Rear ARB removal / 6" rims at the back

[Pendennis]

Hi Peter, I have no idea why I wrote that, got in a right muddle

[6speedmanual]

That's alright mi old bean! If I'd known you'd just written it in a muddle I probably would have spend fewer keyboard strokes re-explaining myself! :))

No worries :)

Peter

[FramerateUK]

Just to add my 2p, I went from the 15" CR500 (195 width) to the 13" CR500 on 6" rims all round.

My car is also a Roadsport 140 that thinks it's a Superlight. 

I've done a few trackdays on both and driven a few thousand miles with both on the road and as far as absolute grip goes, I can't say I noticed any difference.

The 13's are easier to slide if I want to , but it's because I feel they give me more feedback than the 15's, therefore I can tell when the grip is about to go. While I haven't got laptimes or such to back this up, they've made me a faster driver on trackdays, and I'm definately pushing the car harder because I can feel when it's about to let go - where with the wider and larger wheels I couldn't quite tell where that limit was.

[CharlesElliott]

You can just remove a droplink completely to simulate 'removing' the ARB before you go to the effort of actually removing it.

[Julian H]

I never thought such an innocent post by little me would stimulate so much interest and debate! 

I will be playing around with RARB settings and disconnection in the near future. Do I have to remove the weight from the rear wheels to align the different bolt holes or can it be done sitting on the deck?

The reason for considering the smaller rear wheels is to increase the fun factor, make the back end more predictable and easier to get closer to the limit, with more progressive breakaway. I understand that is what it will give me. I also find it interesting that CC themselves fit 6" on the back of the Roadsport and Supersport, including the 180bhp R version. See

at 1min37secs for Chris Harris on the subject.  

Cheers, J

[6speedmanual]

I once presented at mot with an arb drop link disconnected.... caused a comment from the tested but passed as clearly not a fault.

 

It's right that it should cause a discussion. Getting into the nitty gritty of how the car works and how we can so quickly and easily adapt the driving pleasure of our machines is one of the joys of 7 ownership.

 

Ah yes that CH video was one of the items I alluded to above. Same spirt as my R400K on 185/60 all round.

 

Peter

[TomB]

Thread resurrection, as this one is closest and most recent to my query.

Im planning on fitting 8.5in SLR split rims to my 1996 car with an over diff RARB. It's an LSD, and I've got one way adjustable dampers. Currently the drop links foul the wheel, a well known problem, for which the solution is either to swop the links to the inside of the trailing arm and ARB, or remove the ARB all together. If I move the drop links over, I can only use the second softest (2nd hole from end) setting.  

So my question is, should I remove the RARB completely, or keep it but with the 2nd softest setting?

What about adjusting the dampers - if I set them a couple of clicks harder, will this help mitigate roll induced by removing the RARB? 

The car has 150bhp and I'm fitting the wheels mainly for cosmetic reasons and I like the proper split rims.

Finally, and possibly most importantly, the car is almost entirely road use, with maybe a track day once a year if I'm lucky. 

Advice appreciated. Thanks, Tom.

 

[Drumster]

Tom,

I use 8.5" Compomotives for sprinting and decided to remove the RARB completely to get round this problem. No adverse effects noticed. For road use i'm on 6" all round and again I find this all OK. 

[TomB]

Thanks - do you leave the RARB off for road use too? 

[Richard Price]

Tom,

Yes. Take the rear ARB off altogether.

[Paul McKenzie]

Tom,

In a '96 car with the original spring rates and weedy front ARB and no rear ARB, you'll have massive roll and you will grind the exhaust down if you do any track work.

[TomB]

I've got a red front ARB and wide track if it makes any difference.  So the consensus seems to be remove the RARB for road use, and refit it for track use, irrespective of wheel width at the back.  

Ive had the RARB connected for road use for ever.  What difference will it make on the road - apart from rolling more - will it give a softer more pliable rear, better traction?  Should I look to add a click or two to the dampers?    

Ideally Id remove the drop link and tie it up and then it would be really simple to reconnect it for track use - but I don't think this is possible.  

[Smithy77]

I must be in the minority regarding RARBs then. I run 8" rears, softly sprung Quantum One Zeros and adjustable front and rear ARBs. I mentioned in another recent thread that I had the car set up at DPR Motorsport, and on the subject of "settings" for dampers and ARBs, they gave the following advice: "for trackdays you want maximum damping and stiffness, and for road you want minimum damping and stiffness." Pretty generalised advice I know, but it works and works well. So before each trackday I give the dampers +24 clicks all round and set front and rear ARB to 100% stiffness, then when I get home the dampers go back to 0 clicks and ARBs to about 25% stiffness. 

This flexibility is amazing because on the road I have a car which has an incredibly refined ride, soaking up bumps better that any hot hatch, but on the track it handles like it's on rails. On track with fully hard ARBs, it's hard to say if I had rear wheel lifting. None of the pictures show this happening at least. I did, however, get a bit of front wheel lift on corner exit.....