team frame and some others from an I-drive poster I have. I'll see if I can put them in this forum this afternoon.
    2009 GT Marathon Team,GT Force 2.0, GT Jelly Belly TT (nude carbon), and a very special Todd Wells Zaskar.

  5. #5
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    Quote Originally Posted by NoFearATB
    Any advice on servicing the single main pivot and self-lubing bearings from my old 2001 i-Drive 1.0?
    I had also been in search of service information of the main pivot for the older eccentric I-Drives. I made a thread asking for help and i was advised that i needed to use a hydraulic press...

    I've searched the web, and there isn't much material on servicing the main pivot itself, but here are some documents i've come across which may or may not help:

    - Spare parts list from Monza Imports
    - Assorted manuals from GT

  6. #6
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    just started a thread with some pics from an I-drive poster I have at home. Maybe that will help you guys.
    2009 GT Marathon Team,GT Force 2.0, GT Jelly Belly TT (nude carbon), and a very special Todd Wells Zaskar.

  7. #7
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    Just for some clarification, how come you decided to use two bottom bracket splined tools to loosen the pivot? Does it free spin if you don't hold one side in place? Just asking because in the GT video demonstration, the guy just uses one tool, and loosens one side without holding the other.

    And when tightening the two pivots, is there a known torque spec for how tight they should be? Or is it just enough so there is no resistance in the pivot movement?

    Thanks.

  8. #8
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    Quote Originally Posted by peternguyen
    Just for some clarification, how come you decided to use two bottom bracket splined tools to loosen the pivot? Does it free spin if you don't hold one side in place? Just asking because in the GT video demonstration, the guy just uses one tool, and loosens one side without holding the other.

    Nah, the pivot doesn't free spin. When undoing the pivots you have to be carefull because the tool rolls easily and can damage the splines of the pivot.

    You've probably seen a few Forces or iD's with slightly damaged splines before. It's very
    common. The reason two tools are used here is to keep even pressure on the tool so
    neither one does any damage. It's a great idea and i'll be doing it from now on.

    I dont know what the recommended torque setting is. I just do mine up nice and snugg
    then give it a tiny bit more (highly scientific aren't i!!!). The bearings in there need a some
    preload but not heaps.

    Does anyone know if there is a recommended torque?
    I'm Ron Burgundy?

  9. #9
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    Quote Originally Posted by Eatyapeas
    Does anyone know if there is a recommended torque?
    Ah i see, thanks for explaining that, it makes more sense now. Good tip.

    After i posted, i was looking at some of the manuals. In this one here, there are exploded views of some of the older i-Drives (but not the Force/Sanction), and there are torque specs indicated, although none for the actual two main pivots, just the securing bolts. It also shows the torque specs for the rear drop outs and the i-Link (and the flex bone) for the applicable diagrams. There are instructions included explaining how tight to tighten the main pivot, and it doesn't appear to have a torque spec.

    By the way, how nice are the drawings for the first exploded view (when you zoom in).

  10. #10
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    Yeah, but...

    Quote Originally Posted by Eatyapeas
    Nah, the pivot doesn't free spin. When undoing the pivots you have to be carefull because the tool rolls easily and can damage the splines of the pivot.

    You've probably seen a few Forces or iD's with slightly damaged splines before. It's very
    common. The reason two tools are used here is to keep even pressure on the tool so
    neither one does any damage. It's a great idea and i'll be doing it from now on.
    Hey Eat,

    Instead of the second BB socket, couldn't you just use a really big washer that rests against the BB shell? I'm cheap and don't want to buy a second BB spline socket tool thing.
    I dreamed I ate a 10 lb marshmallow. When I awoke, my pillow was gone.

  11. #11
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    Quote Originally Posted by Appendage
    Hey Eat,

    Instead of the second BB socket, couldn't you just use a really big washer that rests against the BB shell? I'm cheap and don't want to buy a second BB spline socket tool thing.

    Yeah that'd still work. Anything thats gonna hold the BB spline socket jigger thingy nice
    and flat and in the pivot will still work.
    I'm Ron Burgundy?

  12. #12
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    The GT website has new pivot disassemble and assembly videos available to watch. (The music isn't so cheesy this time).

  13. #13
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    Could someone please clarify the the difference between regular grease and marine grease? Am i right to say that the marine is meant to be more water resistant?

