20" or 26/700C at the back of a delta trike

[belgiangoth]

I was wondering (no Baz, can't afford your friend's trike) what the advantages of 20" all round are on a delta trike. Same tyre/tube all round obvs, but I would have thought the gearing and tubeless tyres would make this less interesting these days.
On the other hand I have found that I can spin out on a sharp&slick incline on my catrike because there is not enough weight on the rear wheel - is this remediated on a 20" all-round model?

[[XAP]Bob]

General advantages - same tyre / tube all round

Gearing is just a matter of getting appropriate chainrings…

[[XAP]Bob]

Also does it affect seat height?

[UpWrong]

Are there any current delta models with large rear wheels?

On tadpole trikes, i enjoy the compactness of 3x20 and they do tend to climb better than tadpoles with a large rear wheel.

[belgiangoth]

Yeah, I meant tadpole…

[nigelnightmare]

I was wondering (no Baz, can't afford your friend's trike) what the advantages of 20" all round are on a delta trike. Same tyre/tube all round obvs, but I would have thought the gearing and tubeless tyres would make this less interesting these days.
On the other hand I have found that I can spin out on a sharp&slick incline on my catrike because there is not enough weight on the rear wheel - is this remediated on a 20" all-round model?

No.
I have a 20" all round and one with a 700c rear wheel & 20" fronts.
Moving the seat backwards to put more weight over the rear wheel helps though, easier on a 20" rear wheel.
ICE do a bracket for doing just this (it's called the "FB bracket" and is made for tall people so the boom is not over extended) moves back 2"/50mm.
I use it to give better traction on the rear wheel.

[[XAP]Bob]

Yeah, I meant tadpole…

I've been through a few...

I started with an early (Pre ICE becoming ICE) trike which had a large rear wheel. That was written off when I avoided a serious collision and I chose to go to an ICE with all 20" wheels and rear suspension. I've since acquired a wind cheetah (large rear wheel) and replaced the ICE with a velo (all 20" wheels with suspension all round).

In terms of feel - I don't find much real difference in terms of gearing (obviously just used different sprocket sizes). I went for rear bounce because my commute at the time had various rumble pads which were particularly vicious. The differences between the velo, the wind cheetah and the ICE trike(s) are far bigger than just the rear wheel, but the wheel itself is mostly a practical decision and I don't think that changing it on any of those would significantly affect the handling or speed (assuming the frame was appropriately modified).

For a wide range of gearing I added a CS-RK3 based rear wheel, which gave me a "virtual" zeroth and fourth chainring (that's just what the gaps end up being) - but that could be done on either size wheel.

Wider ranges of gearing help with smooth application of power which reduces the tendency to slip on the driven wheel. More weight over the rear wheel is a function of the CoM of the vehicle/rider, and it's easier to get that further back with a smaller rear wheel - but again that's a frame design decision.