Torsion in my frame? Is this bad?
fuzzynavel
Posts: 718
When I put on my front and back brakes and push down on one of the pedals the pedal on the other side moves....Not turning around the crank before you say it....but it looks like my bottom bracket is twisting. Could this be a manufacturing fault?
It's a Giant SCr 1.5 Btw
It's a Giant SCr 1.5 Btw
17 Stone down to 12.5 now raring to get back on the bike!
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I'm so sorry that I can't afford to censored 3 grand on a new bike but I still expect a quality product for the £650 RRP of the bike. My £299 mountain bike has lasted 13 years with no maintenance and I never noticed anything like this before.
I think I'll take it to the LBS just to make sure
he is right though - it is just the frame flexing - there is a reason why £2000+ carbon frames are £2000+ - they don't flex.
My trek Pilot1.2 does it. my specialized langster does it, my S-Works Roubaix does not.
the exercise you are doing shows the flexing at it's worst - I always think that turbo trainers show the worst in frame flexibility too - it won't get any worse while you are out riding and certainly won't rip your bottom bracket out or destroy anything.
you are using effort to deflect the frame though - which is again why people will pay for the stiffness of a top-end frame.
You probably did not notice any flex on your MTB because you never looked and also it was built like a tank.
I sat on the bike and looked directly down to the bottom bracket aligning it with the top tube. It moves laterally...it is not a loose bottom bracket as that is why my mountain bike is currently dead. It spilled its ball bearings all over the road on a hill while I was mashing a big gear...It was steel and not exactly lightweight so probably no flexing in that one!
If this is a common observation at this price point then I shall stop worrying and get on with enjoying riding. Thanks again.
Just examine all the tubes around the bottom bracket - and especially the welds - to make doubly sure that you don't have a damaged frame.
Its probably nothing to worry about but it wont hurt to get a professional opinion to put your mind at rest.
Maybe you're making more of this than it is. I can't think of an instance where I have seen or even heard of someone "ripping the bottom bracket out...." of a bike. Even a cheap one.
Maybe some ultra light track bike with some guy on it with "Arnold" legs, maybe. I think you're worried about nothing. In any case if you do" bust a nut" it will probably have to be removed and then you'll win the TDF. Best of both worlds.
Dennis Noward
He tried to "prove" than flexi frames were more efficient than stiff ones.
I would hazard a guess and say that it probably hasn't been proven either way.
So the OP's frame may or may not be "the way to go". I await further testing.
And while I'm at "Why does it seem that no one is able to prove anything about cycling(i.e.
tubular vs clincher, high cadence vs low, Campy vs Shimano, aero rim vs low profile) that kind of stuff?"
Dennis Noward
Making more of than it is??
I am starting to see the same things cropping up in my short few months as a member here so I am not the only mental newbie here..
I'll keep pushing for that knackered nut so that I can get free entry to the TDF then!
Sort of like the old saying "The only sure thing is that there isn't one". Or something like that. Maybe, "There is no such thing as a sure thing".
Dennis Noward
I apologize if you took that wrong. Wasn't meant to be that way.
Dennis Noward