moeburn

(Forgive me, I am not a knowledgable bicycle enthusiast, I just love riding my bike. I do not know the correct terms for parts, I just make them up based on what they look like)

So I have a cheap $400 Diamondback Venture:



It features an adjustable handlebar angle, using a small toothed metal block (which is the fitted block with a single bolt in it, just above the teeth you can see in the center of the picture), that you loosen, adjust to your desired angle, and then tighten and ideally the metal teeth mesh with the teeth on the handlebar post (the ones you can see in the center of the picture), fixing it in place:



Now I'm a very hard city rider. I take sidewalk curbs, railroad tracks, and lumpy grass/dirt paths all the time, and those teeth quickly stripped down to flat bare metal, so that I could not fix the handlebar angle in any position for more than a minute (after hitting a bump it would just fall back down to its lowest angle).

Here is a picture of the handlebar post, from two angles:



The teeth on the top half of the block are the original teeth, they are relatively fine because that handlebar angle was too high and i never used them. The larger, shinier teeth on the bottom half are new ones that I tried to cut with my Dremel. Before I cut them, that bottom half area was completely flat; the teeth were completely stripped away.

Here is a picture of the small metal block that is supposed to mesh with the teeth on the above post:



It was completely flat a couple days ago, but again, I tried to cut new teeth into it with a Dremel.

Unfortunately, in grinding the new teeth, because I was taking metal away and not adding metal, they are just too short to reach, even when the bolt is tightened fully, so they didn't make any improvement. In fact, before I ground the new teeth, I was at least able to reliably tighten the handlebar in the lowest position; now, it comes loose every time I pull on the handlebar when going up a hill.

I'm a poor man. The obvious solution is to just buy a new bike, and I'd love to, but I simply don't have enough money for even a crappy used bike. So my question is, does anyone have any idea how I can make this work? Welding? Adding some sheet metal to thicken it? I tried using electrical tape to thicken it (on top of the block's teeth, so they could reach further), but it didn't work. Or better yet, are these two pieces the kind of parts that a bike shop is likely to have, or am I going to have to hope and pray that my obscure bike manufacturer has replacement parts?

Thanks for all your help, folks!

jsharr

You can find used adjustable quill stems for under $10 on ebay, but you need to know the diameter of your stem to order the correct size replacement. If you do not have to have adjustable, you can just get a plain quill stem.

likebike23

The cheapest solution is to get a new stem. As jsharr said, you have to know what the diameter of the quill(the tube that slides into the fork) is. In addition to that, you need to know the diameter of the handlebar where the stem clamps to it. Often the quill diameter is stamped onto the quill, you will need to remove the quill from the fork by loosening it with a 6mm allen wrench on the top bolt to see it. If you get a new stem, one with a removable faceplate will make installation easier, though it is not required. My suggestion is to go to your local bike shop and have them order it for you. They will know precisely what you need. You can either have them install it or you can do it yourself to save money. Another bit of advice to help you save money, don't ride your bike in the gear that it's in. This is called "cross chaining" if you want to look it up. Cross chaining can cause early wear to your drivetrain at best, and complete destruction of parts with injury at the worst.

moeburn

Okay, thanks folks! So it's called a "quill stem". It appears mine has a diameter of "25.4mm", although when I measured, it comes out to just under 25mm. I'd like to be riding today, if possible, so is this the kind of part that a bike shop is likely to carry in-store?

Also, I'm well aware of the cross-chaining (didn't know thats what it was called though), but it only does that when the rear is in the lowest gear, which I only use on startups after red lights and such. The gear combo I ride in at normal speeds is well aligned and does not cross over nearly as much.

AnkleWork

What a bizarre world-view. (Points for first attempting a repair.) Have you considered buying another stem? . . . a fixed one this time?

moeburn

Well I just phoned one of my local bike shops, and what luck! They happen to have some 25.4mm adjustable quill stems IN STOCK for $20 (same price as ebay after shipping)!

But before I make a very slow, non-bike-powered journey to the bike shop, whats a fixed stem like? Can't adjust the angle at all? What angle are they set at then? Because with mine, if I set the angle too high, it made me sit up high, which slowed me down from wind resistance. If I set it too low, it hurt the hell out of my hands after a while, because I was putting all my weight on them.

jsharr

Fixed stems come in a variety of angles and lengths and you can adjust them up and down a bit. There will be a minimum insertion line on the stem , which will dictate how high it can go and then your bike will determine how low it can go when the stem neck bottoms out against the head set of the fork.

https://www.ehow.com/video_4985708_in...stem-bike.html

moeburn

It sounds like you're talking about the height of the stem, I'm talking about the angle of the handlebar relative to the stem.

jsharr

YOu cannot adjust the angle of a fixed stem. You buy a fixed stem in the angle and length you want. The only adjustement is a limited range of raising or lowering the entire stem where it inserts into the fork.

Leebo

You could also get some adjustment from turning the bars a little.

moeburn

Well I bought a brand new shimano fixed stem, and it just so happens to be the exact same angle that I always set mine to anyway! (20 degrees) The only downside is that the top part, the part that connects to the handlebar, is now round/cylindrical, whereas my old one was flat/rectangular, so I can no longer attach my awesome home-made cellphone holder to it without it wobbling around like crazy.

Thanks for your help, everyone! Without you guys, I would never have known what the part is called, or that I can just get it from any old bike shop.

The cellphone holder, in case you're curious, is elastic shoelaces. Threaded in and out the back of a silicone cellphone case, which has four holes drilled in it for two shoelaces. The elastic part keeps it tight to prevent wobble, and the shoelace part means you can tie it tight and know that it will never fall off (unless the silicone case rips). When I used it, it was better than any bike cellphone holder I had ever used, and it cost me $0 to make. Oh well.

sreten

Hi,

FWIW without all that dremelling, you could have probably
converted it to permanently fixed 20 degrees with some
two part epoxy resin and a bit of common sense, easily.

rgds, sreten.

moeburn

I wouldn't consider it to be 'common sense' to rely on epoxy resin to withstand the weight of my body after crashing down off a curb, seeing as how METAL wasn't able to withstand it.. But I did consider welding, which would be much smarter & stronger than epoxy.

And I can still do either. In fact, the dremelling would make the epoxy/welding more durable, because without it, I would only have a glued joint, but with it, I have a mechanical joint as well as a glued joint. Not to mention all the extra grooves and valleys it allows the epoxy/weld to fill into, making it much more sticky than if I tried to glue/weld two flat surfaces together.

But surely you must know that any time you use the phrase "it's common sense", you aren't going to get a thankful response?

sreten

Hi,

I didn't say that at all, I said you could have use epoxy and some common sense.

rgds, sreten.

reddog3

Common sense would tell you that that epoxy at this joint, in torsion, would not be best the solution.

Kimmo

My common sense tells me that if there's a question mark over a stem, you ditch it.

Ugly things tend to happen when one fails, and it's not like they're hard to come by.

sreten

Hi,

It could of been degreased and epoxied in place before
it became totally toasted, and that would of worked.
.
rgds, sreten.