OD UD gears for the Portals
 

Is there anyway to OD / UD the R1 axles? I've got them in a couple rigs that would benefit from this gearing.

Re: OD UD gears for the Portals
 

Not that I know of. Almost no one except JunFac make hop ups for the R1. If they magically appear somewhere, you make sure to come back and let us know.

Re: OD UD gears for the Portals
 

I think most people just replace the R1 axles with Axial Axles.. since they have all the hop-ups

Re: OD UD gears for the Portals
 

i have tried to contact gmade and junfac direct for a couple of years but iv'e gotten no reply!! sure would like some ud/od gears:cry:

Re: OD UD gears for the Portals
 

The only option is to use a transfer case that has a split ratio.

Re: OD UD gears for the Portals
 

Then one must ask what transfer cases offer that feature?

I'd consider between 5% and 10% overdrive to be about ideal. I know the TF2 transfer can be modified to do OD, but it ends up being a ridiculous 40% which can't really be practical, can it?

Re: OD UD gears for the Portals
 

I wonder if you can find pinion gears to replace the gears in the portal gearbox and change the ratio. I wish these axles weren't so neglected by aftermarket.

This might seem silly coming from someone who does not own nor have I seem a gmade in the flesh. But I have been looking at them off late and I wonder if it would be at all possible to run 14/14 portal gears together in the front axle for overdrive effect compared to the standard 14/16 reduction?

Re: OD UD gears for the Portals
 

Unfortunately, that wouldn't work. The radii of the pitch circles of the portal gears must combine to equal the distance between the portal input and output shafts. If you were to put a pair of 14T gears in there, their teeth would not mesh properly if at all. However, there may be another way to affect OD/UD.

If the Sawback ring and pinion (bevel gears in the differential) will fit in the R1 portal axle's diff compartment, then you could generate an OD/UD effect since the Sawback ring and pinion are 32T and 14T respectively (compared to the R1 ring and pinion, which are 32T and 17T respectively.) It's funny. I actually jumped over to this forum to ask if the Sawback diff gears would fit in the R1 diff compartment and found this thread at the top of the queue. Anyone know if the Sawback gears will fit??

Re: OD UD gears for the Portals
 

No, the Sawback gears do not fit unmodified, I am sorry to say. I think it is possible to make them work, but that is rather long down on my to do list at the moment :(

Re: OD UD gears for the Portals
 

That is good to know. How much modification would it take to get them in? Do the shafts fit or is it the position of the pinion relative to the ring?

Ok how about swapping the location of the front portal gears so the 16t drives the 14t for overdrive? Just throwing my thoughts out there.

Re: OD UD gears for the Portals
 

That will work, but I think the recesses in the portal gear box are sized to accommodate the specific gear sizes. This would prevent you from swapping the gears around. I could be wrong, though. It has been a while since I disassembled my axles.

Re: OD UD gears for the Portals
 

I have just tinkered with it for an hour or so, but it seems most doable with the original ring gear and the Sawback pinion gear.

The sawback ring gear is a bit shorter in length so it got more room for mesh adjustment compared to the original one. However, the axle engagement will will less and that worries me a bit.

I think, and hope, that the only modification you will have to do on the Sawback pinion gear is to grind it a bit so it sits closer to the bearing in the axle housing.

Re: OD UD gears for the Portals
 

Dead-on with your assessment, Drav. I read this again after I did the mod and realized that I did everything that you said.*grin*