[Closed] Why don't steerer tubes have a groove/spline to line up the stem?

I guess you might actually want the stem to twist in a crash.

dimensions could be standardised across brands

what he ^^^ said plus it's simple enough to set up properly as it is

edit: not him, the guy above him

The dimensions could be standardised across brands

stress raisers, twist in a crash is good, more expensive to make, etc etc.

There are X standards for steerers now.

Someone will come up with a clever, new, better standard to replace all those standards.

There are now X+1 standards. 😉

mrmo has it.

Because there is no reason to have it splined. Most people carry allenkeys so could easily solve the off centre stem....

A printed line on the tube and a dot on the stem would be better, but not really necessary. I've heard some folk intentionally rotate the stem a degree or two to help with a shoulder problem.

And besides, if your route involves lots of turning right, for example a clockwise route at a trail centre, some people need to run the steerer slightly off-centre to allow for this.

martin wins the internet for today 😀

More expensive to make as you'd spend more time getting the steerer aligned perfectly

I think motorbikes are splined.
A spinning stem is my nightmare. Just how tight do you go?
You can snap bolts or have steerer failure if too tight.
Too loose and you lose your teeth.
Splined would sort that.

Do people really rely on stems twisting in a crash? Why is that good? And if the rod/bar were removable this wouldn't stop that anyway - it would just be used for fitting leaving it free to rotate in a crash once fitted.

Perhaps it's just me but I find it very hard to get stems aligned properly - they're too short to be able to eyeball accurately against something with the characteristics of a tyre. It's not about the allen keys, it's about the visual characteristics of the parts involved.

I take the point about standardisation asterix, but it seems to work for most other parts on a bike so it is certainly feasible. And it would provide a small extra benefit (or at least a claimed benefit) that manufacturers could use to market their wares, so there's an incentive for them, assuming it's a cheap thing to do

I'm well aware this this is not a problem of major global importance. It just seems to me that there's value in having something that is designed to be aligned properly rather than relying on trial and error to get it right.

It would. It would also weigh more or be less robust and be more expensive. Given that almost everyone has no issue with the current solution, what about splined is actually better about it?

Mind you, come to think of it, you could probably apply that to a few bike 'innovations' 🙂

my double-groove-with-removable-fitting-rod approach would actually weigh infinitesimally less, and I can't see how it would have a material effect on strength...

If you have problems lining it up by eye, use a broom handle or similar parallel to the bars. You can spot it a mile off then.

Or just do your first ride with an Allen key in your pocket 😉

I take the point about standardisation asterix, but it seems to work for most other parts on a bike so it is certainly feasible.

I think motorbikes are splined.

Some might be but I don't think most are, at least. Triple crown forks, see?
I had a bike with a slightly skewiff front end. All sorted as part of a service.

my double-groove-with-removable-fitting-rod approach would actually weigh infinitesimally less, and I can't see how it would have a material effect on strength

Still promotes a stress point in steerer & stem & mean fork manufs have to make sure steerer is fitted dead centre in crown rather than just pressed into place any old how

Non-aligned stems annoy me too, and aligning to the tyre is generally IME not very successful... my setup method is to look down at such an angle that the middle of the bars line up with the front of the fork dropouts, you can then quickly see if the bars are straight or not. Works for me... Your experience may vary!

I've heard some folk intentionally rotate the stem a degree or two to help with a shoulder problem.

<Waves hello>

Oh well, worth asking - I'm clearly in an anally retentive minority 🙂

PS hello PeterPoddy. We still make your biscuits from the recipe you posted several years ago...yum yum

I use a method similar to nre, but eye the fork brace with the stem faceplate or bolts.

There are a few folding bike designs that have splined steerers or similar - the big problem is that unless your manufacturing tolerances are very, very tight, there's too much slop in the spline to allow spot-on alignment anyway. Or, worse, your stem doesn't quite match your steerer by a fraction of a mm and you can't get your bars straight.

The bar/fork alignment technique sounds good - I'll give that a go - thanks!

Another vote for bar / fork allignment. I've broken my collarbones four times now so both arms extend to a different extent than the OEM. Even when I have the bars straight I think my bars aren't!

Chris

On top of everything mentioned just think of all the increased warranty claims for CSUs that have not been pressed in quite right.

In the detailed working drawing below, you will see that alignment is simply a case of eyeing the top circles of the fork crowns through with the back surface of your bars. Simple.