    Secondly, the GT videos suggest using anti-seize for 'best results', although it seems most people here are using grease instead. I'd like to hear opinions on what people think would be most ideal for the contact points.

  14. #14
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    Yes, marine greases are a bit better at resisting water washout, and have better corrosion inhibitors. This is because they're meant for boat trailer wheel bearings, which end up being dunked in water/saltwater when launching. Unless you're also regularly dunking your bike in water, then any decent wheel bearing grease will work just as well.

    The recommended Park anti-seize stuff didn't work for me. It dried out after a few weeks and the creaking was back. I replaced it with marine grease, and it lasted several months, but unfortunately the creaking returned. I regreased it and also wrapped some teflon plumbers tape around the bearings. It held up for a few more months... then someone stole my GT Marathon . The new Sensor has a redesigned pivot mechanism that issupposed to address this issue. Now I just need to scrape together the funds.....

  15. #15
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    Oh damn, that's a real bummer. I hope that thief gets what's coming to him...

    I don't have any marine grade grease or anti-seize, but i do have the Finish Line Teflon grease. I suppose i will use that. Has anyone used this grease for the pivots?

    About the infamous creaking, i am happy to report that after about a year on my Force, i have not experienced this. But since it has been a year, i would like to give my bike a full service and clean. What is the cause of the creaking exactly? I've read through the forums, and it still seems uncertain. Aside from the dropout bolts, from what i gather about the creaking from the main pivots, is it due to the friction between the floating bb link and the rear triangle, caused be the torque applied from the drivetrain?

  16. #16
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    main pivot and eccentri bearings

    Should I replace the eccentric bearings if I am doing a total overhaul? I know these are hard to find but, how do I know if they are bad?
    Last edited by JCOX98; 07-11-2010 at 12:42 PM.

  17. #17
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    I think mine was creaking due to play in the BB link. The teflon tape really quieted it down, more than grease alone did, since it took up some of the play. Others have also mentioned that using 1/64" headset spacers/shims eliminates the creaking for them.

  18. #18
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    Cool, I just ran across this thread. I'm starting to get a little creak in my iDrive 4.

    Quote Originally Posted by peternguyen
    And when tightening the two pivots, is there a known torque spec for how tight they should be? Or is it just enough so there is no resistance in the pivot movement?
    From the "GT Suspension Frame Troubleshooting Guide" PDF file at http://www.gtbicycles.com/int/eng/Troubleshooting:

    C.Proper pivot adjustment
    1. Proper adjustment will avoid premature wear and possible creaking in the
    pivot system.
    2. Loosen the pivot pin lock bolt.
    3. Use a standard Shimano BB tool to tighten the pivot pin cap from the left side
    of the bike.
    4. Tighten until all play is gone. Note: there is no torque specification for this
    adjustment because these are angular contact bearings (same as a head set).

    5. Adjust the pivots the same way you would adjust a head set.
    6. Do not over tighten.
    In the same guide, the torque on the pivot pin lock bolt is 60 in-lb.

    A.Tighten the pivot pin lock bolts
    1. The pivot pin lock bolts are to keep the pivot pin and pivot pin cap from
    loosening.
    2. DO NOT USE LOCK TIGHT ON PIVOT PIN THREADS.This will make
    future adjustments very difficult.
    3. Tighten this to 60 in-lb (70 kg-cm)
    As a strange aside, the iDrive 4 exploded view parts list identifies the pivot pin lock bolt as the "M6 Sex Nut."

  19. #19
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    I just serviced the frame for the first time today, by fully disassembling it first, cleaning the hardware, then re-assembling it. While assembling, i left the shock till last, so that i could see how much resistance there is in the suspension through the pivots. Here is what i noticed during the re-assembly:

    - The main pivot on its own was very smooth, like a headset. Moving the swing arm up and down was very smooth and effortless.

    - The BB pivot on its own was not as smooth, and was a little clunky. Though i think this is because one of the bearings has worn.

    - The i-Link, which uses bushings, had a lot more resistance than the bearings. Understandable, but i'm not sure how much resistance there should be, and whether it will make any perceivable difference.

    Once everything was connected, when moving the swing arm, there was now a a bit of resistance. The action was smooth still, but i wonder if the little added resistance affects small bump compliance. Can anyone comment on this?

