Length to chop 36" post to?

I have to manually cut my new seat post by hand, and I really don’t feel like doing it more than once or twice. Anyone have some ballpark lengths I should aim for when cutting my post?

Uni: Coker Big One
Cranks: 150mm
Inseam with shoes: 35 inches (88.9cm)

Thanks guys!

I don’t like riding seatposts at full height usually, I prefer a little room to move around. I plan to muni with it at some point as well.

Put the post in, and try to mount the uni. Feel too tall? Cut an inch off. Still too tall? Cut an inch off. Repeat until it begins to feel close to the right height. Ride it around for a minute and decide if it’s still too tall. If you feel like you need to cut more off, only go in 1/2" increments now to fine tune the height.

If you get really into Muni, you may end up cutting more off so you can lower your post more, but for road you’ll be wanting it as high as possible.

I couldn’t tell you what any of my post lengths are, because I cut them until they feel right.

I’m opposite of you, I ride a full length post if possible.

How about you put it together fully, excluding the seat with the seat post. Bring your unicycle next to a fence and slowly stand on the pedal and see how high above the seat tube you are and guestimate it. What I did with my 26" is I put it on the ground and lay down and measure it on the floor with my feet on the pedals. Then I cut a little shorter then my guestimation because I can always raise the seat post that’s tuck inside the seat tube.

Hope I made sense, I gotta go make dinner…

K Back. What you can do is lay your fully assembled coker on the ground, have the seat/seatpost on the side. Take a measuring tape. Move the pedal so it’s at it’s lowest position downwards so it’s fully extended away from your seat. Take the seat/seat post out and hold it to the side of the coker frame where it should be about if you were to have inserted it into the seat tube. Measure from bottom of pedal to the top of the top of the seat so it’s around 34 inch. Mark the bottom of the seat post that should pop out at the bottom or hits the bottom of the seat tube, don’t cut there, cut about an inch or inch and a half more. This will decrease the chance of it being too long and you having to cut more and if it’s too short, you got more than enough seat post length left over to pull up out of the seat tube. So basically you have 33 inch at lowest and plenty of post length inside to get above 35 inch which is your inseam max.

This is what I do to get the right measurements on my 24-26, should work for 36, but I’ve never had a 36 before.

I’m guessing you’re using a pipe cutter? I tried a hand saw before and it was a lot of work…

Oops, misread the OP.

Didn’t see that you don’t want to cut too many times, so my suggestion is pretty much useless.

Thanks guys! Going to have to wait for daylight unfortunately

No worries!

If you have another uni sporting 150’s you can just measure the distance from the center of the spindle to the top of the saddle. Then put your seat post into the Coker and make a mark at the same measurement. Here’s the tricky part: the amount up from that mark (to the top of the saddle) is how much you need to cut from the bottom of the seat post. This should get you close. Small differences in pedal height, and measuring shouldn’t matter too much.

I would put the new post in all the way to the bottom of the crown to give you the most room for shorter cranks in the future. Wherever you put it will be close to where it lands once you cut.

That’s what i did before cutting the seatpost for my 36". I had to shorten the post by 21 cm, and I also had to cut the seattube by 1 cm.



All done! This is at the lowest point. I loved the suggestion about measuring another one of my uni’s with 150mm cranks. I adjusted that uni to the preferred height on average muni conditions, and then measured it out. Chopped the 36er post to match. Easy peasy! Way too much extra brake cable, gotta learn how to shorten it. This baby needs one of Danes special paint jobs.

There is probably enough spare outer on that to fit up the front wheel on a b*ke.

try to keep the cable as short as possible without putting it through anything more than gentle bends.

Yeah, I know nothing about brakes. But it’s about time I learn. Watching some instructional youtube videos.

Sheldon Brown’s site has some excellent info on brakes, as well as cable routing.

The trick with cable brakes is to manage the friction on the cable. With the exception of the actual brake setup (pad alignment, spring tension adjustment…) almost all of the tips and tricks to make them work better have to do with friction. So: a shorter housing, lubing the cable, filing/grinding the end of the housing to remove burr’s left by the cable cutter, reaming the liner at both ends, using ferrules that prevent moisture getting into the line. All of this is to make the cable move better.

On a uni, it can sometimes be beneficial to de-tune the brake. This can give better speed modulation, and minimize the chances of locking the wheel. So, in the end a longer cable may not be so bad. I would still clean the end of the housing, and ream the liner, but as long as you don’t rub the cable as you ride it may be alright.

Well too late I already did it!

Don’t cut brakes

I used to think the brake lines should be cut to the exact length needed. After all, these are high end uni’s, right?

Now my thinking is to leave the brake line alone and just wrap it around the seat post.

Right now your uni is setup for 150mm cranks. The day will probably come where you want to try 135mm; then 125mm; then 110mm; then 100 (maybe); then 89 (ok, that’s sick).

The point is every time you shorten your cranks you need to raise the seat height, which increases the demand for brake line length. At some point a precisely cut brake line for the 150mm cranks will either be too taut or even too short. At that point you’ll find yourself doing creative engineering like moving the brake lever closer to the seat post, re-routing the cable, etc.

Yep, I learned this one the hard way…

Problem is, when your line is too long on a cable brake, it can make it so they don’t work properly.

I have a brake set up on my 36er, and temporarily had to move it further in by my handle. I had a lot of excess cable and wrapped it around my post. The result was a brake that wouldn’t work at all, one side would constantly rub.

I think Dane has plenty of line there to adjust crank length or seat height. And if not, cable is really not expensive at all.

It’s true, and I have seem plenty of brakes that lost everything to friction in the line. In this case since Dane didn’t say it wasn’t working I assumed that it was working, just long. But you are right that to get the most effective braking you want the shortest line possible.

Personally I believe that it’s better to run as much of the cable outside of housing as possible. I know that there is a current trend towards full length housing, but I think it’s more of a compromise on the part of the manufacturers. This way they don’t have to have separate guides for cable vs. hydro brakes, and they can use a single frame on a few different models without modification.

I believe so, I gave it some slack past my maximum height with 150mm cranks. So it should be plenty for whatever I want to do. It’s really going to be a muni, so no bars or anything to worry about.