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Have you tested this effect at track or dyno? Im happy to disagree. Reducing threads usage from 11,2mm to 6mm with 15nm on that bolt also doesnt affect stripping bolts in real world.
No I haven't, simply because this is a level of absurdity that's extremely obvious to an engineer (or most any technically minded person for that matter) that it will have no effect on feel whatsoever. Keefer may as well be arguing that he's best friends with Bigfoot and they just got back from their trip to the edge of the flat earth.
It will absolutely make it more likely to strip the threads for the simple fact that there's less thread engagement. But that doesn't mean it will strip the threads. There's probably still plenty of engagement even with the spacer (depending on how thick the spacer is). That's not my argument here.
I did my undergraduate in mechanical engineering and can assure you for a 100% fact that shims do nothing the the feel of the triple clamps. I'm almost positive this is a troll. It's almost as bad as the ride engineering "floating axle mod" for austrian bikes.
So, it's an 8mm bolt with 6mm of thread engagement?
It's not the tightening torque that would concern me, it's the loads being handled by the clamp/fastener when riding.
Curious to see what an FEA image would look like comparing the stock setup to that one.
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Tek14 isn't a troll, but I'm curious to hear his feedback on the change.
Dont know if Keefer is friend of Bigfoot but my initial test today riding everything same but shims and without shims felt sharp braking bums were not as sharp with shims. Could be placebo effect knowing when riding shims and when not. Keefer talking it will affect turning on lean but that wasnt anything I could feel riding rough sandy GP track with more sand berms than ruts.
Sorry, too little detail. Tek is legit, but I'm thinking Keefer or pulp is pulling a funny on this one. As far as the thread engagement stuff goes from your other post, you don't need too much thread engagement (i think 2-3 threads) for the strength. We like to use more for friction (preventing back-out) and safety factor. Luxon can tell you more probably.
The problem with track testing is that there are tons of other variables changing all at the same time. From one test without shims to one with, your tire pressure is dropping during the switch (a small amount, but it happens). The fuel level is lower (or much higher if you refueled during the swap), the track is changing due to other riders being on it, lines changing, weather, etc. Your forks are cooling down. And so much more.
On top of that, your torque on those pinch bolts is likely a bit different and the resulting tension force in the clamp is different (and that's the important part). Because of uncertainty in the torque-tension relationship, the uncertainty in the torque wrench accuracy, the uncertainty in the user. (Big post about that here: https://www.luxonmx.com/blog-luxon-bolt-torque-tension.html)
And if the resulting clamping tension is different, then a rider can feel the difference. But it has nothing to do with spacers or reduced thread engagement. You could have the exact same effect by just changing the torque without the spacers. And I'd argue that changing the triple clamp pinch bolt torque to effect feel is an absolutely terrible idea, but that's a different topic.
But let's look at what's really happening here. I think most everyone could agree that the spacers themselves do nothing to the feel and are just along for the ride. If anything is changing the feel (let me reiterate, it's not!), it would be the reduced thread engagement, or smaller amount of bolt length in the clamp. Keefer was on mcmaster.com to buy these spacers, why didn't he just buy shorter bolts to do the same thing?!
You could make the argument that a lower bolt length (essentially a steel rod) engaged in the triple clamp will reduce the stiffness in that area. And that's true! BUT, that area of the triple clamp is super stiff already. Taking a small amount of stiffness out of a really stiff area results in... a really stiff area still. The miniscule amount of flex occurring here is far overshadowed by the flex in the rest of the triple clamp and other parts on the bike. This is such a negligible change that there's no effective overall change in stiffness to feel.
I'm sure someone will be along soon to disagree, or Keefer will use his tagline of "I know what I feel", but I assure you, it's quite the opposite. He doesn't know what he feels. That's what a (real) engineer is for. Keefer is a good test rider and he might actually feel something different. But I guarantee it's not the stiffness change due to these spacers. It's more than likely mental or one of the many other changes mentioned above.
Never spent much time on fastener design and it's been 40 years since I went down that (ME) road, but I was thinking if the engagement design used a FOS of 2 (just a guess for illustrative purposes) and you cut the engagement in half, well, there went the FOS. And the initial reaction to a diameter-to-length ratio of 8mm to 6mm seemed more like it's describing a plug for an opening (think bleed screw on water jacket) than a fastener coupling two items under load.
Generally for fastener design you want enough thread engagement such that the bolt will break before it strips the threads when under a big tensile load. We have a detailed spreadsheet calculator for this (and many other parameters); you can actually download it here: https://www.luxonmx.com/resources.html
The default values are already set up for an M8 bolt. Altering the other values accordingly, you need more than 6 mm of full thread engagement (chamfered ends don't count) to ensure a class 8.8 bolt in a Yamaha triple clamp will break before it strips (with a factor of safety of 1). So it doesn't take much in this scenario.
