Lengthening a cycle saddle tube?

[T i m]

Hi All,

I have a folding cycle for the odd local trip and to be able to pop it in the boot when such would be handy at the 'other end' of a journey but the saddle height is a bit low even at it's highest setting (to the 'Upper limit' mark). My other bikes are the right size for me (I'm

6'2") so am used to and enjoy what is 'right' for proper cycling.

The existing saddle tube is steel, approx 34mm o/d with what looks like a ~1.5 > 2mm thick wall [1]. The top is tapered of course to fit into the traditional basic saddle fitting.

I feel I could do with another couple of inches and have considered the following choices so far (not in any order).

1) Cut the existing tube off at the top and turn (Myford ML10) a new alloy top to convert from the internal diameter of the existing tube to the saddle clamp size. The alloy 'extension / adaptor' would be chemically bonded into the existing tube and have enough penetration into the existing tube to give reasonable strength (I'd turn a shoulder on the fitting so it wouldn't want to slip down etc).

2) Get a couple of replacement saddle tubes, cut them appropriately, make / find an appropriate internal sleeve and braise (/MIG?) them together (towards the top where there would be less stress / bending moment?).

3) Find a length of suitable gauge 34mm o/d steel tube and turn an adaptor to accept the saddle clamp?

4) Try and find some similar gauge tube (or an existing saddle tube) with a good fit inside the existing tube [2] and make a 'telescoping' extension (I could even braise the extension tube in place making it 'non-telescoping' as such as I can always remove the entire saddle post for stowage).

5) Other? (and no I don't want my legs shortened thanks) ;-)

All the best ..

T i m

p.s. I had though of just lengthening the peg that goes up into the saddle clamp with a turned steel part that is brazed into the existing saddle tube but I question the strength of doing it that way? Do they make an bolt-on extension that works similarly, eg. bolting over the top and providing a new, higher saddle clamp position (though that doesn't sound a very nice solution)? ;-(

[1] I haven't measured it exactly yet as the ends are 'rolled' a bit. [2] I think I can feel a tiny seam up the inside of the existing tube but it's not big enough to interfere with a suitable fitting tube going inside it.

[T i m]

Or should I have called it the 'seat post' ... not played with cycles for a while now .. ;-(

All the best ..

T i m

[petercharlesfagg]

Tim, I have ridden bicycles since I was 11, am now 60, in my experience longer saddle posts are available from the majority of specialist bicycle shops.

Halfords and the like are usually a waste of time and effort.

Nearly all my bits & pieces I purchase online these days, I will do some searching and come back to you.

Regards, Peter.

[T i m]

Ah, ok. Not sure we still have anything like that round her any more (apart from ultra light stuff that is).

Ok ..

Well thank you for your time in advance Peter ;-)

I had Googled about a bit but after writing my request here I have searched some more and see the likes of Dahon do a 'long' seat post of what could be the right diameter "for riders up to 6'4" " but they are only 20mm longer than the one I have already (which is 560mm).

don't *mind* the suspension bit but then might also need a new saddle (rails rather than clamp?) and this was supposed to be a low cost project .. ;-(

All the best ..

T i m

[petercharlesfagg]

Tim, may I suggest:

(Std)&ParentID=8&subcat=15I realise that these posts are for unicycles but feel sure they can be modified to fit, they will give you the length you need!

one might fulfil your requirements for something realatively cheap and it comes complete with some light fittings.

Anyway, I shall try again to widen the search.

Regards, Peter.

[T i m]

Now there's a bit of lateral (or should it be 'vertical') thinking ;-)

I note that they are all considerably thinner than the one on this folder of mine (25mm > 34mm, I guess because there are no lower torsional loads on a unicycle?). The link might be handy though as I had to cut some off our daughters unicycle when we first got it and would probably too short if she went back to it now ;-)

Unless you meant to link to this:

. as it was one of the things I thought could exist but had never seen?

Again, not sure how well it would work on a conventional cycle (the load being generally along the axis of the seat post on a unicycle)?

Since first posting I measured the existing tube and its 560mm long. This seems *much* longer than most conventional seat tubes. ;-(

You are very kind ..

All the best ..

T i m

[Pete C]

.>Well thank you for your time in advance Peter ;-)

34.9 x 640 here:

so they must be around...

Or try a search under the imperial equivalent of 1.375" eg:

cheers, Pete.

[Ian Stirling]

In the best traditions of thread drift, I raise:

is utterly useless for solving the original problem, but is sort of related to unicycles.

[T i m]

And interesting to boot ;-)

Cheers ..

T i m

[T i m]

That's posh, double butted seat posts ;-)

Thanks for those ..

All the best ..

T i m