Roll Center Adjusters

[ALN]

Hello All,

I am just about to install some BC Coilovers along with T3 GTX2 Lower Control arms and TC Rods and wondered if anyone found the need to install Roll Center Adjusters to compensate for lowering the ride height / center of gravity of the vehicle? The ride height won't be ridiculously low...

Thanks!

Lionel

 

[Rob Gaskin]

I would see how the lowering affects the angle of your TCAs.

You don't want them pointing upwards because your steering geometry will suffer from bump-steer (and your roll centre will be too low). I've experienced quite bad bump-steer - there is a long bumpy corner near me and when corning hard the steering wheel moves like when watching an old film and the driver is pretending he's driving.

 

[Turn & Burn]

I’m using basic bump steer spacers 25mm thick. I’m lowered about 50mm. They seem to work, ie no bump steer, but I’ve not tried without so can’t compare.
I’d never seen the Roll centre adjusters before I googled them, don’t think I’d know what to do with them.

 

[Rob Gaskin]

This guy is worth listening to.

 

[jonbills]

I've got the T3 negative camber RCAs. They're very gold, and do add a couple of degrees of camber.

 

[ALN]

Thanks guys, my main concern was bump steer.
@jonbills I tried to order the T3 negative camber RCA but they arenoutnof stock. So I've ordered some basic bump steer spacers from California Datsun for now to see how it goes with the geometry.
Tempted by the extra chamber, not sure how much chamber I can dial in with the GTX2 LCA's though...

 

[jonbills]

T3 switched to "evolved RCA" and show NCRCA as out of stock, but ERCA is available I think.
I don't drive fast enough to know if it makes much difference, but they look cool.
btw, california datsun have poorish reputation (I've noticed on the US forums)

 

[ALN]

T3 switched to "evolved RCA" and show NCRCA as out of stock, but ERCA is available I think.
I don't drive fast enough to know if it makes much difference, but they look cool.
btw, california datsun have poorish reputation (I've noticed on the US forums)

@jonbills As an update on California Datsun - ordered the items and they ended shipping about 2 weeks later. No bad service received... just very slooowwww...

 

[peter_s]

Hello All,

I am just about to install some BC Coilovers along with T3 GTX2 Lower Control arms and TC Rods and wondered if anyone found the need to install Roll Center Adjusters to compensate for lowering the ride height / center of gravity of the vehicle? The ride height won't be ridiculously low...

Thanks!

Lionel

You need 17 inch wheels if you use the gtx arms and the roll centre adjusters. I just tried... the gtx arms have 25 mm if you need (it's adjustable). 25 is ok for a relatively lowered car.

 

[ALN]

You need 17 inch wheels if you use the gtx arms and the roll centre adjusters. I just tried... the gtx arms have 25 mm if you need (it's adjustable). 25 is ok for a relatively lowered car.

Thanks @peter_s I've now installed the gtx arms with BC Coilovers and they fit well with 15" et0 Konig Rewind alloys. I adjusted the gtx arms to give me the full lower arm spacing. Also had the tracking done earlier in the week and went for a good drive. With this setup I could not detect noticeable bump steer on the street test, maybe a different story on the track or out in bumpy country lanes.

I think I will test it a bit more before installing the spacers, thats if they will fit! They've just turned up, so I will do a test trial and report back.

 

[peter_s]

25mm should be enough!

I can add that my 16inch would have fit with 1 or 2 mm to spare, which meant I would have had to remove the wheel weights. My wheels are not tapered on the inside, so I doubt many 16inch wheels fit.

Let us know how it goes with the spacers

 

[Alphabettispaghetti]

25mm should be enough!

I can add that my 16inch would have fit with 1 or 2 mm to spare, which meant I would have had to remove the wheel weights. My wheels are not tapered on the inside, so I doubt many 16inch wheels fit.

Let us know how it goes with the spacers

I've got circa 22mm under 14" wheels

 

[peter_s]

I've got circa 22mm under 14" wheels

It's the GTX arms that compensates for rollcenter already a little. They are also a lot beefier than the stock arm and ball joint which builds up some height. Then you can shim them if you want more, that makes the balljoint extend:

This is how it ended up in the end for me, I removed the roll center adjuster and just maximized the roll center on the GTX arm. 14inch will not fit these arms:

 

[ALN]

@peter_s Agreed, I've pretty much done the same with shimming the GTX arms to compensate for max adjustment below the steering knuckle. Clears fine on my 15" alloys.