I’ve just noticed a crack under the seatclamp on my Chameleon, should I:

A) Keep riding it and hope for the best.
B) Retire the frame.
C) Try to find an aluminium frame repairer (Any suggestions?)

How much post do you run in the frame?

Could you get the frame cut at the crack and lower the seat collar? (not a professional opinion just a thought)

Plenty of post left in the frame, I did look at cutting it but the seatclamp would overlap the top of the tube.

I’d keep riding it.

If it failed completely you are unlikely to die, unless you have to ride 25 miles home with the saddle in the lowest position.

EDIT: cut it and put the slit at the back so the top tube not an issue?

would drilling 2 small holes at the end of the crack stop them spreading any further ?

I’d get it to a frame repairer. Maybe even put a gusset around it and place a new slot at the front.
Sorry, don’t know any specific repairers

Any decent fabrication shop that works alloy should be able to fix that. Hole drilled either end, weld and then probably need toream the tubbe to get it round again. Then fit a bolt up seat clamp around that area after filtering away the lip or get a proper deep clamp made

The stw favoured repairer….. http://www.argoscycles.com/
Google has more

How old is the frame?
If still under warranty take it back…..

You could also look at double height seat clamps that would go over the damaged area. Repair would be better though.

Looks like its had the wrong size post in there at some point and clamp tightened. I would probably cut the tube down.

It’s a 10 year old frame so well out of warranty, I think it’s just fatigue from the QR seatclamp.

I don’t think Argos do Aluminium repairs but did find this guy.

would drilling 2 small holes at the end of the crack stop them spreading any further ?

given that the cracks have originated from another small hole and the end of a crack, I suspect not 🙂

It could end up making a nice fractal pattern though.

You sure you’re post is the right size for the frame. A touch small perhaps? The crack are right where the stress concentrations would be if the post was too small/large and the circle was being compressed/expanded around its circumference.

The seatpost is definitely the correct size, I think it’s the constant seat dropping that’s caused fatigue.

This will fix it.

This will fix it.

I was going to use this:

but that looks far more professional 🙂

I think it’s the constant seat dropping that’s caused fatigue.

Why?

Why?

Constant undoing and tightening of QR. But I’m no expert, do you have a better explanation?

do you have a better explanation

the seatpost is slightly undersize or the seat tube slightly over – the top of the seat tube is beign compressed more than it’s designed too and causing stress at the bottom of the slot leading to a fatigure crack as you can see.

The seatpost is definitely the correct size, I think it’s the constant seat dropping that’s caused fatigue.

Time to buy a dropper post as well then!

the seatpost is slightly undersize or the seat tube slightly over – the top of the seat tube is beign compressed more than it’s designed too and causing stress at the bottom of the slot leading to a fatigure crack as you can see.

No, seatpost is the correct size, a nice tight fit.

a nice tight fit.

then you’re overtightening your QR 😉

then you’re overtightening your QR

Possibly, but any less tight and it slips.

Been surfing a porn site and without realising switched to STW and saw the title ‘is this crack fatal’ 😯

Could there be a tiny bit of a ‘lip’ on the lower part of the seat clamp, that’s biting into the seat tube – causing a ‘stress riser’?

No, seatpost is the correct size, a nice tight fit.

If it’s a perfect fit, tightening the clamp should generate naff-all stress there – even if you were a complete gorilla with the clamp and somehow compressing the tube through its thickness (grrrrr!), the hole should still see no signficiant stress.

Something else is going on here – my money’s still on undersized post 😉

27.2 Thomson post in a 27.2 seat tube, how exactly is that under size?

easily, as the seat tube slightly to big, and seatpost slightly to small (which can happen with Thomsons)

It is possible to buy a 27mm post – though they are not that common now and not sure Thompson ever made them in that size. Seen similar damage with people running 27mm seatposts in a 27.2mm frame and thinking 0.2mm would make no difference although you state that’s not the case here.

Face it OP, it’s your fault!

stw says so 🙄

I had one of the same era (and even the same colour) fail in the same way. Mine had an Easton EA70 post of the correct size.

I know of 2 others of the same era that failed there.

Perhaps no coincidence that the next versions had 34.9 seat-tubes for 30.9 posts rather than the 31.8 for 27.2 that was used on that version. Stronger, but less comfy!

27.2 Thomson post in a 27.2 seat tube, how exactly is that under size?

as richc says, tolerances. Ive just had to ream the BB of new ally frame as the threads were too shallow to take a BB, probably worn tooling and one of the last to come off the line before they changed cutters. Not “your fault” but a plausible and reasonable explanation given the evidence.

Face it OP, it’s your fault!

stw says so

I know it’s my fault, it’s always my fault 😉

@sillyoldman did you get the frame repaired, or retire it?

as richc says, tolerances. Ive just had to ream the BB of new ally frame as the threads were too shallow to take a BB, probably worn tooling and one of the last to come off the line before they changed cutters. Not “your fault” but a plausible and reasonable explanation given the evidence.

You couldn’t physically get a bigger seatpost in the frame, it’s just not possible. #floggingadeadhorse

You couldn’t physically get a bigger seatpost in the frame, it’s just not possible. #floggingadeadhorse

Alright then – everything is perfectly in tolerance, perfectly aligned and within tolerance. Hmm…. it must be pixies then…. yep, pixes, in the night, with tiny little pixie files, filing out those two cracks night after night, micron-by-micron. B@stard little creatures of the night they are……

+1 on Argos cycles.

We also used Prodrive (WRC rally guys) to fix an Ancilotti DH race bike once.

OOH get her! and her Hand bag!

Can it be fixed – yes. how much do you want spend?
A Argos repair and respray is going to cost you £100+
Slicing the top off and drilling a new slot – nowt.
Its your call, but i know what i’d do with a ten year old frame;-)

I had this on a Rocky Ridge and it was fine for a fair few years until I scrapped it. Didn’t really go much further than yours.

Plus some rattle can touch-up paint and it’ll be good as new!

Try one of these!