Some CR2 mods

[V-Rossi]

The Atomic Carbon CR2 is an excellent piece of kit but nothing is perfect. Here are some modifications to the car, at this moment solely tested on astroturf (high and medium grip) but each of them being a big improvement on the handling of the CR2.


1) XXX rear end:

Those who are familiar with the Losi Forum and/or have ever inspected the car of the Mighty Chris Doughty might have seen this mod already. The rear XXX-CR suspension (pivot block - wishbone - hub) is replaced by parts of the XXX and XXX-T MF2. It looks like this:

http://www.oople.com/forums/picture.php?albumid=512&pictureid=3051
http://www.oople.com/forums/album.php?albumid=512&pictureid=3050http://www.oople.com/forums/album.php?albumid=512&pictureid=3051
and

http://www.oople.com/forums/album.php?albumid=512&pictureid=3051http://www.oople.com/forums/album.php?albumid=512&pictureid=3052http://www.oople.com/forums/picture.php?albumid=512&pictureid=3052

The CR pivot block is very wide, which is good for rough tracks. Its predecessor, the BK2, was extremely narrow. And the XXX one is in between. So from narrow to wide: BK2 < XXX < CR.
This creates an imbalance front and rear, which can be solved by fitting the XXX block. The following image illustrates this:

http://www.oople.com/forums/album.php?albumid=512&pictureid=3053http://www.oople.com/forums/picture.php?albumid=512&pictureid=3053
http://www.oople.com/forums/album.php?albumid=512&pictureid=3053
The block on the right is the standard CR one, as you can see it is a lot wider than the one in the middle (XXX). On the left we have the front Losi pivot block (same on XXX, CR and I think BK2 as well). Notice the same width of the XXX front and XXX rear pivot block => balance.

On the first images you can see which hubs I used: XXX-T MF2 ones. You can use the standard CR ones but their bigger offset makes the car a few millimeters wider, which isn't the goal of this mod. The standard XXX or BK2 hubs have the perfect offset, but! have lower camber link mounting holes than the MF2 hubs have. I strongly suggest using the MF2 hubs (middle hole).

Part numbers:
- Pivot block: LOSA4126 (plastic) or LOSA4149 (aluminium)
- Wishbones: LOSA9800 (BK2 graphite) or XXX
- Hubs: LOSA2128

Both pivot blocks are good but the plastic ones are prone to excessive play. If you don't want to spend your earnings on an expensive alu one, simply use some spacers, cheap and perfect as well :)
Wishbones then. If you use the BK2 ones, use the short VLA hole. This has about the same length as the standard hingepin hole of a XXX wishbone.

Our findings? The Atomic Carbon team in Belgium tested it during a club race and National @ Kampenhout, and found this rear end to be a big improvement. It gives the car more steering while maintaining a lot of rear end grip. The car's suspension reacts in a more balanced way as well. So far we haven't noticed any downsides to this mod.


2) Front wheelbase mod:

This is a very simple one. The idea is to extend the wheelbase of the car on its front end. So dremel about 1,5mm off the front side of the hub (1,5mm is about the thickness of a wheelbase spacer at the back) and move the hubs forward. This will increase the total wheelbase, but that isn't the only goal.
When placing your front and rear hubs forward (so front long and rear medium wheelbase) you don't make the car any longer, but maintain the wheelbase. The only difference is that more weight is shifted to the rear end of the car. Simply moving the rear hub forward does the same thing, but the CR2 is already a short car, so with this mod you don't make it any shorter and you'll still be able to get more weight to the back. Here is an example:

http://www.oople.com/forums/album.php?albumid=512&pictureid=3049http://www.oople.com/forums/album.php?albumid=512&pictureid=3049http://www.oople.com/forums/picture.php?albumid=512&pictureid=3049

http://www.oople.com/forums/picture.php?albumid=512&pictureid=3048
http://www.oople.com/forums/album.php?albumid=512&pictureid=3048

The effect? I used both front and rear long wheelbase, this made the car a lot more stable. It gives you a little less steering, but most people will hardly notice it. And while not being really faster over a single lap, it does make it a lot easier to be fast on a consistent base. Again we are all using it (with great effect, the CR2s had 1st, 5th and 7th place at the National) as it makes the car a lot easier and more fun to drive.


