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  1. #1
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    JANG's review of the Stampede (springs)

    Hello,

    I'm considering buying the Stampede XL-5 as a gift for my son. I've watched JANG's review of the truck and he points out that the shock springs are too long. Consequently they have built in preload. This stiffens the suspension unnecessarily. It makes the truck bobble around unrealistically; "each tire ends up taking each bump as a jump" instead of just soaking it up.

    Went to my LHS yesterday for a tactile look at the truck. My impression was that the rear suspension was instead quite soft, not what I was expecting.

    Is Traxxas building the truck with different springs than they did in JANG's 2012 review?

  2. #2
    RC Qualifier Rich2's Avatar
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    Quote Originally Posted by massenrg4 View Post
    Hello,

    I'm considering buying the Stampede XL-5 as a gift for my son. I've watched JANG's review of the truck and he points out that the shock springs are too long. Consequently they have built in preload. This stiffens the suspension unnecessarily. It makes the truck bobble around unrealistically; "each tire ends up taking each bump as a jump" instead of just soaking it up.

    Went to my LHS yesterday for a tactile look at the truck. My impression was that the rear suspension was instead quite soft, not what I was expecting.

    Is Traxxas building the truck with different springs than they did in JANG's 2012 review?
    Not a concern with today's Stampede. The reviews by Jang are years old.

  3. #3
    RC Qualifier PJbottoms's Avatar
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    Quote Originally Posted by massenrg4 View Post
    Consequently they have built in preload. This stiffens the suspension unnecessarily.
    Preload does NOT add stiffness to the shocks. It's a common misconception. Preload only affects ride height of the vehicle/reduces "sag" and that's it, nothing more.

    And as Rich said, that model he reviews is ages old. Traxxas has updated each of their models quite a bit since then.

  4. #4
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    Quote Originally Posted by PJbottoms View Post
    Preload does NOT add stiffness to the shocks. It's a common misconception. Preload only affects ride height of the vehicle/reduces "sag" and that's it, nothing more.
    I’ve heard this said many times but have never come to fully accept it. Yes, preload spacers do not necessarily add stiffness, but they often do. They are designed purely to alter ride height if they are not compressing the spring. The more a spring is compressed, the more force required to compress it further. Take a spare spring you have laying around compress it 50%. Now Compress it the remaining 50%. You’ll see it’s obviously much harder to compress the spring in its last 50% of travel. Therefore if it’s put on a shock already compressed, the shock is stiffer. JANG’s point on this truck is that the springs are too long. So, they are already compressed some before there is any weight on them. So they are stiffer than they need to be.

    The spring rate remains unchanged with preload (except on progressive Springs). This stuff can confuse people myself included and I’d love to see a mechanical engineer chime in.

    I’d be surprised if Traxxas has changed the springs they’re putting on the Stampede since 2012 but I guess that’s possible. I noticed the rear springs on today’s stampede have the same part number as my 2014 rustler. Does anybody have the part number for the 2012 stampede rear shock springs?
    Last edited by massenrg4; 08-21-2018 at 02:20 PM.

  5. #5
    RC Qualifier PJbottoms's Avatar
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    Quote Originally Posted by massenrg4 View Post
    The more a spring is compressed, the more force required to compress it further.
    And that's the common misconception and not true. Not trying to be argumentative, but it's just fact how that works. It just 'seems" harder to compress. I thought the same when I started out.

    https://www.sportrider.com/technical...te-and-preload

    If the springs are that much of a concern, grab the integy tuned spring set with the truck: https://www.ebay.com/itm/Integy-MSR9...h/392086730513

    I actually bought these but went back to the stock springs on my Stampede and Rustler as well. They're fine.
    Last edited by PJbottoms; 08-21-2018 at 06:37 PM.

  6. #6
    RC Qualifier Synnergy's Avatar
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    PJb, this is for linear springs, yes? I'm curious about progressive springs, they DO have differing rates depending on compression yes? No?
    MTFBWY

  7. #7
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    Quote Originally Posted by PJbottoms View Post
    And that's the common misconception and not true. Not trying to be argumentative, but it's just fact how that works. It just 'seems" harder to compress. I thought the same when I started out.

    https://www.sportrider.com/technical...te-and-preload

    If the springs are that much of a concern, grab the integy tuned spring set with the truck: https://www.ebay.com/itm/Integy-MSR9...h/392086730513

    I actually bought these but went back to the stock springs on my Stampede and Rustler as well. They're fine.

    Don’t worry PJbottoms. You’re not being argumentative. This is just dialogue, and good dialogue at that. I appreciate your willingness to share your experiences.

    The more a spring is compressed, the more force required to compress it further. This is fact. I read the Sportrider article you linked and it reinforces this premise. The author explains that while pre-load does not affect spring rate, it does affect spring-force, which is what my earlier post says. You’ll notice in Fig. 1 he plots Spring Force against Travel for a “Straight-rate” spring. As Travel increases so does Spring Force. So, the further you compress a spring, the more force it exerts.

