Right, gotcha, not sure how to work out which length dropper I’d prefer? Assuming it’s based on distance to the seat stem etc
https://www.youtube.com/watch?v=-Lcdd5-La1c
You generally want the biggest drop you can fit - this is down to the size of frame and the size of you. Sadly, this isn't straightforwards, as the bigger the drop the more distance is needed in the frame for the "compressed" unit. So, a bigger frame can cope with a longer drop... but, a bigger frame on a smaller person will ultimately prevent a dropper, as they will be riding with the seatpost slammed... Also, different frames have different shaped seat-tubes, and thus can accommodate different lengths (ie some frames will allow a long dropper to be slammed, but other frames have a bend in the seat-tube, so can only accommodate a set distance - buy a long dropper on a small frame and its retracted length could well be the ideal extended length of a shorter dropper - if that makes sense).
When you have your bike, set your seatpost to your ideal peddling height (tbh, I probably add a cm or 2, to have it a little more, for steep climbs). Measure the length from the seat clamp (top of the frame) to the top of the seatpost (or the rails under the seat) - lets call this your seatpost height. Now, push your seat tube all the way into the frame and put your thumb against the seat-post, then retract the post to see how long the frame can accept. This is the max insertion depth.
1) Your dropper stroke (150 drop in your link) should be less (or equal to) your seatpost height.
2) You want the total length of the dropper to be no more than the max insertion depth + seatpost height.
3) After that, it's just checking the seatpost height - dropper stroke is more than the min insertion length, that's usually in the frame's handbook.
I think that's what I've done in the past...
NOTE... As you have the Trek Marlin, check the Q&A for the dropper you [ur=[URL]https://www.chainreactioncycles.com/brand-x-ascend-120mm-150mm-dropper-seatpost/rp-prod149024?gs=1&sku=sku669796&pgrid=60711843258&ptaid=pla-671044171380&utm_source=google&utm_term=&utm_campaign=PLA+All+Products&utm_medium=base&utm_content=mkwid|sQKA9oj16_dc|pcrid|309840119912|pkw||pmt||prd|669796UK&gclid=CjwKCAjw2qHsBRAGEiwAMbPoDGuqSJVpYK7Wk_4kOEEz8PTCnv5OePpcfYqH_71233FqLysp-n6f1hoCmI4QAvD_BwE]linked[/URL][/URL]
Will this work with a 2019 Trek Marlin 7 18.5? The Trek website says that it can support internal routing but I can't seem to find where it goes on my bike.
Answers
Looks like there's a spare cable routing entry point at the top right hand side of the down tube. You might need to remove the bb to get it up the seat post. Alternativvl y get the ascend 2 external post. Works great
So... also check on your frame where there's cable routing...
a load of info here too:
https://singletrackworld.com/forum/...er-posts-how-to-decide-correct-length-to-get/