Adjustable Susp Rocker on ebay

[Darren69]

Not mine, but any M900 modders want this?

http://www.ebay.co.uk/itm/281896680486?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[utopia]

Well, I'm all spent out really but I can't help having a certain interest in this nevertheless.
This has lead me to stare at the pics and drool a bit, which in turn has raised a question, namely .....
What is the fourth pivot for ? .... the one with the long bolt in it in this pic ....
Hopefully I'm just being thick or haven't woken up properly yet, but I can't see its purpose.
Any suggestions ?

http://i1326.photobucket.com/albums/u644/photopia132/851%20amp%20888%20SP%20adj%20susp%20rocker%201_zps 3kwdsbr1.jpg (http://s1326.photobucket.com/user/photopia132/media/851%20amp%20888%20SP%20adj%20susp%20rocker%201_zps 3kwdsbr1.jpg.html)

I'm not even sure if I need such adjustment, still less what adjustments to make, but the chance to make any at all doesn't come up very often.
I think this might just end up as one of those auctions where I'm totally unprepared and could easily make a last minute, rash bid in the heat of the moment.
At which point my bank account will have a panic attack.
But then again, the monster has transcended all monetary issues now and has become pure art and emotion, so .........
Quick, somebody tell me that this wont fit my 750.

Oh, and does anybody know ... are these lighter than the std, solid rockers ?
They look it.

ps. perhaps a tad naughty but .... If any other members are planning to bid, drop me a pm and you could probably persuade me to hold back, thus avoiding the price being inflated.

[Darren69]

I was actually thinking of you with this in mind as I think you mentioned them before. You've saved loads on your wheels, you might as well ;) No idea about the bolt mind you.

[utopia]

Don't say that.
Just don't ...... :mand:

And thanks.

[Mr Gazza]

Be strong Utopia...Don't listen to them...You don't need it..

There is no point to this part on a Monster. The adjustment of the rose joints is enough.
This is a trick part for a racer with, at the time, rather radical new rear suspension.

It could have the advantage of a bit more adjustment range, and perhaps more covenient access with the tank and seat off (not really covenient on a Monster?).
It does ensure that the adjustment will be concentric, where as it is possible to wind one rose joint more than the other, if you are a muppet.

The detents would make going back to known settings an advantage for various circuits.

Forget it..You set your bike up with the hoop and then have a nice strong rocker for real roads.

As for the extra pivot and long bolt....The long bolt is in the extra hole just to confuse you...I think that the rocker can be used both ways up with either pivot to futher increase the adjustment range or accomodate a different length shock?....you still don't need it...:rolleyes:

[utopia]

Wise words, Gazza, and they echo my own thoughts really.
And furthermore, my Nitron shock has a length adjuster on the lower mounting so I can make adjustments there too, as well as at the rose joints.
But, I studied engineering in my youth, largely motivated by an interest in bikes, and the opportunity to experiment with various suspension set-ups is attractive just from the point of view of continuing that thread of engineering interest.
In fact, that's a large part of the reason for buying the carbon wheels as well.
So the scope for experimentation is appealing, even if it only proves to be of little if any practical benefit on a bike used mostly on the road.
Just for the learning process really .... though that's not to say that I totally rule out the chance of it actually resulting in some overall improvement, but I wouldn't necessarily expect it.
And another factor is that, though I do very few trackdays, I like to do them on my road bike rather than have a dedicated track tool because that way I find out more about how the road bike works at the extremes of its capabilities, which in turn must make me ride it better under normal road conditions.
The adjustment would add some extra scope there maybe.

I had pondered the strength issue actually, but I think I'm prepared to gamble that it will be within the strength limits necessary for road use.
Mind you, that will include some work with pillion and luggage, which I'm guessing will be a shock for a race component such as this.
But I'm a slender individual, so there's not huge primary weight to cope with.
And the bike will get lighter as time/mods develop.

Capo reckons that the other hole is an alternative shock mount position for more extreme settings (albeit unadjustable, not that you'd need any there).

For the time being I'm going to soak up the adrenalin of a possible purchase for another day or so, 'til the auction ends.
I enjoy that anyway.
Trouble is, you get sucked in then.
I can feel it already.

So well done, you've sown some sensible seeds of doubt there which may help me to resist the bidding temptation, and I thank you for that ... I knew I could rely on you.
Sadly I fear that I may yet need a little more to make me rule it out entirely at this stage.

