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  1. #1
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    The i-Drive system - New vs. Old

    Just wanted to clear something up that i've been unsure about. Some people have said that the newer idrive system is not as efficient as the old one. Is this true? And how do these two designs differ in terms of functionality?

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    I thought i might add some visual references:

    Top: old system.
    Bottom: new system
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  3. #3
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    mmmmm...i-Drive team frame...mmmmmm..sweetness.

    Sorry, got a little distracted there. Though I haven't ridden the newer i-Drives, my understanding is the older design was better suited for XC riding whereas the newer one is a better all-mountain rider. Generally that translates into a little less efficiency for better a DH feel.
    I can tell you the old one is very efficient and a great XC rig, but I wouldn't trust it for any serious DH'ing, it's really just not built for that.

    Hopefully someone on here has ridden both and can tell you how they both feel.
    The secret to mountain biking is pretty simple. The slower you go the more likely it is you'll crash.
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  4. #4
    Awesome not Rad
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    I'd hit that

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    I have a 2001 team frame and a new Force 2.0 and to be truthfull here I can't really tell much of a difference other than having an extra 2.5 inches of travel on the new one. They both are pretty efficient for their respective use. The Team frame has a "bat out of hell" demeanor when you crank on it but it is only 3.5 inches of travel. The Force is a killer on the rough stuff but it isn't a slouch on the take off either. They are both plush and fast, and no I don't do any rough stuff with my Team frame. MMMMMM Team frame!!!!!!

    GT J

  6. #6
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    Quote Originally Posted by fmdj
    mmmmm...i-Drive team frame...mmmmmm..sweetness.
    Hahaha... i agree...

    Quote Originally Posted by fmdj
    I can tell you the old one is very efficient and a great XC rig, but I wouldn't trust it for any serious DH'ing, it's really just not built for that.
    Would you happen to know why it's not built for heavier kind of riding? Like why wouldn't you trust it?

  7. #7
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    Quote Originally Posted by peternguyen
    Hahaha... i agree...


    Would you happen to know why it's not built for heavier kind of riding? Like why wouldn't you trust it?
    The older system uses a concentric bb with a dogbone and they did build a great dh bike using it; the DH-i. I ride an '04 with the concentric bb and dogbone and have it set up for AM riding and it works pretty well.



    I just avoid drops higher tham my handlebars.

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    If you are actually comparing the I-drive Team frame then you shouldn't use it for AM riding.
    The 04 that Rustus is riding is built for more aggressive riding. I had an 04 1.0 and it handled pretty much anything under 4 ft drops. The Team frame is nothing but an XC racing rocket and is not meant for aggressive riding. As pertaining to the I-drive system then yes it can handle the AM riding on another burlier frame and not the XC racing frames. It is still pretty efficient, and keeps the rear glued to the ground on uphills and downhills. The system is really underrated. I wouldn't ride anything else though.

  9. #9
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    True, gt jorgito. The OP and second poster appeared to me to be discussing old vs new systems, as opposed to specific frames.

  10. #10
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    Quote Originally Posted by rustus
    True, gt jorgito. The OP and second poster appeared to me to be discussing old vs new systems, as opposed to specific frames.
    True that i was just comparing the idrive design, but im actually glad to hear that you're rocking it out on a 2004 idrive for AM riding because i too have a 2004 idrive and have built it up for AM riding. Good to know because it gives me more confidence in my bike, because i was told its more of an XC bike, so i had doubts about how much my bike could take.

  11. #11
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    Quote Originally Posted by peternguyen
    True that i was just comparing the idrive design, but im actually glad to hear that you're rocking it out on a 2004 idrive for AM riding because i too have a 2004 idrive and have built it up for AM riding. Good to know because it gives me more confidence in my bike, because i was told its more of an XC bike, so i had doubts about how much my bike could take.
    Cool to see someone else on an '04 I-drive. I almost never see any, other than mine and my wifes'. We got ours as a year end closeout. Upgrades over the years include;
    Marzocchi mx comp fork 120mm
    riser bars
    shorty stem
    SRAM x7 shifters and rear der.
    Azonic magnesium pedals
    Race Face bottom bracket
    Avid juicy 3 brakes with 7 inch front rotor
    Mavic crossride wheelset
    Specialized bg saddle
    Continental tires
    The only time I really hit the limits of the bike itself (as opposed to my own limits) are when doing lift accessed black diamond trails, or super steep downhill stuff.
    The frame has held up really well over the last four years, and almost never bottoms out.
    A great design, in my opinion.

