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51 votes

How to stabilise the bicycle seatpost and saddle when it is all the way up?

Your seat post is not all the way up — it's too far up. If you need the saddle at that height, then you need a longer seat post. As mentioned in comments, there is usually a "minimum insertion&...
Argenti Apparatus's user avatar
31 votes

How do I place the seat back 20 cm with a full suspension bike?

The only safe answer is to buy a bigger bike frame. When your adaptor fails, you will descend rapidly onto the rear wheel. The remaining original seatpost has an excellent chance of tearing your chest ...
Criggie's user avatar
  • 127k
30 votes

How to stop bike renters overextending seatposts?

I assume they are extending the seat post that far because they need it for an appropriate saddle height. So the solution is simple: Offer bikes with larger frame sizes or at the very least equip the ...
Michael's user avatar
  • 28.1k
26 votes
Accepted

Copper pipe seatpost?

Copper has a yield tensile strength of 33 MPa vs 280 MPa for 6061-T6 aluminum or 460 MPa for chromoly steel. Your daughter doesn't weigh 12% of the weight of a typical user of a 1 inch aluminum seat ...
oscu0's user avatar
  • 795
24 votes
Accepted

Why are all road bike frames now squashed parallelograms?

Sloping top tubes started with mountain bikes, and were brought over to road bikes by Giant, following a design from Mike Burrows. Partly because a perpendicular joint between the seat tube and top ...
Adam Rice's user avatar
  • 30.1k
21 votes
Accepted

What are the differences between a seatpost-mounted and frame-mounted rear rack

The advantages of seat mounted racks are that they don’t require rear dropout rack lugs; some of the seat mount racks have quick release levers so you can easily take them off (while racing or ...
RoboKaren's user avatar
  • 29.2k
19 votes
Accepted

Is it safe to drill a cable exit hole in a seatpost?

I suggest to avoid drilling holes in the seatpost alltogether. Just find a seatpost that has an opening at the top, there are plenty available usually on older seatposts with two-bolt mounting system. ...
Art Gertner's user avatar
  • 2,837
18 votes
Accepted

Cracked seat post

That seat post is made of carbon fiber tube and metal seat mount that plugs into it. The carbon tube is about to split and the inner part you see is the metal plug. It should be replaced immediately ...
ojs's user avatar
  • 22.2k
17 votes

How to stabilise the bicycle seatpost and saddle when it is all the way up?

Seat posts are usually marked with a line indicating a minimum insertion point. Extending the seat post past that point poses a risk of the seat post bending, or cracking the frame. While 250-300mm ...
mikes's user avatar
  • 18.7k
16 votes

How to make old bike's seatpost slide smoothly when it needs adjustment again?

There are different things that can cause this problem and different tools and techniques that can be used to fix it, depending on the cause and severity. Frame material cannot be left out of the ...
Nathan Knutson's user avatar
16 votes

Is it unsafe to have a seatpost "slammed"?

Look at it this way: would you feel comfortable taking your saddle off, grabbing a 1 yard/meter long bit of lumber, and whacking down on the top of the seatpost moderately hard with that chunk of ...
Andrew Henle's user avatar
  • 10.7k
15 votes

Copper pipe seatpost?

In addition to structural concerns regarding copper's tensile strength, keep in mind that copper causes galvanic corrosion of both steel and aluminium. Stick a copper seat post in a steel or aluminium ...
SimonL's user avatar
  • 1,083
14 votes
Accepted

Bike comes with frame integrated bolt seatpost clamp - can I cut it off and use QR?

Yes it's possible to hacksaw the clamp bosses off and then file the seat tube round and smooth so that a quick release clamp would slip over it. Before taking such drastic action - which will ...
Argenti Apparatus's user avatar
13 votes

Before re-inserting a stuck seat post what should I do to the steel/alloy surfaces?

