JohnP2

Now that I've been running my truggy stock for a bit, there are a few things I think I would like to tune. I've studied as much as I can on this, and would like your feedback. Please take it easy on me as I am clueless when it comes to suspension, but really trying to learn as I go. I fully realize what looks good on paper might be horrible at the track.</p>

1. Ride-height. Right now I have the front end very low. Right now about 25mm. The back is about 27mm. I've found that the handling is INCREDIBLE, but think this is a little too low. I want to the keep the back higher while still maintaining stability.</p>

2. Downstop. I'm getting a LOT of upward travel when I throttle (thus my front is low). However, I want to apply a little more power out of corners, so believe I can decrease the travel in the front arms to make it a bit more stable?</p>

3. Front diff oil. Running 7k now. I want to go lighter to increase off-power steering into corners, but I know how ride height can affect so many things curious if this is the right thing to do?</p>

Thus the idea here is: Increase ride hight to be normal (as it is way too low), lighten front diff oil to allow sharper off-power turns, and increase the down-stop (less travel) so I can punch it out of corners.</p>

Of course I might completely hate this set-up, but thinking this is what I will try tomorrow.</p>

Thoughts?

Finally - I'm trying to get my arms around the difference between roll-center and roll-axis.If someone has an easy explanation - I'd love it. ;-)I believe I know what it is diagramed out....but how can I "feel" the difference.</p>

mopartybob

while my knowledge is limited, I can start you off with keeping your axles (front) horizontal. (rear) slightly elevated from horizontal, to compensate from torque. as long as you keep this as a base line, your tuning woes should be at least more predictable when you make them, keep in mind, if your runnin at a local track all the time, find out how the others are runnin there set-ups, but since you made no mention of what your runnin, i guess your runnin what others are runnin....... more will come to me as this twelve-pak disappears.... MPB

t-max97

My Feedback: (9)

I don't know about the rest but I wouldn't think limiting the suspension travel is a good idea but I may be wrong. He's running a hot bodies d8t.

JohnP2

Thanks for the responses. Yes, this is for a D8T.

Foxy

Ride height - easy, arms should be level (horizontal)

Droop (what you call down stop I assume) - this is a bit more tricky. More droop is usually better, you will see most setup sheets of racers running maximum droop. The reason for this is that if you reduce downtravel, you make it easier for that wheel to come out of contact with the dirt, losing traction. Be careful with this, cars with little droop can become unpredictable.

Front diff - What kind of driver are you? If you are an aggressive drifty driver, you might want to go down in weight a little, but bear in mind, what makes a car fast is how much speed it can carry OUT of a corner (and therefore hit the following straight with more speed), which is improved by increasing the weight of the front diffs. I would not go lower than 7k, in fact, I recommend you try 10k. It's better to go slower into a corner and faster out.

As for how roll center and roll axis affects things, try this site...

http://users.pandora.be/elvo

JohnP2

AWESOME website, Foxy. Just what I've been looking for. Thanks so much!

Dads like rc too

John, the diffs are the hardest part to tune, mainly because you have to keep tearing them down to try different fluids. I think most people just deal with whatever they're running after the third time. I think what Foxy said is kinda of the norm. 10k in the front, 30k in the rear. Try locking your center diff and see how that feels. Use hot glue in the diff instead of epoxy, this way if you don't like it you can just heat it up and put oil back in.

Foxy

Dads, you meant 3k in the rear, right? Also, one should never lock the center diff of a 1/8th for racing. You instantly negate the effect of one of the most powerful tuning options on the car and the single thing that makes that class better than all others, a locked center turns like a pig. John races his truggy, perhaps you thought he was bashing, in which case locking the center can be fun sometimes, but again, not something I would want to do as a rule.

Personally, I like 10-10-5 for truggies, and for bashing I would switch out the center for another with 50k in it (avoid unnecessary rebuilds).

John, you're very welcome. Xray also publishes a very nicely polished off road setup guide which is worth a look. It's Xray oriented of course, but it can be helpful as a quick reference to what settings causes what effect. You can download it here...

http://www.teamxray.com/teamxray/sho...p?file_id=4461

t-max97

My Feedback: (9)

The only reason to lock the center diff is if you want to wheelie lol that kind of eliminates the whole advantage of a truggy over an mt.