And remember, this bike is THE ONE.
I'm not going to be buying another roadster to replace it ... ever.
So any benefits from trick parts will be for life ... not just for Christmas as they say.
And consider ... this is a love affair.
If your sweetheart wanted a really expensive dress, you'd but it for her if you had the cash handy wouldn't you ?
My problem is that I had a loan repayed recently so, unusually, the options are open (until I do the sensible thing and pay off my outstanding mortgage, but that would be a sign that I'm growing old and boring now, wouldn't it ?)
Buying this would be much more "rock an' roll".

Right then, anyone from Newcastle want to buy any coal ?
I can make out a convincing case .... :mand:

[Darren69]

If you listened to the voice of reason all the time you wouldn't have bought those carbon wheels for a roadbike in the first place, and when you fit them all your suspension settings/spring rates etc will go out the window anyway so you might need the extra adjustments!

[Mr Gazza]

No no no....You're not thinking straight are you?

If you have ride hieght adjustment on your shock already then it makes the rocker a complete chocolate teapot....And think how much chocolate you could get for £250.

I paid my mortgage off about two weeks ago...I can reccommend it...It's a nice feeling..Now looking forward to some spare bike money later this year..:mand:

Don't be a fool...Drill some more holes in the MDF Monster and play with that!

I will give you a ring about twenty to seven tomorrow evening and distract you.

....BTW. Don't think Capo is right about the extra hole being for a shock....It would need a big clevis type yoke at the top to fit, and then I think it would hit the pivot anyway?...Still prefer my upside down theory.....Say hello to Capo for me...Might see him next Sunday?

[Darren69]

I agree its probably overkill on a regular road monster so I can see Gazzas point. Sure you can adjust the height with the swing arm rod ends but what effect does the eccentric have on things as it tips the shock back or forward and changes the leverage ratio as well as change the ride height? Because of that I'm not sure that the eccentric adj would serve the same purpose as the rod end adjustment. the rod end adjustment would effectively lengthen or shorten the arm but at the same time adjust the height as well. After studying the pics I would agree with Capo that the extra bolt hole is indeed an extra pivot point as it looks like it has bearings fitted, but I don't fully understand what it will do. I expect that it along with the other adjustments would allow you to tune the rear to pretty much what you wanted.

[Darren69]

Correction I mean the eccentric adjustment not the rod end adjustment (that only changes the actual height not the arm lever ratio)

[utopia]

Me ? ....think straight ?
No mate, not since the early 70s. :mand:

But I'm not after ride height adjustment anyway.
Its more about the progressive linkage ... basically how to optimise the compression curve that results from its geometry.
edit ... as Darren describes above.
You're right though, the MDF model is an ideal tool to guide my thoughts on this.
Its just that the auction ends tomorrow and I have other stuff to do today.

I must say, one thought that I had about the other pivot on the rocker was that it might run something else, rather like the swingarm operated pumps that I've heard of ?
Or maybe even to operate a data-logging device to monitor suspension movement perhaps ?
Hmmmm, might that be handy ???? (I'm joking ... I think !!).

Wait a minute though.
Did you mention a teapot ? :thumbsup:

Darren ... you have made my weekend even more interesting and exciting than I had expected.

[slob]

I bet Kato will want it if he's down to his last three ;-)

[Darren69]

yes and thanks, glad about that. Some food for thought there I think especially as most rear shock springs are progressive which only adds to the confusion! I'm sure it can't be a bad thing and worth considering (as the factory did) since your radical wheel changes, so you'll be on the look out for some adjustable M900 Maxton forks next I reckon since yours will be way oversprung/damped for those mega light wheels?

[Dirty]

A hollow tube holds the 2 sides together at that point. I don't think the bolt is supposed to be there.

http://lh4.ggpht.com/_4iYlZ1m8UEM/S87woZtgJ-I/AAAAAAAAFf0/35gnt44HVYg/s800/851%20888%20M900%20Billet%20Corse%20Rocker.JPG

https://lh5.googleusercontent.com/-ETZHv9ZVerM/Te1ZXBynIVI/AAAAAAAAHFw/lmHL8FYdUrw/s400/IMG_9570.jpg

https://lh6.googleusercontent.com/-jOvSJA9tHwo/Te1ZXnN2vXI/AAAAAAAAHF4/aVEByPJUbrU/s400/IMG_5673.jpg

[Darkness]

..... so you'll be on the look out for some adjustable M900 Maxton forks next I reckon since yours will be way oversprung/damped for those mega light wheels?

Aren't the springs rated to suit the weight of the bike and rider rather than unsprung weight? Otherwise, if taken to an absurd level, if the wheels weigh nothing, you wouldn't need springs at all as the bike would just hover there above them.

