Does less front sag slow the bikes tip in?

Discussion in 'Tech' started by ibidu1, Aug 16, 2022.

  1. ibidu1

    ibidu1 Well-Known Member

    2017 R6

    Can to tight of a sag cause the bike not to tip into turns? Im running 23-25mm front sag, I love the way it feels under hard braking, but do you think that is the cause of my bike not wanting to dive into turns?

    Isnt too tight of a sag essentially raising the front end of the bike? Too cope with the slow turn in ive been raising the rear end (295mm at the shock)

    Another thing a racer pointed out to me, was the fact that im running stock clip ons. He showed me the stock clip ons are too narrow in and that aftermarket are spread open more allowing more leverage in the front end.
  2. Badger911GT3

    Badger911GT3 Well-Known Member

    Everything else being equal, less front sag would tend to make the bike slower to tip into turns. But merely stating the front sag (assuming that's a measurement of you on the bike vs the wheels suspended) is not enough info for anyone to tell you whether sag is a cause of this or that.

    But most times I hear about total front sag, it's usually more in the mid 30 to high 30mm range.
    ibidu1 likes this.
  3. JCW

    JCW Well-Known Member

    Maybe time to try a different front spring rate to support your bikes front end under hard braking.
    KneeDragger_c69 likes this.
  4. ducnut

    ducnut Well-Known Member

    I’d suggest finding a good suspension shop/guy who knows race bikes. There are tricks to every model of bike that’ll make a world of difference in their handling. Go to them with an open checkbook and let them sort it. Your profile doesn’t show a location, so not able to offer a solid recommendation of a shop.

    Yes. You’re running less sag than what’s typical. However, I’m betting, that’s not all you’ve got going on.

    Clip-on length isn’t going to overcome a poor setup. Suspension setup, with the correct springs, valving, oil height, geometry, etc, is where you need to start.
  5. stangmx13

    stangmx13 Well-Known Member

    Problems caused solely by too little front sag usually occur on corner exit. The front end doesn't track and gets too light because the topout spring can't work properly.

    Problems from too much front ride-height include the bike being sluggish to change directions while off the brakes. Lots of front ride-height can feel great changing directions while on the brakes. When thinking about how front-end changes affect turning, you must remember to include braking amount in those thoughts. The front brake lever practically controls front ride-height, so it really matters.

    Even without knowing the rest of your setup, I'd raise your front ride-height and remove some preload. But you probably have more issues like other's have said. If you want to list your entire setup (spring rates, ride-heights, preload, pace, rider-weight, tires, tracks), we could probably offer more help. But you'd be better off paying a suspension pro that works with racers. Nearly everyone has good R6 numbers these days.
    Last edited: Aug 17, 2022
    Maxtrap, ibidu1 and ducnut like this.
  6. ibidu1

    ibidu1 Well-Known Member

    Im still new to yamaha's even though its been a year. I had the front forks lowered and that help a bunch but the suspension tuner said thats too low to keep the front end, and you may have issues tucking the front end on braking. I like experimenting myself with my suspension, I feel its the best way to dial a bike to my riding. Im going to try removing 2 full turns from fork preload and see how the bike feels. Thanks guys I appreciate all your help!
  7. ibidu1

    ibidu1 Well-Known Member

    Im running stock forks and I weight 182, I plan on getting fork cartridges soon so I will buy the springs with them.
  8. stangmx13

    stangmx13 Well-Known Member

    Lots of people race on the R6 with the front end 5-10mm taller than stock. You can't get to 10mm on the stock fork cartridges, but every little bit helps.

    You probably won't feel a 2mm change.
  9. ibidu1

    ibidu1 Well-Known Member

    I actually had it around 8mm but he told me thats too much, you risk washing the front end.
  10. stangmx13

    stangmx13 Well-Known Member

    That seems like crappy advice. No bike becomes unrideable from adding a few mm of preload. Yes, the bike can be slower or harder to ride. It's up to the rider to not push over any new limits when testing suspension changes - and that part is easy.

    It sounds like you are mixing up "8mm less sag" with "8mm ride-height change". Those are not the same. And if someone recommends you change ride-height, they NEVER mean sag/preload. They always mean move the forks. Ride-height is measured with the forks fully extended. Preload does not adjust ride-height (very much, cuz topout springs).

