I don’t know weather to laugh or cry.
3mm bolts on the steerer clamp were stuck fast.
Twisted every 3mm hex key I own, I own a lot!
Snapped hammered in torques heads.
Ruined 5 drill bits trying to drill the bolts out.
Knackered junior hacksaw blade and the multi-tool blade.
Eventually one bolt cut through by hammering a flat blade screwdriver into it was enough to slip of the top of the steerer!
And I thought ‘Pfffft, that’ll never hold!’ The first time I put it on.
I will buy another one…
And a torq wrench…
5.1 Nm

I would have tried undoing it with an impact driver/allen socket that would have either undone the screws or sheared the heads off.
Carbonium drill bits are awesome too.

What size stem is it BigAd?

Steel bolt in to alloy. Buy some copper slip as well.

Hate those 3mm bolts. Can’t stop one of mine turning with long bars on

3mm seems a bit weedy for a steerer clamp. Never had a Thomson stem.

The clamping method is very different to most stems. the bolts do not need to be done up tight at all

I like Thomson stems but the 3mm bolts are useless. I just replace them with Ti bolts with 4mm heads and problem solved.

Once the bolt head was round nothing will get out.
65mm 31.8bar 1inch1/8th steerer.

Tjagain- in what way? x4 just a pair of bolts on the same side

The old stem design with the wedge hasn’t been made for years

sorry simons – I assumed ( 😳 ) the wedge type

3mm seems a bit weedy for a steerer clamp

I’ve seen them on another brand of stem (Richey..?) and they’re crap. Wouldn’t touch them with a barge pole.
2 x M4 for the clamp
4 x M4 for the faceplate.
Perfect. That’s all you need.

65mm 31.8bar 1inch1/8th steerer.[/quote

Ok. I had all 90mm doing nothing, but that is way longer.

Never had any issues with Thompson stems or the bolts. Best stem’s on the market IMO.

Most of you seem to think you know better than Thomson about bolts ?

They use a very high grade of steel in their bolts – much tougher than titanium.

The 3mm hex socket is perfectly acceptable for a bolt with a max torque setting of 6Nm. Just make sure you use quality allen keys, not the type with rounded ends.

Just need a tiny amount of grease and the correct torque.

Not the best on market by a long shot

But never had an issue with their bolts…..other tha. Sorting out other hamfisted peoples mistakes with them 🙂

3mm seems a bit weedy for a steerer clamp
I’ve seen them on another brand of stem (Richey..?) and they’re crap. Wouldn’t touch them with a barge pole.
2 x M4 for the clamp
4 x M4 for the faceplate.
Perfect. That’s all you need.

Really? M4 bolts won’t manage much clamping.

Oh and DiscJockey is correct

coppaslip not grease

is this an m3 bolt or a 3mm hex? M3 bolts are tiny.

M5 bolts are the usual ones occasionally M6 in stem clamps

PP do you really mean M4? bolts are measured on the shank diameter not the hex head size are they not?

They’re M5 bolts but Thomson changed from a 4mm hex head to a 3mm hex head a few years back as they had too many instances of people breaking stems by way over-tightening the 4mm hex headed bolts. Changing to a 3mm hex head reduces the likelihood of this happening

Poddy was just plain wrong

I bent a Thomson seat post, true story!
I replaced it with another Thomson.
The steel 3mm bolts are unbelievably tough! They will ruin cheap hex wrenches before they round off.
I will probably replace it with another Thomson stem.
Coppaslip and a torque wrench (recommendations please) as well.

I agree TJagain.

Low strength loctite or a copper grease to help prevent them bonding over time is a sensible step when installing. If siezed penetrating oil and a freeze spray and then boiling water can work miracles.

Matthew_h is spot on.

M5 “button head” on the latest versions.

^^^^^ button head….! Really? Button heads are crap because the hex head is so shallow…a lot of hex keys are slightly tapered/chamfered at the end and any type of shallow head fastener means you run the risk of rounding them unless you are really careful…..if they are using button heads to reduce the hex size (to prevent over-tightening) it sounds like they are trying to solve one problem, but are creating another…

Interesting because my bondhaus and wera hex keys are not chamfered at the end.

I wouldn’t use any that were for the reasons you describe.

I know your pain.

This reminds me. I picked up a Topeak torque wrench attachment with bits for £13. It only does 1 setting but seems ok for the price.

It always cracks me up how people will use £10 of tools on a £2k bike?? (I am a vehicle tech though with upwards of £18k invested in Snap-On etc) You really do get what you pay for in tools. Buy cheap, Buy twice or thrice etc… You tend to take better care of something you have paid sensible money for. No1 tool to buy? A decent tongue wrench (Norbar etc) Nothing grinds my gears like seeing someone use a a tool that wasn’t designed for that puprpose (Screwdriver as a chisel etc) Makes my blood boil! 😆

A decent tongue wrench

Oink1 at work yesterday…

Do park make those 🙂

There is a Topeak Combo Torq Wrench one that is about £12 and does 3-13Nm.

I really don’t understand why people would want to do their stems up so tight in the first place, I prefer my stem to rotate round when I crash. Same with brake levers.

I prefer my stem to rotate round when I crash.

Try the factory torque settings and maybe you wont crash so much 🙂

Try the factory torque settings and maybe you wont crash so much

The truth is I rarely crash nowadays, but I formed habits from the days I used to crash with reasonable frequency and stems didn’t have torque specs printed on them back then.
Stem steerer bolts have to be very loose to risk the handlebars rotating round while riding or un-pre-load the headset.
IMHO stem steerer bolts, brake lever bolts, are something that anybody with a modicum of thread sense can do by feel – as it is just a case of taking up the slack followed by 1/8th turn or so of elastic tightening. Torque wrenches are useful for stem handlebar bolts, bolts clamping carbon parts, etc which are harder to gauge by feel.

Trail-rat please enlighten me..what do you use stem wise? Genuinely can’t fault Thompson posts and stems apart from 50mm is the shortest they do.