Need help with KH36 (short rider)

I am able to go for 15km on my 24er, but it feels extremely slow, like running instead of cycling. After reading countless people raving about the big wheel, I think it’s time I get one myself. You only live once! :smiley:

I’m around 5’3", with an cycling inseam (not pants inseam) of 76cm/29.9". The distance from my pedal at the lowest point, to the top of my seat on the 24er, is also 76cm.

The KH36 seems to be the only unicycle that is geared hub ready.

From reading ‘short rider 36er’ threads on this forum, It seems that I can ride the KH36 if I:

  • Change adjustable seatpost to fixed
  • Use a slimmer saddle (Street instead of Freeride)
  • 125mm cranks
  • shorten the seat tube
  • Use a single bolt seat clamp

Is there anything I’m missing? I want to get it as short as possible, so I can use the 150mm when I start, and for muni.
The KH T bar seems to be mounted purely at the seat, and won’t affect how low the saddle can go.

If you have a KH36, I would love to know what’s your lowest possible pedal to seat distance.

This would be a big investment for me, and any advice is appreciated. :slight_smile:
(I will be ordering from Unicycle.kr)

A smaller seat-post clamp will not help…

My inseam is quite small too and I cannot fit on a KH36 with 150mm cranks unless I cut the frame down (which I did). I took off about 1 inch off the frame. I use a street saddle but I do use an adjustable seat-post (with 140mm cranks, seat as low as possible).

With an adjustable seat-post, the longest cranks I can use on a non-cut frame are 114mms.

Hmm. I figured that if a single bolted seatclamp, or quick release was used, more of the frame could be cut off. Is this not possible?

A smaller seat post clamp will help; it lets you cut the frame down to right above the thicker part of the seat post tube, leaving enough exposed for the smaller seat post clamp.

I cut about 1" off my frame. I’m 5’6".

corbin

I’m the same size as Corbin. :slight_smile:

I just made some measurements on my new KH36. If I put a Hope 31.9 seat post clamp on it (which is 5/8"
thick) and cut the frame down so that the seat post clamp rests right up against the place where the tubing
gets wider, then I measure 22" from the center of the axle to the top of the seat post clamp. You have a roughly
30" distance to the “low” pedal, so we need to add to this the crank length. If you want to run 150mm cranks (5.9"),
then 29.9" - 5.9" - 22" leaves you two inches for the seat thickness. My standard freeride seat measures 3.25" from the bottom of the lip to the top surface, but there is another 1/2" inside the lip. If you went with a seat post clamp that used an allen-key (as opposed to the hope clamp) and was a little thinner (I found a 1/2" thick one), you could pick up 5/8" by burying the seat post clamp under the seat. This leaves you only another 5/8" short of being able to ride 150mm cranks, or only 3mm short of being able to ride 137mm cranks.

What is available in thinner seats?

The other option would be to cut the frame even further; unfortunately, the O.D. of the tube below the flair is not a standard bicycle seat tube size. Got access to a good machinist? What about chucking the frame up in a lathe and
machining the tube down to 31.9" a bit lower than it currently goes, then cutting it further? Give the machinist a piece of seat post to insert in the frame when he puts it in the chuck so he can grip it hard without it crushing, and have him grip it above where you plan on cutting it (heck, have him make the cut).

This is a real problem with the KH36 frame. Unlike the smaller frames the KH36 doesn’t need that much beefed-up seat tube (since the seat doesn’t have that much leverage trying to break the frame). The frame should be designed to be cut shorter. I’m 5’ 11.5" and using the stock frame, seat post, seat post clamp, seat, and cranks, I need to turn the seat post clamp 90degrees to get the seat low enough to ride it! So basically, as designed, I’m the shortest rider that can fit a stock KH36 (150mm cranks)!!!

Well I’m baffled. I measured my inseam 31" with shoes. Then I measure my KH36 from the pedal at the lowest (150 crank) to the top of the seat. Straight up it’s 33". It must be that the padding of the seat squishes down some. My knees are slightly bent at the lowest point.

The “longer legs” effect is due to the fact that when you pedal on the balls of your feet, it is like wearing high heeled shoes.
On my road bike it is more pronouced, I have a pedal to saddle height of 840mm/33". But I sure won’t be on clipless and tippy toes on the uni. I ride my mtb with flat pedals and the distance is around 760mm too.

Thank you for so much detail Adelman, I went ahead and drew this up. I hope I didn’t misunderstand your measurements :slight_smile:

(Credit to whoever posted this on the forums!)

