New Haibike has ridge in seat-tube, preventing seat-post from proper insertion

Received my new SDURO Trekking 4.0 from Haibike today, and when setting it up, I found out that the seatpost won't actually insert properly due to an issue with the inner seat tube. There's a section where the seat tube didn't get hollowed out correctly, leaving a little "lip" on about 1/3 of the tube, preventing the seatpost from inserting fully.

I've attached pics showing the issue. You can see the seatpost pulled out, and the grease-line shows the max insertion of 9", or 228mm. I also attached a picture of where the "lip" is in relation to the exterior of the seat tube.

I guess the solution is to just take a hacksaw to the seatpost? Does anyone have experience with this happening / thoughts on what I should do?

Thanks for any help!
 

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BlackHand

Active Member
It looks like you got the mid-step version? Which frame size? How long is the seatpost?

Just for comparison: I have a Trekking 9.0 S high-step 52cm (medium) . My seatpost is 400mm long and can insert to about 290mm. The equivalent frame in the mid-step is a 48cm. If they ship all bikes (both frame styles) with the same seatpost I would expect it to insert to about 250mm.
 
I have the step thru size L (52), so the seat tube length is 520mm (step thru is sized differently)

The seatpost is 350mm, so I have 100mm un-insertable. Unsure if this is normal or not for Haibikes, since I've never come across it with others. Thanks for replying with your bike dimensions - it's super helpful!
 

rich c

Well-Known Member
Thinking they do that so you don't send the tube all the way in to avoid wires going through the frame. Trying to remember if my tail light wire goes through there? But mine are 2016 models.
 
There's nothing down there - the wires run through a separate channel/routing.

I think it's a manufacturing defect since the "lip" is only on 1/3-ish of the inner tube, and there's no shape or uniformity to it.

Due to the location of this lip, it's going to prevent the use of suspension seatpost a that has the tension adjustment at the bottom of the post like a Suntour or Shockstop, so I'm bummed about that. I guess a kinekt could still work, if I use a hacksaw to chop it down a bit.

Just sort of sucks to do that with a brand new bike.
 

batmick1

Active Member
Could be intentional, to prevent you from moving the post too deep and into the bend, which might damage the frame.
 

rich c

Well-Known Member
Could be intentional, to prevent you from moving the post too deep and into the bend, which might damage the frame.
Good point. Not sure it would damage the frame, but could get wedged in if it slipped and the rider weight jammed it into the curve. So with that curve, you wouldn't get much more depth anyway. Cut a little off the bottom of the seat tube if you need that.
 

J.R.

Well-Known Member
I've read of bikes with a seat tube with a bend that didn't have a stop and the post got stuck and the owner used a pipe wrench to remove the post. Destroyed the post and damaged the frame. The stop wouldn't have to be pretty inside to work. I think I'd like the stop if my seat tube had a bend.
 
I suppose it could be intentional...but I just measured the length of the straight part of the seat tube, and it's MUCH longer than the seatpost. So, while the seatpost is 350mm, the seat TUBE is 475-500mm before the curve starts.

I feel like an actual "stop" would be more pronounced and much further down. I have other bikes in a step thru frame, and none have this issue. Plus, the raw aluminum edge inside the tube has started to chip pieces off the bottom of the seatpost...I just can't imagine this is how it's supposed to be.
 
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BlackHand

Active Member
TBH, your pic looks more or less the same as what I see in my tube. Mine has a small lip also that only goes about 1/2 way around the inside surface roughly 1" up from the bend. FYI, My seat tube is approx 320mm down to the bend.

Maybe @TMH will weigh in? They have a couple Trekking 7.0 ebikes and I think at least 1 is a lo-step.
 

TMH

Well-Known Member
TBH, your pic looks more or less the same as what I see in my tube. Mine has a small lip also that only goes about 1/2 way around the inside surface roughly 1" up from the bend. FYI, My seat tube is approx 320mm down to the bend.

Maybe @TMH will weigh in? They have a couple Trekking 7.0 ebikes and I think at least 1 is a lo-step.
No, both of our '19 Trekking 7.0's are high step diamond frames.

A couple of pics - the first showing the full length of my seatpost (XL frame size) and the second showing how far that seatpost fits into the seat tube.

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IMG_0681.JPG


I also tried to take a photo of the interior of my seat tube, but wasn't really successful (you did a good job at that!) I also see something impinging on the I.D. of the seat tube, but maybe it is lower down on my frame (or the fact that I am tall so I need my seat post up higher).

IMG_0688.JPG


Not at all as much impingement as on your frame, but as discussed mine is a different frame style.

I have several bikes where the seat tube stops full insertion of the seat post, and this comes into play on my wife's bikes as she is only 5'6" tall. In some cases I have had to use a pipe cutter to shorten the seat posts on her bikes. (And if you do this don't forget to mark a new line for the 'min insertion' which is higher by the same amount you cut off - for safety's sake in the future).

I would try to find out through the folks at Haibike USA whether this is intended on your bike frame size and style, or whether it is something unintended which happened during manufacturing. It may take longer for them to get back to you, but it seems to me that they would have more knowledge about a situation like this than any dealer (unless you can find a dealer who has already seen this and already contacted Haibike in the past).

Good luck - it should be a really sweet bike when you get it up and running to your needs.
 
Thanks for replying! Yeah, you can definitely insert your seatpost much further. It seems weird to me to only be able to insert 228mm of a 350mm seatpost on a 520mm seat tube. That's 17cm of unused tubing (not accounting for the bend, so probably more like 12cm).

