Ideal race bike weight distribution

[TonyB]

I decided to weigh the Ducati after talking to another racer and hearing how much weight he'd removed from his. At 170.9kg minus fuel, mine was substantially heavier than his. My rough calculations indicate I can drop around 8 to 10kg off it "fairly easily", but thats not the point of this thread.

Is there an 'ideal' that one should aim for, or is it pretty much irrelavent because the weight distribution with the rider on board is far more important? My bike ended up with 86.6kg at the front wheel and 84.3kg at the rear. (50.7% F, 49.3% R).

Anyone care to give their thoughts on this?

[Clivoris]

Good question. I saw something in PB magazine recently that said something like the engine being the heaviest component tends to be placed as far forward as possible by the designer peoples. The impression I got was that having the weight toward the front was good, but reducing overall weight was gooder. The basic layout of a bike limits how much weight can be shifted to the front, so it would be unlikely to shift so much weight forward to cause problems.

[lostinflyz]

I would have thought that the least weight possible was generally good for the most part, as its unlikely your going to excessively reduce weight one end and not the othe, to the point that the weight distribution becomes silly. Changing the weight distribution on the bike may alter the overall setup somewhat though (and vice versa). Inherently some bikes will be front heavy and others rear biased.

[wharfy]

If my reading of Keith Codes book is correct it doesn't matter too much while the bike is at rest, (where most bikes are roughly 50/50) but when cornering most bikes are designed to operate best at about 60/40 (rear/front) and maybe as much as 70/30 and all you need to do is accelerate enough to transfer that weight to the rear ( a smooth roll on throughout the turn ) on the straight it doesn't matter much - Accelerating almost all the weight is on the rear (100% in a wheelie) and braking almost all on the front (100% in a stoppie) .
Sounds simple I dunno why I can't manage it

[Clivoris]

If my reading of Keith Codes book is correct it doesn't matter too much while the bike is at rest, (where most bikes are roughly 50/50) but when cornering most bikes are designed to operate best at about 60/40 (rear/front) and maybe as much as 70/30 and all you need to do is accelerate enough to transfer that weight to the rear ( a smooth roll on throughout the turn ) on the straight it doesn't matter much - Accelerating almost all the weight is on the rear (100% in a wheelie) and braking almost all on the front (100% in a stoppie) .
Sounds simple I dunno why I can't manage it

Bang on mate. The more weight on the front at rest, the greater the potential for accelleration without unsettling the bike? Given wise rider input of course.

[suzuki21]

The new BMW has the motor too close to the front wheel and the front patter's like a bastard. Apparently their WSBK has been struggling with the same problem. Suspension tuning has helped but that can only do so much.

[Clivoris]

The new BMW has the motor too close to the front wheel and the front patter's like a bastard. Apparently their WSBK has been struggling with the same problem. Suspension tuning has helped but that can only do so much.

That's intresting info. What's the world coming to when I can't trust PB magazine?

[Clivoris]

The new BMW has the motor too close to the front wheel and the front patter's like a bastard. Apparently their WSBK has been struggling with the same problem. Suspension tuning has helped but that can only do so much.

Been pondering this a bit more. Isn't it sometimes about chassis flex or lack of flex in the wrong places?

[Maido]

The new BMW has the motor too close to the front wheel and the front patter's like a bastard. Apparently their WSBK has been struggling with the same problem. Suspension tuning has helped but that can only do so much.

Can you quote the web article or give a source for this, I wouldn't mind reading about it.
Cheers
Jeremy

[TonyB]

So from this, I reckon you need to aim for about 50/50 with rider on board. 60/40 being achieved with throttle control

[suzuki21]

Can you quote the web article or give a source for this, I wouldn't mind reading about it.
Cheers
Jeremy

Gareth Jones said so during his test with the factory BMW team. He also said it was the fastest thing he had ever ridden, and it was damn near a stock motor.
Weight distribution is a funny thing, it also depends on the centre of gravity. That chassis book mentioned is excellent but it's easy to "out tech" oneself.

[quickbuck]

Weight distribution is a funny thing, it also depends on the centre of gravity. .

Ummm? What?
Isn't the Centre of Gravity a Resultant of the weight distribution?

[Ocean1]

Think he's talking about cantre of mass height, as opposed to front/rear bias.

[quickbuck]

Think he's talking about cantre of mass height, as opposed to front/rear bias.

Ahhhh,
Yes, I see.
NOT the Centre of Gravity then.
More akin to the "Water Line".

[Ocean1]

Ahhhh,
Yes, I see.
NOT the Centre of Gravity then.
More akin to the "Water Line".

Yup, vertical COG, rather than horozontal.

LWL on several of my dirt bikes has often been well above the vertical COG. I'm too old for that bullshit nowadays.