Rear end Grip ? Help plaese :)
 

I've being running the X11 at Bury indoors with mini pins all round. (sports centre kind of carpet / low-ish grip surface)
Problem i have is rear end grip, or lack of it. Can someone please point me in the right direction.

I'm running the kit / kev lee setup (sort of as I have kit pistons, so heavier oils) Everything else is standard. I'm running 3 degrees of toe in at the rear, 1 degree camber all round.

The car could be ace, but when pushed, especially exiting a corner, the rear end breaks free and becomes the front end ! I've tried softer rear springs and different shock mount positions to soften the rear even more, also i've raised the rear, but it still breaks away.

It's starting to do my head in as the car is really quick and so nearly there, I just can't push it unless I want to powerslide out of every corner os feather the throttle whilst everyone goes past me !! Help.

Cheers. Andy.

Hi Andy

I had a similar problem with mine outdoors the other week - I simply backed off the slipper about 1/8th of a turn and the car was instantly much better for it.

Front ARB? (dunno if you have ARB's on the pred...)

I found backing off the throttle high point on my tranny sorts most of my problems with breaking away. the slipper sorted a lot out, but I found it was always slipping when I didn't want it to.

Hi Andy,

If you have weight in the front, try taking that out and moving it to the rear or shifting your cells back. Also make sure the rear diff isn't too loose causing it to diff out on power.

You could also try reducing the front droop to help the front "let go" a bit quicker out the turn. There should be a bit less droop on the front than the rear anyway.

Hi Kev.

No weight in the car at all really, and the lipo cells are saddle packs. I have the front ride height / droop / links etc set up as per your setup. All looks good on the bench !

I guess I could try the stick setup, but the weight difference would be marginal as the speedo and receiver are to the back and I guess they weigh a similar amount the the weight the lipo would create back there.

Maybe need to add some serious lead ? Just seems wierd, even under power as the car is beginning to straighten up, it can break away if I gun it. I had a few 'wavy' runs down the main straight as I tried to get the power down out of the 1st turn !

I did check the rear diff and it wouldn't slip at all, it would break the gears first !

I do have the slipper tight as i've had trouble with it slipping.

Any more ideas on the right rear setup (springs oil etc) as I have the kit pistons in at the moment.

Thanks. Andy.

and what esc-motor-combo are you running? What Lipo? (c-value)

You might want to try 2-2.5 deg of camber all round. I ran this at worksop at the weekend and loved the car. Also seemed worse with the roll bars off. I think the car might be rolling on to the outside of the tyre under power.

ads.

What setup were you running re shocks / springs please ?
Did you end up running the roll bar ? I took mine off as I thought it would generate less grip with it on.

Lowie. I tried a 6.5 and then a 4.5 in the car with some 25c lipos. I have exactly the same speedo / motors / radio gear in my B44 and it has bags of power and no lack or rear end grip so i know the problem is with my X11 setup.

I pretty much always run the Roll bar.. its helps the car straighten up gives more drive believe it or not. I think ads ran the roll bar too, he tried it without but prefered it with.

I've just re-read your original post... you say that you were running kit pistons and therefore running heavier oils? The kit pistons have 1 hole instead of 2 so you'd need softer oils to get similar static damping. Its worth getting the softer pistons though, or drill an extra hole with a #57 drill.

Hi keV

I'll try with the rear roll bar. I did mean lighter oils ! I've being trying around the 20 / 25 mark, I'll drill another hole. What is 57 size ? I don't understand all this technical stuff !

Cheers
andy

Its an american standard drill size and what losi use for their pistons. http://www.engineersedge.com/drill_sizes.htm

It works out to about 1.1mm

Its useful to have a set of the drills if you want to play around with slightly different hole sizes as they are available in small incremements, but the easiest option is to get the soft pistons from Lewis that already have this hole in.

afaik the 6.5 is quite enough power for the Pred. The Pred has a very light drivetrain and i think 4.5 is bit too much (if you are not an A-driver, I guess).
I just trained with a 8.5 in stead of my usual 6.5 and had plenty of power + made the car easier to drive (on an indoor offroad astroturf track)

Kev.

Had a good fiddle with the Pred over christmas and changed the setup a lot. Looks good on the bench ! Will see how it runs at the next Bury meeting end of Jan.

Went for:
20wt in the rear with kit pistons.
23.5 in the front with kit pistons.
Black springs all round, the ones that come with the X11 as standard on the front. The silver standard rears seem far too hard ?

Roll bars front and rear. Ride height as per your setup, which does look spot on, on the bench !

I've also set the LRP TC Spec speedo to profile 1 for punch, basically it's lowest setting, as it was previously on 3, which may be why it was too aggressive. Loosened the slipper a touch and tightened the rear diff a touch, so here's hoping :)

Thanks for all the info. Andy.

don't take this the wrong way, but that's a lot to change in one go!! how will you know what made the diffrance???

good luck with it though

it may seem a lil odd but hast the prop shaft unstuck its self from the front or rear couplings? had it happen a few times and creates the handling your mentioning?

it's a good call that happend to me only once though!! I would start with the softer springs, then move on to oil. problem is they are such a good looking car that you don't want to put it down!!!! so it's easy to do more than you may need to do !!!!

Yep. I had this happen on the fist 2 indoor meetings I ran the car at, you know it's happened when you brake hard and the car spins out !

I know this isn't the problem though, this time as I had a new prop shaft fitted and it's definitely not come unstuck.

Will run the car and see how I get on, I'm pretty confident it will be better. It was far too hard before on the suspension.
I reckon the speedo settings should help a lot too.

Anyone know what the spring weights are of the older X10 springs ?

I've got black / purple / green & red springs from my X10, then I have the black and silvers that came with the X11, all I know is silvers are really hard and the blacks are softer !

Cheers, Andy.

about the springs: you might count the number of coils.
from hard to soft:
silver, 5,5 coils, 6 coils, 6,5 coils.
(the more colis the softer, but the silver springs (with a white marking) are of a different metal and are the stiffest.)

Maybe this can help you.

Cheers Lowie.

The more coils the softer. Got it :)