No Knurling In Stems?

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11/10/2017 1:07 PM

Idk maybe it's just me but I remember having a Cult stem with knurling in it to help grab the bars better but nowadays I don't see any stems with it anymore. Is it just me or did stems actually have knurling before?

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11/10/2017 1:12 PM

The only stems I've ever owned with knurlings were walgoose. Other than that I've never seen an aftermarket stem with knurlings that weren't put there by the bars on them.

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11/10/2017 1:53 PM
Edited Date/Time: 11/10/2017 1:55 PM

I've never seen a stem with knurling, ever (in over 37 years). Knurling in aluminum makes no sense.unless it is for grip (as in for your hand to not slip, grip) The metal is too soft to be effective at holding anything that is harder than itself. If you ever saw "Knurling" on any aluminum stem, it was probably a transfer imprint from the knurling on the handlebars.

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11/10/2017 2:17 PM
Edited Date/Time: 11/10/2017 2:20 PM

The wtp hydra has something like it
Not sure how effective it is though.

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What I would like to see is a Cromoly stem!
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laughing

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11/10/2017 2:35 PM

Aluminum kinda forms to the steel. I dont think it is necessary. Not even sure it would be benificial. Seems there would be less metal surface contacting by my logic.

I think knurling on the bars is all you need.

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11/10/2017 3:46 PM

am-shaegar wrote:

The wtp hydra has something like it
Not sure how effective it is though.

Photo

What I would like to see is a Cromoly stem!
Photo

laughing

A chromoly stem would be great tbh I'd definitely buy

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11/10/2017 5:37 PM

The only reason your stem had knurling was because aluminum is much softer than steel, so the knurling from your bars will dig into your stem, especially if it's a cheap non t6 heat treated. I could be wrong but I've never seen a new stem with any knurling.

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11/10/2017 5:39 PM

am-shaegar wrote:

The wtp hydra has something like it
Not sure how effective it is though.

Photo

What I would like to see is a Cromoly stem!
Photo

laughing

PapiChuloDru wrote:

A chromoly stem would be great tbh I'd definitely buy

That would never grip your bars though.

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11/10/2017 5:44 PM

ggallin422 wrote:

That would never grip your bars though.

Rip lol maybe I'll just start welding my bars to the stem so they don't move at all laughing

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11/10/2017 6:12 PM

PapiChuloDru wrote:

Rip lol maybe I'll just start welding my bars to the stem so they don't move at all laughing

There are some flatland bars that clamp right to the steerer tube. Terrible for street because instead of your bars slipping you bend/break em, but for flatland are neat.

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11/10/2017 6:14 PM

It would be allot weaker with both bars and stem with knurling ..... you get amplitude land flat and die .... it’d be like hitting a jump to flat with your bars not tightened into a stem

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11/10/2017 6:52 PM

am-shaegar wrote:

The wtp hydra has something like it
Not sure how effective it is though.

Photo

What I would like to see is a Cromoly stem!
Photo

laughing

PapiChuloDru wrote:

A chromoly stem would be great tbh I'd definitely buy

ggallin422 wrote:

That would never grip your bars though.

This!

That's also the reason nobody makes 7000 series alloy stems anymore. By the time you've clamped down hard enough to get a good grab between the bars' knurling and the stem, you've crushed the absolute shit out of your bars.

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11/10/2017 6:59 PM

PapiChuloDru wrote:

Rip lol maybe I'll just start welding my bars to the stem so they don't move at all laughing

KHE did that, or rather, made a combo bar & stem... The downfall was you couldn't adjust your bars forward and backward if you wanted to. Plus, you know how your bars might shift in your stem from landing heavy/weird? That's cause it has some give in the stem and can move if need be... sort of like shocks in a mountain bike, they help absorb the impact. Now if your bars don't have any give and you land heavy, your arms and bars/stem are going to be what gives instead.

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The problem with knurling in stems though, is it wouldn't be effective. First off since it's aluminum, they'd just get shredded anyway. And what if the knurling in the stem didn't line up with the knurling in the bars? It'd be more prone to slipping that way. The WTP stem above and the Cult stem you mentioned might seem like a good idea, but that takes away surface area from the stem & face plate to make contact with the bars. Less surface area = more chance of slipping

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11/10/2017 10:44 PM

am-shaegar wrote:

The wtp hydra has something like it
Not sure how effective it is though.

