18 replies to this topic

[MRA]

Or if the power can cope use a higher gear

Antiroll bars are pointless in a mini, because of the subframe desing.
You have to change springs rating, which in rubber cone suspension, will mean getting red dot cones.

Why does the subframe affect the use of an ARB. I wouldn't fit one to a road mini on road tyres, they're just not needed, but I run front and rear ARBs on my hillclimber, with great sucess.

The main reason for this is that the yellow dot cones are just not stiff enough, the ARB means I get the advantage of stiffer cornering with reasonable compliance, important on a hillclimb.

I think the answer to the originla question was obvious and has been answered, to stop the inside wheel spinning you need an LSD or ATB. But the simplest thing you can do is use a bit less throttle and get stickier tyres, when power exceedes grip then you're screwed.

[adamg1380]

I have the same problem on my hillclimb car, it's ex-road and I'm still getting it sorted for the track - ATB or LSD is the answer. I know someone who fitted the quaife ATB to his pug and he was 2 seconds faster on runs in the low 70 seconds, he said that's all it was, just the ATB - Harewood is tight and twisty though.

I'm going going for the Swiftune ATB as it's a drop in replcaement, a 2nd hand LSD might not be, you might have change other stuff around it.

I'll also be going for ARBs but that's for sprints, as Wil_h says yellow dots (which I'm on) dont' quite do it once you're off road tyres. On road tyres I actually think red dots and no ARBs work well, for road or track.

[Ivor Badger]

Why did you let the front tyres down, so what tyre pressures were you using with what tyres?

I suspect you have the front tyres tucking under so you are running on the tread edge and tyre wall. This causes excess roll and the inside wheel to lift with no effective rubber on the outer wheel and all the spring changes, rose joints and geometry tweaks won't fix that.

Get the back slightly lower than the front and fit a rear ARB with stiff shocks with at least 4 psi more in the front than the rear. Don't use shocks with massively stiff rebound on the front.

[mini7boy]

The first thing you need to do is decide just how much the wheelspin is slowing you down.
Then you have to decide if it's a serious problem or just an annoyance.

Unless it's a serious problem, either in terms of laptime or in wheel-to-wheel racing, it may be something you have to tolerate
so as to avoid causing other, more important problems with an attempted cure of the wheelspin

The impact of wheelspin is usually related to its severity and duration. If you just have it for very brief spells and short distances,
with minimal excessive RPM it's not such a big deal.

Do you find that your wheelspin is mostly in the low-speed turns? Cars usually roll more in lower speed turns, unloading the inside wheel and
exacerbating wheelspin.

The amount of wheelspin is influenced by the circuit. Turns that are slow and/or off-camber on exit will cause more wheelspin.
Circuits with fewer low-speed turns generally have less wheelspin. It's harder to generate much wheelspin when running at
higher speeds.

Since time/speed lost in low-speed turns is the time/speed most easily regained, it isn't as bad as if it occurred in higher speed turns.

As long as you don't run an LSD, you're likely to have some wheelspin in the slower turns.

Also, as long as you also run the car in rallys, you will probably have to settle for some compromises, such as a higher ride height for rallying.

First thing to check. Is your unloaded front wheel's suspension running out of droop/rebound travel because of the droop-limiting "stop"
that is attached to the subframe just below the upper suspension arm? If this is a problem, it would limit the unloaded wheel's ability
to drop and stay in firm contact with the ground.

You might try softening the front shocks in the hope that reduced rebound damping might allow the unloaded wheel to stay more firmly in contact with the ground.

Alternatively, you can try a rear swaybar, but you may have to bite the bullet and change setups on the car depending upon whether you're racing a rally or a circuit.
You might benefit from running the car lower for circuit racing because lower cars usually roll less than cars raised up for rallying.

Edited by mini7boy, 27 September 2009 - 10:45 PM.