- Why don't steerer tubes have a groove/spline to line up the stem?
Having just got back from a ride with a very slightly off-centre stem that bothered me more than it should I’m wondering why steerer tubes aren’t splined. They wouldn’t need the full treatment, just a single groove up the front would do it. The dimensions could be standardised across brands, it could be so shallow that it would have no impact on strength, and it would be completely compatible with existing non-splined stems. The standard could even be based around a matching a shallow groove in the stem with a small diameter rod or bar used while fitting to align the stem with the steerer, as this would then mean that all stems were compatible with all steerers.
Or am I being stupid…?Posted 4 years ago
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.Posted 4 years ago
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’ 🙂Posted 4 years agoDickyboyMember
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 howPosted 4 years agonreMember
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!Posted 4 years agobencooperMember
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.Posted 4 years agokayak23Subscriber
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.
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. 🙂Posted 4 years agothomthumbMember
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.Posted 4 years agorickonSubscriber
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.Posted 4 years agoell_tellMember
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.
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).Posted 4 years agoesher shoreMember
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!Posted 4 years agorickonSubscriber
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?Posted 4 years ago
The topic ‘Why don't steerer tubes have a groove/spline to line up the stem?’ is closed to new replies.