View Full Version : Newbie Help: what is the O-Ring for?

2010.11.19, 05:17 AM

I have a beginner question: I bought a brand new MR03 which I assembled (only with the original parts, I haven't bought anything yet).

In car, they include already mounted in the left part of the differential the wheel nut and a small soft rubber O-Ring.

In the assembly layout in the manual (page 15 for those who have it) they are apparently asking to take the O-ring out in order to put in the rear tire, which incidentally fits perfectly in support of the differential. I've then put in the rim + wheel, then the spacer, and finally the nut.

With the car seemingly well set, I still have the O-ring in my hand. What am I supposed to do with it? Did I miss a step?

Many thanks for your help


2010.11.19, 10:08 AM
Nope, no problem -- the O-ring doesn't serve any purpose in a running MR03. If it were still in there we would have told you to take it out. :)

2010.11.19, 10:19 AM

I was finding it strange as there really wasn't any space left to squeeze the ring in.

Happier now :)



2010.11.19, 03:08 PM
I think the O-ring was just meant to "stop" the differential spacer from falling off in the production line.

2010.11.19, 03:13 PM
I used it on inside of left rear wheel.

Mike Keely
2010.11.19, 08:34 PM
There is no need to use it on the inside of the left rear wheel either. When the nut is tight the wheel can not get out of center because the rim will be up against the hub. Just extra weight that is not needed. I know that it is not much weight but every little bit helps.

2010.11.20, 03:45 PM
Thanks for all the answers!

I ended up using the car without the ring, and, as expected, it works flawlessly.



2011.01.04, 11:01 AM
Back to this....
I use it as a compression device to keep the left wheel centered. I've had situations where I could not use the plastic bushing because there wasn't enough thread for the nut to hold securely when there was a large coned flange on it. For example, the QTEQ titanium axle and the nuts they provide.
I've used it both ways, with and without. I found it helpful to have kept it around.