Monster 900Sie 50000mile refresh.

[Dukedesmo]

Regarding lighter wheels, I too was surprised, indeed shocked at the difference felt.

I replaced the wheels on my 916 with Marchesini forged 10-spokes and whilst not carbon light they are significantly lighter than the original 3-spoke wheels.

Fitting them improved every aspect of riding: acceleration, braking and cornering with no downside (other than the cost). The thing that hit me the most was how much more agile the bike felt, especially tipping into a corner, it was like riding a different bike.

Of course you get used to it after a few hours and it all becomes the new normal but of the many upgrades I have made to that bike (and there are many) - more power, less weight, better brakes & suspension etc., lighter wheels were by far the best, most noticeable of all.

It is definitely something I'd like to do to the Monster one day

My advice to anyone considering any modifications - lighter wheels are the best 'bang for your buck' by far.

[350TSS]

I read somewhere that Michelin tyres because of their softer tyre wall construction are significantly lighter than other brands (from memory about 10%).
Manufacturers do not appear to quote tyre weights in their blurb. If it is true then the combination of lighter wheels and lighter tyres should lead to faster acceleration (the wheel and tyre are effectively another flywheel) improved traction because the lighter wheel/tyre combination is better able to follow the profile of the road surface and better/faster directional change due to reduced gyroscopic forces.

[Mr Gazza]

Just checked the Ti disc bolts against standard ones.
The Ti are 4g a piece lighter than the standard ones so 4 x 12 = 48g. I've got my 49g deficit back.
Also had Ti caliper bolts for a while so that put's me slightly ahead of standard, but not dramatically. I'm staying fairly level weight wise but gaining upgraded brakes.

Hoping for the phone to ring tomorrow, so I can pick up the centre stand for the weekend.

[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.

[utopia]

Also,
Dukedesmo sums up the advantages of lightweight wheels perfectly.

With respect to the improved acceleration, I would say that it felt like the carbon wheels had given the bike at least an extra 10bhp if not more ... and remember the 750 only produces 60 odd bhp in the first place so we're talking over 15% increase.

Another advantage of the tune-up that comes from lighter wheels is that the improved performance (unlike engine tuning) puts no extra load whatsoever on any component part .. in fact it reduces overall stress in more than one area.
Its like magical free performance (apart from financially of course).

[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.)

[Darren69]

Keep your eyes peeled for some S4/ST4 5 spokes! I read that they are 500g lighter ea than the standard ones, which may not sound much. 1kg static is something then you have less gyro aswell. May not be carbon but in the right direction, cheaper too!