What is this

tom_tarbucket

hello

was messing around with the bike tonight. see attached picture. and where the cigarette thing points. ( I'm editing this on my phone ! ) There is a bolt there that takes an Allen key. what is this for ?

petethedrummer

Keeps your handlebars connected to the bike.



http://www.nycewheels.com/install-handlebar.html

tom_tarbucket

petethedrummer wrote: »

Keeps your handlebars connected to the bike.

Thanks. I ended up loosening it. But it did nothing obvious. ...........like moving the handle bars up and down OR left to right etc

morana

tom_tarbucket wrote: »

Thanks. I ended up loosening it. But it did nothing...


like move handle bars up and down OR left to right.

When the bolt comes out of the top tap it down a and they will move. Don't take the bolt all of the way out btw

JBokeh

It adjusts the alignment of the bars to the wheel,i.e. the tracking. With it loosened you would be able to turn the bars without turning the wheel. Sometimes in bike shops they will have it loosened enough to turn the bars to be 90 degrees out,so the front on profile of the bike is narrower to get them closer together

like this


loosen it up enough that it can turn independently of the wheel,make sure everything is aligned up and tighten it up snugly again and your bike will go where you point it

tom_tarbucket

morana wrote: »

When the bolt comes out of the top tap it down a and they will move. Don't take the bolt all of the way out btw

Thanks. buy don't understand what you mean by the tappingit down thing.

Zen0

Tapping the bolt down, if this is indeed a quill stem (can't see the pic clearly enough), knocks the wedge at the bottom of the diagram down. The wedge normally gets, erm . . . wedged in place when you tighten the stem bolt. This arrangement allows the stem to be height adjustable within the headset, something that on a newer threadless headset must be done with spacers.

tom_tarbucket

Zen0 wrote: »

Tapping the bolt down, if this is indeed a quill stem (can't see the pic clearly enough), knocks the wedge at the bottom of the diagram down. The wedge normally gets, erm . . . wedged in place when you tighten the stem bolt. This arrangement allows the stem to be height adjustable within the headset, something that on a newer threadless headset must be done with spacers.

so loosening the bolt I highlighted should allow me to move the stem up and down only ?


I.e does not allow me to move the handle bars left or right ?

rab!dmonkey

This is that. See the section on 'Adjusting Your Stem height'.

Zen0

tom_tarbucket wrote: »

so loosening the bolt I highlighted should allow me to move the stem up and down only ?


I.e does not allow me to move the handle bars left or right ?

Loosening the bolt and freeing the wedge will allow you to move the stem up and down and pivot the bars clockwise or anticlockwise. I presume that is what you mean by move the bars left or right. If you wish to shift the bars to the left or right rather than pivot them, you need to loosen the bar clamp bolt(s). You need to do this to understand it, or search for a YouTube video on adjusting quill stems.

eeeee

tom_tarbucket wrote: »

so loosening the bolt I highlighted should allow me to move the stem up and down only ?


I.e does not allow me to move the handle bars left or right ?

It does all of the above. Up, down, left and right. It may be a bit stubborn if it is old and hasn't been moved, but if you loosen it and don't tighten it your bars will slip down or left and right when you actually take it out on a road, it'll jump it loose. It's extremely dangerous to cycle on it without tightening it as you lose the ability to steer if it's loose.

tom_tarbucket

Zen0 wrote: »

Tapping the bolt down, if this is indeed a quill stem (can't see the pic clearly enough), knocks the wedge at the bottom of the diagram down. The wedge normally gets, erm . . . wedged in place when you tighten the stem bolt. This arrangement allows the stem to be height adjustable within the headset, something that on a newer threadless headset must be done with spacers.

ive taken a couple more better pics - attached

Can you tell me if its a quill stem ?

Also, the bike is a trek 7.0 fx

Alek

Yep, this is a quill stem.

Loosen the bolt a couple of turns, so it turns freely in your fingers and knock it down gently to release the wedge inside (with a rubber mallet or something similar)

Then make sure your handlebar can be turned easily while holding the front wheel between your knees. Set your desired handlebar height and tighten the bolt a bit.

Finally make sure the handlebar is straight, tighten the bolt fully.

tom_tarbucket

Alek wrote: »

Yep, this is a quill stem.

