Hello, I appear to be missing the center gear collar pictured below. Does anyone know of any substitutes to part UPR-2?

I would just replace the bearings with some flanged ones. This way you don't need the center collar. You can use a thinner washer if you still want to use them.

I replaced it with flanged bearings but center gear keeps popping off, for a total of 3 flanged gears on the center gear axle

That's one of the parts that always holds up one of my Optima projects, it seems I can never find one when I need one.

here is the ultima one, I think he has optima ones too!!
http://www.ebay.com/itm/261009077278?ss ... 500wt_1054

I think those are just 5x10mm wheel or gearbox bushings, not the same as the part you've circled in the first post...which is a much smaller 4 x 8mm white plastic cylinder. I think fireboy indeed sells it, but wants more than 3 bucks for it. Evidently he knows how uncommon they are...

EDIT: Here it is, this is the part you'd use if you didn't use bearings. 4 x 8mm bushing. If you use bearings, you need the smaller white plastic collar with the same dimensions. $13+ shipped just for that one collar. Ouch!

http://www.ebay.ca/itm/Center-Gear-Bushing-Kyosho-Optima-Ultima-Outrage-Sandmaster-Tracker-Outlaw-/251046309150?pt=Radio_Control_Parts_Accessories&hash=item3a7386ad1e

Will these work? http://www.nitrohouse.com/4x8mm-Bushings-2_p_7259.html

Possibly, if I can find a spare collar, I'll measure the depth and we'll know for sure. I'm not home now but might be able to get the measurement this weekend. The I.D. & O.D. of those linked collars are right, just the depth is what we need to know.

I'm very confused: how do you get 3 flanged bearings inthere? Please put up a picture.

The only thing that collar does is to prevent the standard bearings to slide further into the centergear.
Get rid of the M4 washers and put 2 8X4 flanged bearings in the spur: 1 on either side and a smaller washer and o-ring at the cover side

There is no reason to use that spacer. If you have TWO flanged bearings, and the appropriate washers (for spacing on the shaft) then you will be fine. Don't waste your money on the spacer! -Jeff

LOL, was I speaking Klingon in my first post?

sure not Richie I just don't get the response on your post...3????

Thanks Ed, can you please send me a link to the 8x4 fanged bearings you speak of?

http://www.ebay.com/itm/Bearing-Flanged ... 43ad90dc5c

flanged, not fanged

This should work too. http://www.avidrc.com/product/8/metric- ... rings.html

BTW, has anyone looked into using the frog cluster gear w/ an Ultima? I think with a 4x11 flanged bearings it could be done. (the small gear is 18t like the ultima one.) You'd have a choice of spurs of 49/50/52 as well. Oh, and I think the fast attack/wild one spur might be adaptable as well (18t small gear-)... And maybe the boomerang gear too...although you may have to do some trimming to the bevel gears on it.

DISCLAIMER: I haven't tried this yet, only counted teeth on ebay pics. Anyone have any of those parts in their box to try?