Shock Angle

[Duuuuuuuude]

Some things 'work' on RC models (air, land & water) that don't work on 1:1 vehicles.

"thumbsup"

And visa versa.

 

[Duuuuuuuude]

Well..im just happy with my set up and that's all that matters I suppose..I would just consider why most rock crawlers use the shocks at such an angle if it had no benefits...why not just much shorter shocks mounted 90 degrees if it better all around? ..My guess is to keep COG low and have the articulation the need...I don't think an SCX10 can out crawl a serious well set up rock crawler...But a rock crawler can do what most any SCx10 can do better IMHO...I just added a small effect as to what a crawlers advantage is..Im not the first and wont be the last..lol

Ill agree to disagree on whats the better set up and be happy with mine for now...I may try a different set up one day to see if its any better.

Comp crawlers do lay their shocks down to gain a lower cog, but only if they are really, really laid down. Moving them just a few degrees like you have done will have negligible effects.

 

[Hardline]

@ K.O.M. I too believe you are totally wrong on your assessment of shock angle vs wheel travel. Angling the shock gives more vertical axle travel, not less, and simultaneously reduces the leverage of the spring and damping forces on the vertical axle travel. At horizontal the spring and damping provide no leverage on vertical motion, but the shock does not restrict vertical motion.

What hasn't been said (unless I missed it) is if the shock/spring is very laid down, not only does it not have much leverage to control the axle, but as the chassis is depressed, the shock/spring become even more horizontal and on the rig I was playing with angle, if I got the chassis low enough it would not come back up at all due to the horizontal(ish) shock angle. I'm not big on highly angled shocks as it seems counter-productive to their purpose.

BTW K.O.M., I hate to disagree with you. Aren't you the guy who did an early Scorpion development thread? I cut my teeth on that thread -- it was great (for the time).

 

[6sharky9]

Comp crawlers do lay their shocks down to gain a lower cog, but only if they are really, really laid down. Moving them just a few degrees like you have done will have negligible effects.

I wanted more of the lowering effect than anything but increased travel..I like how it travels over the terrain and seems to be a better crawler in general compared to how it was...Its not a drastic angle but is enough to see a difference..at least for me it has...I have 3 mm more down travel and 1.5mm more upward travel as I don't use all the shock travel when fully compressed...Which is good as I don't rub my tires on anything.
But best of all my COG stays low.

I know you can accomplish more travel mounting shocks 90 degrees as well but not without buying heavy aluminum brackets mounted high above the chassis to do it with..I like the fact even if you made extensions such as I have the weight wouldn't be near as much even if made from aluminum..I was lucky to have some carbon plate to make mine from...so weight is very minimal for me...Not the case with those aluminum ones with mounting holes most never use...Just more weight than I wanted to add up high...Im not a fan of the big 100mm shocks a huge 2.2 tires..I maximized what the stock truck can offer for its height and tire diameter using the Honcho body.

 

[Duuuuuuuude]

I wanted more of the lowering effect than anything but increased travel..I like how it travels over the terrain and seems to be a better crawler in general compared to how it was...Its not a drastic angle but is enough to see a difference..at least for me it has...I have 3 mm more down travel and 1.5mm more upward travel as I don't use all the shock travel when fully compressed...Which is good as I don't rub my tires on anything.
But best of all my COG stays low.

I know you can accomplish more travel mounting shocks 90 degrees as well but not without buying heavy aluminum brackets mounted high above the chassis to do it with..I like the fact even if you made extensions such as I have the weight wouldn't be near as much even if made from aluminum..I was lucky to have some carbon plate to make mine from...so weight is very minimal for me...Not the case with those aluminum ones with mounting holes most never use...Just more weight than I wanted to add up high...Im not a fan of the big 100mm shocks a huge 2.2 tires..I maximized what the stock truck can offer for its height and tire diameter using the Honcho body.

I would make an educated guess and say that more than anything, going to better quality shocks is what made the biggest change. A couple of mm of travel will not make a huge difference.

