Titanium seatpost that is all titanium

[Cyril Haearn]

Does a seatpost fail, snap suddenly, or does it warn one first?

[Lance Dopestrong]

Metal seatposts will usually give a warning. However, seeing as most riders don't closely examine their seats posts prior to each ride the failures is "sudden" with respect to the riders awareness of it.

[Gattonero]

I wonder where one could buy a nice two bolt seatpost head to bond into a suitable tube?

Do you think you can do better than a manufacturer, and especially to have a guarantee for this?
Getting something from a reputable brand gets your bum covered (pun intended)

[drossall]

Posts always have a minimum insertion mark, to reduce the possibility of bending, yes?

Just to pick this point up, the issue with inserting less than the minimum is generally the load on the frame and clamp, rather than bending the seatpost (which I think is unlikely). You can damage the frame that way, although I can't imagine it doing the post much good either. In extremis, of course, the post might come loose.

[alexnharvey]

I wonder where one could buy a nice two bolt seatpost head to bond into a suitable tube?

Do you think you can do better than a manufacturer, and especially to have a guarantee for this?
Getting something from a reputable brand gets your bum covered (pun intended)

No, I do not necessarily think I can do it better than a specialist although it's not impossible. Having had plenty of experience of repairing and rebuilding composite boats and building new rudders I'm quite happy that I can do it adequately though.

My interest is in making a stainless seatpost, just for fun.

[mikeymo]

I wonder where one could buy a nice two bolt seatpost head to bond into a suitable tube?

Do you think you can do better than a manufacturer, and especially to have a guarantee for this?
Getting something from a reputable brand gets your bum covered (pun intended)

No, I do not necessarily think I can do it better than a specialist although it's not impossible. Having had plenty of experience of repairing and rebuilding composite boats and building new rudders I'm quite happy that I can do it adequately though.

My interest is in making a stainless seatpost, just for fun.

Isn't stainless steel brittle, relative to other steels?

[mikeymo]

The Campagnolo Ti posts pop up on eBay now and again but they do tend to command a price premium. Probably about the same as the JL above, but Campagnolo quality..

Thanks. I would like to avoid anything used. I'd like to know the provenance of anything I'm going to use. Maybe I'm being silly, but it's my decision because it's my life.

I'll probably get the USE Sumo.

[Brucey]

Do you think you can do better than a manufacturer, and especially to have a guarantee for this?
Getting something from a reputable brand gets your bum covered (pun intended)

No, I do not necessarily think I can do it better than a specialist although it's not impossible. Having had plenty of experience of repairing and rebuilding composite boats and building new rudders I'm quite happy that I can do it adequately though.

My interest is in making a stainless seatpost, just for fun.

Isn't stainless steel brittle, relative to other steels?

It is tempting to assume that any steel that isn't going rusty is stainless steel and that all stainless steels are the same. However in fact there are hundreds of different stainless steel grades, just like there are hundreds of non-stainless steel grades. They vary in their mechanical properites. However only a subset of all stainless steels will be available in thin-walled tube form, and that will limit options for making a seat pin.

FWIW you can buy quill stems with a stainless steel vertical section; they can still get seized.

cheers

[mikeymo]

There are a few rusty bolts on my bikes, so I can see the point of titanium/SS there maybe. But otherwise I can't really see the point of stainless on something like a pedal cycle. I built my current bike up from scratch, so gave the inside of the frame a very thorough treatment with Dinitrol. The beauty of a bike is that it's a machine that can be completely disassembled and re-assembled, and pretty much every component can be replaced, and/or is accessible for protection. And there aren't hundreds of parts, so nothing takes a million years.

Grease is a wonderful thing.

[alexnharvey]

KVA could supply some of their MS2 stainless bike tubing in the appropriate diameter, or I'd use some 17-4 precipitation hardening tubing if I could find it in the right diameter. I think Reynolds have also supplied stainless tubing for 18bikes when they previously made some seatpost.

[zenitb]

Does a seatpost fail, snap suddenly, or does it warn one first?

Mine started to "recline" and then just fell away.

