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  1. #1
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    dakar xam 1 or parker 2?

    im looking for a new bike, im partial to jamis, but open to suggestions of course, anyway im looking at getting either a dakar xam 1 or a parker 2 frame and a fork for either that i get on jenson, and then swapping all the rest of the parts from my current bike onto it, and then slowly upgrading as things brake, or i decide what ill like better

    Jamis Dakar Xam I Frame '09 > Components > Frames > Mountain Bike frames | Jenson USA Online Bike Shop

    Jamis Parker II Frame '09 > Components > Frames > Mountain Bike frames | Jenson USA Online Bike Shop
    2009 Jamis Trail X2
    2002 Raleigh Mountain Scout
    2008 Trek fuel ex7

  2. #2
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    I actually built that frame in Dec and love it. I beat the crap out of it and have not had any issues I also have a 2010 parker and have no complaints on that bike either. Out of the 2 I would say get the XAM out of the 2 as a "do it all" bike. Next to my Fuel EX8 its probably my favorite trail bike.

  3. #3
    Australia = phun
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    If you're more into freeride then get a xam.
    If you want a literal 'do anything' (especially 4x, dj, slopestyle, etc) a parker could fit the bill.
    But really, a fully built up bike could be better as both bikes you currently own spec rather low stock parts on them.

  4. #4
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    I have both bikes(same year and everything). I like the XAM a lot more then the Parker, But it realy depends on what you are going to be doing. My XAM is horrible at climbing, so if you do a lot climbing, get the Parker. If you are looking for small bump compliance, the XAM is much smoother feeling.

  5. #5
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    I can't comment on the XAM, but I've had the 2005 XLT and now a 2010 Parker.

    1. The Parker's 2:1 leverage ratio is 100% better than the ratio of the XLT which is the same as the XAM (I think) at 2.33:1. My reasoning is because I'm a bigger dude. The XLT with 5" of travel blew through it way too fast with 20-25% sag. The 2:1 ratio is great for bigger hits, but still supple enough for the small stuff. It uses less air pressure in the shock which will increase the air seal life. Tell ya honestly, I've not had to add any air to it like I did my XLT.

    2. I use my bike for everything. The Parker is kinda snappy, so XC is doable. It's no rocket, but I've got mine down to around 34lbs and setup really comfortable. I changed short'ish crankset for a Hone with 175mm arms and ditched the standard seatpost for a 410mm Thomson. This gives me excellent leg extension for long, pedaly rides. I can still drop the saddle low enough to go out and have some fun. The bike is just as at home on XC trails as it is hopping stairs (urban) and doing ladder bridge drops.

    3. The 2010 frame looks to be the same as the '09. I'm impressed with the large pivots and oversize tubes. My old XLT looks "spindly" in comparison. It's laterally stiff but linearly supple. A good, fun frame.


    One thing to think about is the seat tube length. I'm shy of 6'2", so I ride a Lg. The Lg. XAM has an 18" seat tube whereas the Parker is around 3" shorter. I solved the problem by getting a longer seatpost. When I'm getting tired and raise my saddle all the way to "spandex level", it looks a bit odd. Most of the time though, I'm running it a bit lower for technical riding so it doesn't matter. Appearances aside, it performs very well...if I could drop $250 on a 4-5" drop Gravity Dropper, I would do it in a heartbeat.
    I get my boards at Lux-RC.com

  6. #6
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    The XAM leverage ratio is actually 2.64:1 which is a pretty standard ratio for a 150mm bike.

    I personally had major problems with my Parkers 2:1 ratio and found it to be way to harsh and bottom way to easily. There is a reason why most bikes have leverage ratios in between 2.3-2.8. Bikes with ratios above a 2.8 tend to need to much damping and are to active.(they are mostly found on DH bikes). Bikes with ratios below 2:3 tend to be sluggish and over damped. The extremely low ratio also causes extra stress on the shock its self making it need service at closer intervals.

    All that said, I liked both bikes, but the XAM has much better rear suspension feel. IMO, To make the most out the Parker, you need a custom tuned rear shock.
    My parker(while it was was mine):


    Parker in is current form(now my wifes bike):


    My XAM:

  7. #7
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    Quote Originally Posted by mullen119 View Post
    The XAM leverage ratio is actually 2.64:1 which is a pretty standard ratio for a 150mm bike.