Your lightweight carbon extensions probably didn't offset the added weight of the aluminum bodies of the larger and twice as heavy (8g vs 18g) Losi shocks though...

Its good that you are being mindful of weight, but I think you are cutting things too finely. Fretting over +/- a gram or two on a Honcho is a bit obsessive. I doubt you would see any loss in performance had you gone with aluminum.

 

[6sharky9]

I would make an educated guess and say that more than anything, going to better quality shocks is what made the biggest change. A couple of mm of travel will not make a huge difference.

Your lightweight carbon extensions probably didn't offset the added weight of the aluminum bodies of the larger and twice as heavy (8g vs 18g) Losi shocks though...

Its good that you are being mindful of weight, but I think you are cutting things too finely. Fretting over +/- a gram or two on a Honcho is a bit obsessive. I doubt you would see any loss in performance had you gone with aluminum.

Im now tempted to buy some wraith rtr shocks and limit those to 93mm to see if theres is a difference...definitely weight conscious when it comes to above the chassis...my truck weighs 6.24 lbs with everything ive done to it.

14 oz of that weight is in the wheels. 3.5oz each wheel...slowly removing that as I upgrade the axle assemblies for weight purposes.


I mean the bigger heavier Aluminum lowering brackets on the market now...all 4 at least weight that of one aluminum losi shock...either way its more weight ..A litte here and there add up when its all said and done...I want to be as light as possible up top no matter by how much it is...The losi shocks i got off ebay from a private seller..I bought 2 sets actually..he wanted 20.00 a set for brand spanking new un assembled sets..still have one set untouched. 8 shocks for 40 dollars..Couldnt pass up that deal.

 

[Duuuuuuuude]

Im now tempted to buy some wraith rtr shocks and limit those to 93mm to see if theres is a difference...definitely weight conscious when it comes to above the chassis...my truck weighs 6.24 lbs with everything ive done to it.

14 oz of that weight is in the wheels. 3.5oz each wheel...slowly removing that as I upgrade the axle assemblies for weight purposes.

Wraith shocks weigh 14g (with oil, no spring).

 

[6sharky9]

Wraith shocks weigh 14g (with oil, no spring).

I didn't mean weight difference..but thanks for the info...I mean making wraith shocks 93mm then mounting them like i have my shocks now and see what difference it would make besides weight or maybe a set of traxxas big bores..im sure slightly more in weight than wraith maybe but still lighter than aluminum losi

 

[Duuuuuuuude]

I didn't mean weight difference..but thanks for the info...I mean making wraith shocks 93mm then mounting them like i have my shocks now and see what difference it would make besides weight.

Why? What possible advantage do you see in them?

 

[6sharky9]

Why? What possible advantage do you see in them?

Well that's just it..other than less weight i don't see any advantage..yes the losi are bigger bores and ive done more to them to make them work like they do for me but im not convinced that's the only reason i got better performance from them because they are better shocks...I did work to the stock shocks and liked how they worked but wanted more travel i couldn't get from them..I looked at traxxas big bores first but didn't find springs i wanted for them..they were all to stiff for what i wanted...So i found springs for the losi as more what i wanted (1.8 and 2.0lb) and when i saw the deal i hoped on them..Im sure some performance is from a better shock but i still have to contribute the way they are mounted is helping also...Again my main benefits i see is the added travel with a much lighter alternative to keep COG low based on how they are mounted...I know lighter shocks would be less weight as well.

 

[6sharky9]

I think i can make the wraith shocks work for me close enough to not see a huge difference other than weight between them and the losi shocks...But still mounted like i mount them

 

[6sharky9]

The difference i can see is when approaching a rock or obstacle to go over or climb..when the tire just hits the obstacle the suspension starts working immediately..The tire doesn't have to be almost on top of it or half way on it before you see movement in the shock.,,my thoughts are the movement of the shock is putting weight to the tire(s) giving better traction..And on a trail i notice the suspension working more as opposed to just the tire rolling over the bump and barely compressing the spring..with any speed that would've been a bounce or a small jump...My shocks work with ease over even the smallest bump and are smooth working even over some larger bumps..Thats the best way i can describe it...When i can i suppose i can do a video and show what it is im try to describe...They just work better for me angled than they do straight up and down..and yes i tried them that way also but without the lower CG to go with it.

