Handling issues

[ben]

Raced my pred at the weekend on a rutted grass surface, the track had one particularly bumpy section in it
Most drivers could get round this section at about half speed, I couldn't even do that, I had to crawl, not even quarter throttle, as you can imagine it killed any chance of me doing really well.
The rear end just kept kicking up. I tried silver springs with pre-compression golds, black springs, with & without pre-compression springs (all with 45wt oil), varying amounts of toe-in & camber - all useless!
I need some advice on rear end set ups (ooh-err!) for bumpy tracks.
Somebody please help before I buy a Losi!

Ben

[chris burgess]

buy a Losi? did somebody really say buy a losi on this forum.....jeez, I've never banned anyone before but theres aways a first time!!!! ;D

Right, back end kicking up?
how much ride height did/do you have and what rear toe-in are you running? (this is important if the rear bouncing from side to side, as oppoesed to up and down)

You should never run without the pre-compression springs on the car either. If the track is really bouncy, then you should put the softer (black?) springs on the rear.

You could also try to place your rear shocks on the lower pick up position, to get more droop.

It sounds as though your problem is the car grounding out, and the chassis is forcing the backend in the air as opposed to the suspension setup doing it.

[ben]

Only joking about the losi.

I don't really have any accurate equipment for setting the toe in or camber. I unscrewed the toe in links 1mm each from the build set up, I would say about 2mm looking at the wheels against a protractor.

The camber, in the middle of the top link holes, I'd say about 1mm.

Ride height was set so the driveshafts were level when car is dropped from about six inches, how I've always set my off road cars.

[2lb-racing]

when in USA, drivers ran on a very rutted track, they said, it's a "french track", i race every time on a "french track" and the X10 is very fast on this track, try 60WT at the back with silver or 5,5 with soft piston, use everytime gold pre-spring.

[alfonzo]

Was it that bad Ben? Hell, the Losi is hard to beat for bump handling but all you have to do is wait for its belt to snap, normally no more than 3 - 4 laps. ;D ;D

PS Do you fancy coming 'Up North' to have a go at any of the West Midlands Winter Series? Kidderminister, Coventry etc. Although to be honest we could just make it a beer trip and the RC can take a back seat..

Al

[chris burgess]

when th driveshafts are level, the Pred is quite low....if you go back to that track, stiffen up the back end a little and put the shocks in the lowest pickup point.

one thing to be careful of though (and I am sure i dont need to tell you) is to make sure you are not setting your car up for just one section so that it is a handful everywhere else!

[Northy]

Ride height is very important on the Pred, run the rear at 22mm, that will make a huge difference. Also make sure you don't run the front too low. Take a look at the setup sheet from TTech, they are a very good starting point.

G

[ben]

Thanks for the info guys, I'll get the ruler & protractor out & start again.
Would not having an anti-roll bar make a great deal of difference to the overall handling of the car?

Alfonzo, I wouldn't mind coming 'up north' (if you look at a map I'm actually further north than both Coventry & Kidderminster!) for a spot of racing some time, indoor might be better, wouldn't wanna come all that way & see it rained off. Might have to spend all weekend in the pub!

[chris burgess]

not having an anti roll bar wouldn't affect the bump issues that you have ben.

best thing to do, is to spend £20 on a RPM camber gauge and their toe-in gauge. they are not spot on accurate, but they are better than simply visually aligning things.

[2lb-racing]

ben
on very bumpy track, you can use an antiroll bar on the front to stabilise, for example, in hight speed curve when the wheel down in the hole

[Northy]

I never run the rear anti roll bar these days.

G