Rear Ride Height -- Hooped Framed Monsters

[ducpainter]

For those who use the heim joints to increase the rear ride height, how did you end up with your settings? 

Before I installed the spacers, the rear ride height was as low it could be.  I think I am going to remove the spacers and try to turn out the joints in order to gain some height.  I don't know if I should start at the max and turn them in as needed or the other way.  I am not sure how much I can gain with the joints themselves, anyone know?

For the record:
My front forks are at the stock location as measured from the bottom of the lower triple clamp to the top of the fork tube (excluding the cap) per the FSM for my Monster.  I will check my manual when home to verify the setting. 

I just wound them out as much as I dared...

engineering standards require a full diameter of threads in the hoop for safety. Personally I've been proving them wrong for 30K miles.

Any Ohlin's tech can install an adjustable length options on your DU-440 (I had this done, it doesn't cost much)

And while pre-load does affect the effective length of the shock, it also compresses the spring, so that can have some secondary effects depending on the spring rate.

I'd share my settings, but my set up is so dang weird (SBK front forks and a custom swingarm) that I doubt it'd work for anyone else.

My understanding of the way a linkage system works would lead me to not bother with increased length on the shock. I might be missing something, but unless you also change the length of the hoop you're just going to be adding preload by trying to stuff a longer shock in there.

[Drunken Monkey]

While preload does act as a length adjuster, remember the piston only has limited amount of travel inside the tube and that doesn't get adjusted via pre-load.

Plus the piston's movement in the tube isn't the same throughout it's range of motion (at least on some shocks)

In my case the adjustment on preload had to be so much that I ran low on piston travel and just started compressing the spring. Hence the need for a longer shock. And I was afraid of the shock "topping out" when the suspension was rebounding to it's highest setting.

But this is an extreme case where the shock mounting point and the hoop mounting points were both lower.

Add to that that you want the hiem joint operating as efficiently as possible. i.e. both the shock and hoop to be connecting as perpendicularly as possible to the joint. The further out of whack these get, the less efficiently it's going to transmit forces between the hoop and shock.

So in general, for a higher rear end, I'd go with spacers on the hoop and keeping the shock the normal length, with preload adjusted close to the middle of the piston's travel.

Make sense?

[greenmonster]

raising the rear will decrease the trail in the front that will lead you into the headshake zone.

+1.
Old Mchassie not the best & hasn`t the optimum yokes f best steering/trail.

I have 14mm raised rear & 27mm over triple, no headshakes.
When you get them shakes, you have matched rear & front wrong.
My 2c.

[ducpainter]

<snip>

Make sense?

I never suggested using a longer shock.

Preload only affects spring length. It does not affect shock travel. Too little preload or too soft a spring will use up travel, that's true.

If you lengthen the shock with a fixed hoop length the only thing that can possibly happen when you stuff that shock in that space is for it to compress the shock thereby increasing preload and using up effective travel.

As far as the efficiency of force...waaay too technical for me to even consider. The heim joints remain in a straight line with the hoop and they work.

Maybe we're thinking the same thing and saying it differently.

[Blue]

For those who use the heim joints to increase the rear ride height, how did you end up with your settings?

I think I should have better explained was was happening.  With the heim joints at their lowest (stock setting), I felt I needed more on the front.  With the spacers installed, I achieved what I set out to do; however, I have had two instances of headshake when on the gas over rippled pavement.  One stretch is where I can air out the bike.  Both times the bike recovered quickly and without drama.  I am just not a fan of that experience.  I don't want to add a damper or a longer side stand if I can achieve what I would like to do with the heim joints only.  The trouble is (nice troubles to have) I will be attending a performance motorcycling school this Friday (ZARS), so I am thinking I am going to leave it as it is for now.  I don't want to switch the bike around with this event coming up. 

More info below:

Before I installed the spacers, the rear ride height was as low it could be.  I think I am going to remove the spacers and try to turn out the joints in order to gain some height.  I don't know if I should start at the max and turn them in as needed or the other way.  I am not sure how much I can gain with the joints themselves, anyone know?

The spacer is about 28.5mm long (without the nut at the bottom).  The nut is thinner than the stock nut that comes with the heim joints.  The overall length of the heim joint (measured from the middle of the nut per the FSM), nut and spacer is ~54mm.  Measuring the hoop (as best I can with it installed) minus the heim, nut and spacer is ~215mm (to the middle of the nut per the FSM).  So, the FSM calls for 238mm from nut on the heim joint to the nut on the rocker that holds the hoop.  With my quick measurements, I am at ~269mm for a gain of ~30mm over the stock set up. 

For the record:
My front forks are at the stock location as measured from the bottom of the lower triple clamp to the top of the fork tube (excluding the cap) per the FSM for my Monster.  I will check my manual when home to verify the setting.

This measurement is 279mm.
The clipons are 27mm tall and are flush with the forks tops with the forks at the stock setting.

