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Tapered Head Bearing Help


weven

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From a manufacturer's perspective, KTM have seemingly switched to ball from tapered for their 2017 1090R and 1290R Adventure models. I presume that these bikes would have a harder life than pure street bikes like the VFR, and that warranty issues have been factored in. 

https://transmoto.com.au/ktm-adv-range-technology/

 

KTM Australia’s Motorsport & Technical Services Manager, Rob Twyerould

 

There was a fair bit of talk at the launch about simplifying the serviceability of critical components on the 2017 bikes. What components, specifically?
The steering head bearings are a classic example. With the previous tapered roller bearings that are traditionally used for the steering head, the tension ‘test’ was how easily the wheel flopped from side to side after you’d tightened it. But some guys like a little drag; others prefer it looser. And you needed to do up two nuts – one under the triple clamp, which required a special tool, and then your conventional nut on top of the triple clamp. So when there were reports of the bikes encountering a weaving or instability problem on the really high-speed autobahns, KTM’s design team traced the issue back to incorrectly tensioned steering head bearings. Therefore, the factory introduced all-new caged ball bearings to the top and bottom of the steering stem for 2017, which have a much smaller surface area against the race. And because the race is very deep, it creates a lot more stability in every plane. In addition to it offering a very smooth movement, the design also allowed the factory to come up with one torque setting for the steering head nut, and eliminate the secondary nut under the triple clamp altogether. Now, the top triple clamp sits straight on the dust seal, and the nut is tightened from the top to a torque setting of just 18Nm, after which you re-tighten the pinch bolt. It’s a far simpler and more reliable system, and it means no one will ever be at the mercy of the ‘feel’ used by a particular mechanic.

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Yeah, there's no doubt that tapered roller bearings for the steering head are more easily maladjusted. Going simple makes it less

likely to be maladjusted, costs less, and everybody's happy. Well, almost everybody.

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18 hours ago, Lorne said:

From a manufacturer's perspective, KTM have seemingly switched to ball from tapered for their 2017 1090R and 1290R Adventure models. I presume that these bikes would have a harder life than pure street bikes like the VFR, and that warranty issues have been factored in. 

https://transmoto.com.au/ktm-adv-range-technology/

 

KTM Australia’s Motorsport & Technical Services Manager, Rob Twyerould

 

There was a fair bit of talk at the launch about simplifying the serviceability of critical components on the 2017 bikes. What components, specifically?
The steering head bearings are a classic example. With the previous tapered roller bearings that are traditionally used for the steering head, the tension ‘test’ was how easily the wheel flopped from side to side after you’d tightened it. But some guys like a little drag; others prefer it looser. And you needed to do up two nuts – one under the triple clamp, which required a special tool, and then your conventional nut on top of the triple clamp. So when there were reports of the bikes encountering a weaving or instability problem on the really high-speed autobahns, KTM’s design team traced the issue back to incorrectly tensioned steering head bearings. Therefore, the factory introduced all-new caged ball bearings to the top and bottom of the steering stem for 2017, which have a much smaller surface area against the race. And because the race is very deep, it creates a lot more stability in every plane. In addition to it offering a very smooth movement, the design also allowed the factory to come up with one torque setting for the steering head nut, and eliminate the secondary nut under the triple clamp altogether. Now, the top triple clamp sits straight on the dust seal, and the nut is tightened from the top to a torque setting of just 18Nm, after which you re-tighten the pinch bolt. It’s a far simpler and more reliable system, and it means no one will ever be at the mercy of the ‘feel’ used by a particular mechanic.

 

So they compromised their design in an effort to appease the dummies... a sad day for any engineer. 

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On ‎7‎/‎26‎/‎2018 at 8:50 PM, squirrelman said:

 

Negative !  race bikes use ball bearings (probably ceramic) cuz there's less friction and riders have a better feeling from the contact patch ....... as stated by Miguel's #17 mechanic  to me at an AMA race in 1996.

 

And when i replaced my oem balls with tapered, years ago, i noticed duller feeling from the front tire immediately.

 

 

I see the current GP bikes use ball bearings as well, probably more because they have the steering stems our 5-6 times a week than because the feel is improved.

 

If you are taking more than a season before servicing your steering head bearings then tapered roller (which are OVERKILL for an axis that never makes 1/2 of a revolution) will be q welcomed addition.

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