Cheap rear alloy arms for Optima/Turbo Optima

[besty22]

Hi mate.

Thanks for all that. Looks like I must have gotten 65.5mm shafts.
I might buy the other hubs or just get another set of 68mm shafts (Probably easier)
Thanks for all of your help with this.
Cheers
Chris

[Coelacanth]

I might buy the other hubs or just get another set of 68mm shafts (Probably easier)

Go with the 68mm swing-shafts; the Lazer hubs, though a nice mod on their own, might cause you to need even shorter swing-shafts than the Optima 62.5mm ones, as they each pull in the inner hub bearings a good 15mm. Better to get your 65.5mm shafts working with some shims, mounting the outdrives a mm or two outboard of the gearbox, or get the 68mm ones.

[Hcp22]

Is there a problem that the wheel base exceeds 25mm?

[Coelacanth]

Is there a problem that the wheel base exceeds 25mm?

I used these same arms for both CYANide & Barney. CYANide uses Lazer hubs and hybrid CVDs I made using a combo of HPI RS4 CVD bones (52.5mm long as opposed to the Optima's stock 62.5mm) and Kyosho CVD axles to bring in the track width about 7 to 8 mm narrower than stock, on either side. So even with the GPM arms being approx. 5mm longer, the use of the Lazer hubs & hybrid CVDs decreased width by 7 - 8mm.

With Barney, I was looking for a wider track width, to improve stability. The only thing that's not a stock part is the same GPM alloy arms, which add 5mm to the width. This requires the use of 68mm CVDs instead of the stock 62.5mm units.

I'm not sure about your question, "Is there a problem with the wheelbase exceeding 25mm"...I think you're referring to the track width, not the wheelbase. And, the use of these arms with the stock Optima rear carriers will only increase track by approximately 10mm, not 25mm.

[Hcp22]

I tell you what, I don’t understand myself…
What I meant to ask was; is there a problem exceeding 250mm regarding the track width.

[Coelacanth]

I don't think the wheelbase (front axle to rear axle) is changed much with this mod; if anything only a few millimeters. The track (left wheel to right wheel total width) is only increased by 10mm approximately, with a particular set of wheels.

I chose narrow crawler wheels for Barney because they give a lot of positive offset which again widens the track width, for greater stability...but the GPM alloy arms themselves only add 10mm to the total track width.