2015 Roll center - I am very very very confused

dibble34 · #1 19-01-2015

Right, loving the 2015 spec but these new +2 rear hangers have opened a right can of worms for me. I have read up and read up and these are my findings so far

Running the +2 with no insert under gearbox = lower roll centre. According to hudy setup manual a lower roll centre should be better in high grip. However according to xray the insert under the gearbox should be used in high grip however this would give a higher roll centre and according to the hudy book a higher roll center should be used in lower grip conditions.

I personally find that lowering the rear camber link on the tower in low grip improves rear traction, but this is making a higher roll centre so goes against what xray are saying about the gearbox insert being used in high grip as this also raises the roll centre which they say is for high grip.

Can anyone explain/help a very confused average driver

andoiwebb · #2 19-01-2015

Yup, they've done an awesome job confusing everybody. The hinge pin height has stayed the same, as the hangers have raised the hinge pins by 2mm, but now the 2mm plate under the gearbox is discarded - so the hinge pin height is NOT different. The effect it has is it's lowered the shock tower & gearbox by 2mm, so you get 2mm more droop, the camber link holes on the gearbox are 2mm lower and the gearbox / outdrives are 2mm lower. Hope this helps.

dibble34 · #3 19-01-2015

Think so off for a lie down!

s22jgs · #4 28-01-2015

Easiest thing to do is forget all the changes. Just remember the higher the hinge pins are, the easier the rear will break traction.

dibble34 · #5 31-01-2015

Quote:

Originally Posted by s22jgs

Easiest thing to do is forget all the changes. Just remember the higher the hinge pins are, the easier the rear will break traction.

Now I can handle that

thanks for the info, love tips like this.

andoiwebb · #6 31-01-2015

As long as you remember reading my last post - the height of the hinge pins hasn't changed!

It's just not that simple

s22jgs · #7 31-01-2015

Yes it is that simple. Higher breaks traction easier.

If you want less traction run the pins higher. If you want even less get the optional under box insert to add even more height.

If you want more traction then run them lower. If you want more than kit will allow then get the non +2 rear blocks to lower the pins further.

Where's the confusion?

andoiwebb · #8 01-02-2015

Like I said, just changing the hangers to the +2 and discarding the under gearbox plate (as per the Xray instructions) does NOTHING to the height of the hinge pins, it changes the height of the gearbox and parts connected to it. Granted, the now rereleased under gearbox plate does raise the hinge pins and everything else by 2mm.

s22jgs · #9 02-02-2015

no ure right, but the principle is still the same.

Its all done so the can sell the underbox insert as an option