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  1. #1
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    New question here. ISCG: Yes or no?

    Hi Guys,

    When comparing freeride/downhill frames you will notice that some have ISCG and some don't have ISCG

    Turner for instance make use of the ISCG mounting method for chainguides

    Why is this, what are the advantages?
    And what might be the disadvantages?

    Thanks in advance for your help!

  2. #2
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    lets see if i can do this and not screw somethin up. iscg is a international standard for chain guide mountinting. super secure and works great for single rings but tends to be troublesome for those f/r or trail riders who want 2 or more rings w/ a granny as they get in the way of the inner ring h/ware. most of us just use a b/bkt mount such as the ever popular heim 3 w/ mrp lrp roller combo made popular by sir cheese of fishland. if i were to build a pure d/h rig id do the iscg mount in a heartbeat.

    heres a shot of my heim 3/mrp lrp combo
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  3. #3
    Just roll it......
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    They both have their pro's and cons.

    The main disadvantage of putting the chain guide between the frame and BB cup is that it can mess up the chainline a bit depending on how it's set up. The advantages are that if you smack something hard with it (which happens) it can rotate a bit - even if it's tight - which can mean the difference between buying a new chainguide and simply rotating it back. Also, as CC said, it often has less mounting issues when running a dual ring. I've run a MRP LRP for 2-3 years and it hasn't had any real effects to my chainline

    ISCG advantages are that it won't mess up the chainline since it's mounting to the frame and doesn't push your drive side out. It's on the bike slightly more secure, but I don't think that's a big deal at all. Disadvantages are that if you hit it on a rock really hard, you'll likely bend it pretty bad since it has no chance to rotate like a BB cup mounted chainguide often will. ISCG sometimes requires adjusting the drive side with the use of a spacer or some filing to keep it from rubbing the small ring bolts. Despite being a 'standard', it seems there's enough variance between mfgrs. that there's usually a bit of finagling that you have to do.

    EBX

  4. #4
    FM
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    Quote Originally Posted by ebxtreme
    They both have their pro's and cons.
    EBX
    Word.

    My ISCG blackspire stinger bolted on in less than 5 minutes. If I have a crash and destroy it, I can completley remove it out on the trail in just a few minutes- with self extracting crank-arms all I need it is a 10mm allen key. No special tools or BB removal required and it doesn't mess with my chainline. I've done it twice.

    However, I know that the ISCG mount locations have changed, and while the '02 RFX mounts work great, I hear the newer ones are problematic if you want to run dual rings and ISCG. Could be a lot of headaches whereas BB mount is pretty much easy.

  5. #5
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    Thx!

    Thank you guys, all replies are very usefull with real experience as well, not only smart talking :-)

    I think I prefer a chainguide/frame without ISCG

    Looking at your comments: When your chainguide will be attached to your frame and you hit something really hard it might cause framedamage as well, which is not covered by warranty at all
    That's a major disadvantage..

  6. #6
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    Quote Originally Posted by msxx
    I think I prefer a chainguide/frame without ISCG

    Looking at your comments: When your chainguide will be attached to your frame and you hit something really hard it might cause framedamage as well, which is not covered by warranty at all
    thats a senario ive never heard of yet. not that its never happened but if so, its news to me. i wouldnt worry. and as you can see a iscg frame doesnt lock ya into usein a iscg guide. so theres that.
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  7. #7
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    Quote Originally Posted by cactuscorn
    thats a senario ive never heard of yet. not that its never happened but if so, its news to me. i wouldnt worry. and as you can see a iscg frame doesnt lock ya into usein a iscg guide. so theres that.
    Agree with CC here....msxx, you may be extrapolating a bit too much out of that. Your more likely to bend a thin aluminum chainguide (heim, blackspire, mrp, etc.) than break your frame. Is it possible? I suppose, but less so than tweaking your guide....don't know about the e-thirteen though since that's made of polymer.

    FWIW, I've bent the shite out of my chainguide twice smacking it directly on a rock (mounted between the bb cup) where I had to remove it and straighten it with a mallet and a vice. Usually, it just rotates up and hits my chainstay and I just rotate it back with a screwdriver. Ironically, I'm going with an ISCG setup for a new dh bike though.....

    EBX

  8. #8
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    Ok, I was jumping into conclusions?