    I personally had major problems with my Parkers 2:1 ratio and found it to be way to harsh and bottom way to easily. There is a reason why most bikes have leverage ratios in between 2.3-2.8. Bikes with ratios above a 2.8 tend to need to much damping and are to active.(they are mostly found on DH bikes). Bikes with ratios below 2:3 tend to be sluggish and over damped. The extremely low ratio also causes extra stress on the shock its self making it need service at closer intervals.
    Disagree...(thx for the proper leverage ratio, BTW)...if you put more leverage on the shock, it's going to work harder. Thus the higher air pressure in higher leverage ratio suspension. Sure, a higher leverage ratio will feel more "butter", but if you set the sag properly...you need hella more damping to counter bottom-out...putting more stress on the damper as well.

    A lower leverage ratio (ie...Curnutt 2:1) will allow you to run proper sag with butter sm. bump, but more progressive so you don't bottom out the Parker's 4" rear travel on an 8' drop.

    I used to bottom out my 5" travel high levereage XLT all the time at 1" sag, but with my Parker's 4" travel...even set at the same sag, it doesn't bottom out harsh like the XLT did.


    Like I said, the lower ratio is better for big dudes. (I hover around 205lbs) Now a lightweight little guy...(like 175lbs or less)...probably would feel the lower ratio at proper sag to be a bit harsh.



    Edit: (re: working harder) I think we're talking two different things in somewhat the same way. When I think about the shock working harder, I'm thinking brute force pressure against the shock and damper. With a low ratio, less force is on the shock. Thus the air seals will be less affected.

    On a higher ratio as you pointed out, the shock travels less distance for the same effect, so the oil seals would be less affected.
    I get my boards at Lux-RC.com

  8. #8
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    Quote Originally Posted by chelboed View Post
    Disagree...(thx for the proper leverage ratio, BTW)...if you put more leverage on the shock, it's going to work harder. Thus the higher air pressure in higher leverage ratio suspension. Sure, a higher leverage ratio will feel more "butter", but if you set the sag properly...you need hella more damping to counter bottom-out...putting more stress on the damper as well.

    A lower leverage ratio (ie...Curnutt 2:1) will allow you to run proper sag with butter sm. bump, but more progressive so you don't bottom out the Parker's 4" rear travel on an 8' drop.

    I used to bottom out my 5" travel high levereage XLT all the time at 1" sag, but with my Parker's 4" travel...even set at the same sag, it doesn't bottom out harsh like the XLT did.


    Like I said, the lower ratio is better for big dudes. (I hover around 205lbs) Now a lightweight little guy...(like 175lbs or less)...probably would feel the lower ratio at proper sag to be a bit harsh.



    Edit: (re: working harder) I think we're talking two different things in somewhat the same way. When I think about the shock working harder, I'm thinking brute force pressure against the shock and damper. With a low ratio, less force is on the shock. Thus the air seals will be less affected.

    On a higher ratio as you pointed out, the shock travels less distance for the same effect, so the oil seals would be less affected.
    The reason why you dont bottom out on big hits is because fox air shocks are position sensitive and have a huge ramp up. They ramp up so much that the last 5-6mm of shock stroke are almost impossible to use. That is why so many people send there shocks to Push. Push takes the position sensitive damper and turns it into a speed sensitive damper that allows for less ramp up, making easier to use full travel.

    I dont feel like taking the time to write a long thing explaining why high leverage ratios are easier on shocks. The easiest thing to do is to post this: 2009 JAMIS BICYCLES - DAKAR XAM I

    In the description is says that the higher ratio makes for a longer lasting rear shock. its not an easy thing to explain or else I would, but when thinking of shock leverage ratios, everything is usually backwards from what peoples first thoughts.

  9. #9
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    I had the same Fox Float R on both frames...though I wonder if the chamber is larger vol. on the newer version.
    I get my boards at Lux-RC.com

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    Quote Originally Posted by chelboed View Post
    I had the same Fox Float R on both frames...though I wonder if the chamber is larger vol. on the newer version.
    My guess is that the newer version has the boost valve and the other one does not.

  11. #11
    Australia = phun
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    I have the same problem as mullen119. I pump my shock to about 70psi and get 10% sag (I'm a light rider) and get bottom outs at 3 foot drops...

    And does Jamis contradict itself?
    2010 JAMIS BICYCLES - PARKER SERIES FEATURES (unless it meant that the XAM had a low ratio...

  12. #12
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    All of this is bassackward, LOL. If you aired up the shock and just stood on it, it would hold you up. If you use that same air pressure and apply a lever to it and stand on the end of the lever...it would not hold you up as well b/c you have more leverage against it. It's easier to push it down. Easier to bottom out. If you go from 2:1 up to 2.7:1, it will bottom out easier with the same pressure. That's why people run lower pressure in a 2:1 setup. That's physics. I had to run 10% sag on my XLT to keep from bottoming out on general trail rides.

