unsprung weight.

Hey Padders

How about Ron for guest of honour at Padfest ? Could also invite Tim.

Hand the pills out and off we go .................. (happy2)

            Cheers
                    Matt

 
Very difficult with a road machine.

When it is stripped and I mean stripped down to chassis weigh every thing below
the springs and as stated make a part allowance for springs, including front forks.

Racers for years have gone on about it hence alloy sprockets etc etc but unless you
have endless time to do the set up, inc spring rates, rebound, damping etc etc in my
humble opinion get the best setup for what you got.

Andy

PS Know bugger all about bike set up but wheel weight and unsprung weight on FF
and F3 took bloody hours to do. Every time you altered the weight of unsprung stuff
like discs, even difference in tyres it altered every bloody thing. Many hours with
bathroom scales uner wheels.
 
When I fitted the (much lighter) 320mm front discs to TOG, the first time I rode the bike, I was very pleasantly surprised at the difference the lower front end un-sprung weight was making to the way the bike rode (generally) and steered (specifically), not a big change of weight by any means, but it taught me that the lower you can get that un-sprung mass, then the better it is going to be, so I am looking for some titanium fork leg drain plug screws.
CLEM
 
I've used a Guzzi tubeless type front wheel - the weight saved on a tube - plus the fact it's at a large diameter is a great way of saving unsprung weight without ruining looks of a classic bike. - Regards - Phil

 
John Robinson's book says that the ratio of sprung to unsprung weight should be as high as possible.

Food for thought really.

If my motorbike handles great and I then fit carbon fibre bodywork and a lithium battery (reducing the sprung weight)...............

Whatever.

H.
 
Harry Lime said:
John Robinson's book says that the ratio of sprung to unsprung weight should be as high as possible.
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phil37 said:
Think Laverda would go along with that John
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OK. Fair play. I asked for that!

 
You need to wear your reading glasses when taking your pills Ron.
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I think you need a little clear light 25 to waken your prescription on the topic as you missed my point comparing a Hi-Perf Valve train to Suspension Un-Sprung Weight. The lighter and stronger the Valve is similar to the reciprocating mass of a suspension, whether or not a spring exists - That's why I referenced the Ducati DESMO Engine.
 
The discussion is about suspension, Ron. We can take up valvetrains in another thread if you want to start one.
There are two effects of unsprung weight for us.
One is gyroscopic mass which has a massive (pun excused) effect on steering and manouverability. That is what Clem and Phil were referring to and it really is noticeable.
Suspension wise, you can get far more sensitivity out of suspension the less weight it has to damp, stop and return, the less it weighs the finer you can tune it.
Both of these are what you ideally get as low as possible.
If you are going to the ?nth degree you will have to dismantle shocks and front suspension to get it.
A few people have pointed out what components to include and where to find detailed info.
 
Well you got me but I've ran Mercede's rear Half Shafts and Jaguar Posi XKE Independent 3:90 Suspensions witn in board Dunlop Disc's rear ends in Automotive Road Racing and understand Un-Sprung Weight whether or not it applies to a Valve Train or a Suspension but Un-Sprung Weight is critical for Efficient Hi-Perf Machines.

I wanted to point the comparison and happy some of us recognize what Un-Sprung weight means if you want the upper edge.

Considering the SF and SFC is 45 years old, it had a great Un-Sprung Rate Ratio considering she was a moderate reving 2 cly mill with a fair amount of Hi-Weight and torque to put you under. She did the Isle of Man for 3 years straight, providing the rider had the BALLS.

If you want to see one of the Lowest Un-Sprung Weight Suspensions, look at the Aussie John Britten Motorcycle.

Hail! Italian Motorcycle Spaghetti frames and light Boranni/Cerrani sprung motorcycle suspensions of the late 60's and early 70's.

I still ride one. My 71 SF still feels like a Moto-Cross under 40 mph - LOL
 
Laverda SF said:
Well you got me but I've ran Mercede's rear Half Shafts and Jaguar Posi XKE Independent 3:90 Suspensions rear ends in Automotive Road Racing and understand Un-Sprung Weight whether or not it applies to a Valve Train or a Suspension but Un-Sprung Weight is critical for Efficient Hi-Perf Machines.

I wanted to point the comparison and happy some of us recognize what Un-Sprung weight means if you want the upper edge.

Considering the SF and SFC is 45 years old, it had a great Un-Sprung Rate Ratio considering she was a moderate reving 2 cly mill with a fair amount of Hi-Weight and torque to put you under. She did the Isle of Man for 3 years straight, providing the rider had the BALLS.

If you want to see one of the Lowest Un-Sprung Weight Suspensions, look at the Aussie John Britten Motorcycle.

Hail! Italian Motorcycle Spaghetti frames and light Boranni/Cerrani sprung motorcycle suspensions of the late 60's and early 70's.

I still ride one. My 71 SF still feels like a Moto-Cross under 40 mph - LOL
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Oh oh thats going to annoy some people. Come to think about it a bit like saying Bon Scott, Angus and Malcolm Young were Australian. :D

                                                                                            Dave
 
Oh oh thats going to annoy some people. Come to think about it a bit like saying Bon Scott, Angus and Malcolm Young were Australian. :D
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Well Breganzie's really showed up Honda, Yamaha and Kawasaki Big 4's back then, plus the Ducati 750SS.
 
Ok Ron so your American sorry
                                  Dave
 
I'm North American - NOT American - I'm Irish Canadian and my heritage has nothing to do with the principles of Un-Spung Weight!.
 
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