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Chassis mount servo ???
- Thread starter Frank211
- Start date
Is there a difference in performance from axle mounted servo ?
No.
Is it just for looks to get the servo out of the way to make the truck look more scale ?
Yes.
What is that plate/mount called , if id searched it on eBay ?
CMS
Chassis mounted servo
https://www.rpphobby.com/SearchResults.asp?Search=cms+
No.
Is it just for looks to get the servo out of the way to make the truck look more scale ?
Yes.
What is that plate/mount called , if id searched it on eBay ?
CMS
Chassis mounted servo
https://www.rpphobby.com/SearchResults.asp?Search=cms+
altd896
RCC Addict
I'm going to do the long winded answer
There is a difference in the performance, though I wouldn't go so far as to categorize upgrade, downgrade or otherwise.
CMS really requires a panhard if suspension is a coil over 3 linked arrangement (as opposed to leaf sprung) to mitigate bump steer.
It can by some accounts be tuned with time & patience (of which I have neither) to work without a panhard & still achieve no bump steer, the physics of how this is achieved defies me though.
The use of a panhard does lead to some axle swing as the suspension cycles & the additional linkages can tend to foul under parts of the chassis & interfere with axle travel.
It does however properly mimic the function of most OEM style steering systems versus the ram style axle mounted power systems on comp trucks that the servo on axle does a better job of, at least in function if not form.
There are trade off between the 2 systems & the driving experience is slightly different for each.
Which is better depends on what your looking for
There is a difference in the performance, though I wouldn't go so far as to categorize upgrade, downgrade or otherwise.
CMS really requires a panhard if suspension is a coil over 3 linked arrangement (as opposed to leaf sprung) to mitigate bump steer.
It can by some accounts be tuned with time & patience (of which I have neither) to work without a panhard & still achieve no bump steer, the physics of how this is achieved defies me though.
The use of a panhard does lead to some axle swing as the suspension cycles & the additional linkages can tend to foul under parts of the chassis & interfere with axle travel.
It does however properly mimic the function of most OEM style steering systems versus the ram style axle mounted power systems on comp trucks that the servo on axle does a better job of, at least in function if not form.
There are trade off between the 2 systems & the driving experience is slightly different for each.
Which is better depends on what your looking for
Last edited:
dacaur
Quarry Creeper
Lets not fool ourselves here guys, the one and only reason for a chassis mounted servo is aesthetics.
There is honestly no question that an axle mounted servo is better than a chassis mounted servo. Anyone that says otherwise is fooling themselves. True comp crawlers dont use chassis mounted servos, and there is a reason for it.
Servo on the axle gives a lower center of gravity.
Servo on the axle doesnt require a panhard par, which can cause slight binding as the suspension cycles.
Servo on the axle will never have bump steer.
Theoretically having the servo on the chassis gets it up higher away from moisture, but we are talking only like an inch of difference. It would take a VERY specific situation and a non waterproof servo to ever see a real benefit there, make the servo waterproof and that "advantage" dissapears.....
That said, while there is 100% definitely a difference performance wise, its not really all that big, especially when you consider all the other things that make our trucks crawl worse.. For CG, we are talking like an ounce 1" higher up, not too big a deal. Today's setups with panhard bars and chassis mounted servos are pretty good, and bump steer only really becomes an issue at higher speeds. For the scale crowd, the aesthetics of having it look more scale is worth the performance tradeoff. Just like using 1.9" (or even 1.55") tires instead of 2.2". 2.2" will perform WAY better, but look less scale, so 1.9 it is....
Really, if we were interested in getting every little bit of performance out of our trucks, we wouldn't be into scale trucks.... A well setup up everest/maxtone 10 will out crawl any scaler, but will look silly and not at all scale doing so....
There is honestly no question that an axle mounted servo is better than a chassis mounted servo. Anyone that says otherwise is fooling themselves. True comp crawlers dont use chassis mounted servos, and there is a reason for it.
Servo on the axle gives a lower center of gravity.
Servo on the axle doesnt require a panhard par, which can cause slight binding as the suspension cycles.
Servo on the axle will never have bump steer.
