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I fully understand theory but what I'd like to know is how do they drive compared to the standard a-arm setups? The only trailing arm car I've ever driven is my JRX2 with it's 5 link suspension which is sort of an evolved trailing arm setup. There were different trailing arms out there from the MIP and Bullet which were true trailing arms to the A&L which were semi trailing. They would each drive a bit different too I'm sure. Who here has practical real world feedback on any of them and if you do which one(s)? There are 2 different tracks I run at here. One is a large fast hard packed clay track which my RC10 wasn't happy at. The other is a slower outside loose dirt track. The RC10 didn't seem to do too bad on it and can actually hang quite well on it. I may just run one car at one track and another car at the other track with each car setup for each place. I can get a set of the Bullet trailing arms and am curious about their performance but having never driven a true trailing arm car I'm a bit in the dark about what to expect. I'm thinking the trailing arms may work at that track but I'd like some direct feedback from someone who has actually driven them. As I said I understand the theory behind each design so now I want the proof. Whose got them?

No one runs them? I guess a lack of a response is in itself a response. No one appears to be running them and none of the old is new builds have them so there must be something handling wise that just doesn't work as well as the standard arms setup . Maybe I won't try them.

I think 59burst has been running one, but he hasn't been on since Monday morning so maybe didn't see this post.

fredswain wrote:No one runs them? I guess a lack of a response is in itself a response. No one appears to be running them and none of the old is new builds have them so there must be something handling wise that just doesn't work as well as the standard arms setup . Maybe I won't try them.

They were originally intended for rougher non-Blue groove tracks! As you may or may not know, the tracks from the mid to late 80's were just loose garden soil type tracks that trailing arm cars worked well on. We might as well be racing on carpet now!!

a01butal wrote:I think 59burst has been running one, but he hasn't been on since Monday morning so maybe didn't see this post.

ill tell him his presence is required on the forum

I'm running with this setup http://www.rc10talk.com/viewtopic.php?f=35&t=21533. and the track where I run this is here http://www.youtube.com/watch?v=IBS3DarWnMA

the rear traction was not good enough with my shortened rear tower, 1.18 shocks, and bk bar tires. I never tried the original tower and 1.32 shocks yet. so cannot tell about it. the only difference from the picture are rear tires. i'm using goose bumps now. I'm not a good racer and my english is not fluent either. so I can tell you is this setup is more sensitive than the original. runs straight as the original, and better steering than the original setup. it steers exactly what I want. but got a slight problem with jump. landing is great. it just need more power at jumps. maybe it came from the rear tower which I made.
as you can see, the jump is small and you can call it just a bump. and I assume large smooth jumps won't need more power. it's all I got here. better steering with the tires with radius

aip47-2008 wrote:

fredswain wrote:No one runs them? I guess a lack of a response is in itself a response. No one appears to be running them and none of the old is new builds have them so there must be something handling wise that just doesn't work as well as the standard arms setup . Maybe I won't try them.

They were originally intended for rougher non-Blue groove tracks! As you may or may not know, the tracks from the mid to late 80's were just loose garden soil type tracks that trailing arm cars worked well on. We might as well be racing on carpet now!!

That was back when off road was truly off road. I personally feel that modern tracks are a joke. They are difficult but mostly because they destroy cars they are so hard. There is pretty much nothing realistic about doubles and triples unless we are on a motocross track and even then, they are dirt! There is a track here that isn't blue groove but it isn't all that well maintained and being outdoors with our drought, it is a very hard track to get traction on.

I actually wonder why if trailing arms can get traction on loose tracks, why wouldn't they not still work well on concrete...err..."blue groove" off road tracks?

I'm no expert on the setup, and have never run one. I do recall reading a thread of someone else running one too. IIRC, one of the key issues had to do with chassis roll. Due to the fact that they act in the fore-aft plane, they don't roll side to side as well as an A arm. That plane of action is the reason they are good on rough bumpy tracks. They "float" through the bumps in the direction of travel better. On the high bite tracks (that are like road courses in surface) chassis roll is crucial to cornering with speed. I'll look for the thread and get the link.

fredswain wrote:

aip47-2008 wrote:

fredswain wrote:No one runs them? I guess a lack of a response is in itself a response. No one appears to be running them and none of the old is new builds have them so there must be something handling wise that just doesn't work as well as the standard arms setup . Maybe I won't try them.

They were originally intended for rougher non-Blue groove tracks! As you may or may not know, the tracks from the mid to late 80's were just loose garden soil type tracks that trailing arm cars worked well on. We might as well be racing on carpet now!!

That was back when off road was truly off road. I personally feel that modern tracks are a joke. They are difficult but mostly because they destroy cars they are so hard. There is pretty much nothing realistic about doubles and triples unless we are on a motocrooss track and even then, they are dirt! There is a track here that isn't blue groove but it isn't all that well maintained and being outdoors with our drought, it is a very hard track to get traction on.

I actually wonder why if trailing arms can get traction on loose tracks, why wouldn't they not still work well on concrete...err..."blue groove" off road tracks?

They worked well on rough tracks because the deflection of the trailing arm matched the direction of travel so there was a fluid chassis in rough surfaces, but the trailing arm design ( not semi trailing ) also has vast amounts of negative camber gain through the travel, so when thd rear suspension is compressed there is very little contact between the track and the rear tires, and in s high traction situation the rear end " loads" in the corner and stays loaded all the way through making the car very very tight.

Here's the thread of the car I remembered-

http://www.rc10talk.com/viewtopic.php?f=35&t=1649&hilit=history

A true trailing arm design has zero camber gain. The Bullet and MIP were true trailing arms. The semi trailing arms have camber gain. A&L had an example of a semi trailing arm.

When cornering, a normal wishbone/a-arm and upper link suspension has some negative camber change as compression hanppens. This increase in camber maintains more tire contact patch when combined with the chassis roll. With those "true" trailing arms, there is no camber change, and thus while cornering less contact patch results. This is REALLY bad when your facing tight traction, blue groove surfaces.

Most people today running on modern blue groove style tracks run such low roll centers that they practically have no camber gain. Look at the 22's. Practically nothing. Strange but true.

I have a handmade chassis with the A&L trailing arms that I ran on my old track. The track was small (tight) and bermed, with topsoil packed as hard as my feet could make it. That was my favorite car to drive! Tonnes of traction during acceleration and hard to bend out of shape.
Here is a question about the 22's having very little camber gain; how does that effect tire wear? Or are the new gooey tires used for the hard tracks less prone to uneven wear?

Many of the 22's I've seen at the track seem to have more wear on the outer half of the tire face as opposed to the inner half. On high roll center cars with lots of camber gain you wear the inside first. My personal tuning technique is to set my camber links to a point where I have even wear across the face of the tire. Then if I still need any roll stiffness at either end I'll use sway bars. I want the maximum amount of tread being used as possible.