Seat Post Probs

[Peaky Rider]

My mate has had many, many problems with his Trance E+2 and the latest one I have noticed is that his dropper post wasn't working as it should.
It would not lock in an intermediate position and a couple of times it just sank down when I sat on it.
Is this a common problem and does anyone know if it is fixable. I don't think it is anything to do with the cable but I have not really investigated?

 

[KennyB]

Had this on my brand new bike, it was the cable, a kink in it I think which stopped it fully releasing. An overtightened adjuster would cause this as well I reckon.

 

[Peaky Rider]

Had this on my brand new bike, it was the cable, a kink in it I think which stopped it fully releasing. An overtightened adjuster would cause this as well I reckon.

Thanks, but as I said in my post, not sure it's the cable and as he has said nothing, I presume it was ok when he bought it ten months ago.

 

[MinusPrevious]

Make sure the dropper is not mounted too low in the frame. Ifs its too low it will trigger the mechanism & will not work right

Just a thought / .02

 

[Pdoz]

It was the cable on my giant ( full e pro) - it had been routed in front of the suspension linkage so the cable kinked after I mounted it too low in the frame ( for my kids to ride the bike) . Improved by replacing the cable, eventually fixed when I changed to a one up components dropper . The giant cable enters the post at the back , unfortunately you can't just rotate it because the seat clamp is angled.

The one up components dropper is heaps better - the in frame part is more compact so it tolerates being inserted down to kid level. More importantly, it works perfectly every time. Pressure adjustable so I can dial in exactly how loud that satisfying clunk is when it returns. Even drop adjustable so I can decide between 125mm and 150 mm by inserting the spacers that came in the box. I know it's just a dropper post...but after a year of stuffing around with that giant piece of cr@p it's soooo nice to have something that works.

If it's not the cable, it may be the plunger sticking. A good clean and lube of the mechanism will buy you a few months, just be really careful not to damage the screw at the top of the post when pulling it apart. Once you've had the post apart, you'll understand how primitive the unit is and feel a lot better about investing in a better one.....

NB you DO NOT want that cable to come off when checking the routing....so leave everything hooked up as you bring the dropper out of the frame.

 

[GrandPaBrogan]

My mate has had many, many problems with his Trance E+2 which is a major headache for me as I end up trying to sort many of them out.
I have just had it to change the controller switch and gear cables (inner and outer) and noticed his dropper post wasn't working as it should.
It would not lock in an intermediate position and a couple of times it just sank down when I sat on it.
Is this a common problem and does anyone know if it is fixable. I don't think it is anything to do with the cable.

I had this happen to my Trance E+3Pro when I lowered the outer post as low as it would go into the seat tube of my frame. Totally messed the dropper actuation and caused erratic behaviour - that's not directly related to the cable or the cable release trigger.

Here's what I discovered on my bike, may or may not be applicable for you:

If you look closely at your seat tube, there is a pivot point about halfway down (the main pivot of the rocker linkage). Inside your seat tube, there is an aluminium shaft that splits the seat tube cross-section in half. It forms a D-shaped opening at the front AND and a D-shaped opening at the rear of the tube - like this sketch shows:

The activation cable from the handlebar goes down internally through the battery cavity, swings around and below the motor somewhere (can't see where), but then it comes up the lower portion of the seat tube until the end of the cable pokes through the rear D-shaped opening.

The problem is the Dropper Post actuation lever has the hook (where you latch the cable) that's facing the front of the seat tube (lined-up with the front D-hole). No problems if you install the Dropper Post high enough - but the problem occurs when you want to lower the Dropper Post as low as it can go. What happens is that the cable forms a tight dog-leg "kink" because the actuator lever is situated at the front D-hole, but the cable is routed through the back D-hole. This creates binding - the inner wire should really be moving freely against the cable outer but it can't.

The solution that I took upon myself therefore, is to route the cable so that it passes through the front D-hole so that things would line-up. Not so easily done, but with a bit of patience here's how I did it:

• Disconnect the cable inner wire from the handlebar trigger.
• Loosen the seat clamp and carefully remove the dropper post. It may or may not pull the inner steel wire (depending if the lead ball-end got detached or not). The idea is to unhook the cable inner wire from the post but DO NOTpull this inner wire entirely out of the cable outer, if at all possible.
• Remove battery and then you need to separate and free the dropper post cable from the rest of the other hoses clamped together in there. Then you have to pull the front outer cable away from the handlebar so that end is just next to the rubber grommet that leads into the battery cavity. No worries if you pull it all the way through, you can push it back out later on. You need to free-up that much cable slack ahead of the motor.
• You need to VERY carefully and slowly yank the cable portion from the inside of the battery cavity (away from the motor) so that the cable end inside of the seat post will get pulled lower and lower - until it's just under that pivot point.
• With a fat wire/long screw driver/knitting-needle/wooden stick - whatever works, you need to somehow nudge the cable end toward the front D-hole inside the seat tube. Then push the cable from the battery cavity towards the motor, so that the cable end would rise up and go through the front D-hole.
• Unfortunately you need to keep going until the cable outer end is just about outside the top opening of the seat tube. All of this might be a lot easier if the bottom bash guard of the motor was removed, but I couldn't be bothered to find out. (Oh, if you want to replace the inner wire with a new one, now is your only chance). This is the only way you can push the inner wire back into the cable outer and to also 'hook' the lead ball end of the inner wire back into the bottom lever - THEN also insert the cable outer end into a recess at the bottom of the Dropper Post. Make sure that the inner wire has now come out fully at the opposite (front) end.
• Then as you slowly push the Dropper Post back into the frame Seat Tube, you need to pull the cable outer from inside the battery cavity (away from the motor). The idea is to to drop them both by the same amount simultaneously. Once the Dropper Post hits rock bottom (which is what I wanted) you have to stop pulling the cable away from the motor. If you continue to pull the cable, its end will pop out of its recess and you may have to start again.
• Re-align and reroute everything inside the battery cavity back to where it was, and reconnect the cable wotsithingys back onto the handlebar trigger.

I tried to make this shorter but my OCD won't allow it.
Now if you'll excuse me, I need to get myself a drink! Whew...

 

[Peaky Rider]

Thanks for your comprehensive replies GrandPa and Pdoz.
After reading your posts and viewing several e-tube videos I have a horrible feeling it may be the compression cylinder at fault. Maybe check the routing of the cable first though.

 

[Zimmerframe]

front D-hole, but the cable is routed through the back D-hole

Perfect Photoshop, Snazzy Sketches AND in depth logical descriptions ..

In honour of your post , for the rest of the day, I feel the need to call anyone I don't like a "D-Hole" ..

 

[GrandPaBrogan]

Thanks for your comprehensive replies GrandPa and Pdoz.
After reading your posts and viewing several e-tube videos I have a horrible feeling it may be the compression cylinder at fault. I will check the routing of the cable first though.

Cheers Peaky, it’s just all info - might help someone else that may have a similar problem to mine.

Let us know how you get on with the compression cylinder.

 

[GrandPaBrogan]

In honour of your post , for the rest of the day, I feel the need to call anyone I don't like a "D-Hole" ..

Haha! I called it that on purpose as Zimmer-bait. I was wondering how long it would take for you to find it and put it to good use.

 

[Zimmerframe]

Haha! I called it that on purpose as Zimmer-bait. I was wondering how long it would take for you to find it and put it to good use.

YOU....you .. you..... D-HOLE ! ????

 

[Pdoz]

No wonder the cable gets rooted " incorrectly" - it looks like giant makes 2 different droppers, the short " contact switch sl" uses the front d hole , whilst the longer " contact switch" uses the rear d hole.

Someone at giant hq has height issues

 

[GrandPaBrogan]

No wonder the cable gets rooted " incorrectly" - it looks like giant makes 2 different droppers, the short " contact switch sl" uses the front d hole , whilst the longer " contact switch" uses the rear d hole.

Someone at giant hq has height issues

Oh good to know there are two sorts! But you’d think they’d be consistent and have their dropper posts all the same with the cable connection facing the rear... where the cable has a natural tendency to come out of.

 

[Tony.OK]

I had same issues, was def cable related from lowering post too far, at first I turned the mech at the bottom of the post 180° which unwinds it slightly, worked fine and made dropper slightly quicker as it created slightly less vacuum inside the dropper.
The cable tension is very sensitive on the Giant dropper, a wee bit too much and you have a sinking seat.....after 8mths my dropper was knackered, the coating seems to be just a powder coat, not any where near as hard as a fork stantion and just wore through, it was regularly greased under collar too. Giant supplied a new one which is already wearing coating but still working fine.....
Def move the cable to the front of the susp pivot if you have post even remotely close to lowered, makes a huge diff and yes is a pain in the a** to do ?
I ride a medium and every ride wish I could fit a longer than 125mm dropper to get seat lower but the Trance is flawed in post design with the thru bolt for the Maestro mount unfortunately, a trade off for nice supple rear end.

 

[Life's short live it]

Also make sure your seat post clamp isn't over tightened. Super easy to do with the two bolt system and can cause the seat post to bind and stop it returning.