Theoretically having the servo on the chassis gets it up higher away from moisture, but we are talking only like an inch of difference. It would take a VERY specific situation and a non waterproof servo to ever see a real benefit there, make the servo waterproof and that "advantage" dissapears.....
That said, while there is 100% definitely a difference performance wise, its not really all that big, especially when you consider all the other things that make our trucks crawl worse.. For CG, we are talking like an ounce 1" higher up, not too big a deal. Today's setups with panhard bars and chassis mounted servos are pretty good, and bump steer only really becomes an issue at higher speeds. For the scale crowd, the aesthetics of having it look more scale is worth the performance tradeoff. Just like using 1.9" (or even 1.55") tires instead of 2.2". 2.2" will perform WAY better, but look less scale, so 1.9 it is....
Really, if we were interested in getting every little bit of performance out of our trucks, we wouldn't be into scale trucks.... A well setup up everest/maxtone 10 will out crawl any scaler, but will look silly and not at all scale doing so....
"thumbsup"
Perfect except had to edit out the last sentence. "thumbsup"
svt923
I wanna be Dave
The answer all depends on the exact setup.
A well setup servo on axle setup with the servo moving parallel to the steering knuckles is undoubtedly the best setup. Nearly all the servo torque is transmitted to the knuckles for maximum steering, this is how pretty much every comp crawler is set up.
On the flip side, a bad CMS system is absolutely the worst. Basically everything is wrong with this setup and the steering will be garbage.
When it comes to axle on top of the servo setups like this:
versus good CMS setups like this:
They will perform about the same. Both have inefficiencies in movement and compromises but the CMS will require more trial and error to get it perfect. It's just a matter of personal preference at this point.
A well setup servo on axle setup with the servo moving parallel to the steering knuckles is undoubtedly the best setup. Nearly all the servo torque is transmitted to the knuckles for maximum steering, this is how pretty much every comp crawler is set up.
On the flip side, a bad CMS system is absolutely the worst. Basically everything is wrong with this setup and the steering will be garbage.
When it comes to axle on top of the servo setups like this:
versus good CMS setups like this:
They will perform about the same. Both have inefficiencies in movement and compromises but the CMS will require more trial and error to get it perfect. It's just a matter of personal preference at this point.
WHITE-TRASH
I wanna be Dave
While those rigs are garbage until you replace everything with axial parts he is not wrong with that sentence. Very few gaylers, even class 3 can hang with a basic sportsman. That doesn't necessarily mean the gayler is a pile of junk (most are junk, but there are some capable rigs out there) but they are simply in different classes.
As to cms vs servo on axle that's easy, cms is never an upgrade. On it's best day it can only be as good as a standard axle mounted setup. It cannot be better geometrically no matter how you spin it.
mewalsh100
I wanna be Dave
WHITE-TRASH - So, how do you really feel about scalers? It just wasn’t coming across!:lmao:
Alexander_0_1
Rock Crawler
^^^
Never mind that! I’m still trying to pronounce Geo-metri-ally.
Never mind that! I’m still trying to pronounce Geo-metri-ally.
dacaur
Quarry Creeper
lol, ok I was going "what the crap is a gayler?" Im not 100% up with the lingo but..... Well, I was about to google it till I read your post and went "Oooooooh...".....:mrgreen:
My e10 is one hay of a crawler i havent seen a scaler keep up with it yet and its still mostly stock except the chassie and the rear lockouts and axial parts in the rear axle and some cheap o shocks and driveshafts otherwise its bone stock not comp worthy but still
dacaur
Quarry Creeper
Yea when I got into scale crawling, I wanted to pass my maxtone 10 down to my daughter to try to get her into RC cars, which she has little interest in. But I know from experience that when dad has a sweet truck and daughter has a wal mart RC, she loses interest fast, so I picked up a barrage as a handycap so she would have a chance to keep up with me. Even having pretty much zero skill, she easily keeps up and even sometimes surpasses me on the rocks... We went on a trail run with a local scale group, and my barrage did pretty good, my only limit on obstacles was wheelbase, otherwise it kept up with the SCX10-II's and such pretty well, though it took every ounce of my skill. My daughter with the maxtone 10 and 2.2" pro-line BFG t/a ko2's made every obstacle look easy without even knowing what she was doing, even the ones the SCX10 II's struggled on....
