[Closed] How much should seatposts bend in use?

I'm about 17 stone and haven't noticed my thomson flexing or creaking. Quite a thin one as well (26.8mm) and its a good length out of the frame.

thomsons bend/flex aswell .mine does & im only 9st 6.
infact the fsa one on my other bike does too

See that thing that comes up quickly in front of you - trail, road or track - concentrate on that more. I have no idea if any of my kit flexes

_tom is your post used in a HT or FS?

It's in a hardtail.

ally or steel ? 😀

jimmyshand - Member

See that thing that comes up quickly in front of you - trail, road or track - concentrate on that more. I have no idea if any of my kit flexes

Post of the day!

Glad you liked it.

I didnt think ally was meant to bend much at all

I think you've been reading too much magazine type faux material-science rubbish. All metals flex. Seatposts flex plenty and are usually just fine. I really wouldn't worry about it unless it actually bends (and I've bent a lot of them).

Thomsons flex plenty too.

I'm puzzled as to how you would measure how much the seatpost flexes. As said above, most stuff flexes. If you are genuinely worried then check the post for stress marks. I had a Ritchey post that started creaking badly. When I checked it had quite a few marks down the front.

Hope this helps.

See that thing that comes up quickly in front of you - trail, road or track - concentrate on that more. I have no idea if any of my kit flexes

+1

If you really want to shit your pants, buy a carbon post hook your bike up to a turbo trainer and spend an hour marveling at the flex.

enfht - Member

I didnt think ally was meant to bend much at all

I shall use this on the BS of the week thread on Friday.

Does anyone know if the VCLS seatposts are available to buy?

I know they're fitted to Canyon & Cannondale complete bikes but I was looking for such a seatpost with no luck...

edit: by the way - the 34.9mm carbon post on my Scale doesn't seem to bend very much at all. Ouch.

IME;

Bontrager Posts - Light but extremely flexy but never broke.
FSA - V heavy, indestructable, slight flex.
Thomson - Light, slight flex but not as much as the FSA

Thomson - Light,

I shall also use this in the BS of the week thread.

See that thing that comes up quickly in front of you - trail, road or track - concentrate on that more. I have no idea if any of my kit flexes

Reminds me of the time when that strange grinding noise turned out to be I'd lost my back wheel. 😮

I know they're fitted to Cannondale complete bikes

Every Cannondale I've had over the past 6 years has come with an FSA post, Although looking at their website they now appear to be own brand or USE

[i]Reminds me of the time when that strange grinding noise turned out to be I'd lost my back wheel[/i]

Well, it does take a finely honed mechanical sense to determine that without having a quick glance to check.

To clarify, I believe my very flexy seatpost is creating some occasional creaking so I'm pondering on replacing with either a Thomson or Race Face Diablus post because I'm fed up fettling with carbon paste, different clamps etc.

Well, it does take a finely honed mechanical sense to determine that without having a quick glance to check.

Indeed

it coudl just be that the seat tube is slightly over/seatpost slightly under size.

Ragley do a 27.3 seatpost now for just such occasions.

Thomson - Light,

I shall also use this in the BS of the week thread.

In my experience they are. What's happened to this forum where you put your honest experiences and get shot down for your comments - at least substantiate your comment. I didn't realise the schools had broken up already?

Well said Keiran

Thanks wwaswas I hadn't thought of that

In my experience they are. What's happened to this forum where you put your honest experiences and get shot down for your comments - at least substantiate your comment. I didn't realise the schools had broken up already?

Lighten up, Thomson Posts for e.g 27.2 x 410mm is 290g whilst it's not super heavy it's at least 50g or so above anything I'd consider, their stems are porky as well.

FYI I left school 26 years ago.

If you are using a good quality post, then I don't think you need to worry about it snapping. However, creaking can be VERY frustrating.
Are you sure it's the post ?
From my experience it is usually either: the seatpost to seat-rail, seat-rail to seat, or seatpost to seat-tube interface.

Maybe try stripping, cleaning and refitting them all ?

Set back posts will (like for like) flex more too. I had an EA70, it flexed miles !
Using Thomson's on all of the bikes now. They do flex (it adds comfort) but they aren't going to snap !

(waits for some :-0 to say they snapped one !)

I bent one but it didn't snap 😉

Thomson is great kit, but it sure ain't light. Well engineered kit that lasts, yes. Lightweight, only in comparision to scaff bar.

People takes things awfully personally on here eh what?

Well engineered kit that lasts

The bolts on the seatposts aren't all that IMO.

Can't say I've ever had any issue with the bolts but then I don't reset my saddle every ride with a spirit level like you do KT...

I've had no problems with the bolts on my Thomson either, and I do tend to crank down quite hard on these sorts of things.

Can't say I've ever had any issue with the bolts but then I don't reset my saddle every ride with a spirit level like you do KT...

True, over faffing and crappy tools probably did for them.

The bolts on the seatposts aren't all that IMO.

Is that becuase you've over torqued them to deal with your fat ass?

I have had (counts quickly) 8 of them over the years, absolutely no issue. In fact I think thomson use some of the best fasteners I've ever had on bike kit, no corrosion issues, no binding, threads always run clean and true.

Is that becuase you've over torqued them to deal with your fat ass?

OMG TEH IRONING!!!!1111111111LOLLERCOPTERS.

FAOD FOAD

*puts on his pinny*

Potty mouth clubber [img] [/img]

Thomson posts have got the long axis of the internal ovalisation going across the bike.
Does this mean they are intended to flex fore and aft, but not sideways ?

I don't understand KT's last response...................

.... but find it really funny 🙂

Thanks, that's really made me chuckle 🙂

MilitantGraham - Member
Thomson posts have got the long axis of the internal ovalisation going across the bike.
Does this mean they are intended to flex fore and aft, but not sideways ?

They're thicker front to back to make them stronger/stiffer in that direction and thinner side to side where they don't need to be so strong/stiff.

Anybody bent an SDG I beam post?

No, they all got chucked in the bin after the owners had to have spinal corrective surgery.

😆 I'm lucky to still be walking then 😕

Are you still running one? I'm surprised you're not a parapelgic.

Heading towards the bin as we speak 😉