[Closed] What could make a 26er roll better than a 29er?

I did a ride on the South Downs at the weekend with a friend.

I was riding a 2005 FSR XC (26") with Racing Ralphs, 2002 Marzocchi MXC forks,

He was riding a 2017 Marin Rift Zone 7 (29er) with Rocket Ron (f) and Racing Ralph (r) OEM tyres.

I'm heavier. I noticed from the start that my bike seemed to be rolling better than his - going uphill, flat and downhill, it seemed like he was having to put in more effort to keep up, either pedaling or freewheeling. We're usually fairly evenly matched on fitness on road though he's faster up and I'm faster down. In the end I checked that his wheels were spinning freely with no disc rub (they were fine) and we tried swapping bikes for a bit. Suddenly it was me putting in the effort to keep up and getting my bike back took a little while!

So 29ers are meant to roll better. So any ideas why this didn't work out that way in this particular example?

I think his tyres were harder than mine (roughly 30 vs 25psi). His suspension felt very "numb" compared to mine despite being set up to similar sag percentage. Feels unwilling to absorb bumps.

I'm uncertain how the weights compare (old alloy XC vs new beefier carbon).

Weirdly I've always felt that my bike seems faster and more efficient with the rear suspension (Manitou S-type SRL), even on road.</span>

So what do people think? What combination of the following is it likely to be:

- Rocket Ron noticeably slower than Racing Ralph or Schwalbe's OEM versions are nasty

- Slightly lower tyre pressures rolling better over rough ground

- Numb flex-stay single pivot suspension vs very supple 4-bar suspension

- Something about geometry (the Marin's reach felt shorter to me, the angles are slacker)

- Something else