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Setting up my 15 YZ250F's Sag + Spring Rate Questions

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Hello,

 

I recently bought a used 2015 YZ250F. I'm loving the bike, and am trying to get it setup properly for me. I've owned a couple other bikes in the past (yz125, rm 250), but always just rode them with the stock suspension settings. This was 8 or 9 years ago, and I weighed quite a bit less.

 

For some background, I'm 6'2, 205 lbs. I wouldn't consider myself a great rider by any means, but I'm not a beginner either. I mainly ride pretty open woods, some open fields, hit some smaller jumps, and basically just mess around. Haha. I would like to start doing some track riding, but it would be purely for fun! So far I've just been working on getting used to riding again, and really working on the fundamentals.

 

I'm the 3rd owner of the bike. The first owner had the suspension set up by Race Tech. Other than that the bike is stock. Unfortunately I didn't think to ask the second owner about the first owner's size/riding type/ etc. I thought the bike seemed too "soft" for me when I first rode it, but it was clean, ran great, and was priced well so I picked it up. Earlier today I decided to check out the race sag and found it to be way too high (~150 mm!). From what I've read it should be 90-100 mm.

 

Is it correct to assume tightening the adjuster wouldn't be able to make up that large of a difference and still have an acceptable static sag? I looked up the item number on the rear spring (SRSP 652652) and found the spring rate to be 5.2 kg/mm. I know that the stock spring rate is 5.71 kg/mm, so I guess I need a stiffer spring, correct? Anybody have an idea of what rate I should be looking at?

 

Thanks!

 

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The Race Tech calculator suggests about a 6.0kg/mm shock spring.

The stock fork springs rate (.47kg/mm) seem about right for your weight.

 

Contact some local suspension shops, they might exchange your lighter aftermarket springs for leftover stock components taken off customer's bikes.

 

For the average full-sized MX race bike (with linkage)

adjusted at 100mm of race sag, you should have about 20-30mm of free sag (just the bike's weight)

as for the forks, having 60mm to 70mm of race sag is often mentioned as optimal.

Edited by mlatour
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That bike likes a lot of sag. 105 plus. Every suspension tuner worth their salt will recommend 108 to 112.

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108 112. wouldn't that make the front lighter? seems most say it suffers from front end push. I still don't like how mine turns. trying different things all the time.

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Sag preference depends on your track conditions,

a trade off of stability on long straights or, better cornering/front wheel grip.

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I just took 10cc of oil out of forks and increased sag. hopefully ill hit the sweet spot one of these times.. keep fighting lean in and standing up in corners/push.. my 07 ktm 250sxf would carve but the yzf motor is way better of course.

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Gotta ride the YZ different. Lots of weight on the front. Have to get your head over the triples. Have to get up on the tank when seated. It's not a KTM. 

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