    So with a frame with ISCG you have at least the option to use that feature and you are still able to run a bbmount chainguide anyway
    ISCG can be removed in a more easy manner, but will cause some compatability issues when you want to run dual ring setup

    Hmm, ok. Then ISCG can be an advantage :-)

    Thank you all for the replies :-)

    *newbie to real FR/DH bikes coming from XC/AM* :-)

  9. #9
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    Iscg

    For the record we have never had an impact destroy the tabs on a Turner frame.

    Off setting the ISCG inward a mm or 2 allows you to mount something under the BB cup if you want and it will not touch the guide as CC has done on his RFX. IMO, the reason that NOT using the ISCG tabs is becoming popular in the industry is that many riders are marginal mechanics and if they have to think about using a couple washers between the tabs and guide to put the inner face of the guide on the same level as the BB face it could be a long night in the garage. Assuming (ya know what happens then) that the BB face and the ring relationships are consistant from crank brand to guide brand it would seem that the guide makers would want the guide to key off the BB face so that the consumer does not call asking how many washers are needed to set the guide up right, over and over! Now another reason may be that the guide makers WANT the guide to spin when hit hard so that they don't have to listen to someone whine about the guide being weak when he cased a rock double. If the guide just spins under the BB cup, the rider just takes it all apart and re-adjusts. No liability on the guide makers shoulders. None on mine either come to think about it! But for DH racing there is no substitute for a ISCG mounted guard.
    A racer don't have time to re-adjust when making a run if the guide spins when it is whacked. And with DH bikes having lower BB than FR bikes, it IS an issue. A well designed guide like the E 13 SRS or the Mr. Dirt can take about a thousand hits and not break apart, and when attached to the tabs don't turn when struck, ever.

    Soap box is now un occupied.

    DT

  10. #10
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    Thanks Dave for the clarification and for the confirmation that no harm is done to any Turnerframe in the past by using ISCG mounted chainguids!

  11. #11
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    hey, i'm new at the whole mountain biking thing, still learning the ropes. Just wondering, I have a Norco drop which has the 2 chain rings in the front... I wanted to know if I can get rollers or some type of chain stay to keep the chain more solidly attached. I know i can switch a single ring in the front, but is there a semi-easy way to modify my setup and keep the two rings, or no? Thanks!

  12. #12
    No, that's not phonetic
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    Check out the "e13 DRS" or the "MRP LRP". If you don't know what either of those are, type the names into google.
    My video techniques can be found in this thread.

  13. #13
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    thanks alot! much appreciated! Do you think doing that is worth the effort over going to a single chain ring system? I don't mind having the 2 rings if the chain would stay on it. do you know how much it would roughly cost to go to a full single ring setup??

  14. #14
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    Quote Originally Posted by mrsweet69
    thanks alot! much appreciated! Do you think doing that is worth the effort over going to a single chain ring system? I don't mind having the 2 rings if the chain would stay on it. do you know how much it would roughly cost to go to a full single ring setup??
    unless its a pure dh rig or flatland huckmobile, id go with 2 rings and the flawless performance of the heim3 / lrp system. a e13 srs system with a ring will run about $200 depending on the ring ya choose. this seems to be the hot set up even though the mrp guides have been good over the years.
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  15. #15
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    Quote Originally Posted by cactuscorn
    unless its a pure dh rig or flatland huckmobile, id go with 2 rings .
    I agree with CC. I'm running a 22 - 36T combo up front and have yet to have issues shifting so you can still have plenty of gearing for a good top end with a granny that let's you climb up most anything. A single ring isn't good for all-around riding, imo.

    NSMB just did a quick gear shots on chainguides. It leaves out the two most popular - MRP LRP and e-thirteen DRS, but those have been reviewed plenty.

    They mention the Blackspire Stinger though and, on FM's recommendation, and the fact that it's a fraction of the cost of the MRP, I got that one. I gotta say it's worked out great. The roller is a bit noisier than my LRP, but I'll likely swap out the roller to the LRP roller once it wears out. One thing worth noting is that if you run bigger chainrings as I mentioned earlier, you've got to be explicit about what size you need. I got sent the one that fits a 34T and had to drill out where the roller slides on the boomerang. No biggie as it took me all of 15 minutes, but they have one that fits up to a 40T and wouldn't require any monkeying with it.

    http://nsmb.com/gear/gearshots22_05_06.php

    Cheers,
    EBX

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