  12. #12
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    Quote Originally Posted by peternguyen
    Would you happen to know why it's not built for heavier kind of riding? Like why wouldn't you trust it?
    I wouldn't trust mine for DH'ing because the seatpost weld has already been cracked and re-welded once Though I've also seen posted on here before that the seat post cracks were due more to the location of the weld in relation to where the clamp bolt is, and not due to extra impact if you bottom out, but I'd rather not risk it (I've heard some bad stories)

    That being said, I think the cracks were more common in the 2001 and earlier frames, so newer ones probably don't hold the same risk.
    The secret to mountain biking is pretty simple. The slower you go the more likely it is you'll crash.
    - Juli Furtado

  13. #13
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    Quote Originally Posted by fmdj
    I wouldn't trust mine for DH'ing because the seatpost weld has already been cracked and re-welded once Though I've also seen posted on here before that the seat post cracks were due more to the location of the weld in relation to where the clamp bolt is, and not due to extra impact if you bottom out, but I'd rather not risk it (I've heard some bad stories)

    That being said, I think the cracks were more common in the 2001 and earlier frames, so newer ones probably don't hold the same risk.
    Were those frames the ones with, like that hole in the back of the seat tube?

  14. #14
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    Quote Originally Posted by peternguyen
    Were those frames the ones with, like that hole in the back of the seat tube?
    That hole is a stress relief hole and should not be an issue. like fmdj said, I think it is more a production year issue than a design issue. Just don't land drops sitting down.

  15. #15
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    Quote Originally Posted by rustus
    That hole is a stress relief hole and should not be an issue. like fmdj said, I think it is more a production year issue than a design issue. Just don't land drops sitting down.
    [SIZE=2][/SIZE]
    [SIZE=2]Itís a design flaw because my 2001 model wouldnít have broken where it did if that hole wasnít there and my seat post was well within where it should be and Iím a light rider. That was the first time it broke, the second time the whole seat mast went which I accept maybe a production problem.

    As for the suspension I think the old one was a touch dead feeling and the new one is a bit more active and responsive but youíll be hard pressed to notice any difference.
    [/SIZE]

  16. #16
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    I think one of the original press releases in 05 or so

    said GT purposely made the new I-drive less "efficient" to add to the plush feel of trail bikes. The focus of riding had changed since the original I drive design, from super efficient XC riding to AM type riding. Basically, they said the original I drive was too efficient so the ride tended to be a bit less plush than desired for AM/FR riding. so they detuned it and made it a bit softer/less efficient. The trade was a slightly more detectable pedal influence for more trail compliance.

    I've ridden both. The trade was worth it. Hated the first gen I drive. Love the second gen. And the new I drive climbs just fine, even for a fat guy like me.

    REEK

  17. #17
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    Quote Originally Posted by Reek
    said GT purposely made the new I-drive less "efficient" to add to the plush feel of trail bikes. The focus of riding had changed since the original I drive design, from super efficient XC riding to AM type riding. Basically, they said the original I drive was too efficient so the ride tended to be a bit less plush than desired for AM/FR riding. so they detuned it and made it a bit softer/less efficient. The trade was a slightly more detectable pedal influence for more trail compliance.

    I've ridden both. The trade was worth it. Hated the first gen I drive. Love the second gen. And the new I drive climbs just fine, even for a fat guy like me.

    REEK
    I see. The newer idrives would be more suited to my riding then. I didnt think that the idrives efficiency would negatively influence the plushness, is that that a flaw in the idrives (that they cant have both) or is that just the way it goes with multi pivot point systems?

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    I wouldn't call it a flaw

    Just a different state of tune. I think many suspension designs that use chain tension for bob control have to be tuned for plushness vs. absolute efficiency.

    If the current I drive was initially introduced during the days when XC racing was the rage, it probably would have been seen as an inefficient, bad design. Just like all XC forks had to be 70 -80 mm travel. Now the Idrive is well accepted and most trail riders are using 100 - 130 mm forks, if not more.

    Regardless of all of the above, the current Idrive works well for its intended purpose and is simple to maintain.

    REEK

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    One thing about the I-drive system in case someone here doesn't know, is that the i-drive doesn't use chain tensioning to control bob or stiffen the suspension. They way the i-drive works is that it allows the rider to pedal efficiently by somewhat isolating your pedal force from the suspension. Alot of 4 bar linkage systems like the NRS use chain tension to negate suspension movements. When I had my 04 I-drive, I would run different air shock pressures to control the plushness of it. That is the beauty of the I-drive, it never stiffens the suspension to make it efficient. It is the way it isolates your pedaling that makes it efficient. On another note, I also believe the cracking had to do with model year and improper usage. I've cracked a new 04 I-drive, an 00 I-drive, an 02 I-drive, but I have yet to crack my 01 I-drive Team after more than two years usage and over 200 lbs of rider. If you were to use a screwdriver instead of a hammer to hammer nails, I'm sure it wouldn't last as long either. I'm powder coating my 04 I-drive at the end of the month and making it an urban assault ride. My wife is gonna hate a garage full of bikes but oh well. I guess it's better to be addicted to GTs than to crack cocaine. LOL.