Remember that's just to ensure the bolt breaks rather than strips the threads in a load big enough. Tightening this with 16 Nm of torque results in an overall failure FOS of the bolt of 2.65, but that doesn't account for external loading. The level of external loading is highly dependent on the angle of the pinch bolts to the longitudinal direction of the bike. Most clamps (and stock Yamaha) are 90 degrees to that direction, which significantly reduces the force in the bolt. You'd need about 4500 lbf of axial force (20,000 N) on that bolt before it fails. There's a lot of margin here, so it's not a big concern.
Or in other words, this mod likely won't cause a failure, but it will waste your time as you could be testing something that actually makes a difference instead!
That's why I said I'd like to see an FEA image - to see the calculated stresses in the assembly and the magnitude of change brought on by the new arrangment. Just curious as to the quantitative difference, if any.
The first time I saw the "it's all in your head" in action on an MX bike was in the early '80's. Rodney Barr was complaining about his shock to his dad (Bobby). Bobby reached under the fender (this was the original Yamaha monoshock design with the triangular swingarm), turned the adjuster a couple clicks and sent him back out. When he came back in he said it was better now. Asked what he changed, Bobby said, "Nothing. I turned it a couple clicks one way and then turned it back to where it started, he just thinks I adjusted it. I knew the bike was right, it's all in his head".
Thanks for explanation.
I seemed to remember you want fastener failure before component failure (weakest link), so that makes sense. The other part explains the difference in the loading of the fasteners in a side-clamping design versus a rear-clamping one - one imposes more of a tensile load on the bolt and the other a shearing load (which seems obvious looking at them).
I guess Star racing are complete idiots🤷🏽 Ferrandis top, J coop bottom
That’s not the same thing as adding two independent spacers underneath the pinch bolts. In this case you’ve actually added quite a bit of rigidity to the clamp (although how much you could really feel that is debatable) with the excess material, in Keefer’s case you’re doing nothing but essentially stacking thick washers, making no real change in the function of the clamp as Billy explained above.
Edit: I was looking at the picture wrong, it looked like there was extra casting material under the bolts not machined away but now that I look at it again those just look like regular stock clamps.
Not sure what point you're trying to make? Those photos show stock triple clamps, no spacers or anything special.
Can you dorks just let it go?
Pit Row
You really don’t have a problem with someone with as large of an audience as Keefer just blatantly misleading people? If you carry as much influence with people as he does you have a little bit of an obligation to validate your information before you publish it.
You believe that Keefer is out here just trying to ruin people’s bikes or sour their experience somehow? Regardless of what the nerds are ‘1000% sure’ of or how many degrees and years of experience they have, I believe that he felt a difference. I also believe he knows how to test a bike. Placebo or not, it costs next to nothing to do and poses no real threat to anything other than YOUR ego at this point. Go ride your bike and let it go…
I’m a die hard Honda guy, but my buddy went back to this new yammie. It’s a damn good bike.
I think it's interesting. Why let it go? Lets see where it goes instead...
To be clear, I don't think Keefer has any intent to mislead people or screw up their bikes. He's a good dude and is just trying to help people. But he can get a bit caught up in what he "feels" sometimes and it leads to some ridiculous mods like this and altering torque specs on engine hangers 5%...
Neither is really dangerous, they're just a waste of time as they do nothing to the handling of the bike. There's a big mental aspect to this sport, though, and people will "feel" that change regardless of whether it does anything or not. And if they feel better about it, it can actually make them faster (but not because the bike itself is any different).
No I don’t think he’s maliciously trying to ruin anyone’s bike, I just have a problem with people portraying themselves as an expert while claiming things that are absolutely absurd. You don’t need to be a genius to understand and think logically through the idea that adding a washer under your pinch bolts isn’t going to make any difference in performance. You can believe whatever the hell you want though, if you want to get led down tangents and perpetually chase your own tail because YOUR ego can’t deal with the fact that not everything the Moto industry feeds you is based in reality then more power to you.
FCP uses a solid titanium 9mm front engine mount plate (instead of two split 4mm plates) and a top aluminum engine mount that has a cut out to gain some flex.
So front plate is stiffer? and upper mount is softer?
304-257-4420
I just bought one of them. Two left.
Are OEM shroud graphics available anywhere? I see Rocky Mountain has shrouds that're way more expensive, not sure if it's because they have the graphics?
I know these aren't OEM, but here are some OEM replicas from FX https://store.factoryeffex.com/2023oemgraphicyz450f
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