I would not advise reducing the seatpost, nor widening the frame's ID. A close fit is a good thing for a seatpost. Instead, clean the seatpost using your preferred solvent, and allow to dry. If its ...
Criggie's user avatar
  • 127k
12 votes
Accepted

How to install a saddle on a seatpost with a top facing bolt

You use the front bolt to set the angle first, then torque the rear bolt. Sometimes a few times to get it right. The front bolt is adjusted with the thumbdial or a lever put into one of the holes in ...
Noise's user avatar
  • 14.3k
12 votes

Trying to match up a new seat for my bicycle and having difficulty finding one that will work

Its a Giant Sedona, probably from the 2000's. But that information is not very useful for replacing the saddle. If you look up underneath the saddle, there will be two parallel rails, and the ...
Criggie's user avatar
  • 127k
12 votes

Trying to match up a new seat for my bicycle and having difficulty finding one that will work

The stickers tell you it's a Giant Sedona. To me it looks like a fairly old model (they still make a similar hybrid under that name, but with suspension). But you don't need the model details to ...
Chris H's user avatar
  • 60.1k
11 votes
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Remove lubricant from seat tube and seat post

This is an XY problem. Seatposts should be lubed. While removing all lube may solve your slipping problem, it will likely do so by making the seatpost corrode into place, which isn't something you ...
whatsisname's user avatar
  • 12.2k
11 votes
Accepted

How to make old bike's seatpost slide smoothly when it needs adjustment again?

Check for burrs (a small ‘lip’ of material) on the inside edge of the top of the seat tube). That’s probably what is scratching the seat post. If you stick you finger carefully in the top if the seat ...
Argenti Apparatus's user avatar
11 votes

Aluminum seatpost broken into a steel frame

That's a challenge right there - I hope the bike wasn't being ridden at the time it failed ! Clearly the post is dead, so damage to that is okay. You want to save the frame. Remove the seatpost ...
Criggie's user avatar
  • 127k
10 votes

Safely cutting down a seatpost

I agree with @ojs answer on point (1), you can just cut it with a hacksaw but with the exception of point (2) "the common consensus seems to be at least 5 cm of insertion" - the standard minimum ...
Ivan McA's user avatar
  • 219
10 votes

Remove lubricant from seat tube and seat post

A thorough way to do it would be to: Remove the cranks, bottom bracket and seat post. Make sure there is a decent hole between the seat tube and bottom bracket shell (might depend on the frame). Ram ...
Jambo's user avatar
  • 276
10 votes
Accepted

Is it possible and safe to attach this type of seat to suspension seatpost?

Looks like the new one has the same kind of saddle rails so you can remove the attachment from it and try the bare saddle rails in the suspension seatpost. It should work! Undo the two big black nuts ...
Swifty's user avatar
  • 12.8k
10 votes

Bolt holding saddle to seatpost broke

You need to use high tensile bolts for high tensile positions like this. A class 8.8 bolt (metric) or grade 8 (US) or higher is appropriate. Cheese-grade steel from the local discount hardware ...
Criggie's user avatar
  • 127k
10 votes

Suggestions for protecting jeans from saddle clamp bolt

I would suggest cutting off the extra threads. If you have access to a Dremel or similar tool it wouldn't be too difficult. Doing it with a hacksaw could be a real pain. Alternatively you could check ...
mikes's user avatar
  • 18.7k
10 votes

Bike seat tube is messed up

What’s happened here is that you have expanded the diameter of the top of the seat tube, in the process it looks like you have made some small cracks on the top edge, and created a number of burrs. ...
Argenti Apparatus's user avatar
10 votes

How do I fix the comfort of my bike?

The first things I look at to smooth out a ride are: Least expensive: Tire pressure. Printed on the tire is the recommended maximum inflation. You can experiment with lower tire pressures to smooth ...
David D's user avatar
  • 21.9k
10 votes
Accepted

Will grooves on seatpost cause rusting inside frame?

The best thing to do is apply a thin layer of grease to the inside of the seat tube and the outside of the post (only the part of the post inside the seat tube needs grease) and set the seat height ...
David D's user avatar
  • 21.9k
10 votes

How to stop bike renters overextending seatposts?

If these are beach cruisers or similar, they'll typically have 22.2 or 25.4mm seatposts (7/8" or 1"). If so, putting longer seatposts in all of them would be cheap. This isn't scummy if what ...
Nathan Knutson's user avatar
10 votes

How to mark seatpost position?

Not a strict answer to the direct question, but an answer to the question of sharing between different people. If you are ready to change the seatpost, having a dropper post is a nice solution when ...
Rеnаud's user avatar
  • 20.9k

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