Dads like rc too

Yes, sorry I meant 3 not 30. But I do like the center locked, but then again I'm not a hardcore racer like a lot of the guys on here. Luckily we have a pro track "badlands" a few minutes from where I live. My Truggy runs great there, but let's not forget I'm running a Redcat Monsoon, most of the equipment you guys are running are much better than my rig.

supertib

too much droop is bad !!! unless your running on a super blown out loose surface..... then it helps....but if your on a decent surface with decent traction pull some droop out of the car.............I run my cars with very little droop and if you watch my videos my cars are dialed !!!!!!! droop allows weight transfer...which is good for increasing traction, however it is at the expense of stability...a car with full droop wallows in its own suspension....

t-max97

My Feedback: (9)

See I told you I might be wrong, Lesson learned never listen to me.

supertib

Myself I run my cars with as little droop as possible....... different conditions of course dictate how much droop to use...... If the trackis loose and completely blown out then run max droop, but if the track is nice with decent grip then you dont need much droop, and often times too much droop badly affects the handling

t-max97

My Feedback: (9)

Good to know, suspension tuning isn't my strong point lol. I just figured If there isn't much suspension travel It could cause some really hard landings.

Foxy

I don't think it's Neal's either.

I'm only kidding, I respect Neal's opinion, he's probably run more laps on off road tracks than me. I don't agree that droop should be 'minimum necessary', I think it should be 'minimum necessary, then add some more for safety'.

The detrimental effect of not enough droop is obvious, wheels leave the ground, I've not noticed any serious negative effects to having too much droop except increasing the likelihood of damage to the shocks as they are at full extent when the carlands from jumps.

The documented disadvantage to too much droop is that when you enter a corner, the chassis rolls both sides (compress one side, extend other) and maintains the same center of gravity (predictable, if not the fastetst way, hence I siad low droop cars can be unpredictable). When you have only a little droop, instead of extending one shock and compressing the other (it can't extend any shock beyond its droop stop), the car is forced to compress the opposite shock, effectively lowering the center of gravity as you go through the corner.

The trouble is, on 1/8th buggies and truggies, we have appropriate anti-roll bars which cause the suspension to compress and the CoG to lower as we go round a corner, and they do this more effectively than the droops stops as well. The anti roll bar performs exactly the same effect as running almost no droop, making it much less important to have the right amount of droop, as to have 'plenty'. Having plenty of droop AND the right anti roll bars, is the best of all worlds, all the advantages of both. I agree, full droop isn't needed in most cases, but if you find the back end loose, increase rear droop.

I think the right thing for you to do is to make the front ride-height what it should be (arms level). Reduce front droop a little and perhaps increase rear anti squat as well. On the rear, I'm pretty sure you're going to want close to maximum droop, though you should experiement and see what suits you better. All of this is subjective and can vary based on driving style. I've seen successful (club) racers taking odd lines around tracks and running odd setups, but it works for them, so more power to them.

supertib

My Team wins Pro level races all over the globe, Trust me, run the car with as little droop as you can get away with,,,the car is more stable and more predictable........... droop is only used when the track gets blown out and is rough...........

the more droop you have the more chasis roll you allow, the more chassis roll you have the more your setup geometry is compromised..... As a rule all the fast guys run as little droop as they can get away with .... On my track I run nearly zero droop and the cars handle a million times better then they would with full droop..........The only time we ever put ion full droop is if the track gets blown out the traction is very poor, or a combination of both........... But on a high bite groomed track like mine we run nearly zero droop...........

Foxy

Neal, you do realize that the average Joe has about the same relationship with a team driver as a fish does with a bicycle? Telling average people to run almost no droop is not the best advice, imo. The most common setup mistake I see in 1/8th buggy and truggy is people having problems keeping the back end planted due to not enough rear droop (they build the kit, set the ride height, then screw in the droop screws to meet the chassis with the wheels on the ground, aka zero droop). I can agree to disagree anyway.

If I were a world champion team driver, there would be a hundred setup changes I could make to the car that would be good for me but detrimental to someone else who did not also possess world class skills. Suffice it to say I will continue setting up my cars with a little extra droop and recommending the same to others for the initial reason I stated, too little droop makes the car unpredictable, too much has no major detrimental effect.

mattster1971

I never understood droop. Unless we are talking about how the kids wear their pants now with the underwear showing, that's just too much droop. But seriously, how far should the screws be turned in? What spot do you put the shock in on the shock tower? I just don't get how to make a good setup but then again I haven't read up on it much either.

nitroexpress

I think if anyone checks the setup sheets that the Pro drivers post, it's clear that droop is usually set to the max amount that theycan get away with.

"The Guide" from JQ does a decent job of giving concise droop information.