3) Battery bar - 'the Northy strap'

This is a picture of Jonathan's car (I hope he doesn't mind :)):

http://www.oople.com/forums/album.php?albumid=512&pictureid=3054http://www.oople.com/forums/picture.php?albumid=512&pictureid=3054

As you can see it has only 1 battery bar, which makes it a lot easier to change batteries. You can make it yourself out of a B4 battery brace but JC will make them himself as well, and they look brilliant!

Secondly, the link going from the top of the gearbox to the battery brace is an anti-flex link. This way you don't need the brass gearbox brace anymore. Only difference is that we made a small plate on top of the gearbox with a hole in the middle, to have the link more in the center line of the car instead of having to choose one of the (non-centered) holes.


4) Extra hole in rear wishbone:

We did it on the S2, and we did it on the CR2: drilling an extra inner hole in the rear wishbones. Both on the CR and XXX rear end this helps rotate the car faster and enables a bigger or faster throttle input when riding bumps. In fact on the XXX rear end the extra inner hole is the standard one at the moment. From center of standard inner hole to center of newly drilled hole it should be around 4-5mm. Note that you should adjust your dampening to this new position. I'm using 2,5wt-5wt thicker oil and a smaller piston with the new hole.

I hope this helps :)

[V-Rossi]

Picture problem fixed :)

http://www.oople.com/forums/album.php?albumid=512&pictureid=3054

[Razer]

How did you mount the rear end? The bottom of the chassis rubs the arms if you put on the aluminum pivot block and a9800 arms, and there isn't much material to remove either... I use this mod on my regular CR, and it works great, but I'd like to try it on the CR2 as well.

[V-Rossi]

Take a bit of material off with a dremel or file, you don't have to remove that much as it is quite close.
And of course you will have to do this with the T-plate as well, as the hingepins are closer to each other on the XXX block.

[Razer]

Take a bit of material off with a dremel or file, you don't have to remove that much as it is quite close.
And of course you will have to do this with the T-plate as well, as the hingepins are closer to each other on the XXX block.

So you take away material both from the arms and the t-plate? I took away some material on the t-plate in front of the pivotblock - it feels bad to take away much from a place were there's little to begin with:lol:

I'm nearly always faster with my CR than with my CR2, so I need to try it all:thumbsup:

[V-Rossi]

No off the chassis and T-plate, sorry :blush:

The T-plate (I'm using the Rudebits one) needs quite a lot of dremeling/filing.

On which surface are you struggling with the CR2?

[Razer]

No off the chassis and T-plate, sorry :blush:

The T-plate (I'm using the Rudebits one) needs quite a lot of dremeling/filing.

On which surface are you struggling with the CR2?

What other rudebits are people using? (Saw there was a lot of options...)

I like the CR2 quite well on carpet, but I have been just as quick with the regular CR. Last weekend at the first Norwegian Cup race, running on astro, I also ended up with the CR. It shall be said that it was cold and moist, so that the grip wasn't all there.

I'm by no means a top level racer by european standards, but I can easily run 5 minutes without mistakes and push the car quite well, so I feel that the CR2 hasn't been quite up to the task.

I think playing around with weights and setup should help a lot, I'm just a bit lost on what to do...

[V-Rossi]

Send me your set-up in a pm please :)

I'm using the brass T-plate from Rudebits only, as that is by far the most important upgrade to have.

[Thomas P]

Rossi, what can you do with my S4 =)?...are you a magician :P

Top notch tip...

/T

[V-Rossi]

Rossi, what can you do with my S4 =)?...are you a magician :P

Top notch tip...

/T

Hmm yes sort of, but my sword swallowing isn't first class just yet:lol:

I don't know that much about 4wd cars I'm afraid :blush:

[Stumpz]

Hi Rossi,

Do you know if you can fit RC10b4 Axles on the CR2 and would they work as i have an S2 at the moment and thinking of changing to the CR2 but still have a lot of new tyres on B4 Rims.

Many Thanks.

[DaSloth]

rear ones should be fine, but front wouldnt work i dont think. I swapped the hubs around so i could use b4 front wheels for a dirt event and seemed ok, but there was alot of slop

[V-Rossi]

It works! A fellow CR2 driver did this mod in his car and there is no problem with it, same track width and everything. And it doesn't change the suspension geometry or something.
I'll ask him to take some pictures and then put them (with some info) in this topic :)

[V-Rossi]

Added a 4th item to the original post.


