Help on extending the stem

[Gowerboy]

Guys, as an oldie and a Newbie to biking, I've been given a Raleigh Max lite by my son who used it about 6 times and then stored it in the garage under a blanket ( centrally heated)
The bars are far to low for me and after trawling through pages and pages on this brilliant site, I ordered up a new stem extension, only to find that my bike has a rubber/ plastic bung on the top and no what I would call a 'locking collet' that locks to the inside of the bike stem, so am at a loss as to how I can extent the height, thanks in anticipation,

[Cyril Haearn]

More pictures might help, there are many different types of stems now un-fortunately
Locking collet = expander bolt?

BTW there are plenty of gals here not just guys

[cyclop]

Take stem off,stick the extension on,put stem back,or am I totally misreading your photo.

[slowster]

Your problem is not entirely clear from your description. It sounds like you may be referring to a quill stem as used in a threaded steerer tube with a threaded headset when you describe "'locking collet' that locks to the inside of the bike stem". If so, your bike has a threadless steerer tube, which uses a threadless headset and an ahead stem.

There should be a star fangled nut visible inside the steerer. The bolt in the stem's top cap goes into that nut to load the headset bearings and remove play from the bearings. Then the two pinch bolts on the stem are tightened. I see there is also a black clamp on the steerer below the stem, but it is not clear to me what function that performs.

If you have an extender for the steerer tube, I think it would help us to know the model, in order to explain how you need to fit and tighten it in conjunction with the above process.

[gregoryoftours]

To save any confusion, it would be best to post photos of both that area of your bike and of the extender that you bought.

[Brucey]

there are two main sorts of threadless steerer extender

this one

and this one


to fit the latter type, you need to remove/displace the SFN/bung from inside the steerer



cheers

[Gowerboy]

Thanks for the helpful replies,
When I look at the top of the bike (as per my photo) I removed the plastic push in bung, I expected to see a collet when looking down through the stem tube, ( i.e. Something to which the 6 inch long screw on the top of the new stem can screw into) but there's nothing , all I can see is the top of the tyre, if I lossen the two screws on the existing Handel bar stem, I feel that the forks will just drop out, Brucey, I think has hit the nail on the head, I have a new stem extension like his 'alloy' one on the left, but the long screw has nothing to screw into, his coloured line drawing shows a 'Star nut or bung' I don't have that.

[Gowerboy]

Part 2/
This is the cheap extender I bought, felt there was something funny going on
With the bike not the new extension.

[NetworkMan]

Is that some sort of collar with clamp bolt just above the upper headset cup? If so will it stop everything falling apart if you loosen the stem bolts? I don't think I've seen anything like it before.

[horizon]

Just for clarification, would it be better to call extending the stem (horizontally) extending and raising the stem (upwards), raising. I know extending can refer to both but it's just to do with current usage. Delta call their products stem raisers. In fact, is it not the steerer tube that is being lengthened and the stem (the horizontal bit) raised? Sorry to be pedantic.

[Gowerboy]

Hi Networkman, thanks for the reply, and and yes it is a collar with pinch bolt, from what I can see in manufacture, with empty headstock, forks and head tube have a bearing dropped on, greased, then inserted into headstock from the bottom, then top bearing dropped on followed by the black collar with pinch bolt which is tightened after all play has been eliminated, they have measured the amount of fork tube now eminateing from the headstock, and place 3 silver spacers on followed by the black Zoom stem holding the bars,which are now aligned to be straight ahead, the 2 pinch bolts are tightened and the hole at the top of the headstock is filled with a plastic bung similar to what's on the bottom of a tubular chair leg, having ordered a new stem and an aircraft engineer by trade (retired) I unwilling to install the new stem with only the 2 pinch bolts holding it in place because the 6 inch long bolt supplied with the stem had nothing to screw into, sorry for being so long winded but maybe it's clearer now
Thanks for all your time a patience peeps.

[gregoryoftours]

So you need to take your bike to a bike shop and get them to install a star nut, or do it yourself if you buy the right installation tool or make one. It's quite hard to hammer a star nut in straight just using a bolt. Then you can fit the stem raiser you bought. In order to pre load the headset bearings you'll first have to loosen the bolt on that bottom spacer collar that's already on your bike. Assuming that the 2 stem bolts were tightened up sufficiently the bike was not unsafe with no star nut and bolted top cap, all the latter are supposed to is lightly pre load the headset bearings. The same is true for the bolt running through your stem raiser, the secure holding is all done by the 2 clamp bolts. The long bolt should be used to take play out of the headset bearings before the collar, raiser and stem bolts are clamped up, but nothing more. In any case I don't think a star nut is designed to take a lot of pulling, let alone the compression on the bearings. If you are worried about security you can fit a long bolt all the way through your fork steerer with a large washer or similar under the crown of the fork, and tighten it more once the pre load has been set and the various clamp bolts are tightened. Incidentally those locking steerer spacers aren't often used but they're quite useful if you need to turn your bars to store your bike or transport it or whatever, that way you don't lose your bearing adjustment.

[Gowerboy]

Gregoryoftours, many many thanks, your explanation makes perfect sense, I'll also invest in a good quality better looking stem, all sorted, thanks again

[backnotes]

Hello, I think you may have a Diatech style of headset that avoided the need for a star washer altogether, which explains why you had a plain bung in the top rather than a cap with a bolt.

You may have something like the non-hanger version of this https://cruzbike.com/DOWNLOADS/Diatech_ ... ctions.pdf

You adjust the bearings by pushing down on the stem when it is not tightened up, to adjust the bearing pre-load, and then tighten it and then the locking collar when things feel right.

To do the same adjustment with the extender, you would need to first clamp the stem tightly to the extender, and then use the extender + stem to press down via any spacers to adjust the pre-load. The number of spacers below the extender would need to allow the bottom face of the extender to freely load / unload the bearings, but also allow both the clamp bolts at the bottom of the extender to fully overlap the steerer, so you can get a firm grip on enough of the exposed steerer, fully using both bolts for grip.

If it is this design of headset, you don't need the cap with the six inch bolt, and don't need a star washer, and hopefully the bung you removed will fit back in the top of the extender. The six inch bolt on the extender handles the bearing pre-load in a star washer setup, and the two pinch bolts on the stem and again at the bottom of the extender provide the secure connection through from handlebar to front wheel.

I think this evolutionary dead end in threadless headset design may have been a way to avoid the need to pay royalties on the star washer design. I haven't seen your bike, so this is a suggestion and you need to reassure yourself 100% that this is what you have, and most importantly that the handlebars are still firmly connected through to the front wheel: I hope someone else will jump in and say if this explanation of the missing star washer and top cap bolt seems dangerously wrong!

[Gowerboy]

Hi Backnotes, that's it exactly, 100%, and being 'old school' 50 years ago as a kid on my bikes one had a 3/8 long bolt at the top of the stem and once tightened it felt safe and secure and would've held the Titanic, being 6' 2" tall and 209 lbs I felt the need to fit the long bolt supplied with the new stem, but couldn't, No star washer!! and like you say IMHO a cheap way of saving mone, I'll have one fitted by the local LBS for peace of mind, thanks for tracking down the line drawing and your time, BTW a picture of the bike, as explained, it's an old one but mint and I really do need the exercise and people are more friendly out there,