*** QUILL STEM FAILURES - BEWARE ***

[stevevw]

Another thing to look out for is cracks in your bars. I was lucky that I fancied a change of bar on my fixed gear Bianchi. When I removed them I was horrified to see a crack probably 1/3rd of the way round the bar just out from the stem. These just happen to be 3TTT too. I am a big bloke who pulls hard on the bars when climbing so feel very lucky not to of been stamping on the pedals holding half a bar in my hand just before flying through the air Comet like.

 

[roadking]

Look at how the 3TTT is manufactured compared to the Cinelli.

If I need to explain...

Rk.

P.S it's good to go off at a tangent sometimes - we're not"one club"men!

 

[roadking]

TSR 2

(TSR-2 was constructed at Weybridge, Surrey, I think), unsurprisingly it didn't suffer the same fate. :roll: David

Tactical Strike and Reconnaissance Aircraft, to replace Canberra, development took place at Weybidge and Warton.

TSR-2 was years ahead of its time, but it was all over by 1965, the labour government were"conned"into believing they'd save £300 million by adopting the F-111*. The TSR-2s demise was announced in James Callaghan's budget speech of 1965 - the two aircraft and all of the tooling were to be destroyed.

It was not until 1982 with the debut of the Tornado that the RAF at last had an aircraft designed to carry out all the tasks TSR-2 had been designed to do over two decades earlier.

Rk.

*they never did as the F-111 was dogged by costly development problems.

 

[hirameuser]

If you are near Duxford air museum pay it a visit there is a TSR-2 the photo's just don't do it justice

Phil

 

[Qubit]

Im lucky enough to live close to Duxford and have grown up with visits to the museum there. As a kid the TSR-2 was probably my favourite of all the display aircraft there. Was there a few weeks back and it still looks awesome!

 

[Jonny69]

back to stems ... why are some designed as per the OP, yet some dont expand all round like that, but use a sloping wedge system .... I've done it again ... crap wording to explain sommat technical

It's just a different way of doing it. The advantage of the wedge-style ones is they are *technically* less likely to get stuck, because the wedge won't stretch the inside of the stem tube and jam it in the steerer in the fork.

 

[Citoyen du monde]

I think that posts like this are technically flawed because they don't supply us with sufficient information to be able to properly judge what has happened. In the many years that I spent working in top bike shops, I did get the chance to see more than a few broken stems. I must however state that I never saw a stem "break" like that shown in the original post APART FROM WHERE THE USER HAD DISREGARDED STANDARD PRACTICE, COMMON SENSE AND MANUFACTURER'S INDICATIONS. By this, I mean that every single one that I ever saw with this type of failure had shown some type of user error. This is not to say that this is the case with this particular case, but this is my own personal experience. In one case the error was using a French diameter stem (22 mm) in an English diameter fork (22,2 mm). In another case, the steer tube had been reamed out to remove surface oxidation increasing the inner diameter just enough to make for poor compatibility between the stem and the steer tube. All the remaining cases involved stems that had been inserted into the frame less than was indicated on the stem, allowing for extra leverage. The far more common breakage was at the handlebar clamping end. Most of these breakages occurred due to poor forgings, over-tightening or manufacturer-induced stress risers (some manufacturers used striations on the bar side surface of the stem.