OK, so i’ve got a nice new bike (nearly 1k’s worth) and the seatpost is *very* loose in the frame. There’s about 1mm gap, and it can be waggled backwards/forwards left/right. Its like the frame has the wrong size seattube.

I’ve tried three different seatposts, all 27.2, and its the same with all of them. They work fine in another frame.

It needs lots of tension on the clamp to get the seatpost to stay still, and the clamp is bottoming out.

I’ve got several spare seatpost clamps, but i can’t get them onto the frame because the seattube is too big!

I’m yet to complain… but what are the options? Is this likely to lead to a cracked frame? i’m not sure the gap is big enough for a shim all the way around, but would this be acceptable if so??

Contemplating asking for a refund….

refund or replace. Quickly!

I’d be back to shop. Sounds like it’s got the wrong sized seat post. Next size up would 30.9 but if you’ve only got a mm doesn’t sound like it would fit.
My guess is that it either needs a seat post with a non standard size. But I doubt it as they aren’t common these days. Or the frame has been damaged. Possibly by a spanner monkey with a seat tube reamer.

Have you tried pushing the seat post down a good 100mm to see if it gets tighter further down the tube?
What bike out of interest? If all else fails a shim made from a coke can should work. But not something you want to do on a new bike really.

And yes it is likely to lead to a cracked frame. If the seat post is only supported by the seat clamp you will get flexing around the point where seat tube meets seat stays and or top tube.

Probably worse in an aluminium frame but you don’t want it in a steel frame either.

Next size up would 30.9

No, next size up would be 27.3mm

Take it back, it shouldn’t do that.

Just get the shop to look at it and sort it out.
But soon.
If all else fails you can get 27.4 posts

Yeah, i’ll get it back to the shop, but i fear they’ll just say “its fine”.

Here’s the gap in the new frame

Here’s the gap in the bike its replacing (Revolution Courier)

Both with the seatclamp loosened right off. I swapped the seatposts etc.. the new bike always has a gap. I’ll see what they say….

It’s so obviously not right there can be no objection. What size seatpost is the bike supposed to come with? Have you looked at the frame spec? Do you know anyone with some verniers who could measure it? (If you’re in Cheltenham I could). A seat tube shouldn’t be anymore than a 0.1mm out on diameter really and if that post is the intended size that’s FUBARed.

send it back to the shop and get them to sort it out.
by the way i looked at the first picture and was surprised to see a lot of scuff marks on the seatpost clamp…be careful that the shop doesnt try to use this as evidence and blames you for causing damage to the frame

Makes you wonder who did the PDI on that?…..clearly not right.

What’s the frame / bike?

Should be simple enough to look up the seatpost size for it. Almost certainly they’ve just put the wrong size post in.

Back to the shop. Simple swap over to correct seatpost.

I’ve got several spare seatpost clamps, but i can’t get them onto the frame because the seattube is too big!

Yep, seat tube is just a bigger size, hence bigger post required and bigger clamp. The one it came with obviously fits.

So did you buy the complete bike, or just the frame?

If the complete bike, then take it back to the shop with the original seatpost it came with and get them to sort it out. It shouldn’t have even been handed over to you with a seatpost that can’t be clamped tight.
Was it built-up when you picked it up, or did you buy it still boxed up? Weird that this wasn’t noticed before leaving the shop if it was a complete built-up bike.

If you just bought the frame are you sure it’s a 27.2mm seat tube?

stumpy01 – Member
If you just bought the frame are you sure it’s a 27.2mm seat tube?

It clearly isn’t if none of the other posts fit and the other seat clamps don’t fit either.

deadkenny – Member

It clearly isn’t if none of the other posts fit and the other seat clamps don’t fit either.

What I mean is; is the frame SUPPOSED to accept a 27.2mm seat tube?
Perhaps the OP is trying to put a 27.2mm post into a tube that is designed to be bigger, so it’s not really an issue once the correct seatpost is used – which the shop should be able to supply?
Dunno? Just a thought? The OP hasn’t said what bike it is, so a bit hard to look it up.
But from the photo, the gap looks to be more that just manufacturing tolerance, hence me querying whether the seat tube was 27.2.

Should be simple enough to look up the seatpost size for it. Almost certainly they’ve just put the wrong size post in.