 

[javi]

I have to say this turn out to be very informative for me. I think I get what you guys are saying though.
Thanks

 

[Androtaz]

I run hr remote res on my custom ax10 with very little angle and it crawls just as good as it did in its stock form with the axial shocks. Its all in the angle, dampening and the springs. Im not going to act like I even understand half of the technical terms. As you stand a shock up you will gain ride height, this does not IMO change the amount of travel as much as one would think. A 93mm shock will only move a certain distance, adding angle will not make the shock travel more, you may be getting less travel as the more you compress the angled shock it will actually push your axle away from the center of your wheel base as the shock bottoms out or reaches the springs limit as its compressed. At that point only thing limiting your shock travel would be your links. As far as running stock wraith shocks. IMO they suck. I find that front Traxxas slash shocks work really well.

 

[K.O.M.]

K.O.M. sorry if I sounded blunt or rude - that wasn't my intention (busy day at work). I'm going to itemize my thoughts on this just to stay organized. "thumbsup"

No apologies needed mate. I figured you were on your phone/pad, and just wanted to make sure you got back once you had a real keyboard.

Regarding ride height - if moving the shock accross a horizontal line with the fulcrum being the bottom shock mount, then certainly this is the case. However if you're free to move the shock vertically (and why wouldn't you be? You're already moving it) then there is no loss in ride height.

Agreed and no argument from me here. It's the reason why shock mounting positions move lower as the mounts move more inward. I was addressing the issue of the OP's modification and how it affects the suspension. See my quickly scribbled diagram below.

Regarding travel - the equation is ACF = cos(alpha). ACF is the Angle Correction Factor or the relationship between shock travel and wheel travel.
Source: Pirate4x4.Com - The largest off roading and 4x4 website in the world.

No argument on ACF. My sketch addresses that (at least on the side view). What is not immediately apparent is that you can have compounding alpha angle values as you will have different angles of the damper when viewed from the front/rear and from the side. One should be called beta...

Here's a real world example from one of my first rigs back in 2004 - notice how little the shock is compressed?:

Pause here for a second. We need to dive into this a bit deeper. I think we need to seperate FLEX (whole chassis working together) travel vs. RIDE (one axle moving symmetrically parallel with the ground) travel. You are showing FLEX travel and certainly laying the shocks down provides more flex (less leverage from the shocks, that's why I said earlier that you are partially correct there). I'll try to address this on a separate post

@ K.O.M. I too believe you are totally wrong on your assessment of shock angle vs wheel travel. Angling the shock gives more vertical axle travel, not less, and simultaneously reduces the leverage of the spring and damping forces on the vertical axle travel. At horizontal the spring and damping provide no leverage on vertical motion, but the shock does not restrict vertical motion.

See my reply above and my diagram below. For the sake of simplicity my replies address RIDE travel and the SCX10 chassis for the moment.

What hasn't been said (unless I missed it) is if the shock/spring is very laid down, not only does it not have much leverage to control the axle, but as the chassis is depressed, the shock/spring become even more horizontal and on the rig I was playing with angle, if I got the chassis low enough it would not come back up at all due to the horizontal(ish) shock angle. I'm not big on highly angled shocks as it seems counter-productive to their purpose.

BTW K.O.M., I hate to disagree with you. Aren't you the guy who did an early Scorpion development thread? I cut my teeth on that thread -- it was great (for the time).

Disagree away--it provides for a good debate and it really get's everyone thinking about this--more than toys, eh?

Same guy. Got busy raising two kids (still busy). Got a job in the Natural Gas Vehicle/Fueling industry (hoping none of my designs blow up).

