Thursday, July 29, 2010

2009 Yamaha YZ250F lowering spring rate question

Toby rides a 2009 Yamaha YZ250F. He recently purchased the YamaLink 1.5 and wanted to know which spring rate would be required for his 100kg/220 pound weight. Factoring in the YamaLink's 10% extra leverage here is our reply....


100kg is 220 pounds. With the stock spring you are obviously too heavy at 100kg to achieve proper sag which means so far your bike has been squatting too much in the back/understeering/riding rudely on the small bumps. Without a YamaLink you should have a 5.4 or a 5.6 kg spring.

WITH a YamaLink you should be on a 5.8 kg/mm spring to achieve proper sag setup. Repeat - 5.8 kg/mm shock spring.

We added approximately 10% body weight in the spring calculator to compensate for the YamaLink's extra leverage.

Just in case you need a source, sag set-up can be found here