Have you done any structured training – both for pedal fitness and strength? Might be worth a go.

I still think your gearing isn’t very low – I find on the 29er it goes much better with higher leg speed in a lower gear. It definitely holds speed up better than my previous trail 27.5” – but loses a bit of initial acceleration feel.

Also I find with a good spin I don’t ruin my legs so quickly and I have more energy in reserve to accelerate up through steeper tech climbs.

What shock have you got on there and how is it setup? I always find air shocks feel a bit too much mushy in the mid range and that can make them feel a little lethargic – unless you have them pumped up really high and then you lose the small bump. I’m therefore on a cascade link and coil shock on my sentinel. Feels like there’s more to push against whilst retaining small bump plushness.

the massive flywheels shod in hefty rubber

Big grippy tyres will always be slow to pedal. Great on descents, they suck the life out of you everywhere else.

If you are going to be riding for several hours, you need to find a level of effort that you can sustain and just keep in a gear that lets you spin away. Assuming you are eating some food mid-ride, if you are moderately fit, you should be able to ride for 6 hours or so as long as you just stick to spinning in relatively easy gears. My guess is that those big tyres make it feel slow and you’re overdoing the effort to compensate.

But I’ve got a very competent 140mm forked hardtail,

I would just ride that. I do just ride that. I can’t stand riding a FS bike for any kind of distance.

I use the same gearing as you and don’t have any hill issues up to 25% incline.

And tyres definitely make a difference.

Perhaps the real answer here is a new bike?

My most-ridden MTB is my Orange Stage 4 which is light, super-responsive, fun and engaging – and pretty capable (with some geo mods).

I wouldn’t like to have a long-travel 29er as my only bike, much as I love them.

A mate reckons he laps 3 times as fast on an e compared to a non-e. Still don’t care. Its not about speed, its not about ground covered, its about the satisfaction of doing the job right, and if you’re a healthy, able bodied person, you do not need a motor to do the work for you. I’d also be interested to know if these eriders doing 3 times the distance and thereby causing 3 times the wear on the trails are doing 3 times the trail maintenance and/or donating 3 times as much to their local advocacy groups.
Sorry – bit of a sore point with me. Too many idiots buying their fitness and not having the skills or the respect for the countryside to back it up and just trashing the place instead.

Solidly off topic, with a load of absolute guff on a rant. 😆

FWIW, I would say, like for like, I can probably get 2.5 times the laps in on my ebike over my leg bikes. I don’t actually ride that amount more trails, I just do it all a bit quicker, but to ranting like some virtue signalling martyr is stretching it somewhat.

And to get all presumptuous about trail maintenance because we ride more trails? in my experience where I am, it’s mostly people who dig ride ebikes.

I always associated the rocketmax – particularly the newer ones – with winch and plummet enduro racing. As such not sure it’s ever going to feel great for marathon days out as it’s not really what it’s designed for? If cotic are your thing a jeht or flaremax as an all rounder may give you some more zip? Personally sounds like if you were starting again a 130mm rear / 140/50 front all rounder would be a good bet. Something like the nukeproof reactor or shorter travel canyon strive

I’d maybe try sticking something like a Rock Razor on the back for long rides. You’ll lose a bit of grip for sure, but also shed a massive chunk of rolling resistance and you may not lose as much grip as you think, particularly if your longer rides aren’t as full on technically as your shorter outings.

A mate of mine rides a Geometron with mahoosive, heavy casing tyres on and keeps complaining that he’s lost fitness – I suspect he’s simply dealing with a huge amount of rolling resistance. Or you can simply work at becoming astonishingly strong and fit. The tyre option is probably cheaper and easier.

I expect a lot of it is simply that pushing on the pedals has a less immediate reaction the more travel you have.

23psi F/25psi R

Disclaimer – I’m out of touch with how hard you can hit things on a bike like that and my local riding isn’t as rocky as yours –
Is that a fair bit of air in tyres of that size for someone your weight? Bike could roll better overall with tyres that can conform more rather than ping?

I know little to nothing about enduro bikes, having been out of mountain biking for 10 years and just coming back with a little xc bike, but it seems odd that anyone would look at a 160/170mm steel enduro bike and wonder why it isn’t sharp and snappy out of the corners and is hard work over a long day of climbing.

everything in mountain biking is a compromise and it seems that the complaint is that it’s not very good at the things it’s not intended to be good at.

It’s a main battle tank, not a rally car.

Hmm. Something about the type of bike/wheels/tyres inevitably will make it feel like you describe. My steel FS 29er (with 2.6/2.5 DHF/HRII) is ‘harder going’ and less sprightly than my steel SS HT (with 2.3 HRII/Forecaster), which in turn is harder going than my Ti gravel bike with 700x40c WTB Nano’s)

The other, possibly contributing factor, maybe your increasing age and amount of exercise. I’m 55. Throughout my 40s, I was commuting 4 days a week, plus often a weekday night ride, a big ride on my day off, and another ride at the weekend. Increasingly, over the last 3-4 years, I’ve found that volume of riding just a bit more fatiguing, I could ride it, but would sometimes feel tired, or lacking in that ‘zip’ or top end you feel when you are really ‘on it’. If you’re riding 4-6 days a week, plus gym/weight sessions, you might not be giving enough attention to what recovery and rest looks like, or how important it is for overall fitness.

I’ve recently bought the ‘fast at 50’ book, and read some threads on here about exercise/fitness as we get older. Not read it yet or actively done anything differently, but am conscious that a more sophisticated and focused approach is probably increasingly relevant rather than just the ‘ride as much/often as you can’ to maintain fitness.

I’m not a Peaks ‘specialist’ but have done a few rides to get a feel for it & the reality is, I wouldn’t want to ride a bigger travel 29er for what I have ridden & seen there, for all of the reasons you have stated.

My little bike (Spur) is built light, but with an angleset & its geometry is almost identical to my bigger bigger bike (Madonna) & 90% of the time is the better, faster bike.

I tend to swap out to heavier wheels & bigger tyres for those days that warrant it (steep, S. Wales valley riding) or I run a very light set of wheels with a EXO Dissector/Rekon combo around home (FoD) usually, which can be fruity on the steep stuff, but on everything else, the bike is scary fast.

There is a reason why I ride it most of the time. The Madonna feels like a pig in comparison unless I’m wringing its neck, or racing. But then thats exactly what it’s for, not general riding around (unless I’m feeling sadistic).

I’m very much in the same thoughts as @HobNob
I have a Ripmo AF coil and its a bit of a heffer to ride my usual trails, when I compare it to my Spur. And that sticks in my mind come choosing a bike to ride. The Spur just feels so zippy and so much less effort to ride. But, it has its limits and that is when you need you bigger bike.
To me, the biggest difference is tyres. +1kg tyre and soft compound on the Ripmo makes a huge difference. When I put light XC tyres on my HT a few years ago for a long epic ride, it was so noticeable, so much easier.
The Rekon EXO on my spur is excellent. light, fast, tough and fairly grippy. I would try something like that on the rear first. I use this and an Assegai exo up front for my grippy, winch and plummet riding on my Spur. Rekon/Rekon when its a long day out.
I’d also look at more range on your gears. Its the cumulative effort of 3hrs riding that zaps you. Might be ok for 2hrs, but once you start getting beyond, it’ll drain you quick.
Pro’s can get away with the big tyres front and back. They are much younger and stronger!