[img] [/img]

Another reason against is stems that become quite sticky and hard to remove. Always come loose with a bit of wobbling about which a locator would not allow. 🙂

A groove would also weaken the steerer tube.

you have the practicality of making it central. on steerer and stem. from two different manufacturers.

you have tolerances on both, imagine being unlucky and they stack up and then you can never get it straight.

imagine hunting through the shop for a stem that's a bit clockwise because your steerer's a bit anti CW.

it's be 10 times worse than your ride today.

A splined steerer would also deny us the fun of seeing BSOs in supermarkets with the forks fitted backwards. 🙂

^ nah, they'd just have very short effective top tubes 😉

I'm sorry, what problem are we trying to solve?

The reason why it's not going to ever happen, is that it doesn't solve a problem.

Misaligned bars are not a problem, they are lined up by yourself when fitting a stem.

Regardless of how simple it makes it, there's just no problem to solve. It's the reason why so many *good* ideas fail, trying to solve a problem that doesn't exist.

I can't believe no one has brought up seatposts in this thread.

What about all the poor misaligned saddles out there.
For what ever reason you would purposely want you saddle twisted, please keep to your self. 😀

rickon - Member

The reason why it's not going to ever happen, is that it doesn't solve a problem.

15mm axles.

6/7/8/9/10/11 speed.

press-fit BB's.

post-mount brakes.

i could go on.

[i]What about all the poor misaligned saddles out there.
For what ever reason you would purposely want you saddle twisted, please keep to your self.[/i]

What about the people with un-even hanging... err, fruit?

Those who predominantly dress to the right may wish to have the saddle nose pointed slightly to the left to leave ample room for said appendage(s).

Don't Giant have a D shaped seat post on some models?

the current solution works fine, unless you have OCD

most current stems using dual clamping bolts have a setting torque of 5nm

this is more than enough to hold the stem secure on the fork steerer during normal use (or even quite extreme use i.e. freeride, dirt jump and downhill!)

but will also prevent damage to the stem or fork steerer if you have a big "off" as the design will allow the energy involved to overcome the bolt torque and rotate the stem on the steerer, rather than snap it!

15mm axles.

6/7/8/9/10/11 speed.

press-fit BB's.

post-mount brakes.

Yes, but all those things have tangible benefits - even if you disagree with them being the right standard or not.

Plus they come with a lot of stuff for the market to sell, shifters, chains, cassettes, rings, mechs.... calipers, mounts... BBs, whole new frames.

Splined forks mean a new stem.

Plus I wonder how much that would add to the cost, when it's not just a tube pressed into a frame?

Hmmm, what biscuits are these then? 🙂

Ever had a off where your legs got trapped between the bars and top tube and your momentum has spun the forks using your wheel as a lever? Glad i hadnt got a splined stem on for that one.

Drives me mad trying to get it all lined up. Best idea so far (and very similar to one I had) is the line on the inside of the steerer and dot on the stem. No stress risers and you can ignore it if you wish. Just need all fork and stem manufactures to do it now!

I'd be happy with the line/dot markings., and I am more than happy to accept that I'm in an anally retentive minority, but I don't accept all these objections. The centre line is the centre line, for example, so it can't be *that* hard for different manufacturers to agree on where it is in a compatible way.

Now, seatposts, that's a whole other story, and as for lock-on grips....

surely a spline would restrict the steerer length adjustability? as you wouldn't want the splined part in the headset so the spline would only be say 100mm down the steerer which means you couldn't cut more than 80mm off for the spline to be usable and then if you had a bike where you left it full length you would need splined spacers too

if it's just a single small groove I can't see it would bother the headset. But I think I'm on my own on this one anyway so I have a sneaking suspicion it's not going to happen...

Really? Problems aligning seatposts, and stems with forks? Do you go to your LBS when you need your tyres "more bouncy or less bouncy"?

I think we should have arrows on the cranks so we know which way to pedals. It's SO confusing!

Allen key in the pocket

Don't look at the bars, look at the trail, you will adjust naturally, surely its not that far out?

Get help for OCD

Loads of options out there to explore.

It's just too easy to straighten, just a couple of seconds during the build.
And a torque wrench for those asking how tight, I think most stems have the figures on the clamp.

trivial, mildly tongue in cheek suggestion accompanied by self-deprecation leads to insults on STW forum shocker.

