Jump to content
Sign in to follow this  
IanC

Cannot set sag on rear?

Recommended Posts

IanC

So maybe someone can clear this up?

I've read a few articles and watched a few videos about the importance of static sag and rider sag, so I thought to myself - Yes, i'm going to go dial that in.

From what I've read, ~10mm of static sag, and then on top of that ~30mm of rider sag is appropriate. 

On my bike however, on the rear, with 0 preload, there is no static sag at all, ie: the bike on its own does not compress the rear spring at all - resulting in the 'pogo' effect I've read about.

Then with me on the bike measuring rider sag (200lbs w/ gear), I only get ~20mm sag, again with preload at 0.

 

Does this mirror others experiences? Seems crazy the spring would be that stiff...

 

Ian.

Edited by IanC
formatting

Share this post


Link to post
Share on other sites
le druide

maybe previous owners put a stiffer spring ? what is the year of the bike ?

Share this post


Link to post
Share on other sites
IanC

Its a 2018 MT07 - I bought it brand new last season.

Sounds like its not typical....I wonder if its defective? Out of warranty now unfortunately...

Edited by IanC

Share this post


Link to post
Share on other sites
le druide

Ok so it's the OEM spring , I think the rate for 2018 and up is in the 625 lb/in range , I don't think it's defective, just too stiff, maybe other 200 lb rider can share sag values to compare.

  • Like 1

Share this post


Link to post
Share on other sites
DewMan

Perhaps you're at the wrong end of the preload?
Just a  thought.

  • Like 2

DewMan
 
Just shut up and ride.

Share this post


Link to post
Share on other sites
le druide

good thing to be sure, it may be confusing sometimes! 

Share this post


Link to post
Share on other sites
IanC

Lol I hope not...I dont think I would ever live it down...

I am going to sneakily verify tonight though....

Share this post


Link to post
Share on other sites
stickshift

How much do you weigh?

Share this post


Link to post
Share on other sites
le druide

 stickshift ,look at the first post 

Edited by le druide

Share this post


Link to post
Share on other sites
DewMan
17 hours ago, IanC said:

Lol I hope not...I dont think I would ever live it down...

I am going to sneakily verify tonight though....

Does your lack of a more recent response mean you've resolved your issue in some manner? 🙂


DewMan
 
Just shut up and ride.

Share this post


Link to post
Share on other sites
scat2me
On 4/2/2020 at 11:21 AM, IanC said:

So maybe someone can clear this up?

I've read a few articles and watched a few videos about the importance of static sag and rider sag, so I thought to myself - Yes, i'm going to go dial that in.

From what I've read, ~10mm of static sag, and then on top of that ~30mm of rider sag is appropriate. 

On my bike however, on the rear, with 0 preload, there is no static sag at all, ie: the bike on its own does not compress the rear spring at all - resulting in the 'pogo' effect I've read about.

Then with me on the bike measuring rider sag (200lbs w/ gear), I only get ~20mm sag, again with preload at 0.

 

Does this mirror others experiences? Seems crazy the spring would be that stiff...

 

Ian.

My ex-wife had the same problem..

Share this post


Link to post
Share on other sites
IanC
1 hour ago, DewMan said:

Does your lack of a more recent response mean you've resolved your issue in some manner? 🙂

Sorry - I didn’t get out last night, and got busy this morning. 
 

I’m  out in the garage now and (thankfully?) it wasn’t the issue. I had the rear preload set at#3, but wound it down to 0 and verified that there is indeed no static sag available. 
 

If anyone with a stock suspension is able to corroborate or contrast I’d be really interested. 
 

I’m switching out the front fork oil right now, so if anyone has anything they think I should check with the back I’ll be out here with a wrench and a pint for the next couple hours. 
 

Im at a loss for anything to adjust really. 

Edited by IanC
  • Thanks 1

Share this post


Link to post
Share on other sites
twf

Are you measuring sag with bike on rear stand? 

Share this post


Link to post
Share on other sites
IanC

Nope - front wheel in a chock, rear tire on the ground. However I did initially use the rear stand but moved to a front wheel chock when it didn’t seem to make sense. 

Share this post


Link to post
Share on other sites
twf

Front wheel chock will also screw sag numbers. Bike needs to be on the ground and wheels free.

Share this post


Link to post
Share on other sites
IanC

Thanks for the tip. I’ll check it again once I’ve got someone to hold it upright - but I can’t imagine it will produce anything different. My front chock is a homemade one that is just holding the front wheel laterally - it is touching the ground and fully loaded. 

Share this post


Link to post
Share on other sites
topazsparrow

the rear shock on these bikes has always been pretty soft. I'm finding it super hard to believe there's no reason for the lack of any static sag.

 

Given the other comments, The only think I can think of is that somehow somewhere that spring is being compressed more than it should. It's possible the spring itself is out of spec, but seems pretty unlikely.

