Late spec XXX diff question

[DerbyDan]

So i've been running my XXX CR2 now for a few indoor meetings at the Silverstone Buggy Club venue - where i've enjoyed some minor success considering my lack of time off road racing & the high level of competition (at the first round of SRCMCC's winter series the A & B finals looked more like a who-whos in UK off road racing!)

But I'm struggling to get the differential on this car to grip... & this is an issue i've always had with the car! On first re-building the diff - in order to set it so that the slipper 'slips' before the diff (the slipper being set just about for high grip) I need to adjust the diff so much tighter than say I would the diff in either the XX buggy or XX truck that I have been running recently. Set so tight, its not long before the diff gets rough & needs rebuilding.

I'm wondering if its because with the later Losi diff design the plates/rings are not 'keyed' like they are with the earlier diff & it is the plates that slip on the outdrives.... not the balls on the plates, combined with extra loading caused by the mid-motor layout & brushless power exagerating the problem. Has anyone else experienced this problem with the XXXCR differential?

[Charlie don't surf]

Is this the 2.4 something trans or the 2.5 something ratio, I know they've bounced around both- The 1st gen used thrust washers and was great, 2nd gen was a pseudo AE style (the 22 is now identical to AE) thrust bearing system that let crap in and had soft rings.....I thought they went to the 1st trans on the CR versions- make sure to sand flat the diff and thrust rings on both sides too

[DerbyDan]

Its the same as what came with the XXXCR which reverts the ratio back to that of the original XXX (& XX) 2:19:1

http://losi.com/ProdInfo/Files/Exploded_View-Price_List_XXX_CR.pdf

I always hone the washers (diff plates & thrust washers) using wet n' dry.... building diffs is something i've become a 'dab' hand at, as getting a smooth free yet non-slip action is critical for the touring cars.

The diff in both my XXT & XX buggy are still smooth & free despite many hours of abuse - the XXX one just doesn't last so well (its worth noting that the same 'flat' washer thrust races are used in all of the 3 diffs - as this is what is still avaliable as a maintenance part)

[CON2]

Hi Dan,

My xxxcr2b4 that i run around my grass track runs a 3.5, never had a problem..

Can't say for sure which diffs in, never stripped it, think it's a PE gearbox or something like...

Not at home at the moment so can't say for sure.
Must be lucky, any xxx or xxxt I've hads been fine.

[DerbyDan]

My xxxcr2b4 that i run around my grass track runs a 3.5, never had a problem..

Wow! whats a XXXCR2B4? - if its 2wd then a 3.5 is insane!!

Don't get me wrong - the gearbox itself handles the power fine (6.5bl) & with the slipper set just right (even for high grip astro) then the diff doesn't slip... its just that I have to tighten the diff more than I would like, to achieve this. Performance-wise the car goes really well - last Saturday I finished 22nd out of 90 2wd cars - there was only one Losi ahead of me & that was a 22 driven by a TLR team driver.

Although its not desirable for racing, i've never been able to get the car to wheelie from a standing start

I've just checked & I have a new set of the old style outdrives - I might try those as i'm sure the rings slip on the new style ones!

[CON2]

Don't have a current pic, I've got the side pods built up now, using shorty lipos, sideways. Fits a treat, I'll get a newer picture up tomorrow.

[DerbyDan]

Don't have a current pic, I've got the side pods built up now, using shorty lipos, sideways. Fits a treat, I'll get a newer picture up tomorrow.

That must be a pretty unique car! Whats the idea of using the B4 front end? Have you driven any other mid-motor cars for comparison?

[CON2]

1 of only 3 made, not 100% sure but, I may have another chassis coming soon......Then I'll have 2 of 3 made!!!

Only mid car I've ever driven, must say it's awsome, I only use it in my garden (field) where I built a grass track, local club runs V12's and SCT's, so I don't race it.
If I was being picky, there's a slightly off camber hairpin, always understeers, everywhere else it's the best car I've ever driven.
Only just started racing again this year, since I gave up as a kid!
So don't expect F1 levels of ideas and advice lol.....

[DerbyDan]

Only mid car I've ever driven, must say it's awsome, I only use it in my garden (field) where I built a grass track, local club runs V12's and SCT's, so I don't race it.
If I was being picky, there's a slightly off camber hairpin, always understeers, everywhere else it's the best car I've ever driven.
Only just started racing again this year, since I gave up as a kid!
So don't expect F1 levels of ideas and advice lol.....

Ha ha ok! - looks a cool car for sure!

You're lucky to have land big enough to build a track... i'm afraid for me that is the kinda thing I can only dream of!

[CON2]

Current set up, Schumacher big bore shocks, very nice.

[DerbyDan]

Current set up, Schumacher big bore shocks, very nice.

Wow - throw some Kyosho, Tamiya & Yokomo parts at it & you'll have all the main (racer grade) manufacturers represented in one car!

[crusaderlyf]

I saw one set chassis conversion on ebay uk,but less people notice that

[CON2]

I saw one set chassis conversion on ebay uk,but less people notice that

SHOW ME!!!