struggling for grip

[gd26]

Hi all,

Looking to get more grip on running my 22 mod-motor, as struggling to put down the power outdoors heading out off the corners... Indoors it's fine

running a 10.5
geared diff
speed passion esc with standard/recommended settings
weights were added to help


any help would he good thanks

[Robby]

Realistically, you haven't given enough information and your question is too vague for anyone to be of much help.
And there is no pat answer, or magic dust to sprinkle on your car, to increasing traction.
But the obvious starting point is to ask the fast guys at the track you're running at, for advice, as their's is going to be more relevant than anything anyone here can offer.
Otherwise, my advice would be to go to the set-up threads listed above ^,
http://www.oople.com/forums/showthread.php?t=1493
http://www.oople.com/forums/showthread.php?t=18719
or this database >
http://www.petitrc.com/setup/losi/Se...TwentyTwo.html
> find someone's that races on a similar surface to what you're racing on, and then use it as a baseline and adjust from there to meet your own personal preferences.

[Matt Butcher]

What tires are you using and how old are they?

[Frecklychimp]

Without knowing full set up tyres etc and track conditions then it is very hard to advise.

Straight away i would drop the geared diff and go for trying ball diff as your symptoms are already matching the issue caused by geared diff on less than smooth high traction predictable surfaces.

[gd26]

Tyres rear ballistic spikes white (new and control)
Tyres front Schumacher staggered ribs (new)
Setup according to top drivers is fine camber, links, oils, etc
Ground was grass and astro and dry
Used 5000 wt oil in the diff then ran it dry made no difference

I know it's a kinda odd ball question to ask as all track and conditions are different but I just didnt think I'd have problems when I've ran it on wood and carpet and got setup fine

[Frecklychimp]

None of the 'top drivers' set ups will be with a geared diff

It's the way the diff handles power and delivers it to wheels that will cause loose feeling as it balances out with weight differences on each wheel when exiting a corner.

Remember a diff is a traction device, road cars have planetary diffs, race cars use L.S.D's

A ball diff will 'slip' the power to each wheel in an almost unlimited ratio, it also doesn't matter as much if a wheel goes light where a gear diff is limited by the number of teeth and of course any resistance from oil/grease.

If a wheel lifts or goes light with a gear diff then power goes to that wheel... power will always find the easiest way out of a gear drivetrain, so as you are coming out of a corner the inside wheel is usually light, so wheel is likely to spin up faster then as you straighten and weight settles the diff is unbalanced and suddenly sends power across to outside wheel... which is why you get a 'shimmy' and the feeling of loose drive.

I've done a lot of testing with gear diff and oil settings, indoors on carpet it can be really good and driveable, accelerates quicker and brakes stronger so can outbrake others and stay on power longer.... outdoors on bumps and less predictable grip levels it is very hard work for the reasons you have found.

On a 2WD offroad car the gear diff is a poor compromise, which is why RTR beginners/basher kits have them and Competition cars don't

[jcb]

I found the two biggest set-up changes that increase drive are using the LRC over the HRC block and/or having the rear camber link mounted on the inside hole on the shock tower.

I've never run a geared diff so can't comment their, alhough I would imagine that running it with no oil would make an unloaded wheel spin up very quickly thus losing you drive as all the power is going to the unloaded wheel.

Like whats already been mentioned you need to list your complete set-up. Someone may be able to suggest a set-up change that will assist in your requirements. Everyone drives differently so you may need to tweek a top drivers set-up by changing a camber link or piston their to get it to work for you.

[paulj]

As other posters here have commented at least part of the problem is very probably down to the gear diff. I tried one in my own 22 mid motor, plus my son has a 22 RTR rear motor with a gear diff and I have switched back to a ball diff as it gives better corner exit traction.
The gear diff was ok on carpet but a bit 'loose' on slippy floor sections when exiting corners. It seems to be less of an issue in the RTR but it's running with less power and rear motor is not generally lacking traction on corner exit anyway.

In short put a ball diff in and try it.

[jsw123]

Originally Posted by Frecklychimp

None of the 'top drivers' set ups will be with a geared diff

It's the way the diff handles power and delivers it to wheels that will cause loose feeling as it balances out with weight differences on each wheel when exiting a corner.

Remember a diff is a traction device, road cars have planetary diffs, race cars use L.S.D's

A ball diff will 'slip' the power to each wheel in an almost unlimited ratio, it also doesn't matter as much if a wheel goes light where a gear diff is limited by the number of teeth and of course any resistance from oil/grease.

If a wheel lifts or goes light with a gear diff then power goes to that wheel... power will always find the easiest way out of a gear drivetrain, so as you are coming out of a corner the inside wheel is usually light, so wheel is likely to spin up faster then as you straighten and weight settles the diff is unbalanced and suddenly sends power across to outside wheel... which is why you get a 'shimmy' and the feeling of loose drive.

I've done a lot of testing with gear diff and oil settings, indoors on carpet it can be really good and driveable, accelerates quicker and brakes stronger so can outbrake others and stay on power longer.... outdoors on bumps and less predictable grip levels it is very hard work for the reasons you have found.

On a 2WD offroad car the gear diff is a poor compromise, which is why RTR beginners/basher kits have them and Competition cars don't

Brilliant explanation, I never understood the difference or indeed what they did before. Nice one.

[Robby]

Originally Posted by Frecklychimp

None of the 'top drivers' set ups will be with a geared diff

That isn't true - being as Cavaleri, among others, used gear diffs at the recent EOS race.
BUT, none of them are going to run their diff locked up by using 5K oil in it.

Then again, 'top drivers' would know their carpet set-up isn't going to work on astro anymore than their dirt set-up would work on carpet.

[gd26]

Thanks for all the info folks... I think I will try a few off the ideas out i'e try the ball diff outdoors....

I use 5000 wt oil in the gear diff same to what I run in the rear off my 4wd do you think this could be to heavy a weight

[Robby]

Originally Posted by gd26

I use 5000 wt oil in the gear diff same to what I run in the rear off my 4wd do you think this could be to heavy a weight

Uh..... Yup!

Other than rear tyre choices, 4wd and 2wd set-ups have little to nothing to do with each other.

[Razer]

Originally Posted by gd26

Thanks for all the info folks... I think I will try a few off the ideas out i'e try the ball diff outdoors....

I use 5000 wt oil in the gear diff same to what I run in the rear off my 4wd do you think this could be to heavy a weight

A correctly adjusted ball diff is definitely the most comfortable and easy diff to drive with outdoors.

I usually drive a ball diff most places, but at my home track I run a gear diff with 2000 wt. The oil has mostly been crushed or leaked out though, so I guess it's mostly like grease by now.

At my home track, I'm comfortable enough to use the geardiff, it holds up for a lot of practice without breaking, and even though it's a lot more unprecise and tricky to drive than a balldiff, it's okay there.

For a track I don't know that well? Nah, I'll stick with my balls

[cryer-evo]

Long camber link rear / 2 deg camber on rear / 2000 oil in diff / back the slipper of a bit more / soft insert in rear tyre if running 55 piston put 20 mybe 25 oil in rear shox yellow our white spring should have loods of grip :-)

[cryer-evo]

Forgot to say if you haven't got the cream waght on it get one

[gd26]

Again thanks for all the advice