# 2021 Trek Marlin 7 Dropper post



## timwooten (Dec 9, 2020)

I want to upgrade to a dropper seat post on my 2021 Trek Marlin 7 size Large. Currently I can not drop my seat post all the way down looks like it is getting caught on the bottle cage bolts. I’m new to dropper post, my question is what size would I need. I’m 6 ft tall. I know it has to be external routed no hole in the seat post. I’m just confused on sizing.


----------



## surfnbike (Oct 22, 2020)

I have the same exact bike but in size XL (I'm 6'2"). My advice might not be too valuable since I'm new to the sport. For what it's worth, I got this one in 150mm and it works great for me. An ex-student of mine that works at the Trek store said I made a good choice. I did a bit of research before I bought it. The cable connects at the bottom so there is no slack when you drop the seat(if that makes sense). I also have my water cage on the other tube so there's no interference.

https://www.pnwcomponents.com/colle...-30-9-31-6mm-diameters?variant=33077851226189

Got the lever too. (really nice as well)

https://www.pnwcomponents.com/colle...m-lever-dropper-remote?variant=32087738843213


----------



## ConnorW (Nov 18, 2020)

surfnbike said:


> I have the same exact bike but in size XL (I'm 6'2"). My advice might not be too valuable since I'm new to the sport. For what it's worth, I got this one in 150mm and it works great for me. An ex-student of mine that works at the Trek store said I made a good choice. I did a bit of research before I bought it. The cable connects at the bottom so there is no slack when you drop the seat(if that makes sense). I also have my water cage on the other tube so there's no interference.
> 
> Cascade Dropper Post
> 
> ...


Hey man, I'm new to it too, I'm also 6'2 and have bought a Trek Marlin 7. It's awesome, love it. I've upgraded a couple of things including the stem and tyres etc. Looking for a dropper post now. Where did you run the cable for your externally routed dropper.. I'm almost considering drilling a hole in the seat tube and running an internal dropper through the frame to keep it neat. Cheers.


----------



## ataxis (Apr 7, 2021)

Hey,

also a marlin 7 '21 (size L) rider too. Apparently you can route the internal cable behind the BB. I'm worried about seat height, I might go with a 170mm dropper, as I don't really want to buy the wrong one.


----------



## surfnbike (Oct 22, 2020)

@ConnerW: No need to drill a hole.


----------



## surfnbike (Oct 22, 2020)

@ataxis: The 170 might be overkill. I'm 6'2" with an X-large Marlin frame and the 150 is plenty. I doubt I'll ever drop it to its minimum. I was wondering the same thing before I bought the 150 so I asked my friend with more experience. He steered me away from the 170 explaining I'll never use that much. He's also my size and uses a 150. Hope this helps


----------



## Qualms (Apr 6, 2021)

I have a size M marlin, i drilled a hole in mine to fit the dropper, i also had to to drill out the top riv nut to slam it down to the bottom. Obviously the warranty is now void but i it looks the way way tidier than the one pictured above.

Plan on converting it to an ebike (also voids warranty) but the mid drive motor clashes with the opening for the internal cable routing.. can anyone confirm if that lip of metal sticking out of the down tube by the bottom bracket is structural? Or could i just grind it down out of the way


----------



## Vertex Mario (Apr 20, 2021)

ataxis said:


> Hey,
> 
> also a marlin 7 '21 (size L) rider too. Apparently you can route the internal cable behind the BB. I'm worried about seat height, I might go with a 170mm dropper, as I don't really want to buy the wrong one.





ataxis said:


> Hey,
> 
> also a marlin 7 '21 (size L) rider too. Apparently you can route the internal cable behind the BB. I'm worried about seat height, I might go with a 170mm dropper, as I don't really want to buy the wrong one.


Hey dude if my bike is XL as well. But I love ridding my seat to the lowest option, I even cut off 7cm of my tube to lower the seat to the max, what dropper post would you recommend? 170 mm or 150mm

Thanks for the help


----------



## acedeuce802 (Jun 30, 2017)

Vertex Mario said:


> Hey dude if my bike is XL as well. But I love ridding my seat to the lowest option, I even cut off 7cm of my tube to lower the seat to the max, what dropper post would you recommend? 170 mm or 150mm
> 
> Thanks for the help


You're best off measuring yourself, use this calculator and it'll tell you some droppers that fit OneUp Dropper Post Length Selector


----------



## Westie81 (Jun 27, 2021)

surfnbike said:


> @ConnerW: No need to drill a hole.
> View attachment 1925113


Hi looking for advise I like the way u have done the cable am just wondering what size dropper post u have thanks


----------



## surfnbike (Oct 22, 2020)

Size is 150.


----------



## Westie81 (Jun 27, 2021)

Hi thanks for the reply sorry to be a pain but would that be the 31.6mm x 449mm 150mm and what brand do u have I want to make sure I have asked bike shops but they are very blunt unless I buy from them witch is very expensive


----------