P.S.: I updated my set-up for astro tracks (rather flat, not bumpy like UK ones: http://picasaweb.google.com/bnkoffroad/BelgianGrandPrixMBVKampenhoutThursdayFriday#549124 8501900709746). Stagger front and Mini Pin/Spike rear, both work with this one. If needed, send a pm.

[Legacy555]

Having a crap problem and someone on oople forums must have the answer..... :thumbsup:

I've fitted the XXX (old style) rear end to my CR2, and am pretty happy with it. However, I'm having a small problem and I just wanted to see has anyone got a solution - ie. a part number

With the alloy XXX-T pivot, BK2 arms (outside VLA hole removed) and XXX 1 degree hubs, the XXX-CR CVDs are slightly too short and the end of the shaft almost comes out of the diff outdrive at full droop. So I fitted BK2 CVDs (as they were in the pit box) and they are a pinch too long and are hitting the diff nut at full suspension travel.

So I'm assuming that there is CVD shorter than the BK2 one and longer than the XXX-CR one. Losi manual says I need part # A-9923 - but a google search for this shows it's for XXX and XXX-CR...... not good!

Anyone encounter this? Anyone got a part number for the correct "middle" length CVDs or even just the CVD dogbone?

[V-Rossi]

Have you dremeled the Losi wheel spacer or replaced it with a B4 one? If you do that and put some shims on the inside of the hub, the axle is placed further towards the outdrive. Works very well, even when using the extra hole on the wishbone.

[Legacy555]

Thanks Jorg,

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

[V-Rossi]

Don't know actually, as the CR is the only Losi car I ever used ;)

Elvo might know this though, send him a pm.

[tom plumb]

I have a cr2 but this is my first year racing i love the car do these mods make a brillant car even better and would a beginner like my self realy benefit from these mods cheers:thumbsup:

[V-Rossi]

Not one of the mentioned mods to the CR2 makes it harder to drive, they are mainly suspension geometry improvements, which make it more balanced.

Of the above I think the only thing you should definitely have is the horizontal battery strap which replaces the two standard ones. This is more a security option than a performance increasing option though.

The XXX rear end is being used by an increasing amount of drivers, all of them liking it. The only situation where you could benefit from using the CR rear end (the standard one) is when the track is very rough. Like grass tracks at times.

You will notice the big difference when you use the XXX rear end and after a few weeks/months put the CR one back on to test :)

[elvo]

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! :thumbsup:

[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]

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 ;)

http://www.impaktrc.com/images/9608.jpg

[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 :cry:)

[Gareth Jones]

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

Gareth

[V-Rossi]

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]

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs011.snc4/33888_448142008448_701843448_5071704_3379094_n.jpg

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs427.snc4/47007_448142053448_701843448_5071705_2585480_n.jpg

http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs207.ash2/47007_448142058448_701843448_5071706_8083621_n.jpg

[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]

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?
:confused:
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]

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 :D

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 :thumbsup: cheers

[flipside]

Is the plastic pivot block the same degrees?

Think I'm almost there now :thumbsup: cheers

yes :-)

There are only two blocks, 0° and 2° anti squat. They are all 3° inboard toe in. So just take a look at the hinge pin, if it's under an angle it's the 2° block, if it's not it's the 0° block

[PaulUpton]

Cool, cheers for the help guys, fingers crossed it will be dry Sunday to try it on astro

[Supervlieg]

Cool, cheers for the help guys, fingers crossed it will be dry Sunday to try it on astro

And take a clean pants with you :D 'Cause you gonna like it!

[DerbyDan]

Have you tried it yet Paul with the XXX rear end??

Quick question to all you Losi experts... like Paul i've been collecting parts to update the rear suspension on mine (to narrow VLA XXX spec) I have a very original XXX which has the same wishbones/hubs as a Double X CR, so I ordered a couple of pairs of Graphite XXCR wishbones (Part no LOSA9802) of ebay for a decent price. Like these; http://cgi.ebay.co.uk/Team-Losi-R-Arms-Graphite-XXCR-XX4-XXX-LOSA9802-/320459592580?pt=UK_ToysGames_RadioControlled_JN&hash=item4a9ce15384

Thing is on recieving these arms its is apparent that there is only one option for the outer pivot position - not two as seen in the pictures shown here. Does anyone know if my one hole aligns with the inner of the two holes on the later XXX wishbones??

