conflicting info on flywheel inertia from different businesses

2 replies to this topic
  • HGaither1

Posted September 06, 2007 - 05:06 PM


I was just trying to find the best deal on the GYTR 90z flywheel using part # GYT-2S297-50-50 and some businesses would lidt the inertia as 4.83 and some 6.15. What gives with that? Seems like with the same part# the info should be the same everywhere. How about it Grayracer?

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  • grayracer513

Posted September 06, 2007 - 05:50 PM


The 2S297-50-50 is the heavier of the two weighted flywheels offered by Yamaha, and has a listed inertia mass of 6.15 kg-cm², through the use of a 9.21 oz. added weight.

The lighter 2S297-50-00 has an inertia mass of 4.9 kg-cm² through the use of a 4.83 oz. added weight.

Yamaha never used to publish the added weight because they believed, and very accurately so, that the inertia mass is the important factor, and the same weight configured differently will add a different inertia mass (e.g. welded vs. bolted weights). However, because no one else publishes the mass figures, Yamaha has now chosen to publish added weight to enable comparisons with other available products.

The info above is from Yamaha, and if you see a ...50-50 listed as having a mass of 4.83, either that's wrong, or it's really a ...50-00 (in which case it would still be wrong, since that's the added weight).

  • HGaither1

Posted September 07, 2007 - 05:48 PM


Sorry about that, I wasn't looking at the last two digits in the part number and it was the lighter of the two I was looking at. I did order the heavier on e though. Thanks for the info.

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