I was cycling up a 1 in 4 hill at the time, in the saddle, and as the saddle reclined i just took up the load on my legs, pedalled for a while standing up, and then stopped normally, thinking the saddle had slipped.

The "reclining" / dropping away process took around a second I guess but that was long enough for me to react and stay on the bike..helped by my slow speed uphill maybe?

Cycling uphill in the saddle must have put max leverage on the seatpost fulcrum point. The gradiant of the hill (1 in 4) got ADDED to the 71 degree seat tube angle which got multiplied by the long seatpost extension (12"?) to create max torque on the fulcrum. Then there is the 25 odd years i have had the alloy post to consider - including several big "offs" - probably a "worst case" situation for the post!!!

Did everyone else's seat post failures occur pedalling uphill???

[mikeymo]

Does a seatpost fail, snap suddenly, or does it warn one first?

Mine started to "recline" and then just fell away.

I was cycling up a 1 in 4 hill at the time, in the saddle, and as the saddle reclined i just took up the load on my legs, pedalled for a while standing up, and then stopped normally, thinking the saddle had slipped.

The "reclining" / dropping away process took around a second I guess but that was long enough for me to react and stay on the bike..helped by my slow speed uphill maybe?

Cycling uphill in the saddle must have put max leverage on the seatpost fulcrum point. The gradiant of the hill (1 in 4) got ADDED to the 71 degree seat tube angle which got multiplied by the long seatpost extension (12"?) to create max torque on the fulcrum. Then there is the 25 odd years i have had the alloy post to consider - including several big "offs" - probably a "worst case" situation for the post!!!

Did everyone else's seat post failures occur pedalling uphill???

Interesting, thanks for posting that.

It's a shame there can't be some sort of systematic investigation and analysis of bike component failure and accidents, like there is in the airline industry. As it is all we have are individual experience and anecdotes.

My current (aluminium) seat post has far less above the clamp than your broken one. The titanium one I'm (probably) going to buy is 350mm. Of which 120mm would be showing.

But if I go for aluminium, I'd get a similarly long one, and replace it periodically. Certainly sooner than 25 years!

[zenitb]

Interesting, thanks for posting that.

......

But if I go for aluminum, I'd get a similarly long one, and replace it periodically. Certainly sooner than 25 years!

Fair point about me not replacing the seatpost in 25 years Mikey. maybe I was a bit asleep at the pump on that !! Its actually got me wondering about the Aluminum frame of the bike itself .. that is now 26 years old and I am loading it up more than ever. (I got that long gusset replacement seatpost - shown below - partially to reinforce the seat tube / seat stay joint since I was worried that would fail next). Ok Cannondale talk about a "lifetime frame guarantee" and this was a genuine "made in the USA" frame but even so there comes a time when maybe its time to move on ...

[pq]

I haven't bothered to read this thread, but a few points.

I have the Moots post on my expedition tourer. It is very very strong and well made and the clamp is Ti. It is incredibly difficult to fit the saddle though. I think they do a more recent version which addresses that.

I also have an old Campag Ti post. It's now worth a fortune and although I've been using it for not far shy of 30 years with no problems, it has a bonded alu head so I doubt it's any stronger than an alu post. Brucey mentioned the prices. Mine is a Record which is incredibly rare and worth a small fortune. However the same post was later sold as a chorus and is much less rare and therefore cheaper.

In your shoes, assuming you don't want to pay a small fortune for a seatpin, just get a Thompson. They are alu but totally, totally reliable and in my view the best on the market.

[NickJP]

Pretty difficult to beat the Nitto frog (AKA S83) seatpost. Beautifully made and has an easy to adjust two bolt clamp. Planet-X are selling them at the moment: https://www.planetx.co.uk/i/q/SPNIS83/nitto-s83-aluminium-seatpost. I have these on a couple of bikes and they've seen a lot of miles.



Nitto also make the S84 extra setback seatpost in lugged CrMo with the same design of clamp: https://www.planetx.co.uk/i/q/SPNIN84/nitto-s84-crmo-seatpost