The KH slim saddle is the exact same shape as the street, but from what Kris Holm posted on the forums, the middle part is 10mm thinner. This may not affect the area where the sit bones go, so I’m taking measurements from my street saddle.
Now it looks like I can definitely ride with 125mm cranks, at least.

Here is another data point:

I have a KH with 150 cranks. The seat is a KH fusion slim, and the seat post is the UDC shadow handle setup, which is fairly low profile. I use a 33.5" distance from the pedal to the top of the seat. The seat post clamp is a standard double bolt model. The set up works well.

There is 1.5" of seat post exposed, so one could drop the gap to 32.0" and still ride with 150 cranks. Anything shorter would require some modifications.

I will note that fat pedals would buy you a few more mm.

Scott

Here are two more useful numbers:

On the standard adjustable KH seat post and fusion seat, the distance from the top of the seat post to the top of the seat is just about 3-7/8". The other setup I have is the shadow handle seat post with a KH fusion thin seat. In this second setup the distance from the top of the seat post to the top of the seat is 2-3/4’ (or 7/8"). You save about one inch with the shadow handle and KH fusion thin seat.

Scott

If you have a KH24 and already ride, I would use your top-of-seat to bottom-pedal distance as a starting point for the KH36. On my KH24 I tend to ride with the middle of my foot over the pedal (for MUNI), but for my KH36 I tend to ride on the ball of my foot (buying some extra distance).

Yes, you understood the measurements, except I’m not sure about the different seats. That 22" measurement assumes you cut the frame down and use a narrower clamp. I’m not sure on the slim saddle thickness, but you can probably run the seat post flange right up against the clamp. I think you can make it work.

The trick to cutting the frame is to use the Park SG-6 saw guide (also works great for seat post cutting). After cutting it, you’re going to need to drill a hole 3/16-1/4" diameter below where you expect the seat post clamp to sit. Then use a dremel tool with a cutoff wheel to cut a new slit down the tube which terminates in the hole (usually you need to make two cuts to get it wide enough).

I don’t have a KH24, just a made in taiwan 24" that I put a KH street saddle on. Found this Saw Guide on chain reaction.

I only have a simple bicycle toolset, so I guess I will have to do some shopping, to get a hacksaw, saw guide. I do not have a dremel, but maybe I can borrow it from someone. Wow it looks like I’ve got a lot to do!

I came up with another picture:

Also, the new KH fixed post looks like it’ll save me 1" over the adjustable one:

I’ve emailed Unicycle.kr, and should be making an order soon…

A non adjustable seat post will work great, most people don’t need that much adjustability. Go short on the cranks (125-135), that’ll help, though some climbs will be tough and learning might be a little harder. A thinly padded seat of cutting down the padding yourself.

As to the KH frame, it is possible to cut off the smaller diameter tubing, then modify the larger diameter tubing with an insert/sleeve, possibly there is one pre-manufactured that will allow you to use an OEM seat post. You will ultimately need at least 2" of seat post in the frame to pevent problems.

A 36" wheel is pretty big, but for a smaller statured person it’ll be really big!

Have you ever ridden a 29er? A simpler fix and one that would likely make you happier in the end, is to get a KH 29, ride it for a while, then in time make it into a GUNI. This would require few or no frame modifications, would be more flexible in terms of cranks choices, and a geared up 29er is still plenty fast (33.5").

I have thought about a 29er. But past purchases have shown me that I’ve always regretted compromising. :frowning:

I’ve got good news, and bad news. Unicycle.kr tells me they can do the frame shortening for me, but the shipping would cost 256USD, because it needs a huge box.

My new KH36 has a lot more “thick” part than those pictures would indicate.

I have a few-year-old steel non-adjustable KH seatpost that looks like you could get it even shorter than the one you show a picture of. No thickened part just below the bracket.

Today I went to the clinic at my university, about my 2 month old minor ankle sprain, and was told to rest for another 4 weeks.

Super bummed out… will probably put this project on hold.

Just in case someone is reading this and is thinking about cutting their frame, be aware that if you don’t leave at least a couple inches of frame above that change in tubing diameter, you will risk having the seat post moving back and forth in the frame, which could cause serious frame stress.

The best bet is to either find a frame that has a consistent tubing diameter through the crown (Nimbus) or cut the frame down to the fatter diameter and get a slide in seat post adaptor.

Also take a look at the spacing between the crown and the tire, some frames are spaced closer than others, so pick one that has the least clearance; KH is pretty close, Nimbus not so much.

Does the seat tube also widen internally? Hmm.

Absolutely not, and I think that is the misconception that Nurse Ben has.