Photo

What I would like to see is a Cromoly stem!
Photo

laughing

The éclat slattery stem has the same thing in it. I feel like it would grip the bars better but fuck up your bars if they do happen to move.

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11/11/2017 9:30 AM

My standard strip bars are almost smooth on the clamping area. I've never seen bars that smooth before. They haven't slipped yet, but I haven't ridden them too hard either. I think a nice machined stem makes more of a difference than any knurling does. Stay away from cast stems, and you should be fine.

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11/11/2017 9:54 AM

ggallin422 wrote:

My standard strip bars are almost smooth on the clamping area. I've never seen bars that smooth before. They haven't slipped ...more

Why stay away from cast stems?

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My Sunday Soundwave V3 Build
Insta: @p.gibbons

"You can't educate pork"
- grumpySteve

"Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming "Wow! What a Ride!""
- Hunter S. Thompson

11/11/2017 9:57 AM

ggallin422 wrote:

My standard strip bars are almost smooth on the clamping area. I've never seen bars that smooth before. They haven't slipped ...more

p1p1092 wrote:

Why stay away from cast stems?

A case stem in inherently weaker than a forged stem. For actual bmx riding, a forged stem is safer.

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11/11/2017 10:54 AM

ggallin422 wrote:

My standard strip bars are almost smooth on the clamping area. I've never seen bars that smooth before. They haven't slipped ...more

p1p1092 wrote:

Why stay away from cast stems?

A machined surface is a lot cleaner and more precise than anything that's cast. Not sure about forging, but a forged, then machined stem is probably the strongest, with the least chance of slipping.

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11/11/2017 11:40 AM
Edited Date/Time: 11/11/2017 11:52 AM

ggallin422 wrote:

My standard strip bars are almost smooth on the clamping area. I've never seen bars that smooth before. They haven't slipped ...more

p1p1092 wrote:

Why stay away from cast stems?

ggallin422 wrote:

A machined surface is a lot cleaner and more precise than anything that's cast. Not sure about forging, but a forged, then ...more

A cast stem made by a decent manufacturer with decent molds will have a very good surface, probably to the same level of imperfection as a machined stem. The QC in a casting factory will not allow anything with pitting or bubbling through. Also, a good casting will be significantly stronger than a stem made from extruded billet because of the internal stresses in extrusions.

I think you're putting too much emphasis on surface finish. The knurling on handlebars will rip any surface finish a new one, good or bad, it doesn't matter. If a perfect surface was absolutely necessary, you'd need a new stem every time you changed your bars or their position because the knurling would no longer line up.

Dave Lawrence has a theory, opposite to yours, something along the lines of: the rougher the clamp surface, the better it'll grab the knurling.

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My Sunday Soundwave V3 Build
Insta: @p.gibbons

"You can't educate pork"
- grumpySteve

"Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming "Wow! What a Ride!""
- Hunter S. Thompson

11/12/2017 9:10 AM

Bulletpup wrote:

Aluminum kinda forms to the steel. I dont think it is necessary. Not even sure it would be benificial. Seems there would be ...more

Well your logic is dependent on what bars are being used with the knurling. If the knurling on the bars perfectly matches matches the knurling on the stem, then it will have more surface area. If a company came out with a bar/stem combo that were splined, it would be incredibly strong and hard to slip (think 48 spline cranks). The downfall in this is that you lose the ability to make minute adjustments.