[V-Rossi]

That is a XXX wishbone, the ones with 2 VLA holes are the BK2 wishbones. When comparing the XXX wishbone to the BK2 one, you'll see that the single hole is very close to the inner BK2 hole (a tiny bit further to the outside).

So they are perfect :)

[Northy]

Have you tried it yet Paul with the XXX rear end??

Not sure if Paul has used it yet but one guy did at Worksop on Sunday, ran it std in qualifying and changed to the XXX rear end for the final and loved it :thumbsup:

G

[DerbyDan]

That is a XXX wishbone, the ones with 2 VLA holes are the BK2 wishbones. When comparing the XXX wishbone to the BK2 one, you'll see that the single hole is very close to the inner BK2 hole (a tiny bit further to the outside).

So they are perfect :)

Brill - thanks for the quick reply... it does appear however that I'm stuck using the hole on the hubs that gives the wider track width, the hub cannot be mounted to give narrow track as it interferes with the cross-web of the wishbone... but I guess that setting would be way too narrow anyway? At the end of the day - all my parts match up with whats on the original rear motored XXX so it must work :thumbsup:

[flipside]

In no way you ever have to narrow the car by using the wrong vla hole... That makes your car 2cm narrower, a bit too much imo :)

VLA is there to have variable arm length, not to make the car wider or narrower!!!!!

The xxx arms have no VLA option, but it doesn't matter because it has the correct hole (the inner one). You would rarely use the long vla in combinations with the XXX rear end (only on very rutted tracks you could try long vla).

[Northy]

How about when using the 1 degree hubs? ;)

G

[PaulUpton]

Yeh have ran the car now, certainly felt nicer to drive, back end didnt roll as much. but still offered lots of grip. Have made a fewe changes to try at the weekend

Paul

[flipside]

How about when using the 1 degree hubs? ;)

G

What do you mean? The 1deg hubs have the inside vla hole no? So that can be mounted on normal xxx arms too.

[Northy]

What do you mean? The 1deg hubs have the inside vla hole no? So that can be mounted on normal xxx arms too.

Mine don't, they use the outer VLA hole.

G

[flipside]

Mine don't, they use the outer VLA hole.

G

Do you have 1° hubs with 2 holes?

[Northy]

No, 1 degree hubs with one hole.

[flipside]

Well then they have to correspond with the inner VLA hole compared with BK2 or CR hubs... Isn't the hole located under the inner bearing in the hub?

[flipside]

Here's 1deg that I have, and an MF2 hub (same VLA holes as CR hubs):

The VLA on the 1° is clearly the inner VLA hole, which needs to go onto the inner vla of the arm, or the only hole on a XXX arm.

If you mount these 1° hubs on the outer vla hole of a cr or bk2 arm, your car is 1cm too wide :D

[jimarea51]

School boy error!!:yawn:

JIm

[Northy]

They are different to my hubs :)

[flipside]

Yes, but is the hole for the hinge pin under the outer bearing then? Would be very strange, because I wouldn't know which car doesn't have the VLA option but does have long arms.

Everything before BK2 had normal hubs with only one hole, under the inner bearing.

Can you take a pic of your hubs as I am really curious now :D

[brookie]

Graham,

Are these what you've been using:

http://www.wheelspinmodels.co.uk/car/item/LOSA9806-1Degree-CR-Type-Hub-Set-2__13155/

think it's certainly what most/all of the HHUK team have tried (and many prefer!).
Personally we run these on the outside VLA most of the time, especially in wet/slippery conditions on astro.

[flipside]

Ok that's something in between :o

Graham,

Are these what you've been using:

http://www.wheelspinmodels.co.uk/car/item/LOSA9806-1Degree-CR-Type-Hub-Set-2__13155/

think it's certainly what most/all of the HHUK team have tried (and many prefer!).
Personally we run these on the outside VLA most of the time, especially in wet/slippery conditions on astro.

[Northy]

Yep, that's what I've got fitted, got them off of Si :eh?:

G

[Legacy555]

Hi all,

This may be old news, but I was stuck for a 78T spur gear at racing last night, so I put an associated one on with associated slipper pads.

Direct fit, I found it less sensitive to small adjustments, and it's definitely quieter than the kevlar losi ones when meshed to the extra idler gear.

