I have done about 360 miles so far, I changed the front tire after about 50 miles. I am using a 2.70" Gazza North Shore on the front, It has hardly warn. The Duro on the rear has had it now.
With your 17" rim and tyre, increasing the mass you will loose some HP, because it takes more power to spin up the weight.
On a 4x4 rally car we changed the street type tyres to the rally tires when we were dyno testing, and there was a 50 hp power loss due to the increased mass in the heavy duty tyres.
If you buy a 20" bicycle wheel the rim diameter is 16.5", If you get a 3" tyre you will end up at 22.5" but without the mass.
With your new motor, I would recommend testing it before you mod the shunt in your controller. I think that you should be careful trying to increase the current with the stock battery, as it has a maximum discharge rate, also the BMS will have a maximum switching ability.
If you push the battery to far you may kill it. Lifepo4 are normally around 5c (90A Max) If you move to Lipos you can get 60c , so pulling 100A is nothing.
That is good to know, I suspected that the motor was much hotter inside, because they always heat soak when you stop riding. It is probably a good idea to go steady on the last half mile so the magnets don't get cooked when you stop. How do you get on with dust and dirt getting in through the holes. I have been thinking about how to cool the motor, oil, water or air. They all have there issues.
I know what you mean with HP scavaging losses from rotational mass. But with the hub motor, I am betting that it won't be as significant. I am thinking it will be the equivelant of putting a heavier flywheel on a motorcycle. Revs a little slower, but once up to speed, maintains momentum which should off set the increased rolling resistance and weight a little from the "huge by mountain bike standards" knobbies. I also think some of the scavaging losses from the heavier tire will be offset by the smaller wheel and the mechanical leverage I gain. (78.55" to 72.27" per rotation or approximately 7.5% gain in mechanical advantage). I will not be getting too crazy with the Rshunt mod. I will be pushing between 6 and 6.5 KW max. Figure my CA will be set somewhere in the neighborhood of 75 to 80 amps. Of course, all of this is speculation, wont know until I get the wheel on the bike and start messing around with it. And in the event that my idea with the motorcycle rim and tire suck, I can always go back to a 24" tire (20.5" rim). The more I read and research venting hub motors, the more impressed I am. Referencing a PM I sent to Hyena, he has never ever had a problem with foriegn debris getting into his vented hubs. Judging by Hyena's vids, he's fast and not easy on his bike so that says alot. Also via PM, Kepler hasn't had any problems with pushing 10+ kw through is non vented 5405 either riding smartly. Either way you go, these guys are the go to guys involving anything electrical and the advise we get from them is definately solid. One thing I know for sure, excessive heat is a huge killer for electric motors. For that reason, I will probably be venting the 5404 with 8 14mm holes on each side. On the disk side, I will drill them closer to the center of the hub and out towards the edges on freewheel side. How are the forks working out? Besides the improvement in small bump compliance, are they significantly better on the fast stuff? BTW, I got my flange nuts in from the UK. Just like you said, they are narrower than the stock nuts and the flange portions are not threaded. What a waste of 45 USD. Looks like the caslte nuts and drilling cotter pin holes int he axle is my next move.