<div style="margin: 0in 0in 0pt"><font size="2">Down travel is in my opinion a more critical set up parameter than ride height. It makes a larger difference to the handling I think. By down travel I mean the difference between ride height, and the maximum height the car can be lifted, with the tires still touching the ground. One important thing to talk about is how down travel is measured. Many drivers like to measure the shock length to state down travel. This is however a misleading way to do it. It is good if you only want to keep the information for yourself, but to other people the information doesn't mean anything. This is because to figure out the actual down travel, from shock length, one needs to know which shock positions, and rear hub positions were used, and often this is not possible. Normally only one set up parameter is discussed at a time. So I never measure the shock length, I always measure as I would measure ride height, but measure up to the point where the wheels just touch the ground. This way it can be compared to other cars whatever their set up is, and even other brands. I like to measure without wheels as it is more precise, and when I want to compare, I measure with wheels. Of course to compare, one has to use the same tires, as tire diameters vary.</font></div><div style="margin: 0in 0in 0pt"><font size="2">The more down travel, the higher you can lift the car. On the track, more down travel basically means, that the tires can stay on the ground longer, when going over a bump the wheel can fall into the hole further, and when landing off a jump the wheels will hit sooner.</font></div><div style="margin: 0in 0in 0pt"><font size="2">More down travel will make the car jump and land better, give more traction, and most of the time it will go better in bumps. Too much down travel can make the car roll too much, and make it respond slowly, which could make it spin out and be hard to control. This can also depend on the car. For example Mugens are known for being good with a lot of down travel, and Losis bad with a lot of down travel.</font></div><div style="margin: 0in 0in 0pt"></div><div style="margin: 0in 0in 0pt"><font size="2">I like to measure down travel like this. Shock length doesn't actually tell you the amount of down travel, unless you use the exact same shock and hub positions. When measuring down travel with wheels on, the measurement can be compared to the down travel of cars with a different set up, or other brands also.</font></div><div style="margin: 0in 0in 0pt"><font size="2">Less down travel will make the car jump worse, and most of the time handle bumps worse, but the car will be more stable at high speed, and specially on high traction. It will be more responsive also, and less prone to flipping over.</font></div><div style="margin: 0in 0in 0pt"><font size="2">As for bump handling, it gets slightly complicated, as depending on the track, and driving style, the amount of down travel for the best handling, can vary, a lot of down travel may be the best, but it may also make the car go into all the bumps, and thus slow it down, and make it more unstable. Less down travel may be worse, or it may actually help keep the car on top of the bumps, and actually make it faster and more stable. There really is no magic set up for down travel as far as bumps are concerned, each racer really needs to test this themselves. In general, less down travel for smooth high grip tracks, and more for loose, or bumpy tracks, or tracks with many jumps. Down travel, along with ride height has a tendency to change, so it is good to check it before each run.</font></div><div style="margin: 0in 0in 0pt"></div><div style="margin: 0in 0in 0pt"></div>

Foxy

Http://users.pandora.be/elvo

Suspension section, page 6.

supertib

too much droop has plenty of negative effects LOL......but what do I know about this offroad racing stuff

However it also may be that you dont run on a track as nice as ours here......I mean if your running on some crappy low grip rough track then max droop needs to be used............But on my track which is very smooth and extremely grippy too much droops makes the cars handle very unpredictably for everyone, pro's and novice alike.........

t-max97

My Feedback: (9)

I think that's all he means, every track is different so the track john is running at may benefit to run more droop than the tracks you run at.

Foxy

Doesn't matter how grippy your track is, the only negative effect of more droop is slightly reduced corner speed and more squat, which are hardly going to cost you a race, whereas too little droop will cause the car to be all over the place. Anyway, I'm bored saying the same things, lets just agree to disagree.

supertib

Your wrong there cowboy....talk me in a few years once you have more experience with racing and setup.....

on my track too much droop causes the cars to handle unpredictablly, usually makes them push like slowplows in the corners, which definitely hurts your racing results.....nly have hundreds of hours of chassis testing under my belt on my own personal track..with multiple cars from Kyosho to Serpent, Hot Bodies and Mugen, with my own Tea, of drivers.... but whatever, believe what you want, you know best LOL ! I would almost pay money to have you come race up here....just to see where your skills really are

Foxy

Well said. Yeh, with only my ten year on-road racing career, and decent position nationally in the one and only off road season I ever competed in with a budget car, not to mention that I'm an amateur track day enthusiast IRL, I expect I have a lot to learn from you about car setup.

Furthermore, too much droop does not cause push, why on earth would it? There's no physical way that droop could have any effect on turn-in, what are you on about? Are we talking about the same adjustment?