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  1. #1
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    Gearing's affect on anti-squat suspension

    Hello folks,

    I've read a few posts regarding the chainring size on the amount of anti-squat in dw-link bikes, but mostly qualitative, such as "this chainring size feels better". To be brief, I have Giant anthem that came stock with 32T front, 11-46 rear. I've already stepped down to 28T front for those long and miserable climbs. Recently, I got the smart idea that since I don't use the 11T much, I can save 120g by going to 24T front, 11-40T rear. Just wondering if this big jump in size is going to screw up the suspension properties in some way?

  2. #2
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    Change, yes. Screw up, depends. What do you ride? Do you like a former pedal platform or a more active system?

    You'll probably get about the same since you are changing by both ring and cassette.

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  3. #3
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    I have a Mojo HD3 that I run 2x. Recently shifted from a 32T to 34T larger ring, and like the 34T better - suspension seems a bit more supple for the flats & downs.

    I switch to the 24T ring for longer, non-tech climbs. This increases anti-squat a bit. It's like a climb switch.

  4. #4
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    I ride a Tallboy LTc (VPP2) and went from a 2x 24/39 with 11-36 to a 1x with 32t and 11-42, and now a 28t ring. With the 28t I still have a great pedaling bike and rarely use the climb switch or have issues with traction. Dowhlill it still feels great.
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  5. #5
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    Quote Originally Posted by Doug View Post
    I ride a Tallboy LTc (VPP2) and went from a 2x 24/39 with 11-36 to a 1x with 32t and 11-42, and now a 28t ring. With the 28t I still have a great pedaling bike and rarely use the climb switch or have issues with traction. Dowhlill it still feels great.
    I asked something similar about the downs - whether a bigger ring would make my suspension more plush on the downs, when not pedalling. I have one of the highest anti squat bikes made in recent times - a 2015 Range. The answer was - zero difference on the downs. It was suggested that if I took my chain off, there would be no difference on the downs. I don't mind the high anti squat for climbing or on the flats. I actually like it. It's the downs where my bike is not all that impressive. I expected it to be much plusher than it is. Oh well.

  6. #6
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    I have 2018 Giant Anthem. I wouldn't really know what more or less anti squat feels like. What is anti squat above 100% anyway? Many years ago, I had a 2000 Specialized Stumpjumper FSR, which I think was called fully active, which I think means no anti squat at all? It was horrible to stand and pedal on that bike.

    I also have a 2008 Giant Anthem that is running a 30T ring on 26" wheels. I guess it feels "fine"?

    Does more anti squat mean more pedal kickback when you hit a bump?
    This 2018 bike with the 28T ring has this "issue" when doing seated climbing when hitting a bump on the rear makes the bike "hang up" for a second. Not sure if that is due to pedal kick-back or just damper settings.

    Edit: I just read that anti squat and pedal kickback are not the same thing.

  7. #7
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    Anti squat value above 100% causes the shock to extend, while AS below 100% causes it to compress. check out this video description: https://www.youtube.com/watch?v=D0bAVTiFyy4
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  8. #8
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    Quote Originally Posted by the_joe View Post
    Anti squat value above 100% causes the shock to extend, while AS below 100% causes it to compress. check out this video description: https://www.youtube.com/watch?v=D0bAVTiFyy4
    Antisquat is countering the weight shift from acceleration. Does a higher CoG of the rider mean lower antisquat percentage? Is the calculation of antisquat a convention? Not really an attribute of the bike but an attribute of the bike in combination with a "standard" rider? Should a tall rider always prefer bikes with more anti-squat? Opposite for shorties? How many bike designs recalibrate their antisquat for different frame sizes (implying different rider sizes)?

    High antisquat implies low compliance. Designs more ready to spit their grip out on technical sections?

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    2 points I wanted to add here, based on my knowledge:

    1. Anti-squat is determined by the relation of the main (or with dual link bikes, lower) pivot's location relative to the "drive point" of where the chain meets the chainring - basically, the top of the chainring where the first point of engagement with the chain happens. A bike with a higher pivot relative to that point will have more anti-squat, and a bike with a lower pivot moving toward the BB will have a lower amount of anti-squat. This is because anti-squat is a force generated by the suspension's reaction to chain torque.

