wider rear end on standard rb5

[jon kedge]

Have been racing this car for 2 years and it's very narrow in the box at national meetings on the rear.I have an old zx5 with wider wisbones for the rear and what else do i need (drive shafts,rear carriers etc etc )any part numbers would be helfull,my zx5 is a ready to run but have spare wishbones etc etc doing nothing,i think i have a proline conversion for the rear but it's standard length for the original edition rb5.could i use and zx5 parts without modifying the car..

[RogerM]

You need the dogbones from the CVDs from an original ZX5 (65.5mm set-up) and the LA243 rear arms (from the ZX5 "mid" conversion).

Job done.

The car only becomes 2mm per side wider with these mods but it's the resultant geometry change that is significant!!

When I designed the Mako people kept commenting on how narrow the rear of the car was and I couldn't seem to get them to understand why .... RB5 is the same story, works well to balance the car up!

[jon kedge]

Thanks for that Rogerm,i will have a play over xmas and try it out on the next mam.

[RogerM]

I will probably be running my RB5 at the rest of the MAM events so feel free to pop over and have a chat.
My basic astro set-up is very easy to drive around both Cov & Kiddy so I'd suggets starting there with it.
I'm looking at trying to get a bit more bite from the front of the car for the 2010 season which may or may not be to your tastes but as always I'll let everybody know how that goes.

[Phil Channon]

I was also considering trying the "wide" rear arm conversion.
I have the arms, dogbones and axles, but what about the shock tower?

Tried putting everything together and I can't get enough ground clearance.

What is the part number for the required shock tower?

[njc11]

Phil,

UM520 is what you need

Cheers

Nick

[Phil Channon]

Thanks Nick.

Will hunt round to find one now.

[RogerM]

Putting the arms on doesn't affect ground clearance at all ... the inner hole on the wishbone is still the inner hole, middle hole is where the outer would have been and the new outer is for use with a touring car shell

The later UM521 arms only have the original 2 mounting holes.

I run my cars with the original tower, original length shock bodies and 54mm shock shafts (these are the key really ... wide or narrow rear end!)

All that said I am looking at goging to the shorter shock bodies (still on the Atomic Carbon tower as I prefer the car with the shocks less inclinded than is possible on the plastic towers) for the summer as I like the idea of the lower tower height as it will be less prone to breakage (that said I've run an RB5 since 2007 and as yet only broken one rear tower .. car faired a lot better than the B4 that hit it!!!!)