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7-shaped stems.

lost_in_thoughtlost_in_thought Posts: 10,563
edited February 2009 in The workshop
Hello there!

I have a rubbish roadie which has several problems, chief amongst which is the fact that it's too big for me.

My first thought is to shorten/flip the stem, unfortunately it's one of those 7-shaped ones.

So, can you swap from 7-shaped to normal?

Are all the 7-shaped ones the same diameter of post going into the head tube? How hard are they to change? How are they measured? Do they come in different angles?

As a side question, how hard would it be to change from downtube shifters to integrated shifters? And how much would that cost at the cheapest? It's shimano, BTW, and the bike itself cost me under £100 so i don't want to overcapitalise!!

Posts

  • robbarkerrobbarker Posts: 1,367
    I guess you mean a quill stem, with a hex socket in the top and no clamp bolts behind the stem?

    You can get a quill to ahead convertor like this:

    http://www.sjscycles.co.uk/product-ITM- ... m-1688.htm

    which enables you to fit a new type ahead stem. You'll need to strip the bars down on the bike to get the levers off though, they're not as convenient asmodern front-loading stems.

    It might be just as esy to get a different quill stem though - you can still get them farily easily:

    http://www.sjscycles.co.uk/category-Stems--1-(22.2mm)-Quill-Threaded-277.htm

    Quilll stems are mostly 1" diameter, but later ones were 1 1/8", so measure your existing one to find out which it is.

    You can now get front-loader quill stems in 1 1/8 " -

    http://www.sjscycles.co.uk/product-Amoe ... ridge-beam)-quill-stem-1382.htm

    - but yours is more likely to be 1". There is a "Salsa" 1" front-loading quill stem, but I've never seen them in this country.

    FWIW the quill system is much better engineered than ahead, which was sold as lighter/stiffer blah blah but were really introduced because of reduced manufacturing costs for bike makers. In particular, headsets are easier to service, and half yourbike doesn't fall apart if you take the stem out!
  • biondinobiondino Posts: 5,990
    I honestly suspect that the rubbish roadie is so fundamentally rubbish that binning it and buying an honest, cheap but decent replacement which you can then tinker with and upgrade would be a more satisfying and perhaps even cheaper alternative!
  • robbarkerrobbarker Posts: 1,367
    Oh, and don't bother changing the down tube shifters, although unfashionable they work fine and replacing them with STIs, even if you can (how many gears?) it will cost more than the bike is worth.

    How too big is too big by the way?
  • redveeredvee Posts: 11,921
    Just doing the stem will cost you the stem and bartape and time, usually some kind gent will offer a quill adapter to a fair maiden. Not sure if I've got a 22.2 adapter but know I've got a 25.4 adapter, will need a shim for the 22.2 if I've got it.
    I've added a signature to prove it is still possible.
  • Well, I've just been out and measured and it's a 58cm top tube with a 12.5cm stem with a downward angle of what looks like 5-ish degrees from horizontal, and according to the fitting I had at Epic on saturday, I should be on a 53.5cm top tube with a 9 or 10cm normal stem.

    So it's 7 or 8 cm too big, not taking into account the angle of the head tube which doesn't help either.

    Which is quite a lot.

    And it's 12 speed...

    The quill stems look like a good idea - can you also adjust the height of the stem with them??

    Do you think something like this:
    http://www.sjscycles.co.uk/product-Unbr ... t-6025.htm

    would fit?

    The bike is a Mercurio M12-58 if that helps!
  • biondinobiondino Posts: 5,990
    Liv, for the love of god, put the abomination in a car crusher and siphon off a couple of hundred quid to get yourself a decent runaround!
  • biondino wrote:
    Liv, for the love of god, put the abomination in a car crusher and siphon off a couple of hundred quid to get yourself a decent runaround!

    Yeah, I can kind of see your point here... but OTOH if the stem above is approved by the techy folks that would make it roughly the right length from saddle to bars...

    And if I get another bike it'll prove jash right far too quickly... :wink:
  • whyamiherewhyamihere Posts: 7,336
    As long as the bike has a 1" steerer, then that stem will be fine. An easy way of checking is that on a 1" steerer, the part of the stem that goes into the steerer will be 22.2mm (7/8ths of an inch), on a 1 1/8th headset the stem will be 25.4mm (1 inch).

    The problem is, it will vastly affect the steering. The shorter the stem goes, the faster the handling gets. It will feel more twitchy, it will want to turn more easily, and be a lot less stable. Short stems are used on downhill mountain bikes with very slack head angles, on a steep angled road bike they can be a real handful to control.

    It might be fine, but just a warning...
  • And a valid warning it is too!

    That was my concern... there's a fair bit of rake on the front forks, but for low-speed manoeuvering through traffic very sharp steering would be less than ideal!

    It says 'max height 85mm' - does that mean you can move them up and down? Like a seatpost? Or have I completely misunderstood?
  • whyamiherewhyamihere Posts: 7,336
    Yes. To see how it works, on your current one, loosen the bolt on top and pull, it will slide up, then tighten the bolt at the desired height. There should be a maximum height line like a seatpost.