    Any bike with anti-squat levels in a range of "normal" will see slightly different traits depending on chainring size. I smaller chainring will result in higher levels of anti-squat due to a lower "drive point" of the chain/chainring relative to the pivot point. All frames are designed with a target chainring size in mind when quoting anti-squat levels, so going up in chainring size from there will lower anti-squat, whereas going to a smaller ring will increase anti-squat. I'm not well-versed in this enough to understand how to anticipate that difference in feel, but I've certainly had bikes in the past that have had atrocious pedal kickback when I installed a smaller ring due to heightened levels of anti-squat.

    2. Rider height does affect anti-squat feel, primarily if the bike has a slacker seat angle. As the seatpost height increases on a slack seat angle, the "lever effect" of rider weight shifting over the back wheel increases. In extreme cases, this can result in higher levels of sag while seated that may still feel harsh while standing centered over the bike, and also results in higher tendency of the suspension to squat while climbing. Thus, lanky riders running long posts on frames with slack seat angles may want a bit more anti-squat to counter this "lever" effect, though higher anti-squat comes with increased pedal kickback, and the 2 need to be balanced.

  10. #10
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    When I was building up my HD3, I checked with Ibis on the ideal chainring size, and they indicated replied that 32-34T would work best and that they thought 36T would be a bit too big. Since I would have needed a 28T at the time (pre-eagle) to get a low enough climbing gear for me (older, not very fit), I opted for a 2x build to have an ideal chain ring size for most of my riding vs. a compromised setup all the time.

  11. #11
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    Quote Originally Posted by beanbag View Post
    I have 2018 Giant Anthem. I wouldn't really know what more or less anti squat feels like. What is anti squat above 100% anyway? Many years ago, I had a 2000 Specialized Stumpjumper FSR, which I think was called fully active, which I think means no anti squat at all? It was horrible to stand and pedal on that bike.

    I also have a 2008 Giant Anthem that is running a 30T ring on 26" wheels. I guess it feels "fine"?

    Does more anti squat mean more pedal kickback when you hit a bump?
    This 2018 bike with the 28T ring has this "issue" when doing seated climbing when hitting a bump on the rear makes the bike "hang up" for a second. Not sure if that is due to pedal kick-back or just damper settings.

    Edit: I just read that anti squat and pedal kickback are not the same thing.
    AS and pedal kickback are related though. Going to a smaller front ring will increase AS and make pedal kickback worse. It can make the rear hang up as you're fighting pedal kickback.

    You can have high AS and a solid pedaling platform but you sacrifice compliance. It'll depend on your pedaling style and terrain. I hate high AS especially when tackling loose steep and rocky terrain. I get the pedal kickback and the rear breaks traction as it's harder to modulate pedal stroke/output. So I'll run the shock wide open so it sinks further in travel to compensate.

    Downhill it doesn't matter that much as it's easier to adjust gearing. Run the smallest rear gear you can and if 2x or 3x then run the largest front.
    Everyone is entitled to my opinion.

  12. #12
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    Yep I've noticed a change. My Norco Sight, which has very high anti-squat, came 2x10 with I think 24/38 up front. The problem was that anti-squat was high with the 24T and I needed it for climbing, however the bike design had so much anti-squat that it was a royal pain for technical climbs. Basically hitting a rock garden on a climb was like the cranks had hit a brick wall, and traction suffered too.

    I made a bit of a compromise and made it 1x10 with a 26T up front - not much difference in reality, but I dropped some weight, plus I don't have many places where I hit high speeds so 26x11 was normally sufficient.

    More recently I tried a 30T up front and it was still plenty efficient on fireroad climbs, but the gearing got tough for steep tech (30x36). And now I have 1x11 fitted with 32T up front and 11-46 in the rear, and the smooth climbs are still fairly efficient (still plenty of anti-squat), the tech climbs have become a bit easier, and the descents feel better too. It turns out that this bike - a 2015 model - really needed more modern gearing to work well for what I ride.

    Somewhere amongst having 1x10 I also started running fatter tyres (2.6 on the rear), and I've found that it also goes some way to resolving the tech climb issues.

  13. #13
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    Quote Originally Posted by mtnbkrmike View Post
    a 2015 Range. The answer was - zero difference on the downs. It was suggested that if I took my chain off, there would be no difference on the downs. I don't mind the high anti squat for climbing or on the flats. I actually like it. It's the downs where my bike is not all that impressive. I expected it to be much plusher than it is. Oh well.
    That's odd, as I know Range owners who love it for the downs - used for Enduro and DH races.