    GT J

  20. #20
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    I beg to differ

    Quote Originally Posted by gt jorgito
    One thing about the I-drive system in case someone here doesn't know, is that the i-drive doesn't use chain tensioning to control bob or stiffen the suspension. They way the i-drive works is that it allows the rider to pedal efficiently by somewhat isolating your pedal force from the suspension. Alot of 4 bar linkage systems like the NRS use chain tension to negate suspension movements. When I had my 04 I-drive, I would run different air shock pressures to control the plushness of it. That is the beauty of the I-drive, it never stiffens the suspension to make it efficient. It is the way it isolates your pedaling that makes it efficient. On another note, I also believe the cracking had to do with model year and improper usage. I've cracked a new 04 I-drive, an 00 I-drive, an 02 I-drive, but I have yet to crack my 01 I-drive Team after more than two years usage and over 200 lbs of rider. If you were to use a screwdriver instead of a hammer to hammer nails, I'm sure it wouldn't last as long either. I'm powder coating my 04 I-drive at the end of the month and making it an urban assault ride. My wife is gonna hate a garage full of bikes but oh well. I guess it's better to be addicted to GTs than to crack cocaine. LOL.

    GT J

    Although GT says that it 'isolates' the pedal force from the suspension, there's definitely chain tension involved in the efficiency of the suspension. Otherwise, why would there be any (although minimal) kick back or feedback through the cranks? on occassion you'll feel it while grinding up hill. As well, the I drive depends on pressure through the cranks to 'neutralize' the bob effect. Yes, this is not directly through the chain, but definitely through the pedalling effort. GT's 05 press release addressed the fact that pedalling forces did indeed cause the suspension to 'stiffen' in the gen1 Idrives more so than the gen2 idrives. I wish I still had a copy or a link to this statement, but I don't.

    As for the NRS, I've owned one of those too, it is a top-out suspension design. It is loosely based on the FSR linkage. But it involves a much lower rear drop out pivot and a much more obtuse linkage angle to the rocker that attaches to the shock. The way that the NRS worked, there was no sag or negative travel originally designed into it. Much like the first generation Ellsworth truth. So it pedalled VERY efficiently, much like a hardtail since any pedal effort re-enforced the top out position of the shock.

    Even FSR's, which are supposed to decouple suspension and pedalling forces, display 'sag' when pedalled hard up hill. (I've owned two FSRs as well). Not the pedal induced sag but the rear weight shift sag, when cranking up hill. But the GT ID 5 actually avoids sag and almost 'digs in' to the trail with increased pedal effort. This is NOT unlike the original K2 claim that their high single pivot bikes bite into the hill side when pedalled up hill. You can technically argue it doesn't send forces through the chain itself but through the 'independent' linkage or through the dog bone, but really, it DOES use pedalling input to resist bob. Take the shock off your frame and cycle the rear suspension and watch the 'isolated' bottom bracket shell. See what it does as you cycle the suspension. it moves counter to the forces that would be placed upon the BB shell with pedalling effort.

    REEK
    Last edited by Reek; 10-15-2008 at 11:55 PM.

  21. #21
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    I've never ridden any of the "new" style I-drive bikes but I do own a 2000 XCR 1500, and it (frame and suspension-wise) kicks the hell outa the Fuel EX7 I rode all last year.

    Love the I-Drive


    2012 Norco CCX3
    2014 Nashbar Fatbike

  22. #22
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    Love that paint job!

  23. #23
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    Quote Originally Posted by Reek
    Although GT says that it 'isolates' the pedal force from the suspension, there's definitely chain tension involved in the efficiency of the suspension. Otherwise, why would there be any (although minimal) kick back or feedback through the cranks? on occassion you'll feel it while grinding up hill. As well, the I drive depends on pressure through the cranks to 'neutralize' the bob effect. Yes, this is not directly through the chain, but definitely through the pedalling effort. GT's 05 press release addressed the fact that pedalling forces did indeed cause the suspension to 'stiffen' in the gen1 Idrives more so than the gen2 idrives.
    You're confusiing chain tension related forces, suspension forces and "squat."

    chain tension related forces
    GT's Idrive does a wonderful job of mitigating the first. Chain tension can often effect suspension, soley due to chain stay length increasing and decreasing as the suspension cycles.

    Think back to your old BMX days. Remember after fixing a rear flat, that you had to tension the chain by pulling the rear wheel back? Suspension systems almost ALWAYS do this natively. Idrive, horst links, VPPs even DW links have growing chain stay lenths as the suspension cycles.