I disagree, unless we’re talking a custom build how/why would a shop put the wrong seatpost in? There aren’t any really common sizes these days between 27.2 and 30.9, and you’d sure as hell notice if you stuck a 27.2 post in a 30.9 frame!

I’ve never seen a shop absent mindedly stick the wrong seatpost in.

It was a complete bike but an ex-demo hence the scuffs. I’d rather not say what bike it is until its all sorted tho! The existing seatpost clamp has to be stretched quite a bit to fit over the seat tube.

The frame and seatpost are the same “in house” brand, so clearly designed to work together.

I think the frames been built with the wrong size seat tube. I doubt they’d have them manufactured with an obscure 27.9 size or something. Makes no sense?

njee20 – Member
I’ve never seen a shop absent mindedly stick the wrong seatpost in.

Depends on the shop. I’m sure Halfords would 😉

And if the bike is supplied to the shop mostly pre-built for a monkey to just slot the supplied seatpost in, they may just have assumed it must be the right size. Or if the OP was supplied it in box to do the same then no one would have checked the seatpost and first you know about it is when the OP puts the post in the frame. Either way, back to the shop and get the right post.

I can’t see it to be a manufacturing defect. Wrong tube size would require fundamental change of manufacturer tooling / set up. They’d have been churning out a few at the wrong size and would soon find out the problem. And no QA to spot it?

If it’s ex-demo, is there a chance they were running it with a shim and the shim has gone missing (or dropped into the frame)?

Ex-demo as in one that’s actually been ridden, or just one that people ride around the shop car park?

There’s a chance it should have a shim yes, though to me the gap looks too small to be designed for a shim (though that might work as a fix). Unless its bodged with a bit of coke can, i’d imagine it’ll need shimming down to a 25.4 or something.

I’ll get a shop to measure the size more accurately.

Its definitely going back, but the shops already been quite unhelpful so need to be armed with some information.

I’ll get a shop to measure the size more accurately.

Just go down Halfords or any other tool supplier and buy a set of calipers (£5). This will tell you the ACTUAL size of both the seatpost and tube.

My vote would be for some sort of damage along the way, demo bikes often get a hard life. Really can’t see someone putting the wrong post in, nor that it’s been manufactured the wrong size.

I can’t see a small increase to a 27.4mm is going to fit with that gap. And you wouldn’t shim it down to 25.4mm as that would only fit a 25.4 post.

Have you tried a 30.9 post in there? Also Gary Fisher (used to?) use 30.6 I think. If you don’t have vernier calipers at least stick a ruler over it to see what it says. Remove the seat clamp first as if its tight it may be closing up the frame even when undone. Even without a seat clamp the correct post shouldn’t really have any noticeable ‘wobble’ in it when inserted.

As its a demo some monkey may have swapped out the post without paying attention. The fact the frame and post are the same brand doesn’t mean they are the same size at all.

What make is the bike? (links dont work for me)

Not very common, but frames do occasionally get manufactured oversize, we had a small batch through last year. Said manufacturer supplied us with shims that weren’t much thicker than tinfoil (and looked about as durable), that were binned upon sight, and replaced with correct sized posts of decent quality from a local distibutor.

Yeah, i’ll get it back to the shop, but i fear they’ll just say “its fine”.

Why would they?!?! It’s not fine, they’ll see that, and rectify it. They have to, and they will know that.

If they say “it’s fine” then don’t come back here moaning. Grow a pair and tell them it isn’t and you want it sorting or a refund 🙄

So what happened? Was it damaged or supplied with wrong post?

Just remembered this after seeing the Evans Cycles thread…

I took it back and got a refund. Told them about the seatpost issue, but they just asked if i’d done up the seatclamp (they’d already taken the bike away for inspection). Before i noticed the seatpost thing, i asked them to look at the rear brake as it pulled to the handlebar. I assumed they’d just bleed it, but they refused. They wound out the reach adjuster and said “its not un-rideable”, and said if i wanted it bled its 35 pounds (!).

This was Evans Cycles btw. Bike was a Hoy Shizuoka.

I looked at several others in the store, several seemed to have the same issue. Road.cc have a review in which they state the seatpost is loose … http://road.cc/content/review/97861-hoy-shizuoka-city-bike