Loosen the bolt a couple of turns, so it turns freely in your fingers and knock it down gently to release the wedge inside (with a rubber mallet or something similar)

Then make sure your handlebar can be turned easily while holding the front wheel between your knees. Set your desired handlebar height and tighten the bolt a bit.

Finally make sure the handlebar is straight, tighten the bolt fully.

Thanks very much, I will try this later. I simply thought loosening the bolt a bit would allow me to move the handle bar but obviously I need to tap the bolt down too.

See attached pic and where arrow is pointing, what does opening the big nut allow you to modify then ?

com1

That nut holds the fork onto the frame (via a set of bearings at each end of the head (fork) tube). Tightening this nut will stiffen the steering making the handlebar hard to turn and notchy. Loosening it will cause latreral movement in the steering (hold the front brake and rock the bike back and forward - if you feel movement (while the wheel is stationary) then this nut is too loose).

To remove the fork you need to loosen the quill, tap it down (as described earlier) and pull the stem (and handlebar) out of the fork. Then undo this nut completely (trying not to lose the bearings) the fork should drop out of the frame...

It can be a bit of an art to get this setting right and be careful not to ring the nut - it is easier to do than you would think and will require a new replacement (which may be hard to come by)

Yeah what Zen0 said - there should be 2 nuts

Zen0

The big bolt is used to lock your headset components together. Remove that and you will have access to your upper headset lockring if I recall correctly. Under that are your headset upper bearings. They are easy to lose so don't take this off unless you need to replace the bearings, which is unlikely and probably a job for your lbs.

IF your headset is lose, you can tighten this bolt to remove play in the headset. You loosen the bolt a bit, tighten the bolt just under it very slightly, and then tighten the top bolt while holding the lower one steady. You probably need headset spanners for doing this. How do you know if your headset is loose? Squeeze your front brake lever, and while doing this try moving the bike back and forward. If the headset is loose, the forks will have a bit of play i.e. they will move back and forward a bit. There should be no play in your headset, but it should swivel freely.

I hope I have got this all right, as I'm working from memory, and it's a long time since I did much with a threaded headset.

While I would encourage your desire to learn about bike maintenance, some of your questions are very basic. There is some excellent stuff on YouTube which you should check out. You may need to get to know the names of the components first so that you can google the right term. Any book on bike maintenance will do that much.

eeeee

I wouldn't advise going at those bolts without headset spanners. You can, but as the owner of 5 bikes with that kind of headset it never ends exactly well, you can't get the real fine adjustment, the 'just so' feel.

If you want to lower or raise your bars then use the allen key bolt at the top you pointed at first, that'll do the job. give it a tap and you're away. Don't slam it right down into the head tube (the silver bit it slides into) as you can leave the wedge nothing to wedge against. It happened me on track when I slammed the stem then a week later I came around the second bend in a race with my bars sideways!! Luckily we were only lining up for the whistle but you should be really careful messing with your bars or headset especially if you're on the road. You don't want to turn left or right and have the bike roll on straight.

tom_tarbucket

gadetra wrote: »

I wouldn't advise going at those bolts without headset spanners. You can, but as the owner of 5 bikes with that kind of headset it never ends exactly well, you can't get the real fine adjustment, the 'just so' feel.

If you want to lower or raise your bars then use the allen key bolt at the top you pointed at first, that'll do the job. give it a tap and you're away. Don't slam it right down into the head tube (the silver bit it slides into) as you can leave the wedge nothing to wedge against. It happened me on track when I slammed the stem then a week later I came around the second bend in a race with my bars sideways!! Luckily we were only lining up for the whistle but you should be really careful messing with your bars or headset especially if you're on the road. You don't want to turn left or right and have the bike roll on straight.

to be honest, all I want to do is lower my handle bars

I was just more so curious about them big nuts and what they do

eeeee

tom_tarbucket wrote: »

to be honest, all I want to do is lower my handle bars

I was just more so curious about them big nuts and what they do

The big nuts mainly release a million bearings to your floor. It would appear they have secondary uses but these are merely anecdotal :pac:

piston

It's worthwhile to remove a quill stem once in a while and coat it with grease and put it back in again to prevent it from seizing in place (same with seatpins).

This is especially true with alloy in a steel frame. Steel on steel isn't too bad to work with if it seizes.

Always make sure there is at least two inches on the stem inside the steerer for safety.