anthonygeo

You all see any possible issues I will have if I cut this post and add a handebar stem? Ill have to find the cap and screw for this stem.

rhenning

Is the outside diameter of the original bar the same as the inside diameter of the new stem? That could be a problem. Roger

Dynocoaster 

I would not do it. I will stress it if you do and could be dangerous.

jur

I can't see any problem. If the size of the vertical is 28.6mm (or 25.4mm) then it will fit the stem clamp, the 1" case with a shim.

anthonygeo

I don't see any danger so long as the stem clamps tightly like any other stem.

az2008

I think the bars are a softer/thinner metal than the steerer tube the stem should clamp onto. You'd naturally think the handlebar riser takes just as much stress at that location as a steerer tube does. But, I believe it's the tube extending above that proposed cutoff point which contributes to the strength of the tube *at* that proposed cutoff point. In other words, if you cut it, the tube is more likely to deform. There won't be structural strength (tube) extending above it. I.e., the continuous tube contributes to the strength anywhere along the tube.

I think the way to compensate for this is the fabricated cap you mentioned. If that were done in a way to create a permanent, solid plug at the top (maybe extending 1/2" to 1" below the cutoff, it would create the same structural strength as if the tubing continued to extend above that point. You want to slip something in there. Either another piece of tubing, going 4-5" down, creating a double wall. Or, a 3/4" plug at the top. Maybe spot weld it there, polish it down to smooth, paint the exposed top to have a nice finished look. Nobody would see any discoloration of the chrome riser at that spot because the stem would cover it?

anthonygeo

Good point! I didn't think about the post being softer metal. Hmm I may rethink this mod or find another way to strengthen the post.

BassNotBass

A valid point however the stem can be strengthened by making an insert from tubing or making a plug (I've used blocks of aluminum, delrin, nylon and even hardwood to make plugs that would keep tubing from collapsing). Either method has worked admirably.

fietsbob

how is the bottom of the steering post fitted in the steerer tube?
send a picture of that end.

I'd have a part made to entirely replace the steering post.

But it will likely cost as much as you paid for the whole thing
to hire machine shop time in the US,

for work on a low priced China made bike.. but if that's Ok with you.
then it will be safer at least.. hopefully, and add weight..

anthonygeo

I was thinking of using black pipe but I need to make sure I know the inside diameter. The bottom of the post is actually thinner (where it enters the frame). This is a project that will probably cost me more than the bike is worth. My Raleigh M60 cost me $500 (years ago) and I've spent well over that with mods.

fietsbob

I have a Bike Friday Travel bike , It came with their Optional Folding steering riser.
which uses a 1" OD quill at the bottom, and a threaded headset fork.
On top there is a telescoping tube , which has a threadless stem on top ..

NB a digital caliper [cheap from like Harbor Freight] is a useful tool.
to do accurate measurements ..

anthonygeo

We shall see how this mod works out!

BassNotBass

This reminds me of a tip I try to drop where applicable. If in a bind and one doesn't have a set of calipers to take OD measurements, you can get an accurate enough measurement with an adjustable wrench and a scale (ruler) or open end wrenches and a feeler gauge (of course this method involves simple arithmetic ).

az2008

I think black pipe might be too much. Just some steel tubing similar to the material you're going to cut should be good enough. (I.e., just doubling the thickness of what's there now should be good enough. Black iron pipe would increase the thickness by a factor of 10.). It's obviously strong enough already to withstand the torsional force of riding. You're just trying to compensate for the possibility the tube may collapse/deform at the point you cut it (due to the absence of tubing above the cut contributing to the strength of the tubing at the point it's cut).

If you use thinner-walled tubing to create an insert (a double wall) it gives you more options than black iron pipe. You can pick a tube OD that's close (but larger) to your riser tube's ID. Cut it lengthwise and compress the tube to fit inside (like a spring).

Personally, I like the idea of fabricating a plug/cap. I don't think you need strength running any length of the riser tube. Just strength at the cut so the hole won't collapse/deform. Just a cap, 1/2" tall from bar stock (aluminum?) turned down to the correct diameter to fit snug, and spot welded in. You'll need to grind the weld down to be smooth (grind, file, sand), then paint it. That should make the tube as strong as it was when the tubing extended above the cut.

It may not be a significant risk. The threadless stem clamps over a relatively large area. I'd be more concerned of deformation/collapse if stress was applied to just 1/2"-1" below the cut. The threadless stem is 1-1/2". If you're not jumping off curbs, or riding down San Francisco's steep hills... the risk is probably minor.

The biggest downside to doing either of the above hacks is that you'll be locked into a height. Once you cut it and plug it, you're stuck at that height. You could always cut it 3-6" longer and camp over a larger range. But, the spot where you tack welded the plug in place won't be hidden by the stem's clamp.

One idea I had is, if the existing riser tube really is the right OD for a threadless stem, you could use a Satori Easy Up. It clamps onto a steerer tube like a threadless stem, but has a post which recesses into the steerer tube (or, can be pulled up like a riser, for more height). At the top of that post is where you clamp your threadless stem.

I bought one of these over a year ago because I got a good price for it. I've never used it. But, it appears to be solidly built. Good engineering. The downside to using it on a real threadless headset is that you have to knock the starfangled nut down into the steerer tube to make space for the Satori's adjustable post which recesses into the steerer tube.

