Guywithbike

Hi just got a new bike but it's a bit small. To make it a decent ride I gotta raise the seat above the max line. Is this dangerous?

rccardr 

DrIsotope

Just buy a longer seatpost. 400mm posts are relatively plentiful.

blamester

Why take the risk?
You don't want to be going downhill fast and wondering if it will break.
Get a longer one and be sure.

Aubergine 

79pmooney

It's more likely that having the seat too high will lead to damage to the seat tube than that the seatpost itself will break. Bikes are designed so that the top of the seat tube is strong (on steel bikes, it is well supported by the lug) but that top portion was never intended to be able to support a long lever with most of the riders weight (much more when you hit a bump). Instead, the seat tube several inches below the lug provides that anchor. And the further down the post extends, the less that portion of the tube has to do. Pushing the post too high is running the risk of ruining your frame.

Ben

Bike Gremlin

Yes it is. Longer answer with more details: minimum seatpost insertion length.

jimc101

Apart from it being potentially dangerous to you/damaging to the frame, if you need to get a seatpost raised above the max limit, there will be other issues with the fit, and your probably ever get it to 'make a decent ride' , new bike or new to you, if new, either way, why did you buy a bike that was too small?

Guywithbike

I guess I bought it out of wishful thinking. It was a good deal. I'm poor and it's very hard to find cheap bikes at all let alone for tall people. I'm 6'5". I'm not just barely past the max, I've got it about as far as it will go just about. Rode on it like that for about 5 miles so far and it was nice. Maybe you're all being uptight about this? Cause it seemed sturdy to me. I don't have money for another seat post. I've also got the handlebar stem beyond max too to compensate. Ah well I appreciate that anyone responded at all even if now I'm fearful and don't know what to do.

63rickert

You could get even more poor real quick. Margin of error at handlebar stem is smaller than at seatpost. And now you risk falling on your face. Trade for a bigger bike. Finding cheap bikes is not hard at all. There is a glut on the market. You just don't know where to look. Be patient and you will find them.

WGB 

Check out the photo on the link that Slaninar added because I can't seem to copy that photo.

See points copied below.

3. Dangers of not inserting seatpost deep enough

Seatpost not inserted deep enough into the seat tube (as explained in chapter 2.) can cause the following problems:

• It will not stay firmly in place – dropping deeper, or twisting (this is the least of the problems and it happens most rarely, the other problems are more serious).
• Seatpost could bend, or break.
• The top part of the seat tube (the frame) could break.

Most of these problems can be hazardous if they happen when riding at high speeds and/or on bumpy terrain.

The last bit (Most of these problems can be hazardous if they happen when riding at high speeds and/or on bumpy terrain) is an example of understatement.



This photo is of a post that was seized in place and when the seat was twisted it snapped as shown. No one was on it and if left at exactly that high it might have lasted awhile longer. It was just a bad post which could have hurt someone. No guarantees it would have broke but no guarantees it wouldn't have either.

Your body is frail and that's why we add safety features like helmets. There are risks in almost anything we do and when biking you have other cyclists, cars, bad roads, debris, animals that run out, pedestrians and others that can hurt you. Why add to the list? To mitigate risk to ourselves and out bikes we check for potential issues and repair or replace as needed. Having a tire blow on a downhill is not good, especially if a simple check before revealed it's time for a new tire and you choose to ride anyway. Adjusting a loose brake cable is always worth the time taken to dig out the wrench or socket and tightening a nut. Choosing to ride a bike with an unsafe part is a bad idea.

In your case you need a seatpost and stem. A new seat post can be as little as $5-10 (you transfer the old seat to the new post) and a stem again, also $5-10 (you will transfer the bars to the new stem). Keep the old parts and re-install when you sell the bike.

We have no idea what you ride. Remember mountain bikes generally take different parts than road bikes. You will need to know the size of the seat post you have now and variations between posts are generally 2mm difference so guessing will probably not work. If you can borrow a micrometer and measure both post and stem you have now it will take less than a minute and save you time and money.

We have no idea where you are located. Have you checked Craigslist or in Canada Kijiji? What about eBay or The Bike Shop Store or similar? Perhaps there is a co-op near you? Changing out bars when you have to remove brake levers and then re-tape the bars requires experience and sometimes specialized tools.

Perhaps you need a taller bike. So if you sell this one and take a small loss and then buy a bike with a taller frame now you will be cautious. You have learned something. You know what you need versus what looks nice. Let's say you lose $50 between selling this bike and buying a bike that fits. If you keep the bike 5 years that's $10 a year to be comfortable and to be safe. Sounds like a bargain. Remember clean the bike well and it will sell faster and who knows, you might break even or make a small profit that can off set your next ride.

Crankycrank

With 10 posts as of now all saying it won't work I'm not sure what else it would take to convince you. You originally didn't mention the stem mounted above the max mark as well. It may work for awhile but either the seat post or stem will probably fail and most likely when you hit a bump sending you off the bike. That could really get expensive.

ridingfool

Hate to say it but you might be better off walking til u could afford a new seat post or a new bike that fits better.if u are conttent with keeping the bike try to see if the area u live in has a co op u can buy a seat post for 5 ,bucks or less and maybe even a longer stem

Retro Grouch 

You say that you're poor. You can probably buy a Kalloy seat post for around $20.00. How much did you pay for the whole bike? Your bike frame is the part that's likely to be ruined and need to be replaced after you have your accident Seatposts come in different diameters and it matters - A LOT. If you haven't ruined the one that you have, the size will be stamped near the bottom.

Does your health coverage include traumatic dental? You need to do something different to the handlebar stem too. Otherwise you'll hit a bump some day and realize that your handlebar isn't hooked onto anything.

Guywithbike

It's a cruiser bike, with only coaster brakes. Onex 29 cruiser by genbikes.com. but I got it used off someone. In good condition. I've removed all the decals and guards and fluff so reselling might be hard. I can lower the handlebars, no big deal. But the seat post I don't know what gonna do cause I ain't walking, and I recently.blew the budget.om other stuff, and there's no bike shops or anything in this area. I'll see how much I can lower it and still be comfortable.

fietsbob

Or breaking off the frame , at the seat post clamp...




I bought a long Chromoly 1" (25.4mm) seat post from Seattle bike supply , to be strong as i was having the top 12" of it out of the frame..

(a Schwinn Mesa runner , FWIW)




....

Aubergine 

Guywithbike

Guywithbike

That's the situation.

AlmostTrick

OMG, no way is that going to be safe to ride over extended that far. Find a longer post. Oh, and lower your stem to the line too.

Guywithbike

Could someone help me find what I need to get...the cheapest solution!

alcjphil

The cheapest solution is a longer seatpost. Good news is that 27.2 mm is one of the most common seatpost diameters out there

Crankycrank

Ebay has a few choices $10-$15 shipped. Look for something at least 350mm long by 27.2 diameter.

Guywithbike

Do I need to get one with a clamp or not....any considerations other than size? Never replaced a seatpost

Crankycrank

Just get one with the clamp for the seat built in. If your current setup is a separate clamp that attaches to the seat you can just remove it and mount the seat rails directly to your new post. A photo of your what you have now (bottom shot of the seat clamped to the post) would be helpful just to make sure though.