It’s very rare that anyone changes the eye-to-eye length of a shock, that’s when you’d see geometry changes. Sometimes people change the stroke of a shock, and this is often how bike manufacturers offer one bike model in both an XC or EVO/Trail/Downcountry model. Doing this changes rear travel, but doesn’t meaningfully impact geometry (no effect on static geo, meaningless impact on sagged geo).
For example, a lot of brands use 190mm rear shocks for their XC models. 190mm shocks can have 45, 42.5, 40, or even 37.5mm stokes. Technically, there are 190x50mm shocks out there too, but they’re increasingly rare and predate the industry move to “metric” shock standards.
Changing fork travel (overall fork length) changes head-angle, seat-angle, BB height, reach, and stack, as the whole bike effectively pivots at the rear axle in a static state.
Being the owner of the current Epic EVO I would say leave it the way it is. My last two XC race bikes were 100mm f/r and the EVO is faster. Tons of anti-squat for super efficient pedaling and the new SID and Fox 34’s are so light anyway that it would not be much of a difference. There is a reason that even the World Cup racers are running 120mm forks and longer travel these days. The EVO is soooo fast the way it is that you are unlikely to (measurably) go any faster with those changes. Plus you would change the great geometry that the EVO has
I am leaning that way… My fork is the Reeba (from the Comp version… which I upgraded to XO1) so that is what made me want to think about the swap. Like you said the Evo is fast and firm. The fork is stiff though, can’t seem to get it dialed in compared to the SID SL I have. Maybe now I have an excuse to upgrade the fork.
I’m going to second @scottsimon . If someone told me two years ago that I would own a 120mm xc bike, let alone a specialized, I would have laughed in their face. Here I am two years removed and on an Epic Evo… And, I can honestly same I’m faster than I ever was on any of my past 100mm weight weenie build bikes, even without a lock-out which is still a bit mind blowing to me. The Evo is so good just as it comes.
Most of the serious racers on the local scene here (all much faster than me) have sold their 100mm Sparks and Epics (w/ brains) over the past 6 months or so and all shifted to the Evo. Everyone I’ve talked basically said they would never go back.
Speaking of Epics, how long does Spec usually go between refreshes? The current model came out fall of 2021.
I have a 2019 Orbea Oiz TR that’s served me well the last handful of years. They were ahead of the curve on offering the 120mm option to their XC race frame. It’s a bit heavier than the latest bikes and certainly not as slack as the latest but so far nothing out there on the 2023 horizon seems like it will move the needle enough for me to upgrade.
That’s great. Super exciting!! XX1 AXS or mechanical? I am thinking about going mechanical with a fox seat post versus AXS to save some cash, but still on the fence about that or just waiting for the new AXS in March.
The real question??? What paint job did you go with?
How does the AXS weigh 600g more? It’s total weight is 768 g for a 170mm including remote and battery according to the website. Fox performance weighs 733g just for post, not including lever and cables. The axs should weigh less (unless I am missing something)?