    It follows that if it’s already loaded up it will require more force to compress it a given distance than in its “free-length”.

    The spring-rate (a ratio) is what remains constant no matter how much preload exists. Spring-force does not. It changes dramatically, but at a constant rate....2.5 for the Traxxas Ultra Shocks.

    I think the misconception you’re talking about is that preload spacers will automatically load up the springs, which isn’t true. It is possible to have preload spacers (or threaded shock bodies) and no discernible compression. This is how ride-height is changed.

    I’m glad to hear you say the stampede springs are fine. Again it’ll be a gift for my son. I know the xl-5 is not a high performance vehicle but I’d love to see it soak up the terrain they way he’ll expect a monster truck to.

  8. #8
    RC Qualifier PJbottoms's Avatar
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    Quote Originally Posted by massenrg4 View Post
    So, the further you compress a spring, the more force it exerts.
    See, I always understood that as spring force being exactly what you said, the amount of force it "exerts" or "puts out" (i.e. the spring back) when it uncompresses, not while it's being compressed, meaning it has the same rate when being compressed no matter how far it goes. But when it uncompresses, the further it is compressed, the more force it will exert. For example, if you compress a spring slightly on a table and then let it go, it will hop up a bit. But if you compress it almost fully and let it go, it will shoot up in the air rather high (and most likely on the floor somewhere never to be found when it comes to RC parts, lol). I always thought that's what was being referred to as 'spring force" but maybe I misunderstood so don't quote me on that for sure.

    Yeah Syn, we're talking about linear springs. Progressives are a whole 'nother bag of fish.

    Anyways I'm sure your son will love it nonetheless! Stampede is a really fun truck. I just got a Rustler a couple weeks ago and I was afraid it might "replace" my Stampede in use but I love running both just as much, specially being I live in a heavily wooded area and my 'Pede still goes places my Rustler can't.

    One nice thing about the xl-5 is that as your son grows and maybe gets more into the hobby, the truck can "grow" with him. Tons of upgrade options available. Brushless systems, bearings to replace bushings, suspension tuning, aluminum parts (but only in certain places, flexible plastic is still better in some areas), the list goes on.

  9. #9
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    This spring conversation has me interested. If I may put my two-cents in, I have to agree with massenrg4. By adding preload, it does mean that more force is required to initially start compressing the spring, and the spring can exert more force on an object. To back this up, you could look up adding a preload spacer to a spring in a Nerf blaster. If the spring exerted the same amount of force with the preload, there would be no difference in the performance of the blaster. Not so, the range, and muzzle velocity of darts leaving that Nerf blaster will actually increase with the preload.

    https://www.youtube.com/watch?v=Tk2pFgJ4a0k

    So yeah, you can test this if you want, but definitely does more than change ride height.

    And to answer the original question, yeah pretty sure Traxxas put softer springs on the Pede since Jang's review. My Dad got a Pede xl-5 about 2 years ago, and you can see quite a difference. Driving it is quite fun, handles surprisingly well considering how high the center of gravity is. Seems the tires, weight, and power of the xl-5 Stampede is very well matched out of the box. It's more getting into brushless that I would watch out for handling issues, but I imagine it will be some time before you do any of that.

  10. #10
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    Thanks PJ and N3RD.......what got me into the Stampede is that Traxxas dropped the price. A new one can be had for $160. Plus I’ve been using a rustler for years and have a ton of spare parts/batteries laying around.

    PJ good point that it’s a platform that can grow with him....the after market for Traxxas stuff is unmatched!!!!

  11. #11
    RC Qualifier chops1sc's Avatar
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    One thing we all have to remember is that these are light RCs so any little bump will not make the suspension move because there is only 2-3lbs on each shock/spring. If you want realistic results then you need to add weight (or get a scale truck).

    I always have to remind myself when I start getting upgrade-happy; these are just toys (yes they are) that we use to entertain ourselves. Sometimes you just need to let it rip and kick up a bunch of dust and maybe break something in the process, LOL!
    Revo .18TM BL Rustler Stampede MERV HPI Sprint 2

  12. #12
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    I love that Traxxas has an option to buy these trucks without batteries. Having an included battery with your first RC is nice, but after that you're just gonna wanna ditch that thing and throw in your Lipos anyway so it's a pretty good deal. I think he'll be really happy with this truck.

  13. #13
    RC Qualifier chops1sc's Avatar
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    I am sure he will. My 2 year old loves to watch mine run and loves to watch it jump! I let him turn the steering knob and I know it wont be long before he's able to drive it too!
    Revo .18TM BL Rustler Stampede MERV HPI Sprint 2

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