I have two mtbs - scott spark full suss and an On-One Whippet rigid hardtail. I mainly use the hardtail for winter riding to save wear on bearings/shocks etc. One thing that’s bugging me is that although the spark is substantially heavier it’s still fast ascending that the lightweight hardtail. The only thing I can think that’s majorly different between the two is that the hardtail has 170mm cranks and 36t round chainring whilst the spark has 175mm and 34t oval.
I can’t just swap cranks over to see what difference that makes but I can only think there is something in crank length to chainring size that I have no clue about. Any thoughts / help?
Could be the geometry of one suits you more than the other. I’ve a Cotic Solaris (fully rigid) and a Salsa Spearfish (full suss) both 29ers with identical drivetrains. It’s not often the Spearfish outperforms the Solaris.
One is full suspension and one is a hard tail….if you are climbing on trails, the suspension makes you much more efficient.
Crank length / CR size is immaterial, assuming you are riding at the same power.
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@Power13 I’m taking a fire road climb as an example for comparison. Spark is fully locked out the entire way. I don’t have a power meter to compare exactly - heart rate was 180 vs 185 so relatively close for me to think its roughly a similar effort
I’d suspect geometry. Or maybe tyres. As above, FS tends to be more efficient as it lets the rear wheel track the terrain better.
Also are the wheels similar in weight? Heavier wheels, particularly rims will slow you down. On-One/PlanetX aren’t exactly known for lightweight components.
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I’ve changed most of the stock items. Whippet now has hunt wheel (approx 1500g) with 2.2 IKONs. Spark has standard syncros (approx 1900g and 2.35 Rekons
Its the suspension. Even when locked out, it still works, but limited. Another thread talks about this, And it pops up from time to time on the forum. Suspension makes bikes faster, and saves rider effort, regardless of energy loss (that no one seems to be able to measure).
Ever think about trying your climb without locking out the suspension? We might all be pleasenly surprised with your results…
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I’ve not thought about the suspension being active whilst it’s lo ked out. Always thought it was prettybsolid to be honest. I have done several climbs without lockout and if bumpy then it’s a lot better than a hardtail. Thanks for the link - will have a read
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@iceaxe I’m only 20 replies in, not watched the videos yet but that has blown my mind completely 
There I was thinking this would be a simple component change. Thank you
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I have 2 mtb with power meters, sure one is a hardtail and the other is 10lbs heavier but CRR with mtb tires is vastly different. A proper test would be on a road paved climb with the same tires (or wheels). The way power doesn’t always yield a faster time on the road, that is even more true on mtb terrain.
If they are both 12s, I wonder if the chairing size has you at different spots in the cassette therefore yielding better (or worst) chain line and drivetrain efficiency.