    It "will" bottom out easier at the same pressure with higher leverage unless you damp the shizz out of it.


    Running higher leverage as stated will give you a more supple ride, but if you pump it up to where it won't bottom out at proper sag...it's going to actually be harsher in the beginning of stroke. If you have it set where it feels nice for small bumps...it's going to bottom out easier at end of stroke.


    The beauty of the 2:1 ratio is that it ramps up (more progressive) quicker or more exponentially than the more linear high leverage. Yes, you will require a longer stroke shock. Yes, there will be more piston movement on a 2:1 than with similar travel high leverage model. Yes, this puts more "stress" on the oil b/c you're running more volume through the damper.

    But...there is less pressure / force on the air seals and less likely to bottom out b/c of the more progressive (anti-linear) exponential travel.

    I don't usually have oil seal issues in my rear shocks. I've had air seal issues where I need to add volume occasionally. I run considerably lower pressures in my 2:1 suspension than I ever did in my 2.7'ish :1 suspension. I mean seriously...why the hell do you think they went with 2:1 on a light FR / slopestyle bike? It's b/c it's 4" travel and it needs to ramp up quickly.

    Most bikers are smaller dudes though, so this doesn't really apply.
    I get my boards at Lux-RC.com

  13. #13
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    A leverage ratio has nothing to do with bottoming if it is a straight ratio. Yes, you have to run more air in an air shock that has a higher leverage ratio, as you said that is just physics. But running more air has nothing to do with changing the feel that you get from higher or lower ratios. You need the higher air pressure to achieve the same amount of sag. Saying a 2:1 ratio is progressive is completely untrue. 2:1 is a linear rate and just as 2.63:1 is a linear rate. If anything, running lower air pressure would make the shock its self less progressive making for easier bottoming.

    On the other hand, most bikes do not have a straight leverage curve. Most bikes have a raising rate design to give a ramp up towards the end of the shock stroke, helping to prevent bottoming. Most people think that a rising rate design starts at a low rate and end at a higher rate, but its actually the opposite. Rising rate designs start at a given leverage ratio and the ratio drops as the shock travels through its stroke. Falling rate designs(which are very rare) are the opposite.

    The reason lower ratios are harder on shocks internals(the simple version) is not because of air pressures, its because lower suspension ratios tend to make shocks run deeper in their travel more often, making the shock cycle more often then a shock with a higher ratio.

    The true answer is both high and low ratios have pros and cons, but rider weight and bottom out resistance has nothing to do with leverage ratios unless you are talking about rising or falling rates(which is this case we are not, even though the XAM has a slight rising rate)

  14. #14
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    Quote Originally Posted by mullen119 View Post
    A leverage ratio has nothing to do with bottoming if it is a straight ratio. Yes, you have to run more air in an air shock that has a higher leverage ratio, as you said that is just physics. But running more air has nothing to do with changing the feel that you get from higher or lower ratios. You need the higher air pressure to achieve the same amount of sag. Saying a 2:1 ratio is progressive is completely untrue. 2:1 is a linear rate and just as 2.63:1 is a linear rate. If anything, running lower air pressure would make the shock its self less progressive making for easier bottoming.

    On the other hand, most bikes do not have a straight leverage curve. Most bikes have a raising rate design to give a ramp up towards the end of the shock stroke, helping to prevent bottoming. Most people think that a rising rate design starts at a low rate and end at a higher rate, but its actually the opposite. Rising rate designs start at a given leverage ratio and the ratio drops as the shock travels through its stroke. Falling rate designs(which are very rare) are the opposite.

    The reason lower ratios are harder on shocks internals(the simple version) is not because of air pressures, its because lower suspension ratios tend to make shocks run deeper in their travel more often, making the shock cycle more often then a shock with a higher ratio.

