Modified SV 650s? - Page 9 - SV650.org

northwind · 09-08-09, 04:10 PM

Just using shorthand there mate, leverages tend to be fairly comparable. But, it's not true that displacement counts for nothing, it's just not everything.

yorkie_chris · 09-08-09, 04:18 PM

Ok so maybe the weight of the caliper, but it is the area of the piston(s) which makes the difference, you could have a bore a mile long containing 200 gallons and hydraulically it would act the same as one an inch long containing 2 ounces.

northwind · 09-08-09, 04:43 PM

Meh, that's just semantics, since the bore length is pretty much standard. Find me a motorbike with pistons a mile long and I'll accept your point

yorkie_chris · 09-08-09, 05:26 PM

So if they're all about the same, then why is displacement a factor?

northwind · 09-08-09, 05:31 PM

Because, if bore length is the same or similiar, and displacement varies significantly, then the surface area is the varying element. So it's just 2 ways of saying the exact same thing.

<edit- stroke not bore, oops>

yorkie_chris · 09-08-09, 05:36 PM

No it isn't, surface area is the fixed factor, as well as the one which makes the difference to behaviour.

Where do you measure displacement? Pistons retracted, extended?

Look at caliper on my RD400, HUGE volume, 1 piston, no power!

I bet if you were looking to measure up some calipers to have a rough guess at how they'd behave you would measure diameter of pistons, work out the sectional area and work from that. I bet volume of caliper would not even be considered

northwind · 09-08-09, 05:39 PM

Ach, I said bore when I meant stroke, scuse me

Bore length makes no sense at all.

09-08-09, 06:13 PM

So your saying brake power is effected by Piston bore more than anything? Stroke doesnt matter as the piston usually only moves back away from the Rotor a small amount anyway... Though a bigger stoke might help with brake fade as there is more oil to warm up... That would make sense to me. Having a bigger bore is kinda like having more leverage. But then brake pads material and set-up make a difference, more leading edge means more initial stopping power... apparently. I expect bigger area means more actual stopping power.

Is that what you lot were saying?

northwind · 09-08-09, 06:28 PM

Nah, power has so many variables I don't even start making assumptions about what works best.

09-08-09, 07:39 PM

Its only what I read about the different callipers on the market. There was a great article in PB about it all.

09-08-09, 04:10 PM	#81
northwind Moderator Mega Poster Join Date: Jan 2004 Location: In the garage where I belong Posts: 17,083	Re: Modified SV 650s? Just using shorthand there mate, leverages tend to be fairly comparable. But, it's not true that displacement counts for nothing, it's just not everything. __________________ "We are the angry mob, we read the papers every day We like what we like, we hate what we hate But we're oh so easily swayed"

09-08-09, 04:18 PM	#82
yorkie_chris Noisy Git Mega Poster Join Date: Apr 2007 Location: Halifax/Leeds Posts: 26,645	Re: Modified SV 650s? Ok so maybe the weight of the caliper, but it is the area of the piston(s) which makes the difference, you could have a bore a mile long containing 200 gallons and hydraulically it would act the same as one an inch long containing 2 ounces. __________________ Currently Ex Biker Now rebuilding a 63' fishing trawler as a dive boat

09-08-09, 04:43 PM	#83
northwind Moderator Mega Poster Join Date: Jan 2004 Location: In the garage where I belong Posts: 17,083	Re: Modified SV 650s? Meh, that's just semantics, since the bore length is pretty much standard. Find me a motorbike with pistons a mile long and I'll accept your point __________________ "We are the angry mob, we read the papers every day We like what we like, we hate what we hate But we're oh so easily swayed"

09-08-09, 05:26 PM	#84
yorkie_chris Noisy Git Mega Poster Join Date: Apr 2007 Location: Halifax/Leeds Posts: 26,645	Re: Modified SV 650s? So if they're all about the same, then why is displacement a factor? __________________ Currently Ex Biker Now rebuilding a 63' fishing trawler as a dive boat

09-08-09, 05:31 PM	#85
northwind Moderator Mega Poster Join Date: Jan 2004 Location: In the garage where I belong Posts: 17,083	Re: Modified SV 650s? Because, if bore length is the same or similiar, and displacement varies significantly, then the surface area is the varying element. So it's just 2 ways of saying the exact same thing. <edit- stroke not bore, oops> __________________ "We are the angry mob, we read the papers every day We like what we like, we hate what we hate But we're oh so easily swayed" Last edited by northwind; 09-08-09 at 05:39 PM.

09-08-09, 05:36 PM	#86
yorkie_chris Noisy Git Mega Poster Join Date: Apr 2007 Location: Halifax/Leeds Posts: 26,645	Re: Modified SV 650s? No it isn't, surface area is the fixed factor, as well as the one which makes the difference to behaviour. Where do you measure displacement? Pistons retracted, extended? Look at caliper on my RD400, HUGE volume, 1 piston, no power! I bet if you were looking to measure up some calipers to have a rough guess at how they'd behave you would measure diameter of pistons, work out the sectional area and work from that. I bet volume of caliper would not even be considered __________________ Currently Ex Biker Now rebuilding a 63' fishing trawler as a dive boat

09-08-09, 05:39 PM	#87
northwind Moderator Mega Poster Join Date: Jan 2004 Location: In the garage where I belong Posts: 17,083	Re: Modified SV 650s? Ach, I said bore when I meant stroke, scuse me Bore length makes no sense at all. __________________ "We are the angry mob, we read the papers every day We like what we like, we hate what we hate But we're oh so easily swayed"

09-08-09, 06:13 PM	#88
ThEGr33k Guest Posts: n/a	Re: Modified SV 650s? So your saying brake power is effected by Piston bore more than anything? Stroke doesnt matter as the piston usually only moves back away from the Rotor a small amount anyway... Though a bigger stoke might help with brake fade as there is more oil to warm up... That would make sense to me. Having a bigger bore is kinda like having more leverage. But then brake pads material and set-up make a difference, more leading edge means more initial stopping power... apparently. I expect bigger area means more actual stopping power. Is that what you lot were saying? Last edited by ThEGr33k; 09-08-09 at 06:16 PM.

09-08-09, 06:28 PM	#89
northwind Moderator Mega Poster Join Date: Jan 2004 Location: In the garage where I belong Posts: 17,083	Re: Modified SV 650s? Nah, power has so many variables I don't even start making assumptions about what works best. __________________ "We are the angry mob, we read the papers every day We like what we like, we hate what we hate But we're oh so easily swayed"

09-08-09, 07:39 PM	#90
ThEGr33k Guest Posts: n/a	Re: Modified SV 650s? Its only what I read about the different callipers on the market. There was a great article in PB about it all.

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