I own a Trek 4500. To sort out a clicking noise that was coming from the bottom bracket while I pedalled, I took it to the local repair shop.

They clamped the seat post of the bike onto a bike repair stand, lifted the wheels of ground and proceeded to tighten the crank and pedal posts. The clicking noise disappeared subsequently, but I'm worried that unnecessay stress was placed on the seat post and bike frame because it was lifted off the ground (while the adjustments to the crank and pedal posts were being made).

Is this the correct way to tighten the crank and pedal post? Or should bike have been on the ground while the adjustments took place.

What you saw has been SOP for 100+ years. Fear not.

Keep in mind that the bike weighs ~25 lbs. I presume you weigh some multiple of 25 lbs and you put all that on the seat. Have you damaged your frame by riding it? I think not.

+1 to the above

Thanks, melville. It's a relief to learn that other bikes are also abused as such.

However, the stress I place on the frame and seat post, when I ride the bike, is vertical. Whereas, crank and pedal tightening places a rotational stress on the frame and seatpost; more so when it is suspended in the air with the seat post clamped.

What kind of gorilla was working on your bike? Did he grunt? Did he call for the BIG hammer? If the BB was creaking, all they did was tighten it like it should have been done in the first place (when you weren't watching) and the crankarm tightening places nearly no stress on the frame due to the bearing interface provided by the BB.

You had me in splits, melville. Compliments on your sense of humour.

Would you be able to tell me how much I can abuse the Trek 4500, while I ride it ( jumps and all). I've read it is very strong for a xc bike.

Again, thanks for cheering me up!

Actually, it's more like 50+ years:

https://www.parktool.com/about/history.asp

Your comment about the stress a bike repair stand puts on a seat post versus the stress the weight of a rider puts on it is right on. Seat posts are pretty strong.

Actually, unless your seatpost goes straight up perpendicular to the ground (probably not) the force you put on the post from riding is similar to the force the mechanic put on it. Seatposts slant backwards so you are putting vertical and leverage force on it when you ride. Imagine the amount of force generated when you hit a good sized bump with your butt on the saddle.

Clamping bike in repair stands by the seatpost has become very common with the advent of thin wall frame tubing, particularly aluminum and carbon. These tube sets won't tolerate the clamping pressure that their heavier wall steel predecessors would. What your LBS did is now standard procedure.

ROFL.

Your bike is completely trashed now, unrideable even. Bike shops don't put bikes on repair stands to repair them. What kind of nonsense is that!

How much does the bike weigh? How much load is the seatpost facing when it's hanging and holding the bike?

How much do YOU weigh? How much load is the seapost facing when you're sitting on the bike and riding it?

Tightening the crank with the wheels ON the ground would place less stress on the bike.

However, I guess it is easier to work with the bike suspended. On second thoughts, it is also easy to tighten the crank with the bike inverted- the seat and handle bar taking the weight of the entire bike.

I guess these bike mechanics are lazy bustads.

Seat posts are a lot cheaper than frames.

One should never watch a bike being repaired. Kind of like sausage being made...better not to know.

And usually, a lot stronger too.

Yup and it's ALWAYS a mistake to allow the customer watch while you work on his bike.

What kind of babbling nonsense is this?

Crank bolts are tightened with the arm as leverage (either side). How the flying hell would having the wheels ON the ground help?

You ask a noob question, but proceed to offer expert analysis? Give me a freaking break.

There is no such thing as a dumb question.

Some should be thought of before they are asked.

Some should be worded very carefully.

Some are better left unproposed.

But asking questions is how you learn [ noob or not ].

That's why this and other forums are here.

All take care.

Huh********** If the force on the wrench isn't going into spinning the crankarm-bolt, then you're doing something wrong. Even better is to lay the bike on its side on the ground and tighten the crank that way. Then there's no weight on the wheels at all.

Jumping your bike off a 3 foot drop will easily place 8 to 10 or more times as much force into both the frame and fork than what that guy did to it in the stand.

This definetly equates to worrying about a tempest in a tea pot compared to what your bike is asked to soak up on any trail ride even without a 3 foot jump.

Question,

If you can conceptualize the difference between a compression and a torsional load what would make you think this would be an issue?

Precisely! I would assume think that the seatpost and frame are designed to take tremendous compression loads. However, inspite of being a complete novice, I would think that the frame and seatpost would not be able to take similar torsional punishment.

Then you would be wrong.

Don't worry all you gasping, incredulous experienced cyclists. This is a trend that is going to increase manyfold over the next several years... people who've suddenly discovered cycling as a cheap means of transport, posting a question with a defined answer in mind, then getting all upset and argumentative when *their* answer isn't given by the people who really do know what they are talking about.

operator, I don't normally quite take to your style, but in this case, BRAVO!

Rowan- presumptuous....... aren't we? Since when did cycle mechanics get so clever?