since6

My Grand Daughters first big bike has a fluted seat post. Given her current size it will likely be nearly all the way down which may mean that the flutes will be open on top and bottom when the seat bolt is tightened allowing rain to either pass through the flutes like a channel or gather and pool in the flutes seeping down the seat tube and letting water gather in the bottom bracket shell.
A thought is to take a clear caulking compound and fill in these flutes to make a positive seal until when she has grown long enough legs that the flutes are above the seat post binding ring making a positive seal against moisture.
But surely this is not a new problem. Are there any other ways to protect the frame from this risk of rain with a fluted seat post?
Thanks for your thoughts and help.

Aubergine 

Wildwood 

juvela

-----

Flutes do not generally go all the way to the bottom of the pillar.

​​​​​​​-----

T-Mar

IMO, it's never a good idea to give a child an ill-fitting bicycle and have them "grow into it". At worst, you're risking their safety and at best you're compromising their enjoyment. Put the bicycle away until they've grown enough to fit it properly. This situation is perhaps the best rationale you'll ever have for n+1. A spouse cannot argue against a grandchild's safety.

randyjawa 

A comment offered from the "drive side" and excellent advice! As for the post problem - remove, clean, apply lots of grease to the post and the inside of the seat tube and don't worry about it for a while. My guess is that this will protect against seizure for many years, under normal use and storing.

As for the grow into it comment offered by TMar. Pay attention! He has offered exceptionally good advice that parents often miss just to save a few dollars.

since6

Thanks all the grease idea is great, keeps the seat post tube lubed and seals as needed.

As to size, we will see how she fits after things get dialed in, they're always growing at 8 years of age. Safety yes comes first, but what is safety?

You see I started at 6 first with a 20-24" bike to learn balance, which was a hard thing for my parents to find in the early 60s and frankly for me that small bike was a very wobbly thing to ride on to learn balance with. Then Mom won a Coast to Coast full size single speed, coaster brake with carry a buddy rear rack and double D cell feeble light that weighed either the same or a little more than I did and that became my bike. I rode that bike for years then moved up to an older brother's three speed hand brake Schwinn Corvette and rode that until the end of grade school. Both were great bikes and both once moving were far easier to ride and safer ( I had a lot more confidence) than the smaller bikes. The Coast to Coast required learning the lean over and then jump on stomp down on the pedal start, but once moving it was oh so stable on its balloon tires, then brake to a near stop and lean over leg out stop. Once mastered there was no issues in starting or stopping (oh a hill yes, if you stopped on a hill, you just turned around and went down).

I see the children every day on the trail with their small bikes and yes they pedal/kick along on their bikes, but I also see them darting about a lot and falling over as the short wheelbase makes them very twitchy to ride. So which is safe a large stable bike or a twichy small bike? In the case of the former If I could pedal seated and steer with the handlebars, kick back on the coaster brake to stop I felt much more confident and in control than on the smaller twitchy bike where if you looked away you steered away too the next thing you knew you had to over correct and/or fall.

randyjawa 

Safety is a gigantic concern but that was not my point. My point was that a child riding a bike that does not fit, or a bike that is cheap department store offering, might not enjoy the experience. And that initial lack of enjoyment might prove life long.

Kontact 

And yet we grow up to eat brussel sprouts.

Kids are just learning to like and dislike things at that age. Unless something traumatic happens, few of those dislikes create lasting bias.

I'm sure the OP's bike fits his daughter no worse than the bikes we all rode as kids.

texaspandj

I think fluted post are a design flaw. Grease is definitely your friend.

63rickert

It's her first big bike? So she already knows how to ride? She'll know if she likes the new one. Listen to her.

Try filling the flutes with beeswax. A lot cleaner than wads of grease. Or just find another post.

Once you are all sealed up you need a drain or a vent. Does not sound like a open top seatpost. Drill the BB shell.

