Normal for stem to rotate on steerer during crash?

Is it normal for the stem to twist on the steerer during a crash?

It’s happened to me 3 times lately and I’m starting to wonder whether it’s effect or cause.

Stem bolts are done up nice and tight.

far from abnormal. It’s a massive impact on what is quite a low torque on bolts.

I’d be asking myself more why i’ve crashed 3 times recently 😉

Stem bolts are done up nice and tight.

Doesn’t mean the stem is clamping the steerer though. What make/model is the stem? Do you tighten each bolt incrementally or one at a time? With the front wheel clamped between your legs, is it possible to rotate the bar?

I’d be asking myself more why i’ve crashed 3 times recently

This!

Depending on how hard the crash is, yes, perfectly normal. Having it move will cause less damage than having it cracked up rigid.

Big wide bars do act as a great lever 😉

Sounds like the steerer might have debonded from the crown. Happened to me after a heavy front end impact. Put the front wheel between your knees, turn bars and get someone to look and see from underneath if the steerer is rotating in the crown

Normal and expected. While the stem shouldn’t twist during normal riding (if so, the bolts aren’t tight enough) your expectation should be that it twists in a crash – thus saving more expensive bits from actually breaking.

Something has to give and ime if it’s happened once it’ll happen again with less effort.

Try crashing with a dual crown fork and a direct mount stem and see what happens 🙂

I’d rather some of the force from my inept crashing went into rotating the stem rather than shearing off various bits of metal/carbon fibre.

My rule with stems, leavers shifters is tight enough so they don’t move normally but move in a crash. Saves broken parts (maybe, sometimes)

Those fiddly little stem bolts are all well and good, but once you’ve got the position right there’s nowt stopping you drilling straight through stem and steerer and putting a nice big bolt through, with a nylock nut to be on the safe side. 😉

Or as davosaurusrex says, check it’s not the steerer tube rotating in the crown, undo the top cap and mark across steerer and stem with a sharpie, do the same at the bottom end with steerer and crown then clamp the fork legs as best you can and twist away.

Sounds like the steerer might have debonded from the crown

I’ve seen my fair share of wacky sh1t issues over the years but that’s a proper “Zebra!” conclusion to jump to. It is possible his steerer has de-bonded but it’s magnitudes more likely that it’s just the stem slipping. Still worth checking though…

Stems can slip for numerous reasons, greased interface, poor tolerance fits (stem or steerer), incorrect torque on bolts, $other clamping issue.

I’ve seen my fair share of wacky sh1t issues over the years but that’s a proper “Zebra!” conclusion to jump to

😆

Have we discounted the thought that it’s not the bike and actually the crash has caused mild concussion and his depth perception to be momentarily out of line? I suggest you go to A&E immediately.

If his steerer’s debonded it’ll certainly explain why he keeps crashing. Easy to check: Do you crash within about five yards of setting off? If so, maybe your steerer’s debonded. Otherwise it almost certainly hasn’t.

😉

(Anyway… yes, perfectly normal for bars to rotate in a crash.)

It happened to me and the more obvious one to check the stem clamping (despite the OP stating he already had) had already been suggested. I managed half a run downhill in a bike park, when someone crashed in front of me and I braked hard to avoid them and crashed again resulting in apparent stem rotation I suspected something was amiss. Just because it’s debonded doesn’t mean there isn’t sill some friction between crown and steerer there. Or I could not suggest it and the OP could have a catastrophic failure at speed next time out. Or you can jog on you numpties. 😉

Touché 😉

hey, I said it’s still work checking…just that it is unlikely given all the more normal and common reasons.

Or you can jog on you numpties

I think it’s a little extreme to suggest we all take up running instead out of fear of steerer failures 😉

C’mon you guys, group hug!

Maybe you have one of those new fangled MIPS stems?