Grip Roll on Astro Turf - Anti Roll bar

[mikeyscott]

Took my car out to Titchfield tonight to see how it runs and found it suffering from grip roll. Started to feel better after I change the rear tyres to mini pins - shumacher and fronts are mini spikes at the mo (need wheels for my stagger ribs). It was particularly bad with mini spikes on the rear. ( I will add that the tyres on it now are worn)

Shocks are :
blue spring & 35W on the front
silver spring and 30w on the rear

I have an anti roll bar sat in my box, worth fitting? I got it due to the manual stating that it's a good option part for high grip tracks.

How much would it help to fit it?

[Mike Hudson]

have you tried cutting the outer row of spikes off the rear mini spikes and the inner and outer rows on the front mini spikes?

[mikeyscott]

Hi,

Yes the front tyres spikes have been removed ont he outside edge which certainly helped. Nothing has been done to the rear tyres

[mikeyscott]

Since the new 7.5T motor has gone in I'm getting grip roll again. Do I stiffen the car up or change componds on the tyres? Anti roll bar will come off as the track has quite a few bumps in it.

[blue_pinky]

Not sure if it's the right way to go, but I've always softened the car up to reduce grip roll...reduces the grip and allows the body to roll more without taking the whole car over...well that was my logic anyway!

[blue_pinky]

Also, I've just gone from a 10.5 bonded to an 8.5 sintered motor in my x6, with no other changes I'm now getting grip roll...I'm wondering if it's got more to do with my throttle control and cornering speeds than the car setup!!!

Faster motor and heavy handed throttle control...more practice needed for me I reckon...what a shame!!!

[mikeyscott]

Originally Posted by blue_pinky

Also, I've just gone from a 10.5 bonded to an 8.5 sintered motor in my x6, with no other changes I'm now getting grip roll...I'm wondering if it's got more to do with my throttle control and cornering speeds than the car setup!!!

Faster motor and heavy handed throttle control...more practice needed for me I reckon...what a shame!!!

Very valid point and at the moment I'm heading down the softening the car up.

I've gone from a 19x2 to a 7.5T Losi brushless motor and it's way too quick! More practice required!

[Lowie]

i'm no expert but
* softening the front will make it grip more ... If you want to loose grip in the front, I should use a stiffer spring and/or thicker oil, not the opposit.
* Also more body-roll will make the car have more mechanical grip. The car will "push" more to the outside-wheels, giving those wheelsmore grip.
* Also, a roll bar on the FRONT will make the front less roll and thus softening the grip and response.

AFAIK, rollbars aren't used if the track is very bumpy. Astroturf-tracks overhere (Belgium) are very smooth (although with significant jumps) and so we use rollbars on them almost all the time.

If I were you I would use a rollbar in the front if posible, make the front suspension a bit stiffer and not softer, and cut the first outer row of pins on the rear tyres, as this gives the car more sliding and less grippy in the corner, and on Front tyres: cut one row on the inside and two or three rows on the outside

Please correct me if I'm wrong

[Lee]

Grip roll is a funny thing. Yes stiffening the car will reduce overall grip but pinky has gone in the right direction on this as softening the car will allow the car to move more and it will stop the initial bite on the side of the tyre. If the car is too stiff then all the weight is immediately put on the tyre wall and the tyre will just fold and the car will fall over

[blue_pinky]

Aaaah, ok, that makes sense...so it's the speed of the weight transfer that helps to make you flip!

Softer = slower weight transfer = less flippage...and higher ultimate grip and therefore faster cornering speed! I like it...I still need more practice too though...gotta get the turn in controlled nicely too!

[mikeyscott]

So green springs on the front etc. and soften the rear too. I'm removing the AR Bar

[Lee]

An anti roll bar should help prevent grip roll too but if you feel it unsettles the car then remove it, a roll bar reduces the side to side weight transfer so in turn prevents flippage

If you are feeling brave have a read here, depending on how your brain works you may need to read it a few times for things to sink in. its also handy to have a car in front of you so you can see what is happening/being talked about.

http://users.telenet.be/elvo/

[mikeyscott]

Think I'll just have to head to the track and see what it does. The AR Bar seemed to help with a 19x2 motor, but not this wild thing

[Lightblue]

Just to add my $2, I found less grip roll once I removed the front roll bar on the B44, and kept the rear on. The car had more front 'push' but this saved it from flipping.

[Lowie]

well guys, I really wanted to thank you here.

I raced on a grass track this weekend and had issues with griprolling. I remembered this conversation and all I did was softening the front rollbar one notch ..
and the car was dialed.
I'm happy with the result but most of all, that I learned something again.

THX Heaps!

[millzy]

most of the time you can fix the grip roll by changing your camber link height and puttinging litimers inside the shocks

[Lowie]

Originally Posted by millzy

... by changing your camber link height ...

How so

Does this mean, changing the Roll Centre?

[Fiddybux]

Originally Posted by Lowie

How so

Does this mean, changing the Roll Centre?

As I understand, changing the camber link height with washers under the ball joint keeps the tyres flatter in bends, so it should be less likely you catch the outside edge and flip over. A bit of negative camber will help too.

[Lowie]

and are you talking about making the camber link higher on the wheel-(out)side or on the car-(in)side?

[Lightblue]

To adjust the camber link as stated in the above posts, just add washers under the ball stud where it attaches to the front and rear top decks on the b44.

Adding more washers will alter the angle of the camber turnbuckles.

The more you add, the steeper the angle, and the less the wheels will alter in camber if pushed side to side. The manual suggests 2 washers front and rear.

Hope that helps!