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Layback seat posts


timepoor's picture

By timepoor - Posted on 16 November 2011

NB: Originally posted elsewhere on the Global Riders Network and appears via syndication.

I have a hard tail Giant XTC1 2010 medium, being 5 11" and 80Kgs I am at its hight max

I'm more than comfortable on the bike but ride with the seat adjusted as far back on the original post as it will go. often if i come down hard on the seat it will tilt back, which is not helpfull .

Question would a new seat post like a layback seat post help ? I.E Thomson Elite 16mm set back or simmilar.
Yes i could go a slightly larger frame however i'd like to give this bike another year yet befor upgrading

[Mod. moved to MTB gear]

Mamil's picture

Hi Darranthebear,

I too have an XTC, but a different model. But mine, and yours too if the Giant specs here http://www.giant-bicycles.com/en-au/bikes/model/... are right, already has a set back seatpost. It achieves it in a slightly different way by the clamp being offset from the tube, rather than a bend in the tube itself likle the Thompson Elite, but it has the same result. In fact I just measured mine and the offset is 16mm, exactly the same as the Thompson Elite.

Now, there are setback seatposts out there that have more than 16mm offset, but even then you'll only gain a few mm at best, as you're already starting at 16mm.

So, I'm sorry, I think the answer to your question is - no, you won't gain much by getting a new layback seatpost, except maybe the clamp will be better quality and won't keep tilting Smiling

If you really don't want to go to a larger frame yet, maybe a longer stem would allow you to stretch out a bit more?

loud's picture

I have a thompson layback seatpost for sale. North Perth. PM me if you are interested.

timepoor's picture

Thanks, yeah thought as much,was a little unsure where to measure the offset from.

Maybe will try loclite on the clamp, see how it goes

Gepro's picture

Mate, I reckon the problem is with the seatpost itself - it shouldn't be tilting like that....i'm thinking your XTC has a giant branded seatpost named ''contact'' series. They are crap seatposts!....When I bought my Giant Trance in'10, within weeks the seatpost was tilting even when tightened fully.I purchased the same post again (thinking the first one was just a dodgy 'one off') but the new seatpost was just as useless. I then bought a Thomson seatpost and have had NO issues since. I too have a Thomson layback post for sale if u want....30.9mm diameter and 410mm long....$40 (worth $100+)

bergrad's picture

Gepro, I'll take that seat post off your hands for my new Trance. Cheers & I'll send you an email....

Mamil's picture

Most clamps, and certainly the Giant Connect ones they use on the XTC line, work by having a concave cup on the seatpost with a lot of small ridges, which mates against the convex surface of the clamp, also with lots of small ridges. You adjust by losening the clamp bolt enough to move the two ridged surfaces against each other, then clamp it down to hold it. Sorry if you know all this already - its always difficult on a forum to guage what level to pitch advice at!

First thing to try is wind the seat clamp bolt up real tight, but if you've already had the seat tilt on you under use, then odds are these ridges have been worn smooth, and there's not much you can do to recover the situation. You could try something sticky like carbo grip to stop the surfaces moving against each other, hadn't thought of loctite but that may work too! Alternatively, you can try re-cutting the grooves with a hacksaw or similar.

Edit: Or as above - just accept the Giant seatposts aren't very good and buy a better one!

To measure your current offset, and see whether a different seat post would give you more offset - measure the horizontal distance from the centre of the seat post, to the centre of the seat clamp bolt. On an 'in-line' seat post this will be zero, on yours it will be about 16mm.

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