Rear Shock or Spring


12 replies to this topic
  • Drfletcherdc

Posted January 02, 2007 - 03:18 PM

#1

Lately I have noticed a tendency for the rear of the bike to bounce and not settle. Turning up the compression seems to magnify the problem. Since I am about 210 and still on the stock Ti spring, I am wondering about putting a steel aftermarket spring on the bike. The rear shock has been revalved by Race Tech. Has anyone around my weight use a different spring and which one? All the charts say I need a 5.7 but no one makes that just a 5.6 or 5.8.

  • Wyatt

Posted January 02, 2007 - 03:44 PM

#2

I am quite a bit lighter than you, so the stock spring works fine for me. But, I think the best thing you could do is ditch the stock spring for one that is set for your weight. You will probably not beleive how much better the bike handles if you do.

  • grayracer513

Posted January 02, 2007 - 05:05 PM

#3

... the best thing you could do is ditch the stock spring for one that is set for your weight.

This is probably the single most important element of suspension tuning. Without the right springs, the damping will be doing work that should be done by the springs, and you'll just never get it right.

  • YZ426F Rider

Posted January 02, 2007 - 05:07 PM

#4

Sounds like you need to increase the rebound a couple clicks and decrease the compression.

  • YZ426F Rider

Posted January 02, 2007 - 05:09 PM

#5

Racetech revalved the shock but left the stock spring?

Did they revalve it for you or did you buy the bike used?

  • Bmartin

Posted January 02, 2007 - 06:37 PM

#6

I weigh 200 or so and just put a 5.6 on. Made a difference in the corners and rollers.

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  • Drfletcherdc

Posted January 02, 2007 - 06:50 PM

#7

Racetech revalved the shock but left the stock spring?

Did they revalve it for you or did you buy the bike used?


One of my "friends" had Race Tech do it as a favor to him. The guy for Race Tech said that the Ti spring is the best out there and I should try to use it if at all possible. I was hesitant because the lowest we could get the sag was 105mm.

  • Drfletcherdc

Posted January 02, 2007 - 06:51 PM

#8

Sounds like you need to increase the rebound a couple clicks and decrease the compression.


I am already bottoming out there is no way I would decrease the compression.

  • Ga426owner

Posted January 03, 2007 - 11:38 AM

#9

One of my "friends" had Race Tech do it as a favor to him. The guy for Race Tech said that the Ti spring is the best out there and I should try to use it if at all possible. I was hesitant because the lowest we could get the sag was 105mm.


that is why you are too heavy for a 5.5kg spring.... I have been there done that ....for your weight you need a 5.6kg to 5.8kg spring...all springs are rounded off to closest rate...5.6 is a 5.568-78. Your stock 5.5 is a 5.455-79
I went with the 5.6 Ti yami spring...it cost 338.00 :lol:
It is more progressive than a steel 5.6kg spring. Some people like this..some don't. I would buy a steel 5.6kg spring if I had to do it again as $99.00 vs 338.00 is a lot of cash difference......please tell me you have .48/.49 fork springs as you will need these to...otherwise it will be all out of whack with .47 /5.6 rear

  • Drfletcherdc

Posted January 03, 2007 - 03:17 PM

#10

that is why you are too heavy for a 5.5kg spring.... I have been there done that ....for your weight you need a 5.6kg to 5.8kg spring...all springs are rounded off to closest rate...5.6 is a 5.568-78. Your stock 5.5 is a 5.455-79
I went with the 5.6 Ti yami spring...it cost 338.00 :lol:
It is more progressive than a steel 5.6kg spring. Some people like this..some don't. I would buy a steel 5.6kg spring if I had to do it again as $99.00 vs 338.00 is a lot of cash difference......please tell me you have .48/.49 fork springs as you will need these to...otherwise it will be all out of whack with .47 /5.6 rear


I don't know what front springs I have. The deal was that my friend Justin Buckelew who used Race Tech at the time got Race Tech to do my suspension for me during a WORCS race at Taft. The tech asked my weight and all that but suggested to leave the stock spring in since it is such an expensive part. I am pretty sure that the front fork springs were replaced according to my weight. I have no issues with the front only the rear. Do you think the 5.8 is too heavy?

  • Wyatt

Posted January 03, 2007 - 04:22 PM

#11

Man, if that is the case, i don't have much respect for that guy as a suspension tuner. You need the right springs, especially at your weight.

Proper springs and stock valving would give a better ride than what you now have.

  • Drfletcherdc

Posted January 03, 2007 - 08:45 PM

#12

Man, if that is the case, i don't have much respect for that guy as a suspension tuner. You need the right springs, especially at your weight.

Proper springs and stock valving would give a better ride than what you now have.


I just had the fork seals replaced and the shop that did them said whoever revalved my fork did a great job. My question is do I go 5.6 or 5.8 on the rear spring?

  • Ga426owner

Posted January 04, 2007 - 06:22 AM

#13

I just had the fork seals replaced and the shop that did them said whoever revalved my fork did a great job. My question is do I go 5.6 or 5.8 on the rear spring?


Here is the Racetech spring calculator:
2006 Yamaha YZ450F
Select Type of Riding:
Desert / Enduro / Trail
Motocross
Supercross / Arenacross
Enter Rider Weight (without gear): lbs OR kg.
Type of Riding: Motocross
Rider Weight: 220 lbs
Recommended Spring Rate: 5.78 kg/mm (use closest available)
Stock Shock Spring Rate (measured): 5.5 kg/mm (stock)

So Racetech recommendsa 5.8. I find Racetech is on the stiffer side - with their spring rates. I would go with a 5.6 and lose 5 to 10lbs personally





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