So, I sketched this in literally 2 minutes flat, so pardon the sloppy handwriting and it is definitely NOT TO SCALE

 

[javi]

When you do make a thread to explain more of the angles please send me a pm I would like to read more and try to understand as best as I can.

 

[Duuuuuuuude]

They just work better for me angled than they do straight up and down..and yes i tried them that way also but without the lower CG to go with it.

Then try a softer spring. All laying down a shock/spring does is change the way it reacts to suspension movement, i.e., softens it...and you didn't lay them down all that much. Axial rigs are somewhat notorious for having overly hard springs any way.

You are also seeing a shock that performs better by design. Remember that even though scale parts are smaller than their real life counter parts, molecular density remains the same. The Losis have the advantage of larger bores, larger pistons, and more fluid, which simply makes them work better.

If you're really after a lower cg, flip the Losi shocks upside down.

 

[Calderwood]

@ kom - if you lay the shocks forward just a bit the spring rate rises when you compress the suspension. This happens if the shock to link angle gets closer to 90* when compressed. When the shocks are layed down even more the shock to link angle actually closes when compressed and you achieve a falling rate.

@ sharky - when you try to sound smarter than you are you sound dumber than ever.

 

[K.O.M.]

@ kom - if you lay the shocks forward just a bit the spring rate rises when you compress the suspension. This happens if the shock to link angle gets closer to 90* when compressed. When the shocks are layed down even more the shock to link angle actually closes when compressed and you achieve a falling rate.

Correct sir. That's what I posted initially on page 1, post #5. But since I'm on my pad, I have a hard time qouting myself.

I also mentioned that the initial damping is less when compared to a shock standing straight up and down, since now part of the, ahem, *dampers* ability to resist the vertical bump force has to partially be resolved in the horizontal direction because of the angle.

I didn't quite clarify myself earlier, but in just about any real-life car design, you would not angle the shock past a certain point so as to achieve a digressive or falling-rate damping ability (they do this with motorcycles and bikes though...) hence my initial post on Page 1, Post 5.

But like you mentioned above, past a certain angle, the damping becomes digressive, which if your only experience with suspension tuning is with super-laid down shocks on comp crawlers, you would think this is what ALWAYS happens.

So to paraphrase where we are so far:

If you don't change anything on the shock other than angle.

1. Any shock angle will ALWAYS result in less INITIAL damping force. The greater the angle, the lesser the initial damping force will be when compared to the same shock in a vertical position.

2. Up to a certain shock angle from vertical--dictated by chassis design/link arrangment, your damping rate will be progressive.

3. Beyond a certain shock angle from vertical--dictated by chasis design/link arrangemnt, your damping rate will be digressive.

I would be happy to sketch this out, I'll give it a full 10 minutes this time So it's easier to visualize what's happening.

 

[javi]

Correct sir. That's what I posted initially on page 1, post #5. But since I'm on my pad, I have a hard time qouting myself.

I also mentioned that the initial damping is less when compared to a shock standing straight up and down, since now part of the, ahem, *dampers* ability to resist the vertical bump force has to partially be resolved in the horizontal direction because of the angle.

I didn't quite clarify myself earlier, but in just about any real-life car design, you would not angle the shock past a certain point so as to achieve a digressive or falling-rate damping ability (they do this with motorcycles and bikes though...) hence my initial post on Page 1, Post 5.

But like you mentioned above, past a certain angle, the damping becomes digressive, which if your only experience with suspension tuning is with super-laid down shocks on comp crawlers, you would think this is what ALWAYS happens.

So to paraphrase where we are so far:

If you don't change anything on the shock other than angle.

1. Any shock angle will ALWAYS result in less INITIAL damping force. The greater the angle, the lesser the initial damping force will be when compared to the same shock in a vertical position.

2. Up to a certain shock angle from vertical--dictated by chassis design/link arrangment, your damping rate will be progressive.

3. Beyond a certain shock angle from vertical--dictated by chasis design/link arrangemnt, your damping rate will be digressive.

I would be happy to sketch this out, I'll give it a full 10 minutes this time So it's easier to visualize what's happening.

I would like that.