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[Rafita06]

I have a Trek Rail 7 Gen 3 2024 MTB ebike, which comes with a RockShox Deluxe Select+ RT rear shock, 230mm x 57.5mm, and I want to replace it. Would a Fox Float X2 Performance 230mm x 65mm shock be compatible?

 

[Greg Watts]

I have a Trek Rail 7 Gen 3 2024 MTB ebike, which comes with a RockShox Deluxe Select+ RT rear shock, 230mm x 57.5mm, and I want to replace it. Would a Fox Float X2 Performance 230mm x 65mm shock be compatible?

@Rafita06 The short answer is no, not without consequences. Your stock shock is 230mm x 57.5mm, and the Fox Float X2 you're looking at is 230mm x 65mm. The eye-to-eye length (230mm) is correct, but the stroke length is 7.5mm longer than stock. That extra stroke would increase your rear wheel travel by a meaningful amount and, more importantly, could cause the rear tyre or linkage to contact the frame at full compression. That's not a theoretical risk on a Trek Rail, it's a real one.

That said, going slightly over stock stroke on the Rail isn't unheard of. Community members have experimented with 60mm stroke shocks on the Rail and found it workable, with reports of roughly 5mm clearance on a Medium frame when fully bottomed out. The jump from 57.5mm to 60mm is one thing; 57.5mm to 65mm is quite another. That's a 13% increase in stroke, and on a bike where the frame clearances are already fairly tight, you'd almost certainly run into contact issues before the shock reached full travel.

If you're after a significant upgrade in damping performance (which the Float X2 would absolutely provide over the Deluxe Select+), I'd look for a Float X2 in the correct 230mm x 57.5mm size. Fox does make the X2 in that spec. Alternatively, if you want a bit more travel and are comfortable with a small gamble, a 230mm x 60mm shock is a more reasonable stretch, though you'd want to check clearance carefully on your specific frame size before sending it down anything consequential.

There's also been some very positive feedback from Rail owners fitting RockShox Vivid coil shocks in the stock 57.5mm stroke, with reports of massively improved traction and a general sense of falling back in love with the bike. The DVO Jade X coil is another option being explored by Rail owners, with @Doomanic currently waiting on a fitment check for a Medium frame.

I've got more detail on spring rates, sag settings, and specific shock fitment reports for the Rail if you want to dig deeper into the upgrade options.

 

[Rafita06]

Thank you very much, I appreciate your help.