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11/12/2017 9:21 AM

bobPA wrote:

Well your logic is dependent on what bars are being used with the knurling. If the knurling on the bars perfectly matches ...more

Well actually that's not a bad idea. I'm pretty sure a splined bar stem combo would have more than enough adjustment for most people to find their sweet spot but then the bars would probably never give on hard drops which would probably hurt your arms if you land a little funny like sundaybmxRR said a little further up. Is it strong? Definitely but for more hardcore riding like big ass drops it probably wouldn't be the most favorable option

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11/12/2017 6:03 PM

bobPA wrote:

Well your logic is dependent on what bars are being used with the knurling. If the knurling on the bars perfectly matches ...more

I always thought something similar to 48 splined cranks being used in a stem would be a neat idea. Machining costs would probably make those bars and stems more expensive though

The closest thing I can think of is 2Hips Groovetech system. The stem has splines in it, which correspond with 2 splined shims, one of which has 2 little pegs that slide through 2 little holes in the bars and to the other shim preventing the bars from moving when everything's tightened down. It also has grooves in the steerer tube with notches in the stem which slide down into the grooves and keeps things from moving.

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11/12/2017 7:11 PM
Edited Date/Time: 11/12/2017 7:12 PM

A splined bar and stem would make a lot of sense.

The cranks use it, the pivotal seat uses a similar concept.

I would invest in the technology.

It would make setting up your bars less infuriating...

And while we are at it, make a splined steerer tube and stem clamping area as well.

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11/12/2017 7:24 PM

Bulletpup wrote:

A splined bar and stem would make a lot of sense.

The cranks use it, the pivotal seat uses a similar concept.

I would invest ...more

A splined steerer tube would be a godsend.
No more eye tricks and bs when putting the stem on.

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11/12/2017 10:08 PM

Bulletpup wrote:

A splined bar and stem would make a lot of sense.

The cranks use it, the pivotal seat uses a similar concept.

I would invest ...more

GCBMX69 wrote:

A splined steerer tube would be a godsend.
No more eye tricks and bs when putting the stem on.

I think we can all agree it's about that time to spline everything so we have to get the word out and get this ball rolling. We've made a lot of good progress in this thread let's keep this up wink

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11/12/2017 10:30 PM

Adding splines to a steerer or bars would be a bad idea. As Brandon mentioned with the stem/bar combo, there needs to be a degree of flex/give. If the bars were splined, they'd be weaker just by design (the way it's formed, etc.), and they won't allow any movement. Instead of your bars slipping a little on heavy impact, you'd rip them to pieces. Unless of course you added a load of material in that area. But that would inherently create other weak spots, and add weight.

The classic bar/stem interface has been around longer than any of us, and very rarely fails. It's just one of those things that doesn't need to change.

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11/13/2017 12:04 AM

I could imagine the bars would slip more with knurling on the stem. Definitely a no no, but I could be wrong. I doubt it.

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11/13/2017 5:02 AM

I said something about making stems and bars like 48 spline cranks a few months back, and everyone said it was unnecessary, and a bad idea lol.

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11/13/2017 5:10 AM

ggallin422 wrote:

I said something about making stems and bars like 48 spline cranks a few months back, and everyone said it was unnecessary, ...more

I don't think it is a "bad idea" but I think it is an added cost to production that isn't necessary. Plus, you would have to add splines PRECISELY to the steerer tube and they would have to be exact to the stems being produced or there would be a ton of complaints. You'd have to change the whole industry in order for it to work, etc... or you'd be locked into one manufacturer. You'd also have a hard time transferring an old stem to a new fork if the new fork didn't have splines, etc... Have you ever seen anyone sell used cranks without the axle? You;d be selling stems with forks, etc... Right now, pretty much any stem can be used with any fork. WAY more simple to produce. Less hassle across the board.

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11/13/2017 5:29 AM

I went back to my Shadow stem from 06 and it has yet to have a bar slip in it. Any new stem I have bought has been cleared of any anodizing etc in the clamping area, and then I CAREFULLY take a box cutter and carve small grooves into the clamping area.

The stem is now 11+ years old, never had a bar slip. It has been ridden pretty consistently for about 8-9 of those years, with around 5-6 sets of bars in it. I have also painted it a few times.

So in my experience, a little bit of roughness in the clamping does WONDERS. Any smooth clamping area stem I have had allowed bars to slip if I did not do the above to it.


Also back in the early 00's I had a couple aftermarket stems that has some grip in the clamping area. They may have stopped that for cost reasons-machine, ano and send out the door is cheaper than machine, knurl the clamping area/change the CNC bit and run another program on it, and then ano. One less machine or CNC bit/time on it.

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