    As you already know - harkening back to the old BMX days, this increases chain tension. The difference with a mountain bike is the tension is applied evenly due to the drive train - the effect being, when suspension compresses - it pulls the cranks back/rear ward.

    suspension forces
    Conversely; in suspension systems that have growing chain stays, when you pedal forward - your chain stay has a tendancy to shorten - simply due to the pedal force. You're literally pulling the rear wheel forward.

    The effect of this is pedaling firms up suspension - and suspension interferes with pedalling.

    Quote Originally Posted by Reek
    As for the NRS, I've owned one of those too, it is a top-out suspension design. It is loosely based on the FSR linkage. But it involves a much lower rear drop out pivot and a much more obtuse linkage angle to the rocker that attaches to the shock. The way that the NRS worked, there was no sag or negative travel originally designed into it. Much like the first generation Ellsworth truth. So it pedalled VERY efficiently, much like a hardtail since any pedal effort re-enforced the top out position of the shock.
    By that measure - EVERY suspension system is efficient - so long as you run it topped out! Makes no sense.

    See above - the NRS had huge problems with pedal feedback - due to large changes in chain stay length early in the travel.

    Quote Originally Posted by Reek
    Even FSR's, which are supposed to decouple suspension and pedalling forces, display 'sag' when pedalled hard up hill. (I've owned two FSRs as well). Not the pedal induced sag but the rear weight shift sag, when cranking up hill.
    Horst links only address chain tension related problems. They don't address squat. Atleast not inherantly.

    People like Dave Turner used anti squat designs in combination with HL design to make the bike more efficient. You can only go so far with anti squat on a HL bike though, before you kill efficiency. It's a balancing act.

    Squat is simply the riders weight transfer effecting suspension. The bike moves forward, intertia holds the rider weight back - suspension compresses.


    Quote Originally Posted by Reek
    But the GT ID 5 actually avoids sag and almost 'digs in' to the trail with increased pedal effort. This is NOT unlike the original K2 claim that their high single pivot bikes bite into the hill side when pedalled up hill. You can technically argue it doesn't send forces through the chain itself but through the 'independent' linkage or through the dog bone, but really, it DOES use pedalling input to resist bob. Take the shock off your frame and cycle the rear suspension and watch the 'isolated' bottom bracket shell. See what it does as you cycle the suspension. it moves counter to the forces that would be placed upon the BB shell with pedalling effort.

    REEK
    This is the culmination of the idrive design - idrive allows you to address squat and pedal forces independantly.

    The K2's for example had lots of anti squat - but the single pivot had lots of chain growth and hence pedal feed back and bob.

    As you mentioned - Horst Links reduced pedal feed back, but couldn"t fully address squat.

    Idrives can have main pivot placement designed for the job at hand - DHI's can have higher pivots, inline with larger chain rings - XCR idrives have lower pivots.

    Main pivot placement on the idrive can still create a system where the rear wheel/axle path moves rearward - but with the ECCENTRIC (not concentric as someone else posted) mounted BB - which moves the BB rearward (yes REARWARD) - chain growth is diminished to the point where you can't notice it.

    That's how it works - mitigate chain growth - but allow for "high pivot" anti squat characteristics.

    To this end - the level of efficiency is unaffected by version 1 and version 2 necessarily - it's up to the engineer to determine the amount of anti squat they want. You'll notice the 4" 6" and 8" bikes all vary slightly to fine tune the ride.

    Idrive = very good design.
    Last edited by iheartbicycles; 10-17-2008 at 01:14 PM.

  24. #24
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    My two bikes

    My first ever full suspension bike was the Team I-Drive. I held out just knowing that GT would make a full ready FS race bike. And they did. I got the frame and built it up my self. 23.69lbs. This was a sweet ride. Fast! But keeping with the ever changing bike industry I got a "07" IDXC. Built up it came in at just a little over 24lbs. I rode and raced both bikes hard. And out of the two I would have to say for me I like the IDXC over the Team I-Drive. To me it climbed better with out of the saddle efforts. Here some photos.
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  25. #25
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    Quote Originally Posted by XCPRORACER
    My first ever full suspension bike was the Team I-Drive. I held out just knowing that GT would make a full ready FS race bike. And they did. I got the frame and built it up my self. 23.69lbs. This was a sweet ride. Fast! But keeping with the ever changing bike industry I got a "07" IDXC. Built up it came in at just a little over 24lbs. I rode and raced both bikes hard. And out of the two I would have to say for me I like the IDXC over the Team I-Drive. To me it climbed better with out of the saddle efforts. Here some photos.
    So if your Team is just sitting around the garage gathering dust, let us know
    The secret to mountain biking is pretty simple. The slower you go the more likely it is you'll crash.
    - Juli Furtado

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