Some CR2 mods

[elvo]

Originally Posted by Legacy555

Thanks Jorg,

Is there a drive shaft available that is between a XXX-Cr and BK2 in length?

Don't think so. The trick is to get BK2 stub axles and play around with different shims and top hat spacers.

[PaulUpton]

just ordred the parts for the rear end mod, but the hubs i have got only have 2 mounting holes for camber link yet the photo shows 3, are they different hubs in photo or wrong part number?

Many Thanks

Paul

[Supervlieg]

We often use the normal cr hubs. So you don't need to wurry about them.
The most important parts are the xxx arms, and the bulckhead. That will
change a lot!

[PaulUpton]

thanks, which hole do i need to mount camber link then? in or out?

on the packet it says hubs are for XXX/4/T ? Is that right?

also which hole on the wishbone for the hub?

[V-Rossi]

Yes those are the correct hubs. I always use the B hole on the XXX-CR hubs, which is the middle one (on your 2 hole hubs that is the outer hole). On the shocktower I use hole #3 (upper row, 2nd from the outside)

About the wishbone hole: always use the inner hole, aka short VLA (Variable Length of Arm). For very bumpy of rough tracks, long VLA (outer hole) will be better as the car will ride the bumps a lot better.

[V-Rossi]

Originally Posted by PaulUpton

the hubs i have got only have 2 mounting holes for camber link yet the photo shows 3, are they different hubs in photo or wrong part number?

There are 3 options: BK2 hubs (2 holes), MF2 hubs (same as BK2 but with an extra hole) and CR hubs. I always use the CR hubs as they make the car a bit wider, which stabilises the car greatly. But you have to dremel the wheel spacers a bit or use the thinner B4 ones, as otherwise the car will be too wide.

A good starting point for every track is this rear end geometry:
- XXX pivot block
- BK2 wishbones
- XXX-CR hubs with dremeled of B4 wheel spacers
- Camber link position 3 on tower, B hole with 2 washers on hub

[PaulUpton]

Thanks under stand now. When you say wheel spacers you mean the one behind the pin? Then shim axle from behind the hub?

[Supervlieg]

The blue wheel spacers he means

[PaulUpton]

ok so to use the CR hubs, you need the B4 wheel spacers and shims behing but the hubs listed on first post the standard wheel spacer is ok, but better to use the CR hubs?

have done the mod tonight, after dremelling half he car to get it to fit.

Just want to check you use the inside hole on wishbone and hub? which means the camber link will be quite short?

drilling the extra hole will return the droop to the car?

sorry for all the questions

[DerbyDan]

Will have to have a close inspection of your car Paul next time I see you.... I ordered all the same parts to do the XXX rear end conversion on mine... when it all finally arrives.... (I think the wishbones I ordered from Ebay.US are going to beat the parts I ordered from Podium )

[Gareth Jones]

Can someone post up the brca width limits for me? Seem to have lost my manual!

Gareth

[V-Rossi]

Originally Posted by PaulUpton

ok so to use the CR hubs, you need the B4 wheel spacers and shims behing but the hubs listed on first post the standard wheel spacer is ok, but better to use the CR hubs?
We use the B4 wheel spacers for 2 reasons: to avoid the car being too wide and to be able to put some washers on the axle on the inner side of the hub to push it further into the outdrive. This way you can have full droop without the axles falling out of the outdrives.
MF2/BK2 hubs with standard wheel spacer are great, but after doing some testing I chose to run the CR hubs and dremeled/B4 spacers everywhere (partly because of laziness). Works all the time.

Just want to check you use the inside hole on wishbone and hub? which means the camber link will be quite short?
Can you post a picture of the rear end of your car? On wishbone I nearly always use the inside hole (short VLA). On hub I always use the B hole. You know it is the B hole when it is located right above the inside VLA hole.
Most of the time I run a slightly shorter rear camber link than the standard one in the manual yes.

drilling the extra hole will return the droop to the car?
Yes, but that isn't the main reason to drill an extra hole. The extra inner hole is better on bumps and gives a better rotation to the car without losing a lot of stability. The extra droop is nice, but always check it at the front as well, especially on rough tracks you'll want about the same droop front and rear.

Answers in red

[PaulUpton]

[flipside]

I would advise to use some kind of brace behind the shocktower, even when using the alloy pivot block. It gives extra strength to the shocktower, makes sure it won't rip out the bottom screw.

With minispikes, you don't have to worry about the car width too much, it will be ok with wathever hubs you use. The main reason for using a thinner wheel spacer is as vrossi says to make sure the driveshafts go in the outdrives a bit more.

Try one of the setups posted here:
http://www.rc-offroad.be/setup.htm

Oople race or eden park setup was really really good on your UK style astro tracks!!

I would also use the normal CR hubs, then you have the option to change the camber link height easily. The hubs you have will make the care narrower quite a bit (2mm), will give you even more steering. I only used these hubs on a very smooth astro track where the complete setup is all about lots of steering. Might be good on carpet tracks too.

[PaulUpton]

Cheers flipside, how would I brace the shock tower?

I offerered up the 1' cr hubs to the car, the hole on the hub and to the inner hole on wishbone and the car would of been shorter width? That's what I don't get. Or do you use CR hubs in outer hole on wishbone?

[V-Rossi]

Originally Posted by PaulUpton

I offerered up the 1' cr hubs to the car, the hole on the hub and to the inner hole on wishbone and the car would of been shorter width? That's what I don't get. Or do you use CR hubs in outer hole on wishbone?

The outer VLA hole doesn't make the car wider, it only makes the wishbones longer.
XXX-CR hubs have a slightly bigger offset, and thus make the car a bit wider than the BK2 or MF2 hubs.

Just take a small plate of carbon fibre/steel/aluminium/whatever and dremel out a plate that connects the rear inner hingepins.

[flipside]

Just slide two different hubs over a hinge pin, align them and you'll notice where the difference in width comes from. The bearing on the cr hub is about 1mm more outside than on the older hubs. So like Vrossi says, more offset.

[PaulUpton]

I'm with you now. Thought you would run inner hole on hub but outer on wishbone, but you only ever use outer and outer or inner and inner.

What degree is the pivot block used?

[flipside]

Originally Posted by PaulUpton

I'm with you now. Thought you would run inner hole on hub but outer on wishbone, but you only ever use outer and outer or inner and inner.

What degree is the pivot block used?

The vla is no different than on the normal cr. Always use corresponding holes, or your car will become 2cm wider or narrower

Pivot block in alu is 2° anti squat, 3° inboard toe in.

[PaulUpton]

Is the plastic pivot block the same degrees?

Think I'm almost there now cheers