Kontact 

The flutes weren't designed to be down inside the frame, and they make the post lighter. If flutes are a bad design, aero posts are much worse.

texaspandj

Perhaps some But not all.I'm aware why they made flutes however, The flutes on this seat post were designed to go in side seat tube.

texaspandj

OP, bitd ('80s iirc) campy had some high fluting seatpost, but if yours is anything like the pic or you slam it. Grease , grease and more grease. And check it periodically.

CliffordK

Did you mention what size the post is?

If it is just 27.2, then find a good round post and install. That will also keep the top part of your post from getting scratched as the post is being adjusted.

malcala622

Its always a good idea to wipe down your bicycle after ridng in the rain or at the beach. Its what i tell everyone after riding.

Too much water won't seep into the post and whatever does cant cause any severe damage. Id remove the post after riding and dry off any moisture.

Final comment I agree with others is getting a proper sized bicycle for your grand daughter..

verktyg 

I picked up this 1987 Centurion Ironman cheap a long time back. It had been abused hard by a triathlete and put away wet - many times. Truly a poor design and Dave Scott SHOULD have known better than to use a fluted seatpost in a purpose built tri-bike!

The seatpost was beyond stuck! I cut the top off and went after it with a jab saw and a folding buck saw. About 3 hours work to cut out the seatpost, ream and hone the seat tube.



You can see how much room there was for water to get into the seat tube. The BB was rust city too!






After I cut through the seatpost all the way to the bottom, I had to use 20" Channel Lock pliers to crush the post enough to break away from the seat tube.



It's a good thing Tange # 1 has a double butted seat tube that's 0.9mm thick at the top rather than a single butted tube 0.6mm thick.

I went through everything else on the bike and it turned out to be a nice beater.



I always clean out the old gunk and hone the insides of seat tubes and steerers. When I assemble them I spread a big glop of grease inside the seat tube and steerer as well and coat the seatpost and stem too.

NO EXCUSES FOR STUCK SEATPOSTS AND STEMS!

verktyg

jyl

KraneXL

To tell you the truth she's 8, so she's just going through a phase and is unlikely to continue for long: she doesn't know what she likes. Rather than getting too involved at this point, better to just make the best of it while it lasts.

I first learned how to ride and subsequently got into cycling because I ended up riding my big sister's bike that she dumped after just 1 year.

One more thing, yes, I know. There are always exceptions.

The Golden Boy 

If the rule of thumb is to have a 'handful of seatpost' exposed, I see an awful lot of seat posts that have fluting that extends farther south than what a 'handful' would be. By contrast, most aero seat posts do not have the milled portion extending that far south to go into the seat tube.

I'd imagine the amount of weight relieved from the seatpost would be minimal, at best. I seem to recall the weight difference of different drilliumed items compared to stock pieces and came to the conclusion that it's to make it look pretty. Nothing wrong with that.

I have several (OK, 2) SP-KC seat posts in use right now. I fill up the little "ruler" with grease and squeeze in a little grease at the top.

tiger1964 

As someone who just got a seat post out that was stuck for 40+ years, I'd like to avoid experiencing it again and I have "new" post coming, and wondered if -- instead of grease -- anyone has tried a little anti-seize compound. I presume it might prevent any dissimilar-metals reaction but not act as a lubricant and thus a slipping post.

Kontact 

You and @texaspandj are right, I was wrong. I was only thinking of the kinds of posts that have the light flutes around the top 2" or so, not the kind with the measuring slots.

I don't know if flutes are actually any more of a problem for corrosion than a round post because a certain amount of it is galvanic.

randyjawa 

Perhaps the worst and ugliest vintage road bike seat post ever made, in my (sometimes not so humble) opinion..!

3alarmer 

...yes. I use an anti-seize for this application. I don't mention it on teh BF any more, because it always seems to generate controversy.
I'm uncertain why. It works well, and is relatively inexpensive.

There are different compounds for different applications, but a copper/zinc general purpose one seems to work well for aluminum alloy/steel interface.

If you have a plastic bike or post, go with something different.

Kontact 

Seems like a wonderful design if you are going to frequently remove and regrease your post, as it has the handy height marks. Not so much if you aren't going to do that.