    My 2015 Sight came with a rubbish rear shock, and replacing it with a higher spec version made a massive difference. I can't be sure that it had identical compression damping though, however the new one had an "L" tune and has adjustable low speed compression. What shock are you running?

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    phreeky - I'm running a Monarch Plus RSC shock.

    I suspect we experience much the same thing, with both of us riding 2015 Norcos. My anti-squat/rising shock does not settle down until you get to a 36 tooth ring on the front, which is not possible for my legs on the terrain I ride. That said, I climb 90% of the time seated, and I have always tried to remain as "quiet" on my bike as possible, so the anti-squat is never an issue climbing for me, even on the steepest, most technical climbs there are in my area. It actually feels like I glide over everything.

    Not to go down a gopher hole, but for me, my Range rides much better/faster/smoother with the shock and fork set up much firmer than what Shockwiz suggests. At the suggested Shockwiz settings, it feels like the rear tire actually hooks rooks, rocks and ledges at times, but that is mostly on the downs. I have never been disappointed climbing on that Range, regardless of shock/fork settings.

    And yeah - I know. I read all the time about the praise the Range gets on the downs. Not mine. Not in the rooty, rocky gnarly shit I ride in. Perhaps I am expecting too much.

    Time will tell. I am 85% sure I am going to pick up a 2018 carbon Process as soon as they drop. The only issue will be which one...

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    I think itís a bit more complicated than just smaller ring increases antisquat. Instant centre has a lot to do with it and on some bikes thatís a moving target as suspension travels. Have an Intense Primer which when checking on linkage design shows very high antisquat. Running a 30t ring with 11-42 out back, recommendation is for a 34 ring.

    Decided to throw caution to the wind and dropped to 40%sag territory (was looking to figure out insufficient travel use problem). What a massive difference. Suspension is super active (not bobby though) when climbing and on the down the wheel is glued to the ground and really noticeably carries speed, especially over square edge stuff. Transformed the bike completely. Now i have come to understand just how complex the situation is...

    Will I get the same effect with correct sag and a 34t ring, is it the sag moving the Instant Center thatís achieving the changes with the 30t ring. I need to do more homework. Wonít be changing anything for now, but need to get my head round it properly.

  16. #16
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    Quote Originally Posted by Mackmountain View Post
    I think itís a bit more complicated than just smaller ring increases antisquat. Instant centre has a lot to do with it and on some bikes thatís a moving target as suspension travels. Have an Intense Primer which when checking on linkage design shows very high antisquat. Running a 30t ring with 11-42 out back, recommendation is for a 34 ring.

    Decided to throw caution to the wind and dropped to 40%sag territory (was looking to figure out insufficient travel use problem). What a massive difference. Suspension is super active (not bobby though) when climbing and on the down the wheel is glued to the ground and really noticeably carries speed, especially over square edge stuff. Transformed the bike completely. Now i have come to understand just how complex the situation is...

    Will I get the same effect with correct sag and a 34t ring, is it the sag moving the Instant Center thatís achieving the changes with the 30t ring. I need to do more homework. Wonít be changing anything for now, but need to get my head round it properly.
    The leverage rate varies through the travel and where you are on that curve has a lot to do with how the suspension works, it may have nothing to do with the AS qualities of the bike.
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  17. #17
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    Quote Originally Posted by Jayem View Post
    The leverage rate varies through the travel and where you are on that curve has a lot to do with how the suspension works, it may have nothing to do with the AS qualities of the bike.
    +1

    Climbing versus descending your dealing with different forces as well. Weight distribution bias as well as force being applied at the rear wheel.

    Go up your putting the highest mounts of force through the crank and thus through the chain and cassette.

    Going down on the other hand even if your pedaling your not putting much force through to have any real effect on the suspension. A clutched RD set tight will have an effect since it wants to resist chain "growth" as well. Which means it fights against the suspension moving in the direction that would increase the rear wheels distance from the crank.

    There is a lot of variations and forces at play here. Even rear shock tune can make a huge difference just as your seeing by increasing sag. Literally something as simple as stem length, bar height and saddle position can change weight distribution enough to mess with how the rear suspension reacts to your riding.

    Remember, ALL settings are nothing more than recommendations as a starting point. Setting for feel, comfort and performance can throw you way out, again as you just found out. 40% sag just gave you a whole new world of improved riding feel and performance. Dont dwell on it but if a change to a bigger front ring happens, expect a change in feel of the suspension when climbing.

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