Its pretty simple really, the instructions tells you install the diff assembly with the arrow facing up on the belt tension adjuster, just rotate it so that the arrow is pointing down, this allows the diff to be lowered

I see... Thank you. So I just do it for the front diff spool to have better steering. What kind of effect is expected if I lower the rear diff spool too (also by rotating the arrow downward)?

I have no idea if there are actual effects of lowering the front and rear spool. I guess the best way to find out is to try it on the track

I wouldnt be surprised if you didnt feel any noticeable difference either

High diff has more traction on that end of the car and conversely with low diff.

Just use the clear tamiya O rings if you do not want them to leak. The Blue ones are much lower friction but can sweat a little. I put in clear o-rings on my club car, I only bother with the blue ones if rebuilding for a big comp.

Can you support that statement?

I've tested them back to back and that is what I felt. Other drivers have noticed the same. But what do I know

Thanks for sharing with me your experience and will test it out when I have a chance to run on my local track.

Hey @all

search for --petitrc setup helper--

@ damper leaking
add to the blue o-ring a 0.1mm shim with 4mm inner diameter
(part 53586)

greeeeeeeeeeeeetingssssssssssss

Harry

lol..... you're only a Reedy champion, multi national champion , and Tamiya World Champion !

Hi,

I have never tried shims under/between blue o-rings and neither have leaking experience.
however damper (mini big bore on 419 with low profile) gets air bubbles after couple of runs. Dampers are perfect after assembling...Any advise not to have so frequent?
I assemble it with zero rebound, drilled hole in the cap (I do the 1mm hole via center point of the cap way to up to the connector).

Thanks
Marton

Ive added a 0.3mm shim and it still leaks, trying the x-ring and see if that helps.

I asked because the question is often asked and never answered in dedicated threads.

I took the suggestion below and have checked petitrc and couldn't find one shred of reference to diff height.

Trawling further, the "hardest" "evidence" I found is a recurrent reference to the same jrx manual over and over in several threads, with people having completely conflicting opinions, sometimes the same person in the same post.

Most people mention the effects of CG height, driveshaft angles and gyroscopic effects. All are pretty solidly refuted by others, possibly the gyroscopic effect might hold some influence, but it is difficult to ascertain with any certainty if enough to impact in any discernible way on the car's grip.

See the quote below for reference.

If you can explain it, please do so, if not you might as well be honest rather than try the offended primadona line. "That is what I felt" and "others said so" never got a scientific paper published.

Read what you want in this, I don't see any hard evidence of anything really (and making logic sense of what is explained is pretty difficult when such a cryptic way of presenting things is used. What the heck does "keep the car in the turn longer" mean?!), apart from reference to the same magic "feel" invoked in the answer to my initial question above.

Analysing deeper, it seems that you get more "overall traction" with both diffs in the low position, but if the rear diff is moved high and the front left low, that will give "maximum total steering" (does this mean the front end has more grip? - because that would contradict the statement made in the post I challenged).

Of course, not too many lines further down, the jrx-s R manual turns the whole thing on its head! This time there's another variable set added: we're talking about rubber tyres on asphalt: You get maximum total steering with the front diff high and the rear low. What was the jrx-s manual talking about then?!

Going back to physics first principles I see little sense in what is "explained" hence my question.

My impression is that most people are just repeating some bullcrap they can make absolutely no sense of, because they want social acceptance from their idols, whilst the latter want a bunch of yesmen around to disguise their ignorance but hey, don't be discouraged just because you have won some troffees. It's guaranteed you are a top grade physicist because you can play with a toy car! And you "feel" things others have felt too, let's not forget that.

This is well described in the T4 manual. See attached image.

Although a different model chassis, I made this change for the AOC race on black carpet and it made the car a lot easier to drive. Got no reason to think it would be different on a 419.

Phil.

Now I'm confused haha. Honestly, just try it and see how it feels for you. It's only four screws for each end of the car