Monster 900Sie 50000mile refresh.

[Mr Gazza]

The Ti bolts, nipples and axle nut were delivered this morning from RaceTi.
I also got an email from the carrier to say that they would soon have the Tyres from M&P!! (I ordered those a day before the Ti bits!)

I've fitted and weighed all but a couple of the Ti bits. All put in with Moly grease on the threads as I do with all nuts and bolts, but especially important with Titanium to prevent it galling and making expensive trouble!

Total weight saving on what I fitted today is 147g of which 77g is unsprung.
Comparing callipers, the Goldlines are 948g each including very worn organic pads.
The Brembo P4 four pads are 1011g each with new sintered pads piled on top.
I think the sintered pads account for most of the difference as they are mostly metal.

So I've gained 126 grams there, but saved 77g unsprung, so I'm up 49g on unsprung but hopefully with a tangible gain in brake power.
I haven't taken into account the Ti disc bolts yet, so there's a chance to get back that 49g.
Of course new tyres are considerably heavier than worn ones, especially all weather sports touring tyres, but new tyres just make the whole bike feel lighter and newer, so well worth it.
I remember Capo compiling a list of tyre weights and even comparing worn with new, but he was a good deal more obsessed than me. He did manage to hulk about 6 stone off his S4R though.

Also dropped the centre stand into my cousin for welding and bending. Interesting to see if I can save most of it's weight with the rear brake parts that I'm shedding. Haven't dared put it on the scales yet!

[utopia]

Originally Posted by Mr Gazza

I remember Capo compiling a list of tyre weights and even comparing worn with new, but he was a good deal more obsessed than me. He did manage to hulk about 6 stone off his S4R though.

If memory serves, he used to use michelin pilot pure tyres.
He was certainly obsessed with shedding weight.
He once got me to make him a titanium rivet to reassemble his seat latch after he had replaced its steel backplate with a hand cut titanium item.
I do miss his boyish grin when we addressed such issues.

We once slung his bike from the roof trusses of my garage via a pair of electronic balances.
His S4R clocked around 145kg ... again if memory serves.
My 750 did 165kg, though its lost 2 or 3 more since then.

Gotta say though, ultra lightweight wheels are a revelation.
My carbon Dymags were even lighter than Capo's mag-alloy Marchesinis and the difference they made was startling.
A triple whammy as they reduce unsprung weight, rotational inertia and gyroscopic effect all into the same bargain.
A big surprise to me was the effect of the reduced rotational inertia which had a serious influence on the bike's acceleration as they spun up much more easily.
It was really noticeable as soon as I took the bike out.
I wasn't expecting that.

[Mr Gazza]

Yes that is quite a Monster, I wonder if we still have visiting rights?

I'm going to contend the gyroscopic effect that you mention in a playful way, as I don't fully understand the details of the principle.
Does the weight of the gyro have an influence or is it the speed of rotation?
Motorcycle steering is initiated by interference to the gyro's procession and if the effect was reduced by weight then I think you would have noticed more effort required to initiate a turn and overcome the bike's mass? Whereas I think you have said the reverse in the past?

I would also posit that the effect has been increased, (or remains the same?) if the major weight is now at the periphery (the tyre) relatively speaking, The central part, (the wheel.) having a lesser effect? That brings diameter into the equation too come to think of it.

There's a nice think for you if you fancied a think and couldn't think of a think..

[utopia]

Originally Posted by Mr Gazza

I'm going to contend the gyroscopic effect that you mention in a playful way, as I don't fully understand the details of the principle.
Does the weight of the gyro have an influence or is it the speed of rotation?
Motorcycle steering is initiated by interference to the gyro's procession and if the effect was reduced by weight then I think you would have noticed more effort required to initiate a turn and overcome the bike's mass? Whereas I think you have said the reverse in the past?

I would also posit that the effect has been increased, (or remains the same?) if the major weight is now at the periphery (the tyre) relatively speaking, The central part, (the wheel.) having a lesser effect? That brings diameter into the equation too come to think of it.

There's a nice think for you if you fancied a think and couldn't think of a think..

Ha !
Back down the rabbit hole we go.
I've never yet found my way out.
Anyway, let's have another go.
And joke on you, mate, cos I'm now going to clutter your thread with goodness knows how much ramble.
But first, I might say (and here I quote Jefferson Airplane in paraphrase) ...
Well I thunk and thunk.
Couldn't think of anything better.
I tried so hard.
But thinking ain.t doing me no good, people.
Thinking ain't doing me no good.
https://www.youtube.com/watch?v=JRNRVe0kgC0
Though maybe I'm wrong ... it probably helps keep the Alzheimer's at bay.

I have some notes in the attic from my days as an engineering student in the mid 1970's ... but I'm going to leave them there and instead try and reason my own way through the warren .. cos that's more fun.
I'll get stuff wrong, probably, but it won't be the first time.

So...
Lets say that gyroscopic forces arise from the angular momentum of a rotating mass.
The two variables here are 1) the mass and 2) the radius of rotation .. and 3) the speed of rotation (nobody expects the spanish inquisition) ... but lets rule the latter out by assuming a constant speed.
The mass is distributed over the whole radius, from wheel spindle to tyre periphery (and across the width of the wheel too, but ...)
Lets resolve that mass distribution to a single centre of mass ... imagine a rotating wire hoop of infinite density and thinness (although I use the word infinite loosely here otherwise it would disappear up its own black arsehole, but I digress).
So we now have a single hoop of infinitely thin mass rotating at a single "effective radius".
And here I can say "yes", it seems obvious that lighter wheels would not only reduce the magnitude of the mass but also its distribution and hence the effective radius, both of which contribute to reduced angular momentum.
Since gyroscopic forces arise from angular momentum then those gyroscopic forces must be reduced if the wheels are lighter.

Here is where words start to play tricks ... well on me at least (if they haven't done so already).
But in for a penny .....

So ...
Less angular momentum (from lighter wheels) should mean less force necessary to overcome said angular momentum (Newton's laws of motion). Hence easier steering.
But at the same time I can see your argument, Gary, that if there are more gyroscopic forces acting (from heavier wheels) then there are grounds for saying that there would be a greater tendency for the bike countersteer. Hence easier countersteering ???

I remain somewhat baffled and perplexed by all this.
And there I'm going to leave it, for now.
Capo would have said that only calculations will provide the answer, but that would mean a good rummage in the attic for my 50 year old notes.
I might just go out for a nice relaxing ride on my old Raleigh bicycle instead.
Trouble is, I think there's something wrong with it.
Every time I steer left the bloody thing turns to the right.
Which isn't great on the canal towpath.

By the way, no substances other than tea were used in the production of this rambling.

[Mr Gazza]

Originally Posted by utopia

Though maybe I'm wrong ... it probably helps keep the Alzheimer's at bay?

Oh dear! I don't think so..
I do like the Jefferson Airplane association though, as I'm a big fan and of Grace Slick in particular, but hadn't come across that track before. I instantly though of her when you mentioned the rabbit hole, but actually had Spike Milligan in mind with the think of a think thing.

Glad it gave you a think though and also a bit sorry really! I do realise of course that light wheels are a good thing.
Pondering, after writing the comments I also realised that bicycle wheels are considerably lighter than you could possibly get a motorcycle wheel and yet the gyroscopic forces still work to initiate a turn even at very low speeds.
It is probably not possible to make a rotating mass light enough to negate the gyroscopic force? Certainly not on a motorcycle where a tyre will always be required.

Thanks for the think and careful with that tea (Eugene.)