[V-Rossi]

I used that for a few months as well, it sure isn't bad! But I like the Losi slipper pads (and thus the spurs as well) more, they maintain their rough surface a bit longer.

[V-Rossi]

For the 2011 season I won't be driving the CR2 as it was time for something new, but I'm still available for help with setups, tips, whatever :)

[area52]

It's a bit off-topic but what are your plans chassis-wise for next year, Jorg?

[V-Rossi]

TRF201, possibly with Atomic Carbon mid motor conversion (201 GTO) :)

After a year of testing, trying new stuff I felt the CR2 was finished, it is a top notch car now. So I went back in time and got a rear motor :D

[flipside]

What happened to your Niko sponsorship deal then???

[V-Rossi]

Their front wheel drive car was pretty awesome, but spares were hard to get :woot:

[area52]

TRF201 GTO

:thumbsup:

Good luck with the Tamari (?) Ferriya (?). ;)

I guess I stick with the CR2 altough it (still) really sux on the slippery stuff. :(

[V-Rossi]

Thanks :thumbsup:

Do you mean dirt, indoor floors or wet astroturf?


:thumbsup:

Good luck with the Tamari (?) Ferriya (?). ;)

I guess I stick with the CR2 altough it (still) really sux on the slippery stuff. :(

[flipside]

Have you ever tried any of these clay setups?
http://www.rc-offroad.be/setup.htm

[area52]

Clay/hard packed dirt is a pain. But to be frank even 20th century old-school-rear-motor buggies have problems on that specific track. I tried several set-ups, higher total weight, lower total weight, weight distribution, different motors, speedo settings, tyres (as far as I could with German spec tyres). Nothing really helped.

Damp Astro is ok (never used it on wet Astro so far).

Anyway.

[Northy]

Is it steering or traction you are lacking?

G

[area52]

Is it steering or traction you are lacking?

G

Mainly side-bite. Steering is more than enough, traction is 'o.k.' but I have a heavy snap-oversteer problem with that car (on that track).

On Astro or carpet the CR2 really shines and as I (and some others) had similar experiences on that specific clay/dirt track this year, I/we blame the partially new clay surface for the problems.

[V-Rossi]

Have you tried running a longer rear camber link, 0° anti-squat and both front and rear more inclined shocks?

[Northy]

Mmmm, that's just mid motor I think :cry: Got to be some compromise somewhere :D

[area52]

Have you tried running a longer rear camber link, 0° anti-squat and both front and rear more inclined shocks?

Copy.

Tried both longer and shorter links (the shorter gave me a tad more side-bite but still not enough and I ended up with 2-A and two shims under the ball stud). The more angled shocks took away too much traction (2-inside at the end on CR arms).

[V-Rossi]

I'm afraid Northy is right and you'll have to wait for the track to settle then. Tried slightly harder inserts? Won't make a big difference, but you do feel it.

[area52]

Never played around with inserts tbh. I normally use the TL inserts that come with TL tyes and PL's that come with PL's although the latter are pretty shit.

I think I go old school for next season's dirt track races.

[rcjunky]

I assum you've tried PL holeshots? ever tried traction compound?

[area52]

I assum you've tried PL holeshots? ever tried traction compound?

Negative on traction compound as forbidden.

[sfry61]

:

http://www.oople.com/forums/album.php?albumid=512&pictureid=3054http://www.oople.com/forums/picture.php?albumid=512&pictureid=3054

Does anyone make this battery bar/ posts, or am i going to have to make it in my shed:lol:

[V-Rossi]

Jonathan of Atomic Carbon makes these, just send him a pm (OldTimer on this forum).

You then have 2 choices: mount two links on the holes drilled in the battery bar, or drill an extra hole in between the pre-drilled holes and use 1 link. I did the latter.

