What do I do next? Please help 😀

That’s an excuse to get some ti replacements from Uberbike

http://www.screwfix.com/p/hilka-pro-craft-stud-extractor-set-8-pieces/20084

Are all 4 rounded? if not you could try tightening the good ones up to relieve pressure on the rounded one(s).
And don’t be so ham-fisted next time…

Can you tighten one up to loosen the other?

disposable slightly over size torx bit hammered in would be my first port of call.

disposable slightly over size torx bit hammered in would be my first port of call.

This

Its stem bolts so they shouldn’t be massively tight in the first place.

If they are 4mm hex bolts then T-25 torx should be tight enough to get them loose

I admittedly do over tighten stuff but the move to smaller bolts on Thomson stems must make this more likely and I have done exactly the same.
I cut a slot into the head and then undid with a screwdriver

Think the logic is that the head will round off before it is tight enough to do any damage to carbon steerer/bar.

That’s an excuse to get some ti replacements from Uberbike

I actually took this as an excuse to purchase a whole new bike. Not even joking, the headset came loose and I went to tighten it and then realised the stem bolts had rounded. My lbs is an evans so had a chat with them, came away unimpressed and just ordered a new bike. Now need to strip this one to sell it. In my defense though I was considering a change, I took this as a sign. I will have a look at the torx route and then if not I’ll try cutting into the bolt and using ascrewdriver, thanks all.

“I admittedly do over tighten stuff but the move to smaller bolts on Thomson stems must make this more likely and I have done exactly the same.
I cut a slot into the head and then undid with a screwdriver

Think the logic is that the head will round off before it is tight enough to do any damage to carbon steerer/bar.”

NO NO NO AND NO

if your rounding bolts your just being a hamfisted oaf. theres no other reason especially on a thomson.

Nice bike buying logic.

If the stem in question is 50mm I’ll give you a tenner for it as is.

How the Christ do you round off bolts on a stem ? That’s just mental.

if your rounding bolts your just being a hamfisted oaf. theres no other reason especially on a thomson.

There is a reason on a Thomson due to the very small bolts they use (they are around 3mm aren’t they? That is very small for a stem bolt and many stems use 5mm bolts)

I have NEVER rounded an allen bolt other then the new Thomson bolts so although I like things tight I know when to stop.

If the question is “Aargh I’ve rounded off these bolts what do I do” the answer is basically never “get some extractors”. Because anyone that’s rounded off a stem bolt is going to end up with holes drilled everywhere but the bolt, and then with a snapped extractor in the bolt.

Hammer in a torq, you probably only need to shift the bolts on one side this way, once they’re loose the rest should come more easily. Penetrating oil everywhere, obviously.

Thomson, you can probably find a replacement faceplate easily because of their consumable faceplate bullshit, so if in doubt, I’d sacrifice that over the other bits but it shouldn’t be necessary

By not inserting the Allen key sufficiently deep – probably due to crud in the hole

Not by overtightening I’d hope

your just being a hamfisted oaf

This so applies to me.

more than 6nm it would seem.

I guess thomson specify 4nm torque value.

I carefully torque everything around my bars and stem and I’ve only rounded off Thompson bolts which I don’t believe are the toughest out there. I tried cutting a slot in them and hammering in a Torx but eventually drilled the heads off (v. carefully).
Get the Uberbike ones.