 |  | | | |  | |  |  | Need a longer stem - I think |  | |  |  | |
 Posted: Fri May 08, 2009 8:32 pm |
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| scozim |
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| Joined: 26 Sep 2008 |
| Posts: 629 |
| Location: Ellensburg, WA |
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I determined while out on another ride with the Sprint that the stem is just too short at around 90-95 mm (I'm using a tape for an approximate). My TdF and Bianchi seem to be between 110 and 115 mm.
I feel just a little too compact while riding the Sprint and think the best option would be a longer stem. I'm assuming a 22.2 mm is what I need since this is an '84 model. Any suggestions on an appropriate replacement? I'd like to stay with something period specific (i.e. the 80's).
Scott |
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| | | | | | | | | New Longer Stem | | | | | |
| Posted: Fri May 08, 2009 11:57 pm |
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| verktyg |
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| Joined: 14 Jan 2007 |
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| Location: SF Bay Area |
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Scott,
What brand of bars and stem are you currently using?
I'd recommend that you get a forged aluminum stem such as a Cinelli 1a (requires Cinelli 26.4mm diameter bar) or a Nitto forged stem (uses a 26mm diameter bar).
I'm using Nitto bars on a number of my bikes. They look just like a classic Cinelli bar.
Chas. |
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| Posted: Sat May 09, 2009 12:48 am |
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| Gtane |
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| Joined: 14 Sep 2007 |
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| Location: UK |
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Scott,
I too recommend the Cinelli and agree with Chas. The stem is such a wonderful looking piece. Classic, clean and beautiful.
The 3ttt quills are also very nice indeed.
For something slightly different, if a little out of place regards originality of the machine, is the Shimano stem of the early 1980s. The Dura Ace is particularly nice. I just love the clean lines and ingenious engineering - both binder bolts are accessed through a single access point at the elbow of the stem.
http://tinyurl.com/o7y9up
Tim |
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| Posted: Sat May 09, 2009 7:29 am |
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| scozim |
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| Joined: 26 Sep 2008 |
| Posts: 629 |
| Location: Ellensburg, WA |
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Hold the presses. I should have "thunk" before I posted last night.
The stem and bar are original to the bike. But, when I bought it the bike came with a really ugly set of early tri bars. I had completely I forgot that I'd kept those bars until I went to my shop this morning.
They have a Nitto Technomic stem that is the right length and with a temporary measurement with my non-metric calipers appear they'll fit perfectly. So, now I just need to do the swap and try to save my bar tape.
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| | | | | | | | | HB Diameters | | | | | |
| Posted: Sat May 09, 2009 6:12 pm |
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| verktyg |
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| Joined: 14 Jan 2007 |
| Posts: 2814 |
| Location: SF Bay Area |
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Scott,
The Nitto Technomic stems come in 2 bar diameter sizes, the older 25.4mm and newer 26mm.
DON'T try to stretch the stem opening to fit a larger diameter bar OR tighten it down to fit a smaller bar.
Nitto makes a shim to use a 25.4mm bar in a stem designed for a 26mm bar.
http://tinyurl.com/ohc2fq
Below is a Cinelli 1a French size 22mm stem that was made for a 26.4mm diameter bar. I used it with a 25mm French bar from 1975 until last year.
In those days forged stems with 22mm Metric diameter quills were very hard to find and pretty much limited to Cinelli and 3TTT brands. Not knowing any better, it was common practice to fit an undersized bar in these stems.
Last year I decided to switch to a wider set of bars using this stem. When I expanded the clamping area of the stem to change the bars, the front broke off with a musical 'ping'. 
Occasionally the clamping bolts would break from over tightening but I hadn't seen a stem fail like this one before.
This could have happened at any time while I was riding with this stem!
You can still get 25.4mm Nitto bars that looks like the newer 26mm diameter model 176 Nitto bars (which are Cinelli 64D Giro D'Italia or 66D Campione del Mondo knockoffs).
Nitto B-115 25.4mm 42cm wide http://tinyurl.com/o464z8
Nitto B-115 25.4mm 45cm wide http://tinyurl.com/qrk7qm
Chas. |
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| Posted: Sun May 10, 2009 3:28 pm |
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| sandranian |
| Site Admin |
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| Joined: 27 Feb 2006 |
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| Location: Southern California |
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| Nothing like pictures of broken bike parts to scare the sh*t out of you. |
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| | | | | | | | | Stem and Bar Safety | | | | | |
| Posted: Mon May 11, 2009 9:21 am |
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| verktyg |
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| Joined: 14 Jan 2007 |
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| Location: SF Bay Area |
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| sandranian wrote: |
| Nothing like pictures of broken bike parts to scare the (expletive deleted) out of you. |
Better safe than sorry.
I'd hate to see a member of the forum have a bad experience over a simple safety issue.
When you're assembling or servicing your bike (bikes), it's easy to do a quick safety inspection on the stem, bars, steering tube and fork crown. If something doesn't look quite right, check it out further.
This is an example of a crack developing in an old Pivo cast aluminum stem. These kinds of cracks can be prevented by drilling a small hole in the stem at the top of the expander split.
This was one of the worst examples of a Bike Boom cast aluminum stem (death stem). It was poorly cast throughout and should have been thrown back in the melting pot. Notice the bulge at the bottom of the quill.
This is what can happen when one of these cast aluminum stems fail. Notice the size of the grain particles at the break compared to the forged Cinelli stem below.
Forged Cinelli 1a stem that failed from using with a 25mm bar (stem made to fit 26.4mm bars). Notice the fine grain structure in the metal at the crack. This is one of the benefits of forging.
This 3TTT forged aluminum stem has what appears to be a "lap seam failure" due to a defect in the metal. The crack could also been caused by using an undersized bar. These stems were designed for use with 26mm bars.
Later stems use an angled expander wedge rather than a split in the quill with an internal expander. These style cast aluminum stems are generally safer because there's more material in the quill area.
Example of a crack in a stem. This is the result of having the stem too high and the quill expanding in the threaded area. Cracks can also occur around the threads which result in catastrophic failure. This is one of the reasons why I frequently comment when I see a picture of a bike with the stem too high
Droopy bars. Don't ride a bike with bent or drooping bars! 
Replacement stems and bars are a cheap investment. Cast Pivo stems are always listed on eBay. They sell for $10-$20. If you get a bad one send it back to the seller. Same for bars.
Ride safe.... 
Chas. |
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| Posted: Tue May 12, 2009 10:10 am |
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| Gtane |
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| Joined: 14 Sep 2007 |
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| Location: UK |
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Gosh! I can imagine, no, sorry, correction. I cannot imagine at all what it might be like to have a stem break on a ride. Particularly on a descent. I think I'll leave that one. Thanks for the graphics Chas.
It's rather like the 'C' word that the Pros never talk about or use before a race.
I hope my internal an external calipers are calibrated. I think I better check.
Tim |
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