[COP TZR]

I think I should have better explained was was happening.  With the heim joints at their lowest (stock setting), I felt I needed more on the front.  With the spacers installed, I achieved what I set out to do; however, I have had two instances of headshake when on the gas over rippled pavement.  One stretch is where I can air out the bike.  Both times the bike recovered quickly and without drama.  I am just not a fan of that experience.  I don't want to add a damper or a longer side stand if I can achieve what I would like to do with the heim joints only.  The trouble is (nice troubles to have) I will be attending a performance motorcycling school this Friday (ZARS), so I am thinking I am going to leave it as it is for now.  I don't want to switch the bike around with this event coming up. 

More info below:The spacer is about 28.5mm long (without the nut at the bottom).  The nut is thinner than the stock nut that comes with the heim joints.  The overall length of the heim joint (measured from the middle of the nut per the FSM), nut and spacer is ~54mm.  Measuring the hoop (as best I can with it installed) minus the heim, nut and spacer is ~215mm (to the middle of the nut per the FSM).  So, the FSM calls for 238mm from nut on the heim joint to the nut on the rocker that holds the hoop.  With my quick measurements, I am at ~269mm for a gain of ~30mm over the stock set up. 

This measurement is 279mm.
The clipons are 27mm tall and are flush with the forks tops with the forks at the stock setting.

Sorry for going totally off topic here on you, but I have the same clip ons as you.  What brand are they?  I also have the same suspension risers installed on my rear hoop.  My clipons also sit flush like yours.  I havent been able to ride the bike yet, but once I do I will give you some feedback of the handling characteristics.

[DaFoose]

Blue, have you had your suspension set up properly? My understanding is that will greatly reduce your chance of headshake, as th reason for headshake, is that the suspension can't deal wit the bumps. Plus if you are still rocking the stock springs, you can upgrade those, for about $200 plus labor (or do it yourself). Alot cheaper than $4-600+ for a steering dampner. Plus it will ride a lot better anyway.

[Blue]

Sorry for going totally off topic here on you, but I have the same clip ons as you.  What brand are they?  I also have the same suspension risers installed on my rear hoop.  My clipons also sit flush like yours.  I havent been able to ride the bike yet, but once I do I will give you some feedback of the handling characteristics.

The clipons are from the DP catalog.

Blue, have you had your suspension set up properly? My understanding is that will greatly reduce your chance of headshake, as th reason for headshake, is that the suspension can't deal wit the bumps. Plus if you are still rocking the stock springs, you can upgrade those, for about $200 plus labor (or do it yourself). Alot cheaper than $4-600+ for a steering dampner. Plus it will ride a lot better anyway.

My suspension has been upgraded for me.  RaceTech up front and an Ohlin's rear shock.

I went for a 100 mile ride yesterday with my Dad (Father's Day).  I flogged the bike really hard and had no headshake at all; riding over all types of pavement.  I really like how quick the bike changes direction.  So, I am back to considering all options.
Decisions, decisions...

[ducpainter]

Have you considered removing the spacers and just winding out the joints?

The threads are long enough to make quite a change in height.

[Blue]

Have you considered removing the spacers and just winding out the joints?

The threads are long enough to make quite a change in height.

Yes, I have. 
Since I am about 30mm up front stock, I thought about removing the spacers and going 10mm up on the heim joints to see if the bike still handles as I want it to.  If not, then 20 mm. 
Do you know how long the threads on the heim joints are?  I did not measure them while they were out. 

[ducpainter]

Yes, I have. 
Since I am about 30mm up front stock, I thought about removing the spacers and going 10mm up on the heim joints to see if the bike still handles as I want it to.  If not, then 20 mm. 
Do you know how long the threads on the heim joints are?  I did not measure them while they were out. 

I don't know the length. I do know you can get the 10mm relatively safely. I have 1/2" of threads exposed below the jamb nut, but I have ignored the engineering standard of a full diameter of thread in the hoop. I feel safe enough, but I can't recommend that you do it.

No way you can get 20mm.

[greenmonster]

W that nice suspension you have & forks 27mm over triple,
I again recommend 10-14mm raise on original heim joints, threads are 22mm IIRC.
I have almost same suspension as you & mine stears quick enough w no shakes.

[Blue]

I don't know the length. I do know you can get the 10mm relatively safely. I have 1/2" of threads exposed below the jamb nut, but I have ignored the engineering standard of a full diameter of thread in the hoop. I feel safe enough, but I can't recommend that you do it.
No way you can get 20mm.

W that nice suspension you have & forks 27mm over triple,
I again recommend 10-14mm raise on original heim joints, threads are 22mm IIRC.
I have almost same suspension as you & mine stears quick enough w no shakes.

Thanks for the added information, I think I will go with 10mm to start with.  If 2mm got me where I wanted to be, that would be what I would go with.  It is all in pursuit of front end feel and loading the front tire. 
Thanks for length of the heim joints information.  I agree, the suspension is wonderful; I just need to sort out the right amount of trail for my Monster. 

[greenmonster]

And I`ve been where you are:
+28mm rear, feels like I need a steering damper.
Back to 14mm rear, hmmm, feels like I don`t need st damper!

[koko64]

Hey Blue

Hows that bike handling?