Does anyone know what size seatpost collar the Stromer requires?

Operator7

Active Member
I've been trying to get a rack installed for three weeks now... I have tried multiple collars, and the current one is a 31.8, which is just shy of the seatpost width. Has anyone out there purchased a seatpost collar for the Stromer, or do you know where I might try to call to find out what size collar is required? Or is this some sort of odd-sized seatpost or something designed not to fit any collars because they want you to buy the City Kit???
 
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Deleted member 803

Guest
What does the rack issue have to do with the seat post clamp? I use a Cirrus Body Float that comes with a 31.8MM post and works just fine. Not sure what problem you are having with the collar. What kind of rack are you trying to install?
 

Operator7

Active Member
I am trying to install this rack - http://www.amazon.com/gp/product/B004094HY2?psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

At first, I thought I could hook it directly to the frame. I then learned that I need to use a seatpost collar with rack mount. The seatpost says it is size 31.6, and I just tried a 31.8 collar (http://www.amazon.com/gp/product/B0025UQ3I6?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00). I can't even put the tail light on my bike now, because I can't get the rack installed.
 

J.R.

Well-Known Member
I am trying to install this rack - http://www.amazon.com/gp/product/B004094HY2?psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

At first, I thought I could hook it directly to the frame. I then learned that I need to use a seatpost collar with rack mount. The seatpost says it is size 31.6, and I just tried a 31.8 collar (http://www.amazon.com/gp/product/B0025UQ3I6?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00). I can't even put the tail light on my bike now, because I can't get the rack installed.
I provided a link on your other thread about this for an XLC post collar. I don't know Axiom stuff, I've used XLC products.

You will need to know part sizes often if you really get into biking and an inexpensive dial/digital caliper ($10-20) would be very helpful.
 

Operator7

Active Member
I got the Axiom collar because it was an Axiom rack and both collars looked identical and supposedly the same size (31.8 mm). What I don't understand is if the seat is 31.6, and the collar is 31.8, why the collar won't go around the post.

I'm guessing everyone pretty much just goes with the City Kit for this reason. I'm riding around now with no tail-light.
 
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Deleted member 803

Guest
You have surpassed my knowledgebase with your rack. Sorry I can't help further.
 

BTB

Member
Maybe they shipped you the 29.8mm version of this Axiom collar by mistake. Have you measured it?
 

Operator7

Active Member
Maybe they shipped you the 29.8mm version of this Axiom collar by mistake. Have you measured it?

I don't have calipers, but I measured with a tape measure... the outside of the frame looks to be the right size, but the inside appears to be slightly smaller than it should be. I am just surprised because I would think that Stromer owners would know what size collar should fit the seat post.
 

David1

Active Member
On my St2 2015, I purchased two extra seat collars through my dealer. I broke one bolt over tightening. Pretty sure 31.6 is the size. I will try to post pic. Not to techy though. Wish me luck. No luck, could not find how to attach pic. Hope this helps. I have the package number it came in maybe someone can help me on posting pics
 
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Ravi Kempaiah

Well-Known Member
I don't have calipers, but I measured with a tape measure... the outside of the frame looks to be the right size, but the inside appears to be slightly smaller than it should be. I am just surprised because I would think that Stromer owners would know what size collar should fit the seat post.
Ok, I think I found a solution to your problem!! (you can thank me later ;)
The seatpost dia of ST1, as mentioned by others is correct i.e., 31.8mm but the OD of the collar should be 34.9mm (ID will be 31.8mm)
I know, there is something wrong with the nomenclature. Here is a collar I had ordered last year and you need find the same with some attachment points to add your rack. You should be able exchange your current one for a 34.9mm (Thanks Amazon for your amazing return policy!)

seatpost.JPG
 
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I purchased a Bontrager rack for my ST 1 and also a 31.8 seatpost clamp for forward attachment of the rack. I too found the collar too snug to slide over the seatpost. I used my Dremel and ground a little from the inside of the collar and WaLa, perfect.
 

Peadar

New Member

  1. I just added a similar seat post collar too (from Amazon see below) to fit a rear rack, although I needed a little rubber fill to make it fit snugly. No problems at all. Now the question is why stromer didn't include frame screws / bolts for a rack on the ST1, like they do on some of their other models? image.png
 

Ravi Kempaiah

Well-Known Member

  1. I just added a similar seat post collar too (from Amazon see below) to fit a rear rack, although I needed a little rubber fill to make it fit snugly. No problems at all. Now the question is why stromer didn't include frame screws / bolts for a rack on the ST1, like they do on some of their other models? View attachment 4550
They use Racktime design and it kinda keeps the lines clean and elegant.
 
I got a black Salsa brand collar that I placed on the seat post and the top of the bike frame. I bolted my Iberra rack to it and it works great. I mounted a Planet Bike red flashing tailight using their mount to the back of the Iberra. And on long rides I snap on my Iberra pannier bags (taking along food, water, lock, rain gear, and up to 2 batteries and it works great.

I do recall that the Salsa collar has some strange nibs or bumps inside that didn't seem to belong there, so I used a drill bill to share them down and it fit beautifully on the seatpost.
 

Operator7

Active Member
So I got my 34.9 collar, and of course now it is too big. It's been almost a month now, and I still can't install a simple rack to my Stromer (what a headache!!!).

Peadar, you mentioned you used "rubber fill" to make the collar work. Can you elaborate on what you used? I'm trying to think of what I might use now, to jeri-rig this collar to make it work, but I'm simply astounded that one can purchase a $4500 bike and you can't even get a freaking collar on it. Sorry, I'm just a LITTLE bit frustrated at this point.
 

Peadar

New Member
Yikes, I agree - why not have pre installed fittings for a rear rack, since many people do use this bike for commuting, and their other models (my wife ST Sport for example) have ones.
Anyhow, rest assured, you can get this done. I too bought the Sunlite Bicycle Rack Seat Clamp, 34.9mm, Black. I did NOT use it as a substitute for the existing collar, rather I slipped it onto the seat post ABOVE the existing collar (about 1.5-2 Cm above, to allow for raising and lowering he saddle post if need be), and used a simple rubber strip (the kind that often comes with bike lights, reflectors, bells), cut to size, and coaxed the collar over it snugly, with a very sharp blade trimming the excess visible material) Then voila tightened the collar and Bobs your uncle. Let me know if this isn't clear. I bought a Topeak rack that I got in REI, very solid, with extra wide legs to go around the disc brakes etc.
 

russ moir

Member
Disk brake clearing racks aren't needed as the brake caliper is mounted between the chain and seat stays. Many other brands have them above the dropouts behind the seat stays, and are right in the way of rack supports.