    The true answer is both high and low ratios have pros and cons, but rider weight and bottom out resistance has nothing to do with leverage ratios unless you are talking about rising or falling rates(which is this case we are not, even though the XAM has a slight rising rate)
    Hmmm...very interesting things for be to now ponder. Makes sense. My theories are less scientific and only supported by limited experience...though the outcome of my experience has been strong enough to give me confidence in my claim. Be it wrong, I'll be openly willing to accept it.
    I get my boards at Lux-RC.com

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    Quote Originally Posted by chelboed View Post
    Hmmm...very interesting things for be to now ponder. Makes sense. My theories are less scientific and only supported by limited experience...though the outcome of my experience has been strong enough to give me confidence in my claim. Be it wrong, I'll be openly willing to accept it.
    In your defense, higher rate designs have higher shaft speeds. One would tend to think that could cause for slightly faster wear. In the real world, the difference in shock life between different ratios is not going to be significantly different. Most of our discussion on the topic pointless because the difference in wear is so small that in 95% of situations, it never becomes an issue. Im just a sucker for tech talk.

    icalebkim is correct about Jamis contradicting itself. Its hard to tell the difference between hype and the real world. The difference between 2:1 and 2.63:1 is pretty large. Using the same hype for two completely different designs has me baffled, regardless of which is correct.

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    Quote Originally Posted by mullen119 View Post
    In your defense, higher rate designs have higher shaft speeds. One would tend to think that could cause for slightly faster wear. In the real world, the difference in shock life between different ratios is not going to be significantly different. Most of our discussion on the topic pointless because the difference in wear is so small that in 95% of situations, it never becomes an issue. Im just a sucker for tech talk.

    icalebkim is correct about Jamis contradicting itself. Its hard to tell the difference between hype and the real world. The difference between 2:1 and 2.63:1 is pretty large. Using the same hype for two completely different designs has me baffled, regardless of which is correct.
    Here's an interesting tidbit from Foes that may or may not matter to anyone to help understand suspension a bit more. It helps me anyhoo:

    Advantages to the 2:1 leverage ratio, Foes says, are lighter spring rates and reduced stress on suspension components. In addition, seals inside the shock are subjected to lower pressures, thus reducing stresses on the seals for less stiction. Because low-leverage shocks move more, and therefore flow more oil, they're easier to tune via the suspension's leverage ratio, though Foes says it also means that having the correct valving is critical.
    I get my boards at Lux-RC.com

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    Okay.
    mullen119, I hardly ever put platform on my Lyrik because my suspension servicer said that blown seals were due to stiff damping (which, in the case of high ratios, would be more evident). Blown seals due to overdamping sounds more likely to cause the shock to fail than cycling through the travel to much, doesn't it?

    But I agree with both sides of the argument.

    (This thread has evolved into like a leverage ratio/shock life 'argument' instead of XAM vs Parker...)

    I can't understand why manufacturers make the ratio high first and then low. Wouldn't it make sense to ramp up the leverage just before bottoming to reduce the impact? Or is it to provide platform? (Or am I getting it backwards?)

  18. #18
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    Quote Originally Posted by icalebkim View Post
    Okay.
    mullen119, I hardly ever put platform on my Lyrik because my suspension servicer said that blown seals were due to stiff damping (which, in the case of high ratios, would be more evident). Blown seals due to overdamping sounds more likely to cause the shock to fail than cycling through the travel to much, doesn't it?

    But I agree with both sides of the argument.

    (This thread has evolved into like a leverage ratio/shock life 'argument' instead of XAM vs Parker...)

    I can't understand why manufacturers make the ratio high first and then low. Wouldn't it make sense to ramp up the leverage just before bottoming to reduce the impact? Or is it to provide platform? (Or am I getting it backwards?)

    The seal your suspension service tech is referring to are the oil seals in your damper. The more compression damping you use, the more oil pressure needs to build before the fork will move. If you use too much and still take bigger hits, the seals can fail because of the high pressures.

    As for the ratios, you have it backwards. Starting at a high number first and then dropping it through the stroke does provide a ramp up. If it starts as 3:1 and ends at 2:1, the shock only needs to move 1mm to make the rear axle move 3mm. at the end of the stroke, the rear wheel only moves 2mm for every 1mm of the shock stroke. This means the shock has to work harder at the end of the stroke then it does at the beginning, giving a ramp up feel.


    Anyway, thats enough tech talk for this thread. OP, Both bikes are good. If you enjoy going down hill and are willing to sacrifice some climbing ability for a more active suspension feel, I would pick the XAM. If you looking for a jack of all trades/can do it all bike, I would pick the Parker. You will most likely enjoy either one.

  19. #19
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    I ended up getting a practically new 2008 trek ex-7 now i just gotta ride it
    2009 Jamis Trail X2
    2002 Raleigh Mountain Scout
    2008 Trek fuel ex7

  20. #20
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    Ohhh and its 2.4:1 ratio
    2009 Jamis Trail X2
    2002 Raleigh Mountain Scout
    2008 Trek fuel ex7

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