    All my comments about ride-height assume you are using a normal amount of preload - which you aren't. My comments also assume your springrates are within range for your weight, riding, and tires - which we have no idea about. So take those comments with a grain of salt. Here's more info: 8mm of extra ride-height AND very little sag may be way too tall. 8mm less sag with the stock ride-height might be ok, minus the issues discussed previously.
    ibidu1 likes this.
  11. ibidu1

    ibidu1 Well-Known Member

    I set up my suspension by setting sag first at 25mm, then while at the track messed around with compression and rebound.

    At the track I felt the bike slow to tip in, and slow to throw it into the fast corners. It tracks fine on exit! So I experimented by raising the rear shock, and that helped a bit but still not quick enough tip. Then I changed the front ride height 8mm lowered the front end of the bike, through the triples. So 8mm was poking out of the top triple more then stock setting. That setup felt great and the bike was fast. But the mechanic said that, having the rear raised and the front lowered is a bad recipe to wash out the front end. Now im thinking maybe the 25mm sag in the front is the reason why my bikes not wanting to turn in

    2017 R6
    Stock forks, stock spring just fresh seals and fluids
    Ktech rear shock sprung to my weight
    Im 182 pounds
  12. stangmx13

    stangmx13 Well-Known Member

    What pace are you running? Do you know how far-off expert winning times are?

    Your setup isn't in the ballpark for what racers run. I couldn't race with the front-end that short, as it's probably 15mm shorter than my minimum (hint). But I doubt our riding styles are comparable.
    Last edited: Aug 18, 2022
  13. metricdevilmoto

    metricdevilmoto Just forking around

    Quick, post a picture of your tire. Then your setup will really get dialed in.
    stangmx13 likes this.
  14. metricdevilmoto

    metricdevilmoto Just forking around

    It's odd that you're obsessing over a few mm of preload and sag but your unknown spring rate is definitely perfect for your weight. Numbers, dude. Numbers.
  15. ibidu1

    ibidu1 Well-Known Member

    Heres my front tire, 2 trackdays on it. Pirelli sc1 front (36psi hot) and (21.7psi) 180 rear

    Track is in the middle east Losail circuit, its very abrasive

    Attached Files:

    JCW likes this.
  16. JCW

    JCW Well-Known Member

    I can help maybe explain things theoretically but as mentioned above, more numbers and exactly what issues you are having on track are going to be needed to give you specific answers to your questions.

    To understand the reason high preload is undesirable you must understand how preload effects the suspension...
    Preload as you know compresses your fork springs in the tubes. This accomplishes ONE THING ONLY- to achieve a higher ride height on your suspension travel. There is NO change in your spring rate or harshness of the ride or suspension (except maybe internally in the dampers as they near the end of travel).
    Why might the suspension FEEL stiffer with more preload? Well, under hard braking, the front will take a set higher and not dive as deep with more preload, but this is simply because you started from a higher position. NOT because the suspension is stiffer.
    Why is excessive preload undesirable? Because at ZERO inches of compression where your suspension is completely unloaded, the spring is still compressed a certain amount (your preload) and it will not react to small forces (read- bumps) that are less than the preload force. Compress your 500# per inch fork springs 1/2" and you've added a huge 500# of preload!!! At full extension, nothing less than 500# of force will move the suspension! So... that's where the old mechanics thoughts that excessive preload will wash out the front suspension on acceleration when (or IF) the suspension is topped out... comes from.

    This may or may not be an issue with you at a particular track and at a particular pace and with a particular riding style... it all depends...

    How rebound or top off springs come into play is that they act to counter the preload so that small bumps at full droop CAN create suspension movement and avoid this rigid system at the top of travel.
    There are neat youtube videos of bouncing a mountain bike with zero preload compared to one with more than zero preload... The bike with some degree of positive preload bounces a couple times whereas the suspension with zero preload absorbs the contact and levels out immediately.

    playing outside the "normal" range of preload will overcome these helpful preload springs.
  17. ibidu1

    ibidu1 Well-Known Member

    I havent raced in US in a long time. But I would say a bit faster then mid pack
  18. JCW

    JCW Well-Known Member

    I think he was being facetious...
    metricdevilmoto likes this.
  19. ibidu1

    ibidu1 Well-Known Member

    See thats the thing, im stumped on why this bike isnt doing what it should. The only thing I can think of is the the front preload, not allowing me to turn
  20. JCW

    JCW Well-Known Member

    So it makes sense to me that the bike doesn't want to turn in with high preload because the front is sitting high and your geometry is not in good position to turn in...

    If you trail brake it into a corner you could lower the front end on brakes and get the bike to turn in easier. This is an example of changing your riding style to suit the suspension if for some reason you value more preload more than ease of turning....

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