    Edit: A lot of rake (and there is quite a lot on your fork) will also make the bike twitchier, so I definitely wouldn't be keen on fitting a very short stem.
  • Blast and damn! I thought rake made it less twitchy!

    Well I'll certainly try moving it up and see what diameter it is to try and get a shorter but maybe not 55mm one...

    Thanks very much!!
  • whyamiherewhyamihere Posts: 7,336
    http://www.phred.org/~josh/bike/trail.html explains a bit about rake and trail.
  • Also, what about a stem with an upward angle? Granted it may look a bit weird, but it miight help??
  • robbarkerrobbarker Posts: 1,367
    Hmmmmmmm. That's massively too big. I'd flog it and get something else. Cyclescheme an option for you?
  • whyamiherewhyamihere Posts: 7,336
    If the bar is higher, you will definitely have an increase in comfort in the lower back and hands/wrists (I would guess that these areas get quite painful for you on a long ride). The higher bar offered by a stem with rise essentially rotates you up, so is similar to putting on a shorter stem with the same rise, although the effect is obviously not so pronounced. The warning about going too short still applies though; the important measurement with stem length is how far away from the centre of the steerer the bar is, measuring horizontally rather than along the line of the stem. That sounds complicated, so a picture:

    stemek6.jpg
  • Yeah, I tried to put the bars up last night, but the allen-key-screw-thing in the stem wouldn't budge, and the LBS couldn't get it to move either.

    I'm going to take it to a different LBS, see if they have any more joy.

    I can't see the picture, whyamihere, but I understand what you mean.

    If I can't get the stem off the above all becomes theoretical and a tad irrelevant! :D

    And robbarker, yes, I now realise how massively too big it is! I would buy another geared roadie to commute on until I can get back on teh SS, but I have a serious roadie on order and this is only a temporary measure until it is relegated to pub bike!!
  • robbarkerrobbarker Posts: 1,367
    Understood.

    To free it ,try some ice on the stem, and boiling water on the headtube. Make sure you have plenty of ice so if it doesn't work, or if you scald your fingers, you have some left for a big G&T.
  • Thanks Rob! Well, it didn't work, I have poured coke into it and will leave it sitting overnight.

    We shall see, stem, we shall see! Even if I can just put it up that would help...
  • that bike is by many many margins too big, don't thow good money or time on it. you'll risk getting sore etc from it not fitting....
  • biondinobiondino Posts: 5,990
    I changed stems on both my bikes tonight (flipping the 17 degree stem on the Trek - it looks ridiculous now and is probably more upright than a penny farthing) and went from 110mm to 90mm on the Focus. Will report back to see how both work out.
  • crankycrankcrankycrank Posts: 1,830
    I would agree with the camp that says get rid of it and get something that fits. If you're set on owning a proper rubbish bike, just get one secondhand with the brake/shifters and the right size.
  • biondinobiondino Posts: 5,990
    Update - the Trek with the silly stem is very comfy and rideable (a sportive bike no less), and the shorter stem on the Focus makes little difference except to the way the front end reacts when I stand up and put the power down - not a problem just something to get used to I think.
  • wgwarburtonwgwarburton Posts: 1,863
    Hi,
    I wouldn't worry about the steering geometry, the stem doesn't make that much difference and since you're competent enough to ride fixed you arn't going to struggle.

    A shorter stem will help, though I'd be inclined to get an alloy one rather than steel, even on a rubbish roadie. I've probably got an old one in the shed- you can have it if you want, PM me a maildrop (I'm in Scotland, so you don't need to worry about being stalked!).
    I needed a longer one on the winter hack (RIP), so took off the short one that came on it.

    Adjusting them is relatively easy. You need to free off the adjuster bolt, which can be hard if the bike's old and it's rusted in place but otherwise should just need a smart tap with a hammer on the bolt, after backing it off a bit. take the front wheel off and prop the forks securely before hammering, so that the impact goes on the forks & steerer-tube and NOT on the headset bearings...!

    Changing them is a PITA. You have to strip down the bars (tape & brake lever) off at least one side, slacken the clamp bolt and slide the stem off. Reverse to fit the new one.

    With your shorter stem, you can adjust the height and also play around with angle of the bars- If you ride on the hoods most of the time then you can get a more upright position by rotating the handlebars so that the "drops" are higher up, then move the brake levers up or down the curve to suit. The "85mm" is the maximum height that the stem should extend above the headset- there's usually a mark on the stem showing this).
    The bike's probably too big to ever fit you perfectly, but you should be able to get it reasonably comfortable for use as a hack. I ride road frames from 22 1/2" to 25" without any real trouble.

    Hope that helps.

    Cheers,
    W.
  • Bin the Rubbish Roadie. It's only gurlie sentiment that's causing you to keep it.

    By the time you've spent the money sorting it out, you could have spent the same money on a low end, up-to-date fully built new bike which would ACTUALLY FIT!

    If you had a pair of shoes which was two sizes too big, you wouldn't bother putting new buckles on them, would you? :wink:
    Swim. Bike. Run. Yeah. That's what I used to do.

    Bike 1
    Bike 2-A
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