Anyway, in your case, this would at least protect you against catastrophic failure. Even with the post all the way up there is 2" of post still inside the steerer tube. I.e., your riser won't collapse/deform too far before it runs into that inner post.

If you can get an accurate measurement with a micrometer, I can give you measurements of my Satori. It's designed to work with 25.4 and 24.4mm ID steerer tubes (the difference between alloy and steel fork tubes, the instructions say). What I would do is measure the OD at the point you're considering cutting, and then remove a grip and measure the wall thickness. Use that to calculate the ID. I assume the horizontal bars are the same wall thickness. Maybe you can see something from the bottom of the hinge that would confirm the thickness.

I just received Harbor Freight's flyer. Their digital caliper is on sale for 9.99 this month. You need a store coupon to get the price. Usually you'll see customers walking around with a flyer in their hand. You could probably get the coupon from one of them.

anthonygeo

Well folks I did it! I know its been a minute since I last posted about this and you all probably thought I crashed and burned after the handlebar mod. I actually just did the mod this evening and so far it looks good and its a nice tight fit. I do plan to have a ring welded under the stem for added security and I still have to slam in the star nut and cap. I was super nervous once I started cutting but it all worked out and the stem pictured is just temp until the new one comes in. The folding pedals are now gone and replaced with bmx platform pedals. Yes, time I am done spending money on this bike I could of bought a Dahon or something but oh well I still enjoy the bike.

anthonygeo

I like this idea and plan to try it but for those wondering this bike will only see straight paved roads.

tds101 

Just don't forget to post the finished pics of th bike please,...the WHOLE BIKE. I want to see how it looks,...I think it'll end up fantastic.

badmother

Threads about modding older often cheapish bikes are way more fun than the " I bought this bike and dropped $500+ on modding it the first week" threads. I miss the R20 modding threads we used to get. Keep it comming OP and others .

Often I am to lazy to take pix and post when I work on bikes.

anthonygeo

I have about a week to get this done because I want to take it with me to Orange Beach for vacation. Tossing this in the back seat will keep me from having to rack my bigger bikes a long distance and I can bring it into the hotel. I would like to get new crank arms but I'll have to investigate how different parts are for a folding bike.

anthonygeo

I ended using an adapter to raise the bars and have two different points of contact. I cut a piece of tubing and made an insert to add support at the post where I made the cut (also put in a star nut). So this mod is done and said with no slipping even going off the pavement into the grass. The bike is fun and the pedal extenders make it easier to ride since I have wide feet. Enjoy.

tds101 

Pics of the whole bike please!!!

az2008

Since it's a single-speed (and has horiz. rear dropouts) your bike would be a good candidate for an internal geared hub. A 3-speed Sturmey, or a 7-speed Nexus.

If you get one with a coaster brake you can remove the rear v-brake. Gives it a slightly cleaner appearance without the right-side brake lever, and the cantilevers gone. (You already have a fairly clean look without a derailer. The IGH would give you a bit more comfort peddling up/down hills.).

If you wanted to consider this the first thing to do would be to measure your rear dropout space to figure out what you could fit in there. For example, a 7-speed Nexus with coaster brake requires about 129mm (if I recall correctly). An SA 3-speed is 116mm.

anthonygeo

Thanks for the info! The rear wheel needs to be replaced/reworked to convert to coaster brakes correct?

az2008

Yes. If you have a good rim and the number of spoke holes match the spoke holes of the hub you buy, all you need is new spokes. Lacing a wheel is a bit of a project. It's just a lot of minutia you have to take into account, and a lot of faith that the spoke calculator is correct. I did mine 6-8 months ago. I might have saved $50 over my LBS doing it for me. But, I put a lot of time into it trying to understand it all. I learned a lot. But, I had a lot of time on my hands. Not everyone will be that ambitious. This is one of those things that would be better left to a shop unless you have a lot of time on your hands and/or you're really smitten by cycling and *want* to learn (experience) building a wheel.

I did this Nexus 7 hub, this Sun Rhyno Lite rim, and my LBS has a spoke cutting machine. I went there with my exact spoke lengths[1] and paid about 75 cents per spoke ($30). (There's a slightly narrower Sun CR18 rim if you intend to run narrower tires. I chose the wider rim because eventually I want to put some fatter 2" tires on the bike. When searching for 20" rims you also have to be cognizant of the fact that there are two standards. The popular 406 diameter and a less used 456 which is narrower and more like a mini road-bike wheel. Sometimes referred to as 1-3/8".).

Since you don't have a derailer you'll need to do something for cable guides. I'm not familiar with what's available. My bike had one continuous cable housing which passed through 4-5 brazed on guides. It didn't have the more customary guides where the cable housing stops and bare wire runs to the next one. For a folder, continuous housing might be better since it allows the cable to float and adjust itself to the bike being folded. (Point being, you could get by with loose zip ties and continuous housing.).

I still need to post photos of my finished product to this thread. I intended to give it awhile before cutting off the v-brake posts (make sure I'd never want to go back to the original configuration).

[1] I used spocalc and this and this site's explanations of the measurements.