I can see that the damping may need to reduce though to reflect the reduction in unsprung weight, though I'm thinking that would be the rebound setting only?

Or am I being too theoretical for a New Year?

[Darren69]

No I think you're right the sprung weight would be the same, give or take a few good meals. But the unsprung weight (rebound) would be a lot less hence the need to adjust or it could be like riding on a pogostick! Well I'm guessing it will be harsh since the rebound weight will not balance out with the compression weight, so it would be underdamped?

[Darren69]

Overdamoed even! In any case not balancing out equally.

[Mr Gazza]

Ow yeah...suspenshun..Marvelous!.
Where would we be without it?...Eh?
http://i68.tinypic.com/11i09y9.jpg

[Nickj]

Trick parts can be as much about bragging rights as function and that feeling of knowing that you have that odd esoteric part.
I'd agree that it's of little real or practical use on a road bike

But it is a cool part

[utopia]

It went for £360-ish.
I didn't bid in the end, just hovered in case of a bargain.
Gazza was right .. I don't need one of these.
Well, certainly not this time anyway.
In fact I think I would be more sensible to first (attempt to) calculate the effects of altering the rocker length before deciding whether or not I need one.

Btw, I don't think my new ultralight wheels will have any significant effect on the suspension.
Their reduced inertia will mean that they will respond faster to road imperfections, but beyond that I don't see the suspension being affected much if at all because the sprung weight of the bike will be unchanged.
But I will be putting that question to Mr Maxton for confirmation when the time comes for him to breathe on my forks.
And my creative accountant says I now have about £300 in the kitty towards that, rather than the rocker. :mand:

[Darkness]

...I will be putting that question to Mr Maxton for confirmation when the time comes for him to breathe on my forks.:

I shall be interested in his response?

...And my creative accountant says I now have about £300 in the kitty towards that, rather than the rocker. :mand:

I like that accountant: does he do tax returns too?

:chuckle::chuckle:

[utopia]

Yes, I'll be interested too.
At least I'm changing the wheels BEFORE attending to the front suspension, so if there is any knock-on effect it can be taken into account.
See, I told you I HAD to buy the wheels now !
I had no choice.
And my creative accountant loved the massive discount ... and was heard muttering something about FCRs.

I did ask, but he says he doesn't know what tax is.

[slob]

For 360 quid you could have manufactured your own from scratch.

The creative accountant's tax returns are great but you still get to pay the fines or do the time ;-)

[Dirty]

For 360 quid you could have manufactured your own from scratch.
Where, who? I'm interested!


The creative accountant's tax returns are great but you still get to pay the fines or do the time ;-)

Like Jimmy Carr?

[Darren69]

For 360 quid you could have manufactured your own from scratch.

The creative accountant's tax returns are great but you still get to pay the fines or do the time ;-)

|I was just thinking the same thing, you could get one made for that much! It may have been necessary with the hoop setup, but its interesting that they didn't find it necessary carry the adjustable rocker design over to the later 'rod' type setup?

[slob]

an engineer... utopia for example

[Mr Gazza]

Well done for resisting Jeff...:biggrin:

My maths says that it went for £376.07...Ludicrous!! Unless perhaps you are restoring an 851 or 888, but utter nonsense on a Monster.

Further man maths tells me that you would have had to put in another bid to secure it...I didn't watch the auction, but it looks like the bids were at about £23...So if one more bid would have been enough to win it, it would have been near as dammit four hundred quid.

If some one was daft enough to bid against that, you would have had to go to £450.

So I think you have just saved a definate £400 and a possible £450....That should easily cover new rubber for the new wheels and some towards Mr Manxton too...Win win...:biggrin:

[utopia]

Yeah, it was a funny one really.
Made no financial sense at all .. "bang for buck" was abysmal and it was of dubious practical value to me, considering the riding that I do.
It was really the scope for experimentation which appealed to me.
And I wasn't really bothered about the bling value or bragging rights at all (well only maybe a teensy bit anyway).
But the chance to experiment and learn was appealing.
In the end though, there was just something wrong about buying the kit before I had a clear idea of what experiments I was intending to carry out.
What I would really like to do would be to plot the curves for shock compression vs wheel movement for various combinations of linkage (hoop length, shock length and rocker length) and to do that by calculation and computer processing.
If I ever get that far, it would be then that I might be needing one of these rockers, but not before.
Not that I need to do all this at all .. I'm just curious. (and that might be a pun)