[Legacy555]

2) Front wheelbase mod:

This is a very simple one. The idea is to extend the wheelbase of the car on its front end. So dremel about 1,5mm off the front side of the hub (1,5mm is about the thickness of a wheelbase spacer at the back) and move the hubs forward. This will increase the total wheelbase, but that isn't the only goal.
When placing your front and rear hubs forward (so front long and rear medium wheelbase) you don't make the car any longer, but maintain the wheelbase. The only difference is that more weight is shifted to the rear end of the car. Simply moving the rear hub forward does the same thing, but the CR2 is already a short car, so with this mod you don't make it any shorter and you'll still be able to get more weight to the back. Here is an example:

http://www.oople.com/forums/album.php?albumid=512&pictureid=3049http://www.oople.com/forums/album.php?albumid=512&pictureid=3049http://www.oople.com/forums/picture.php?albumid=512&pictureid=3049

http://www.oople.com/forums/picture.php?albumid=512&pictureid=3048
http://www.oople.com/forums/album.php?albumid=512&pictureid=3048

The effect? I used both front and rear long wheelbase, this made the car a lot more stable. It gives you a little less steering, but most people will hardly notice it. And while not being really faster over a single lap, it does make it a lot easier to be fast on a consistent base. Again we are all using it (with great effect, the CR2s had 1st, 5th and 7th place at the National) as it makes the car a lot easier and more fun to drive.

I did this mod and ran it for a few months and it was an improvement. But found a much better method of extending the wheelbase, without upsetting the weight balance at the rear, and without offsetting the steering.

http://lh3.ggpht.com/_XbMlay4rD20/TQfcJXQK7LI/AAAAAAAABPY/mh-ulssQFAA/s640/DSCF1368.JPG

This is a XX4 wishbone flipped with XX4 upright and hub. You gain about 8mm in wheelbase. You have to ad a shock spacer and small shim to fit the wishbone to the XXX pivot - as below. I used a cut down rear hinge pin, but you could use a shock shaft or suitable hinge pin from another car.

http://lh3.ggpht.com/_XbMlay4rD20/TQfcE_O8uZI/AAAAAAAABPM/WhOJN4F-CQw/s640/DSCF1363.JPG

I've been using this setup on a tight high grip carpet track with the uprights reversed - giving 10 degrees of castor. You can drive it like a 4wd!

All of the pics of the car and more of the mod are here:
http://picasaweb.google.com/irishwill555/WilliamWhiteWinter2010#

Can anyone who tries it let us all know what you think?

[ian h]

I saw the car run with this mod and it was awesome!

[blade]

saw this car also in action looked the business so yea will be giving this mod a try as soon as my wishbones come in :thumbsup:

[ian h]

saw this car also in action looked the business so yea will be giving this mod a try as soon as my wishbones come in :thumbsup:
Use cat SX2 wishbones.

[Legacy555]

Use cat SX2 wishbones.

You can use CAT SX2 wishbones on the XX4, but as the wishbone is flipped for this mod, there is nowhere for the shock to mount as the webbing is different - you are restricted to using the standard Losi XX4 wishbone (or graphite one). You can use schumacher 7.5 degree alloy uprights though.... hint hint :)

[snige]

what front axels are you using?

[Gareth Jones]

I am about to ask the dumb question:

What does this latest modification do to the handling of the car?

Regards
Gareth

[Legacy555]

what front axels are you using?

Xx4 hexes, wheel bearings and plastic driveshaft yoke. You'll need xx4 front wheels too

[tony12795]

I guess what people are ultimately tiring to achieve is to lengthen the wheel base....

With the help of AC we have been testing a LWB chassis over the last few months, I am sure if people ask or PM he will produce a chassis and side pods for you. The chassis is 6mm longer and is lengthened around the battery area, don’t worry, the electrics and servo still fit as normal but you get an option to move the battery forward by 2mm if you want too.

What the LWB chassis does is smooth the steering out and gives you more corner speed, that’s why the new Losi 22 is so long!!

Tony

[Legacy555]

What the LWB chassis does is smooth the steering out and gives you more corner speed, that’s why the new Losi 22 is so long!!

Spot on :thumbsup:

[nevens]

Secondly, the link going from the top of the gearbox to the battery brace is an anti-flex link. This way you don't need the brass gearbox brace anymore. Only difference is that we made a small plate on top of the gearbox with a hole in the middle, to have the link more in the center line of the car instead of having to choose one of the (non-centered) holes.


What's the length of the rod?

[V-Rossi]

I don't have my CR2 anymore, so can't measure it. But it depends on the height of your battery pack: a higher pack will need a shorter link and vice versa.
But it is a camber link, so not too hard to adjust :)
I think I used a Losi front camber link, with 1 normal ball cup and 1 8ight steering ball cup. Use as much of the 8ight cups on your car as possible, they are perfect!