I think changing the rear sprocket is easier.. Iirc the current one is 16T, which is the smallest.. Going to 20T (23 is also possible) should help a lot, and does not require taking off the chain guard and messing with ths crankset. It also should take about 2 links of slack out of the chain.
'Possibly', but you'd be messing with the Bosch crankset, and probably doing bad things to your warranty, and you'd have even more slack chain to tension. Sticking a larger sprocket on the back instead might be a possible/safer option, but I probably won't try it.
They are pretty good bikes that's why they score 3.5 or 4.0, they are just not (IMO) well suited (at least in hub gear form) to very hilly terrain and/or heavy riders. You definitely pay extra for a) the Tern name and b) the FOLDing. If you didn't need to get 2 of them into a smallish car...
The spec for this can be viewed at https://www.ternbicycles.com/bikes/471/vektron-p7i
I got my bike from 'Bicycles by design' in Telford (OK, really in Coalport), since they were one of the few places that actually had a usable demonstrator, which I could try before parting with a 50% deposit...
Bicycles by Design at Telford (well coalport) had a motorised 3 seater (in line) outside last time i was there. Of course they can/do build them from tubing, so no problem, just a tandem plus. The motor was in the front crank iirc, but i didn't see the make.
Yep, 3 keys, and store the makes and numbers on a pc file or two, as backup. Of course I bought a 3rd key for my abus sold secure gold D lock, and then found it doesn't work best well on a small wheel folder ... Open to offers! (Never actually used).
Is the juddering tied to wheel rotation speed or something else? If it hics once per rev, then the disc is maybe suspect, damaged or contaminated at a particular point.. The simple option is to swap pads, then disc, and see what cures it. Not the cheapest option though.
I've had multiple fitbits and garmins over the years, and currently run an antique charge 2. The GPS watches have (historically) generally lousy battery life, relatively poor antenna, compared to a proper GPS or phone, and anyway I really don't see why garmin or fitbit (now Google?) should have...
Slime in my (tubeless) ride on mower tyres is a life saver, with hedges all around. Slime in inner tubes is, imo, dumb. Messy and dumb. Bike came with big apple tyres, so now it has tannus Inserts, and I pray a lot.