Either way, something seems weird. I will contact Haibike and see what they say. The dealer who sold me the bike said "oh that's normal, 350mm is long for a seatpost and you're supposed to cut it" which seems interesting.
 

BlackHand

Active Member
Thanks TMH!

Yeah, my biggest takeaway from this thread is that TooMuchWitt's seat tube photography skills put mine to shame.
 
  • Haha
Reactions: TMH

Mike TowpathTraveler

Well-Known Member
I can't imagine why you need to go so far down in that seat tube unless the frame you bought is just too big for you.

I thought I read years back that Haibike hydroformed all of their tubes. If you think about it, having the lower third of that seat tube at double or triple the wall thickness is sound engineering; considering the motor's special dies cast frame mount is welded up to that lower end of the seat post. As well on their dual suspension frames, there is substantial supporting exterior pieces that are welded up to that seat post.

Such good engineering the frame is, I seem to recall only one person reporting of a cracked frame on this seat tube, down low; I believe on this forum, but it's been quite a few years ago. And we don't really know what kind of abuse that person subjected that frame to.

I have a 2016 Haibike Full FatSix. It appears that alot of the individual frame components are closely matched to each other; ie, your Trekking seat tube might also fit a hard tail mtb Haibike, so close in family appearance they are. Many Haibike mtb's have a hole cut on the lower third of the seat tube to accomodate a dropper seat post cable.

Maybe a bike shop owner can chime in and assist you here or you could take your bike to an LBS and talk to them about your concerns. Myself, I'd trim a bit off the seat post till you got your best, most comfortable fit.

Nice bike, btw!

100_2114.JPG
 
I can't imagine why you need to go so far down in that seat tube unless the frame you bought is just too big for you.


I sure hope that I got the right frame size! I bought the step-thru 52cm frame, and I'm 5'11".

As it is, I probably only need to take 2 inches off the post, so it's not the end of the world.

Unfortunately, the seat tube being so long (relative to other bikes with similar geometry) makes it so I'm going to be just-shy of the clearance needed for a suspension seatpost. That sucks cuz I was looking forward to getting one.

I think the Kinekt is the lowest out of the popular ones (can't use Suntour or ShockStop due to having the preload adjustment on the bottom of the 350mm post)

If anyone has the kinekt, what is the lowest clearance that would work for it?

I'll do a full write up in the Haibike forum!
Just pumped up the tires and took it on a ride around my parking garage - everything seems to be in order. The motor has a slightly higher-pitched whine than the one I demoed, but that's likely due to being brand new.
 

J.R.

Well-Known Member
I sure hope that I got the right frame size! I bought the step-thru 52cm frame, and I'm 5'11".

As it is, I probably only need to take 2 inches off the post, so it's not the end of the world.

Unfortunately, the seat tube being so long (relative to other bikes with similar geometry) makes it so I'm going to be just-shy of the clearance needed for a suspension seatpost. That sucks cuz I was looking forward to getting one.

I think the Kinekt is the lowest out of the popular ones (can't use Suntour or ShockStop due to having the preload adjustment on the bottom of the 350mm post)

If anyone has the kinekt, what is the lowest clearance that would work for it?

I'll do a full write up in the Haibike forum!
Just pumped up the tires and took it on a ride around my parking garage - everything seems to be in order. The motor has a slightly higher-pitched whine than the one I demoed, but that's likely due to being brand new.
Maybe your setting your saddle too low. Are you trying to setup the bike so you can rest your foot on the ground from a sitting position? That wouldn't be the best thing to do with a trekking style bike. It's not good for your knees, hips or back and you won't have a proper pedal stroke. You'll have less power. There are crank forward, flat foot bikes designed for that style of riding. Properly set most people can barely touch the tip of their toes with one foot. If that. You really need to leave the saddle to put your feet down. A 52cm frame should work for most 5'-11" riders, unless you have a short inseam.

 

rich c

Well-Known Member
Seat tubes don't get "hollowed out". It's tubing. These pics are my 2016 Haibike XDURO Trekking S RX. There looks like a tab inside my tube, 10.5" down from the top.
 

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Yeah, looks like it's entirely possible I went one size too big on my frame lol. Haibike sizing is weird. All the other geometry measurement are just right (such as reach, stack, wheelbase) but even the low standover is pushing right up against my crotch when I get off the seat. Like, it's not crushing my future kids, but it's definitely getting a bit too friendly with them.

Actually, it's possible I'm just used to too-small frames and seat heights, and it's something that I'm going to have to get used to.
 

BlackHand

Active Member
Yeah, looks like it's entirely possible I went one size too big on my frame lol. Haibike sizing is weird......
Actually, it's possible I'm just used to too-small frames and seat heights, and it's something that I'm going to have to get used to.
FWIW I felt the same way at first. It's just so much more bike than the Rockhopper I was using. I'm riding now with the seat almost 1 1/2 inches higher from where I started just as my comfort and confidence have grown. Take your time, and don't be afraid to tweak.​
 

Ravi Kempaiah

Well-Known Member
I bought the step-thru 52cm frame, and I'm 5'11".

That is the right frame size. I am 6ft and I had a 52cm - step over frame and I never had to push the seatpost down.
If you need to go all the way down, then I suspect you not getting the bike fit right. When you are fully seated on the bike, your toes should barely touch the ground.