    I'd like to hear other people's experiences in regards to the pivot motion.

  20. #20
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    Just did my first pivot rebuild

    I was getting odd clacking and tinking sounds when I'd hit square-edged bumps. My biggest worry was that the frame was cracked. So, for the first time, I took the whole thing apart. Mostly, I wanted to be able to closely inspect the frame for cracks, especially in those hard-to-see areas.

    I didn't find any cracks, but I did find that one of the two main pivot bearings was in bad shape. I replaced it and reassembled everything according to the video on the GT webside. Note to peternguyen: according to the video, you attach the shock before tightening the pivot bolts. So, that's the way I did it.

    I got no noises during a test ride up and down the curbs in front of my house, whereas prior to the service, I got plenty. I haven't had time to take it out for a full-one thrashing, but I'm optimistic that the problem is solved.

    Like yours, my main pivot was smoother than the crankset pivot or whatever it's called. Personally, I don't think that a little drag in the movement of the pivots is a big deal. Think about how much leveraged force (ha!) moves these things. But yeah, I used to ride a DW-Link bike, and it was a little more sensitive to small bumps.

    I'd like to shake the hand of the guy who designed this system. It is beautifully simple and easy to service. GT says the Sensor has a "simplifed" version- criminy, how simple can it get? Anyway, props to GT.
    Last edited by Appendage; 11-25-2010 at 12:41 PM.
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  21. #21
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    Quote Originally Posted by Appendage
    Note to peternguyen: according to the video, you attach the shock before tightening the pivot bolts. So, that's the way I did it.
    Yeah i saw this too, but i assumed they did this so that the swing arm was in a 'neutral' position making it easier to assemble the rest, instead of it hanging down.

    Did anyone also notice that for the two pivots, for each pair of bearings, one was etched with

    "TH INDUSTRIES 1 1/8' ACB 36x45 873# STAINLESS", while the other was etched with:
    "TH INDUSTRIES 1 1/8' ACB 36x45 873S# STAINLESS"; note that an "S" suffix is present here.

    Does anyone know what this means?

    EDIT: After searching the web, apparently the 'S' signifies that it is stainless steel. Maybe the 873# didn't have 'STAINLESS' etched after it; i only jotted down the 873S#. So i guess then my next question would be, does it matter which side either of them goes on?
    Last edited by peternguyen; 11-25-2010 at 05:11 PM.

  22. #22
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    No, but

    Quote Originally Posted by peternguyen
    Yeah i saw this too, but i assumed they did this so that the swing arm was in a 'neutral' position making it easier to assemble the rest, instead of it hanging down.

    Did anyone also notice that for the two pivots, for each pair of bearings, one was etched with

    "TH INDUSTRIES 1 1/8' ACB 36x45 873# STAINLESS", while the other was etched with:
    "TH INDUSTRIES 1 1/8' ACB 36x45 873S# STAINLESS"; note that an "S" suffix is present here.

    Does anyone know what this means?
    Yeah, mine had the same stuff on 'em. Dunno what it means, but they're just standard headset bearings. Got my replacements at the LBS, but they could probably be purchased from a bearing supplier for a lot less.
    I dreamed I ate a 10 lb marshmallow. When I awoke, my pillow was gone.

  23. #23
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    Quote Originally Posted by Appendage

    I'd like to shake the hand of the guy who designed this system. It is beautifully simple and easy to service. GT says the Sensor has a "simplifed" version- criminy, how simple can it get? Anyway, props to GT.


    There are less parts involved with the pivots. So less to go wrong. And its easier to disassemble and reassemble.

  24. #24
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    It's fixed!

    Okay, I took the bike out for a good test ride today, and the noises are definitely gone. Dunno if it was the bad bearing or just the cleaning/relubing of the pivots, but the problem is solved.
    I dreamed I ate a 10 lb marshmallow. When I awoke, my pillow was gone.

  25. #25
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    Quote Originally Posted by Appendage
    Okay, I took the bike out for a good test ride today, and the noises are definitely gone. Dunno if it was the bad bearing or just the cleaning/relubing of the pivots, but the problem is solved.
    Nice! Good to hear it is running well. After replacing the bad bearings with new ones, did you notice any improvement in bump sensitivity in the back end?

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