rear spring

RAMSY SLIDER · Post by **RAMSY SLIDER** » Sat Mar 10, 2007 9:52 am

HI THERE,
I'M A NEW KID ON THE BLOCK.
I'VE OWNED MY TRX FOR ABOUT 5 YEARS AND I'M JUST ON WITH UPGRADING IT...I'VE PUT SOME YZF 6POT CALIPERS AND DISCS ON / PROGRESSIVE SPRINGS AND A STEERING DAMPER AND I'M PUTTING A YZF SWINGARM + WHEEL ON THE REAR.
DOES ANYONE KNOW IF THE STANDARD YZF REAR SPRING IS THE SAME OR STRONGER THAN THE TRX ITEM????

I'M SORRY IF THIS HAS BEEN COVERED BEFORE BUT I'VE NOT COME ACCROSS IT WHEN READING THROUGH.
THANKS
P.S. I'LL POST A FEW PICCIES WHEN I'M FINISHED WITH THE MODS
THANKS AGAIN

HansJ · Post by **HansJ** » Sat Mar 10, 2007 10:59 am

Sorry, I don't know that, but the TRX shock fits. I don't have a problem with the rear being too soft, on the contrary, and I'm weighing in at 85-90 kgs.

steve speed · Post by **steve speed** » Sat Mar 10, 2007 9:25 pm

HansJ wrote:Sorry, I don't know that, but the TRX shock fits. I don't have a problem with the rear being too soft, on the contrary, and I'm weighing in at 85-90 kgs.

you will have no problems getting the correct static sag if you are 85kg with the std spring

Post by **Max** » Sat Mar 10, 2007 11:15 pm

Unless it's a Japanese import model, they have a 1kg softer spring.

dfh · Post by **dfh** » Fri Mar 23, 2007 4:59 am

steve speed wrote:
HansJ wrote:Sorry, I don't know that, but the TRX shock fits. I don't have a problem with the rear being too soft, on the contrary, and I'm weighing in at 85-90 kgs.
you will have no problems getting the correct static sag if you are 85kg with the std spring

Well I weigh in at 90-92kg in my leathers and helmet ready to ride

( yeah yeah, but can you find a more elegant way to say it?) and whilst I could get the correct static sag -35mm- the spring was over pre-loaded to achive that. Even though you can set the sag the soft spring will allow the bike to squat and run wide under power and crash through on bumps. Most people crank up the compression damping to kill the squat but this stuffs the ride quality and bump compliance and tyres.

The test is to set the preload to get the static sag correct, then hold the bike without rider upright from behind with the tail piece, push down sharply then let it rise freely. If the bike rebound quickly and tops out with a solid thunk, then the spring is too soft and excessivly preloaded to compensate. A too stiff spring will not top out at all and an appropriate spring will top out quite gently, something you will feel through your hands rather than hear

I first used a eibach spring rated @ 550lb/inch or about 9.5kg/mm (stocker in Oz was supposed to be 7.8kgmm but mine tested @ 7.2kg/mm) but it still wasnt right, especially with a weeks worth of touring gear on board

Now I use 600lb/in or 10kg/mm spring with a revalved shock and matisse risers on a bike with the standard (heavy )pipes and with my weight I leave the preload set @ #1 for general fanging, #2 for track days, and #3 or #4 with all my gear for a fast tour...

Hope this helps