Rear spring weight - SV650.org

DomP · 27-08-17, 10:27 AM

Just looked on ktech to calculate a spring rate for my 142lbs without gear, it came up with 6.8kg/mm which sounds incredibly low. Not even sure I could find a stock replacement from a gsxr or zxr that would be that low?

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Bibio · 28-08-17, 12:56 PM

my advice is keep saving for a proper shock.

DomP · 28-08-17, 07:54 PM

Yeah I know I should but having hacked the toolbox I'm now desperate to do some modding

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Bibio · 28-08-17, 08:09 PM

some good news i suppose is if you can change out the spring on the new shock and its the same size as the SV one then the SV one is perfect for your weight. only problem is you will have to demolish the SV shock to get the spring off.

DomP · 28-08-17, 08:10 PM

Hey now there's an idea! How self serviceable is a zx6r shock then?

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Bibio · 28-08-17, 10:12 PM

you would need to have a look and see if the spring seat is removable. if it is its just a case of winding the collars up and removing the spring seat, change the spring out and put the spring seat back in.

johnnyrod · 29-08-17, 01:49 PM

Am 99% sure my Ohlins has a 9.0kg spring. I'm about 10 stone, I was told it was good for up to about 15 stone of rider.

DomP · 29-08-17, 04:57 PM

Is that not quite a heavy spring for 10st, everything I've read suggests no more than 8.0 for my weight. Having watched some youtube vidoes I'm tempted to buy a second hand zxr shock of the right length and service it using my spring like Lance suggested.

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Bibio · 29-08-17, 05:31 PM

a 9.0kg spring is waaaaay to heavy for a 10st rider it should be around 7.0.

unlike front springs there is a greater range of rear springs, the reason for this is to match rider weight better.

easy way to tell is set the static sag to around 7-10mm then jump on and see how much it compresses. your looking for a total of around 35-38mm drop for road use. if its under the 35 then the shock wont be working within its proper stroke and topping out too easily.

a pointy SV rear will hop and skip and slide all over the place with too heavy a spring as the linkage rate is around 1.8-1 which means that for every 18mm the wheel rises the shock shaft only moves 10mm, unlike the curvy which is a 1-1. so adding too heavy a spring will not allow the shock shaft to work properly and not allow the valving to do its job.

johnnyrod · 29-08-17, 08:23 PM

Will check tomorrow. The SV's linkage has more leverage than e.g. GSXR

27-08-17, 10:27 AM	#1
DomP Member Join Date: Oct 2014 Location: Kington Herefordshire Posts: 916	Rear spring weight Just looked on ktech to calculate a spring rate for my 142lbs without gear, it came up with 6.8kg/mm which sounds incredibly low. Not even sure I could find a stock replacement from a gsxr or zxr that would be that low? Sent from my SM-G903F using Tapatalk __________________ Black 2010 SV650S Fully faired White 2011 YZF R125 sold

28-08-17, 12:56 PM	#2
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: Rear spring weight my advice is keep saving for a proper shock.

28-08-17, 07:54 PM	#3
DomP Member Join Date: Oct 2014 Location: Kington Herefordshire Posts: 916	Re: Rear spring weight Yeah I know I should but having hacked the toolbox I'm now desperate to do some modding Sent from my SM-G903F using Tapatalk __________________ Black 2010 SV650S Fully faired White 2011 YZF R125 sold

28-08-17, 08:09 PM	#4
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: Rear spring weight some good news i suppose is if you can change out the spring on the new shock and its the same size as the SV one then the SV one is perfect for your weight. only problem is you will have to demolish the SV shock to get the spring off.

28-08-17, 08:10 PM	#5
DomP Member Join Date: Oct 2014 Location: Kington Herefordshire Posts: 916	Re: Rear spring weight Hey now there's an idea! How self serviceable is a zx6r shock then? Sent from my SM-G903F using Tapatalk __________________ Black 2010 SV650S Fully faired White 2011 YZF R125 sold

28-08-17, 10:12 PM	#6
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: Rear spring weight you would need to have a look and see if the spring seat is removable. if it is its just a case of winding the collars up and removing the spring seat, change the spring out and put the spring seat back in.

29-08-17, 01:49 PM	#7
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,122	Re: Rear spring weight Am 99% sure my Ohlins has a 9.0kg spring. I'm about 10 stone, I was told it was good for up to about 15 stone of rider.

29-08-17, 04:57 PM	#8
DomP Member Join Date: Oct 2014 Location: Kington Herefordshire Posts: 916	Re: Rear spring weight Is that not quite a heavy spring for 10st, everything I've read suggests no more than 8.0 for my weight. Having watched some youtube vidoes I'm tempted to buy a second hand zxr shock of the right length and service it using my spring like Lance suggested. Sent from my SM-G903F using Tapatalk __________________ Black 2010 SV650S Fully faired White 2011 YZF R125 sold

29-08-17, 05:31 PM	#9
Bibio Member Mega Poster Join Date: Jul 2008 Location: here as devil's advocate Posts: 11,540	Re: Rear spring weight a 9.0kg spring is waaaaay to heavy for a 10st rider it should be around 7.0. unlike front springs there is a greater range of rear springs, the reason for this is to match rider weight better. easy way to tell is set the static sag to around 7-10mm then jump on and see how much it compresses. your looking for a total of around 35-38mm drop for road use. if its under the 35 then the shock wont be working within its proper stroke and topping out too easily. a pointy SV rear will hop and skip and slide all over the place with too heavy a spring as the linkage rate is around 1.8-1 which means that for every 18mm the wheel rises the shock shaft only moves 10mm, unlike the curvy which is a 1-1. so adding too heavy a spring will not allow the shock shaft to work properly and not allow the valving to do its job.

29-08-17, 08:23 PM	#10
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,122	Re: Rear spring weight Will check tomorrow. The SV's linkage has more leverage than e.g. GSXR

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