I was running my car in transverse 2 weeks ago and as the grip came up it would start lifting. The higher the grip the more it would lift and even traction roll if fronts were over 41mm

I just built my new chassis (RR12v2) inline and as the grip came up Saturday I noticed my car was not lifting at all. I drove as hard as I could...it was awesome.

i was looking at petitrc i was trying to find a setup for a 13.5 CRC and didnt find much luck. anyone w/ a CRC (currently running a xti) what kind of general setup? i guess i should ask are thicker grease on the side post and thicker oil in the center shock being run?

i eventually want to get a separate chassis to run 13.5 in a pan, but for now there's a upcoming race that they are running 13.5 and kind of want to get a head start

Check the CRC thread for setup information. A lot of guys running the Xti seem to do well with the kit settings.

With the Xenon spur, there are 2 rows to put the diff balls in, the outer and inner row.
Has anyone tried using both rows?

Any thoughts on using both rows?

I generally run differential balls in all the outer holes. You might see a slight performance gain in differential action when using all the holes. Though I wouldn't think it would be very noticeable. More than anything else it's going to add weight to the drive train.

But, I would love to hear what others think or have experienced

Generally speaking yes the more the better...however you want to only run 1 row for 2 reasons...first diff rings are not flat. Because of the way they are punched out they are slightly coned so the inner row and outer row won't make contact at the same time and you will be effectively only running on 1 row. There are rings that have been flattened through sanding or grinding but then you run into the 2nd issue...the rings flex. Because the diff hub and axle hub do not go all the way out to the edge of the diff ring it doesn't support the whole ring so when pressure is applied at the outer row of diff balls the rings flex again causing them to cone so running 2 rows again doesn't work as well as we'd like.

I think if someone makes a diff axle and hub that fully supports the diff ring and we run a perfectly flattened ring set then running both rows would work nicely.

Are you guys still sanding the diff rings to ensure flatness?
In the past...I've also had a situation where my diff balls weren't spherical, which contributed to a slightly crunchy diff. And this was AFTER sanding diff rings...took me a few races to figure that out.
Also...are you guys using steel or carbide balls?

Running a thrust bearing instead of a normal washer setup and silicon nitride diff balls makes a diff pretty much bomb-proof. Sanding rings is old-school, it's easier to get prepped rings from someone like Tuning Haus. With this combo I glue the ring to the axle so it won't move and just drive. The only downside to the silicon nitride diff ball that I can find is that when you re-assemble the diff with these non-metal balls you can have problems getting the ball to bite the surface of the ring if you use too much grease, but sometimes the diff seems to be almost completely dry and runs just fine.

Bingo!

From Kimihiko-Yano

We are testing various compounds. To distinguish them, I gave a name in order of A,B,C... And, because the tire that had been named G was good, I decided to sell it. GX is the latest product that gives the same grip level of G tire but eXtend. - I think he means extended wear characteristics or grip level. Or both!

I had this exact same issue with several sets of differential rings and I ended up switching over to another brand. I discovered this issue when I gave my car to a factory driver to check the overall setup of the car. First thing he did was check the differential settings. What he did was he firmly wrapped his hand around the wheel/spur gear and with his other hand turned the left wheel. A loud squealing sound came from the differential. Not only that I was shocked to see the differential slipping with ease.

He ended up tightening the differential until it stopped slipping. Which was great. However, the differential was not working properly. Very gritty and you can feel the differential had high and lows in its movement. He then took it apart, rebuilt the differential with new rings that I gave him. It improved slightly, but it still had the same issue. The he turned to me and said "rings are flexing, no good." He went ahead and built my differential with a set of Square RC mirror finish rings. He said "these are very hard and have no flex."

From that moment on, I've been using Square RC rings with amazing results.


Running a thrust bearing is the #1 upgrade for a differential, #2 differential rings, #3 ceramic diff balls.

Curious, what makes the Square RC rings not flex (I assume you meant less flexible, it's not possible to have zero flex). Are they thicker than the old rings? Remember, even if it's a harder material or stronger, that doesn't change the flex as long as you are not exceeding the strength of the material (then it will have permanent deformation). The flex is a function of the load, the cross sectional inertia of the ring, and the elastic modulus of the steel (and again, the E of steel is around 29,000,000 psi regardless of the strength or hardness). Given all of this, I have to assume that the rings are thicker.

Yes, I understand it's going to have some flex. Square RC must be using a harder material or a special hardening technique. It really makes a difference.

Glennhl - Thank you for providing us with the material strength information. Much appreciated.

Are we really back to diff rings for the 50th time ?

Ah I got it... diff rings are the reason I suck. Must change diff rings!

Can you explain rollout to me