XRAY - Model racing cars

Has anyone tried out both the Spec R and Xray gear diffs? I am asking coz someone is offering a spec r for sale at 20 UKP, whereas the Xray item is 30UKP.

Whilst on the subject, I notice that people seem to be using the gear diff outside, and the ball diff inside. Does that seem to be the consensus? What are the general effects of using a gear diff?

xray all the way, does not leak, lighter, you dont need different driveshafts which makes the spec dearer and full spares available

i dont have spec r gear diff or xray's but my friend told me few words about them

spec r diff does not fit in lower position of diff
in some time(after 5-7months in modified) it is starting to leak just a little bit with 1000oil in it,with thicker it isnt
you can feel gears in spec r diff when you are turning one of the shafts

you can buy spec r diff,if you are racing just for fun
but if you dont want to have in future problems with diff you should buy xray's

xray's diff has got better quality

difference beetwen gear diff and ball diff:
ball diff cant handle so much power
you can adjust just on track in 10sec tightness of ball diff

gear diff can handle much more power,but to adjust its working you have to change oil

A gear diff is heavier which the pros may notice in handling. The big advantage of the gear diff is that it can be locked very soft without slipping on hard acceleration. The big advantage of the ball diff is that it responses finer, works absolutely without play and that it's very fast to set like Stanley said already.

My does not work with 52mm drive shafts

I'm not an expert but from my experience of running a geared diff today I have found that as the car turns into a slow speed corner all the power is transferred to the rear wheel with less load, resulting in excessive wheel spin.

This had resulted in an overall decrease in lap times. Therefore I will be returning to the trusty rear ball diff.

Mike

Since everyone claims a gear diff is to heavy I put them all on a scale to be sure.

Xray ball diff
Xray multidiff set as one-way
Xray gear diff
Spec-R gear diff

I don't remember the exact weight but the Xray gear diff was the leightest with 2g lighter then the one-way. Xray ball diff was heavier and Spec-R (which is world champion) was definitely heaviest!

after running mine yesterday i will not be fitting my ball diff back in

Tried the Xray gear diff yesterday.

Worked well, no leaks etc.

The only thing I found was that due to the smoother action of the gears, the Xray diff feels like it has thinner oil in, even though I run the same 1000w in both it and the Spec-R I have been using.

Skiddins

Were any setup changes reuqired to retain original handling? Hoping to try ours for the first time tomorrow or Wednesday

Interesting difference of opinions on this thread!

We tried a gear diff for the 1st time yesterday (XRAY diff with 1000 oil). It was very planted on our two fast corners (into and out of the straight) but somewhat loose elsewhere on the infield. I am kind of assuming the niceness of the fast corners was due to both wheels spinning together and of course helped by the rear wing downforce. The handling on these two corners seemed better than with the ball diff. And I assuming the wheels are not spinning together in a balanced way on corner exit.

Practice lap times were substantially slower.

For the 2nd run I laid the rear shocks down one more notch (never had then laid down that much before). Whilst the rear was still loose it was smoother, more predictable. Then the rain came down

A club member told me last night that in his experience a gear diff will give more steering. As we already run a very pointy car my next step is to put 2000 oil in and if necessary to start to dial out some steering.

a thicker rear diff oil will give you far more on power steering i have 600 in mine and its planted at the rear with not other set up changes

Ah don't forget Skiddens I have an '009 not an '011

Mark, well that is what I thought too! But the guy I was talking about is top notch and spent considerable time experimenting with setup to maximise the gear diff and that is what he found. I think a lot of it does depend on setup and I have a lot of steering dialled into the car and my guess is that gear diff with 1000 took it over the edge. It has to be more likley to diff-up with the light oil surely, especially as the earlier rain will have taken some of the grip away.

Either way I have some 2000 and some 700 oil so I hope to try both tomorrow and get sorted before the Nats on Saturday.