Do thinner tyres make much difference?

I suppose it would depend on riding conditions. In the snow or mud you would want wider tires. Thin tyres are suppose to offer less rolling resistance, just ask the endurance cyclist. For ebikers, i doubt we are on these things long enough to appreciate any major difference.

 

Another point, i recently discovered the sizes you mention, refer the the width of the wheel rim where the bead sits. Assuming you intend to use the same wheels, you might find the 1.5 tyre a loose fit in the rim of a 1.95 wheel.

 

I wait to be corrected.

I thought the 1.95 or 1.5 or 2.0 refers to the width of the tread area, Not the dia of the wheel which is say 26 inch then the 1.95 etc is the width. So any 26 inch tyre should fit a 26 wheel.

 

I stand to be corrected.!

 

I wonder if I would benefit from a semi slick on my ebike as I mainly ride track and road, all be it, it

wont make the bike any faster on electric side but wonder how much drag the nobble tyres create.

There's a fair degree of width compatibility so not a worry in a change of this sort.

 

The main difference is that the thinner tyre needs a higher pressure to support the weight of bike and rider for a given rolling resistance, so is less comfortable.

The reduction in the weight of the tyre, plus reduced rolling resistance makes for quicker acceleration but at the cost of reduced comfort.

 

Rolling resistance also depends on the tread pattern. If you were going from a 1.95 knobbly tyre to a 1.5 semi slick tyre you would really notice the difference, as I found using a mtb for commuting.

The reduction in the weight of the tyre, plus reduced rolling resistance makes for quicker acceleration but at the cost of reduced comfort.

 

Rolling resistance also depends on the tread pattern. If you were going from a 1.95 knobbly tyre to a 1.5 semi slick tyre you would really notice the difference, as I found using a mtb for commuting.

Yes, you really notice it when you're on pedal power only. Otoh, being motorised removes that drag of knobbly tyres and reminds me I have to ditch the knobbler on the front. Who knows, the reduced RR might pay off in slightly lower power consumption - it all adds up.