PS the seatpost and lock-ons comment really was a joke. you may benefit from lightening up a bit...

you may benefit from lightening up a bit..

Or loosening up.

Or not, if it's in the handlebar area.

I'll get my my torque-wrench...

[i]if it's just a single small groove I can't see it would bother the headset. But I think I'm on my own on this one anyway so I have a sneaking suspicion it's not going to happen... [/i]

Probably because the rest of us don't have a problem lining them up?

yep, b r, it looks as if I'm alone on this one. It's not that it's so hard to line them up - even I can do it, without recourse to my LBS - more that there might be a better way, even if only marginally so. Progress is full of tiny incremental improvements each of which on their own may make little or no difference to most people, but which collectively lead to significant changes over time; I was vaguely wondering if this might be one of those. The fact that most STW forum dwellers, not necessarily a representative group of the world's population, find it easy to line up their stems, doesn't invalidate the proposal. But the balance of cost, complexity, strength, and so on, relative to the size of the problem (tiny) that has been pointed out by some on here probably does.

But really, it was just a flippant suggestion. For my next thread I think I will suggest alignment notches on rims, with corresponding nubs on tyres, so we can get logos lined up with valves....

I spannered pro for a while - lining up handlebars [i]exactly [/i]is hard without riding the bike.

Ever had a off where your legs got trapped between the bars and top tube and your momentum has spun the forks using your wheel as a lever? Glad i hadnt got a splined stem on for that one.

I have had this a couple of times , over the bars flat on you face with the bars under my legs and the back wheel up on my shoulders

Resulting in two sprained wrists and massive bruising across the top of both thighs like I have been hit with a bat.
But would still rather my bars stayed where they were its there relation to the wheels that stop my stanchions from scraping on the ground when I go for a burton.

Still think splines would be solving a non issue and stop you using a pipe cutter so more chance of cutting your steerer wonky.
When setting up bars, once adjusted if I look and it's straight, it's straight. If I look and I can't make my mind up of its straight or not, then it's straight.

I do use torque drivers and wrenches when at home but when out the size of the Allen key required to do a job is a good indication of how much force required, which is normally when Allen key starts flex , except when it comes to preloading bearings.

Shocker, banterous response to banterous thread leads to offence...

*sigh*

I’ve not spannered pro ever - lining up handlebars exactly is a piece of piss using a bit of string tied around the seatpost (assuming exactly to be ± a couple of mm).

just for the record, I've probably got the language wrong - I wasn't suggesting multiple splines, just a single shallow groove, probably at the very front of the steerer. This could then line up with a small ridge on the stem, or perhaps a matching groove or even just notch that would allow a centring tool (bit of metal, nail point, 1mm allen key, etc) to be inserted to line them up before tightening everything (this would mean that the stem could still rotate on the steerer in a crash). So most of the objections provided here still stand, but I don't think it would have any impact on using a pipe cutter 🙂

no offence aphex_2k, just don't see the point of ad hominem jibes rather than just slagging off the stupid suggestion itself on its merits or demerits. I'll survive... 😉

But really, it was just a flippant suggestion. For my next thread I think I will suggest alignment notches on rims, with corresponding nubs on tyres, so we can get logos lined up with valves....

See, I knew I'd get there in the end! That's what I meant about the marginal improvements - the steerer stuff is just a step on the road to properly aligned tyre logos.

Great, I was really happy that I had double-crown forks and avoided this problem (at least on one bike), but now I'm thinking I'm going to die in a horrible crash because my bars can't spin!

May I be the first to say - great idea!

People here just love to find faults - don't let it get to you 😀

I was concerned about stress raiser but then remembered that threaded steerers already have a groove for the tab washer....

Also more expensive to make a threadless stem with a spline sticking out if you actually think how it is made - it isn't jut a case of boring a simple hole through it anymore - has to be CNC bored or broached etc. I guess it could be a small tapped hole in the stem bore and a grub screw sticking out to go in the groove.

Just winding you up bro. You came across all serious initially and perhaps the amount of poo-poo responses made you backtrack a little but hey, you gotta have the sh1t thoughts flowing before a good idea gets growing. I just totally made that phrase up, so it seems like my new mantra works.

[img] [/img]

I’ve not spannered pro ever - lining up handlebars exactly is a piece of piss using a bit of string tied around the seatpost (assuming exactly to be ± a couple of mm).

I'm a very picky bar-steward, a couple of mm may not be enough - but I'll try it 🙂