Shocks off the Back!!!
 

Can anyone explain to me why I'm seeing people running their BJ4's with the rear shocks hung off the very back?! i.e, the wrong way round to the standard kit way. It looks like an easy job to do, re-mount the rear tower off the back brace, drill the wishbones on the rear and re-hang the shocks!!
But, what effect does this have on the handling of the car?

Never seen it personally mate but i would imagine its to stop the rear end collapsing. i dont know why they would do it though or what difference it will make

If I didn't explain myself very well perhaps this picture will help!!

they are that way round on an Atomic Carbon S4 aswell...

maybe Jonathan can enlighten us?

You're quite right, the Atomic run's this way too! They're also like this on the Losi! I'v even seen it done on some Yok's?!

i thought id seen on a yok
i think it just makes it more stable at the back

Is it because it looks better? :confused:

It moves the weight further back, not that 99% of us would ever feel that effect to be honest.

if the wishbones flex, then having the shocks on the rear mean the wishbones will never flex into a state of pro-squat... although with the materials used in todays kits - nothing flexs so much anyway.

Im trying to apply some logic, and can't think of any other reasons - other than taste and perhaps a slightly different mounting position but I can;t vouch for that.... Im sure somebody must know.

thers many reasons for this but not as many reasons in numbers to mach the amount of sponsors in Chris Longs sig !!! LOL

must work, most of the top cars have this sort of set up

So, other than perhaps for it's looks and a very,very,very slight chance it will handle a touch better, we saying we don't really know?!

id imagine at high speed corners you wouls feel a difference

No i don't think you would to be honest.

Imagine the shocks weighed 1kg combined, then moving them like this would perhaps reduce initial steering and increase pendulum effect. But they weigh a 10th if this at the most, and I really don't think it'll e felt.

This is also a mod done to Bosscats, and more recently to XXX4's (which I think it was designed to be done as a choice)

i have no idea
but have heard it moves the weight around so its all sprung weight between the shocks
help settle the car down
not from experience but over heard conversation

Does it alter wheel rate slightly? :confused:

The rear inner pivot point is wider than the front one due to the inboard toe-in. Elvo will tell us.

G

All it will do is move the weight very slightly, I can't see it making any other difference except as Chris has said about the wishbones flexing a tiny bit.

Rich Cree tried it at Southport and I think the conclusion was it made no difference :)

Rich,

But is the wheel rate affected by the inner pivot distance?

G

Since you have to drill your own holes to mount the shocks on the back of the wishbones I wouldn't think so ;)

But only if you cad'ed it all up and calculated where to drill the new holes to keep the wheel rate the same?

ELVO!!!!!!:confused:

G

I think G is right here, if you drilled the hole inline with the one at the front, i think you would be changing the wheel rate, i think it would give the feel if standing the shocks up more and without moving them out on the tower:eh?:.

Could this stop the arse end leaning so much?:confused:

if you drill the holes the same distance from the inner pivot on the wishbone the same as they are on the front the wheel rate wont change (the leverage will still be the same)

however, this distance on the back side of the wishbone will be wider appart than on the front of the wishbones due to the toe-in, so if you leave the upper location of the shocks the same, your rear shocks would be layed down more.

but I think the biggest thing you will notice is the rear weight, and also, if you do it right, the rear wing will be further back.

Your's wasn't moving round much at the back from what I could see at NERCR Lee :confused:

That's it Chris, brain not working this morning :thumbdown:

G

It felt like it was, especially coming through the chicane onto the straight, that was the only place i could feel it though;)

was that just you shaking to the music though

What? Who?

Doughty got it spot on.

Blimey!! That all started to get quite technical, but thankyou all for your opinions!!
So Chris is saying by moving the shocks to the rear of the wishbone it will cause more flex in it. What will this do to the handling?
Richard & Mr.Doughty are both saying it will shift the weight distribution about and push the wing out further. Again, what effect will this have on the performance of the car?

I think the conclusion is that it probably isn`t worth doing, there is very little to be gained if anything, if rich cree cant tell if there is a difference then us mere mortals wont either;)

I normally think that having weight 'hanging' over the rear keeps the rear end planted when hitting a kicking style rut or bump.

the wing further back I find is more stable in flight.

I think the wing on a 10th scale buggy is like the flight on a dart, the further back it is from the CoG the more likely it is to stay flying forwards when its in the air.

He also tried it at Batley and did notice a difference ;)

I find the car is better over highspeed bumps with the shocks at the rear.

Do you mean Batley indoor Jonathan?

Might be worth a try to tame the car over the super random mats

No it was at the national outdoors.

Did it fly better? :confused:

G

Except for the last two World champions, Euro champions, US champions, etc.

Brad wins the thread :lol:

If the bottom shock mount were in the same place relative to hole in the front of the wishbone the wheel rate would actually get softer. It's a bit counter-intuative as the hole is moving out on the car but if you think about it the distance between the inner pivot point and the shock pickup point is the same. All you are doing in effect is laying the shock down, therefore making it a bit softer initially.

Don't think so lol, so the XX4 did not win any worlds or euros then :D

Ah, another trick question, 2 in this forum in one week, I can;t handle it! :woot:

I said the last two, as in the two most recent of each event. The XX4's last World Championship was six years ago.

The XX4 is still a great car. However, its days of domination were before the current crop of four wheelers existed (BJ4, 501X, D4, B44, Aero, etc.), all of which have the shocks mounted in front of the rear arms.

I will let you win this time Brad, but you did miss off the S4 which was the highest placed car in production in our national series last year ;) oh with shocks at the back lol.

but it wasnt really in production....it was a conversion...................

hehe

You know what i mean ;) and it does use a lot of Jconcept parts so win win for brad :lol: