Trek Powerfly 5 dropper seat post

[WWJ]

Hi can anyone shed some light on what length travel dropper seat post I should be fitting to my 2020 Trek Powerfly 5 size medium frame.
I am sure that the post diameter is 31.6mm, however I am unsure what the dropper travel should be 100/150/170mm.
Has anybody fitted one of these themselves without removing the motor to run the cable through the frame to seat tube area.
Any advice gratefully accepted.

 

[ronianash]

The dropper travel depends on what height you want your seat to be at.

 

[IndigoUnicorn]

Hi can anyone shed some light on what length travel dropper seat post I should be fitting to my 2020 Trek Powerfly 5 size medium frame.
I am sure that the post diameter is 31.6mm, however I am unsure what the dropper travel should be 100/150/170mm.
Has anybody fitted one of these themselves without removing the motor to run the cable through the frame to seat tube area.
Any advice gratefully accepted.

Which dropper are you looking at? I recently installed a PNW Ridge on my Specialized Pitch and I literally finished up installing one on my Trek Powerfly 5 about 15 minutes ago.

You need several measurements to ensure that the dropper will A. Fit your seat tube and B. Fit you.

I found the info PNW provides on their site really helpful: How to Choose A Dropper Post

 

[Philly G]

Put your seat at the optimum pedalling height for you. (i.e. slight bend in knee with pedal down in the 6o'clock position)
Measure from the top of the seat post down to the seat post clamp. (measurement "a" in the diagram @IndigoUnicorn posted above) This is the amount of travel you want. Note that some posts have adjustable travel, down 20-30mm from the quoted travel. So if your optimum measurement "a" is 160mm, buy a 170mm dropper post with adjustable travel and you should be able to get pretty close to that by adding in the spacers that restrict the amount of travel.

 

[Cricket23]

Hi can anyone shed some light on what length travel dropper seat post I should be fitting to my 2020 Trek Powerfly 5 size medium frame.
I am sure that the post diameter is 31.6mm, however I am unsure what the dropper travel should be 100/150/170mm.
Has anybody fitted one of these themselves without removing the motor to run the cable through the frame to seat tube area.
Any advice gratefully accepted.

Hi,

I too have a Powerfly 5 and spent ages looking into this a few months ago.Here's what I found:

1) The diameter is indeed 31.6. Have a look at the spec on the Trek website.
2) Somewhere, and I can't find where, but it was official Trek info, states that the max dropper post length for a Powerfly 5 hardtail with a medium frame is 125mm. As mentioned, I can't recall where I got the info, but the Trek helpline was also really helpful, so perhaps try them.
3) I did loads of research and the best value for money / quality was the 'Ascend' brand. I had this fitted and it's been great. Reviews have said that the changer on the handle bar is poor, but I have not found this to be a problem. I did swap out the wire for Jagwire which claim to give better service.
4) I tried for a couple of hours to fit mine, but couldn't get the wire past the motor. My local bike shop charged me £40 to do the work. The had to take out and reinstall the motor to do the work. If you do this yourself it will invalidate the warrenty.

BTW, I shd add that this is an internally routed dropper post. If you get an externally routed one, then it's easy to do your self, but you'll have to secure the cable to the frame with something as there are of course no routing points.

Hope this helps,

C23

 

[IndigoUnicorn]

I installed an internally routed PNW Ridge 125 with their Loam lever (for bikes with a single front ring).

Took a couple of hours thanks to removing: the battery, the battery lock assembly, and the battery plug plate. Then, had to loosen the cabling stays and drop the motor (6 bolts and four screws to drop the motor, btw).

Honestly, if you’re fairly mechanical and have a good set of tools and a cable cutter (note: a “tamper resistant” torx set is needed for a few of the screws), it’s a pretty straightforward install.

 

[IndigoUnicorn]

Hi,

I too have a Powerfly 5 and spent ages looking into this a few months ago.Here's what I found:

1) The diameter is indeed 31.6. Have a look at the spec on the Trek website.
2) Somewhere, and I can't find where, but it was official Trek info, states that the max dropper post length for a Powerfly 5 hardtail with a medium frame is 125mm. As mentioned, I can't recall where I got the info, but the Trek helpline was also really helpful, so perhaps try them.
3) I did loads of research and the best value for money / quality was the 'Ascend' brand. I had this fitted and it's been great. Reviews have said that the changer on the handle bar is poor, but I have not found this to be a problem. I did swap out the wire for Jagwire which claim to give better service.
4) I tried for a couple of hours to fit mine, but couldn't get the wire past the motor. My local bike shop charged me £40 to do the work. The had to take out and reinstall the motor to do the work. If you do this yourself it will invalidate the warrenty.

BTW, I shd add that this is an internally routed dropper post. If you get an externally routed one, then it's easy to do your self, but you'll have to secure the cable to the frame with something as there are of course no routing points.

Hope this helps,

C23

I would agree that 125 mm is about the absolute max post depth for the Powerfly. At least on a medium or small frame. Not sure of the difference for a large frame, though.

 

[Stihldog]

Hi,

I too have a Powerfly 5 and spent ages looking into this a few months ago.Here's what I found:

I did the same. I got his/hers Powerfly’s 5 in June 2020. (Medium/Small) We use them for road and local trails but I needed a dropper on mine. I ordered a 150mm dropper but the LBS (Trek) said “no-way”. So I let them install a 130mm dropper instead. I think the dropper was around $400cdn including the install. I was pleased with the remote and the operation of the dropper. Since I have difficulty getting my leg over the seat this worked out good for me.