Give that spring a good look over again and make sure its seated fully and there's no other weirdness going on. If that doesn't bear any fruit, you may have to take it out of the bike and inspect it.

Have you discussed it with the dealer you bought it from?

Share this post


Link to post
Share on other sites
IanC

I haven’t discussed it with them - maybe I will. I didn’t take any suspension measurements until about a month ago, which at that point it was out of warranty. 

I just assumed they were all like that, however after reading a bit I started to think maybe that wasn’t right...so I posted this up to try and get a feel for everyone else’s experiences. Certainly seeming like mine is not the norm. 
 

I’ll take another good look at it for binding, and try and find some measurements for the spring. Hopefully I can ascertain something with pulling the whole lot out and breaking it down. 

Share this post


Link to post
Share on other sites
mossrider

So here's my 2 cents. Granted I'm not a suspension guru or even knowledgeable for that matter but I have spent countless hours fooling with suspension. 

No one in the history of motorcycling has ever riden their bike w/o being on it. What I mean is static sag is great in a perfect world but it's not the end-all. If you have zero static sag but can get around an inch and a half or so rider sag you're in the ball park. If you can't get enough rider sag then your spring is too stiff. 

It's that simple in basic terms.

Now, having said that: You do need a fair amount of sag for the suspension to function properly, to keep the tires in contact with the road surface, to give a comfortable ride and to let the motorcycle perform well over rough terrain and on the brakes/gas.  As to your mention of "pogo". Pogo is more a result of uncontrolled or poorly damped suspension than it is related to sag. (assuming both ends have the proper spring rate) If the front forks have proper compression damping they don't over-dive on the brakes. In like fashion if the rear shock has proper rebound damping it doesn't over-rise on the brakes. The converse is true on the gas; rebound on the front, compression on the rear. A properly set up suspension will work in unison, feel settled and composed over rough ground, feel like it squats rather than pitch or rock when hard on the brakes and rise not rock on the gas. The bike will also handle better, hold a line in corners, change direction easilly to avoid hazards and tighten or relax it's line in turns effortlessly and w/o drama. 

I don't know if any of this makes sense but there it is.

BLR

 

  • Like 2
  • Thanks 1

Share this post


Link to post
Share on other sites
IanC

What you're saying certainly makes sense, however I am also not a suspension guru (as far from it as possible in fact).

What got me interested in trying to figure it out was a couple rides recently where, cresting a bump in the road at speed, the rear unloaded quickly, and ends its travel abruptly, giving me a noticeable bounce off the seat as it tops out. 

Maybe I can dial in a bit more rebound to compensate as you mentioned. I set that up as per a Dave Moss Tuning video, but perhaps in my situation I need to (over damp?) the rear. I suppose the trade off is high speed rebound will suffer a bit, but that might be a trade off worth making.

Thanks for taking the time to share that.

Ian.

  • Like 1

Share this post


Link to post
Share on other sites
twf

 

5 minutes ago, IanC said:

What you're saying certainly makes sense, however I am also not a suspension guru (as far from it as possible in fact).

What got me interested in trying to figure it out was a couple rides recently where, cresting a bump in the road at speed, the rear unloaded quickly, and ends its travel abruptly, giving me a noticeable bounce off the seat as it tops out. 

Maybe I can dial in a bit more rebound to compensate as you mentioned. I set that up as per a Dave Moss Tuning video, but perhaps in my situation I need to (over damp?) the rear. I suppose the trade off is high speed rebound will suffer a bit, but that might be a trade off worth making.

Thanks for taking the time to share that.

Ian.

More or less damping has nothing to do with sag. 

Too little sag with make you bounce around.

  • Like 1

Share this post


Link to post
Share on other sites
IanC

Which is certainly happening with my bike. 

I let a friend of mine with an R3 ride it and he had the same criticism without being prompted. He mentioned he felt like he was being launched out of the seat...which I'd agree with!

So if increasing rebound over what would be considered ideal is not helpful, and sag doesn't exist even at the lowest available preload setting, then I guess that just how it is (unless it is mechanically binding/stuck/defective) as mentioned above.

I'm going to look again in the morning, but I've stared at that thing long enough that I should have noticed a mechanical issue with the spring.

Ian.

Share this post


Link to post
Share on other sites
twf

Increasing rebound may help some but is not fix for wrong spring or preload or whatever is going on with your set up.

There is no ideal rebound for stock shock, it simply does not have enough. Again you can compensate for luck of it by adjusting low speed but real issue is high speed. 

  • Like 1

Share this post


Link to post
Share on other sites
robbo10

I have read all this but cannot remember if it's been said already: is there something wrong with your shock absorber? Is it jammed (or nearly)? Apologies if repeat.


Just do it! 

Share this post


Link to post
Share on other sites
IanC

It looks ok to me - but i'm going to get out there soon and have a closer look.

That is however exactly what it seems like....as if even at preload setting 0 it is significantly loaded.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×

Important Information

By using this site, you agree to our Terms of Use.