How to: fit a BMW s1000rr rear shock to a VFR 400 nc30

[CMSMJ1]

You can just file off something though?

[jetblack]

So, i've done a bit more reading and the stock BMW spring is, apparently 90 Nmm which if my maths is correct is about a 520lb spring. (please correct me as maths has never been my strong point)

So...if we go sticking a 800lb spring on it then we are increasing the spring rate by about 55% over stock.

Does this help us to calculate the corrections required to the shim stack to restore the damping properties to the stock range?

How do you factor in the NC30's linkage/dogbone into the equation?

Oh and by the way, apparently the 2010/11 S1000rr shock is 4mm longer than the 2012 model version so this will affect ride height...

[speedy231278]

90 Newtons is 8.829KG. I presume Imperial is pounds per inch. 8.829KG is 19.447 pounds. 25.4mm to an inch, so I reckon the spring is 19.447*25.4=493.957lbs, so say 500.

[jetblack]

90 Newtons is 8.829KG. I presume Imperial is pounds per inch. 8.829KG is 19.447 pounds. 25.4mm to an inch, so I reckon the spring is 19.447*25.4=493.957lbs, so say 500.

Cool, so your maths comes out similar to mine (within 27lbs)

So, now we just need to work out the effect of fitting a spring with a rate approx 55% more than the stock spring that ships with the BMW shock, and how that wll affect the ability of the shock to work correctly...When bolted to an NC30 linkage, who's ratio will be differnt from that of the stock BMW set up.

Any suspension/engineering experts out there care to help us work this out?

I'd rather get the BMW shock rebuilt before fitting it.

[999Gomerz]

90 Newtons is 8.829KG. I presume Imperial is pounds per inch. 8.829KG is 19.447 pounds. 25.4mm to an inch, so I reckon the spring is 19.447*25.4=493.957lbs, so say 500.

Cool, so your maths comes out similar to mine (within 27lbs)

So, now we just need to work out the effect of fitting a spring with a rate approx 55% more than the stock spring that ships with the BMW shock, and how that wll affect the ability of the shock to work correctly...When bolted to an NC30 linkage, who's ratio will be differnt from that of the stock BMW set up.

Any suspension/engineering experts out there care to help us work this out?

I'd rather get the BMW shock rebuilt before fitting it.

Buy an HRC link from Rick you Pikey, it will cost you almost the same to get the BMW revalved and with a heavier spring.

[jetblack]

90 Newtons is 8.829KG. I presume Imperial is pounds per inch. 8.829KG is 19.447 pounds. 25.4mm to an inch, so I reckon the spring is 19.447*25.4=493.957lbs, so say 500.

Cool, so your maths comes out similar to mine (within 27lbs)

So, now we just need to work out the effect of fitting a spring with a rate approx 55% more than the stock spring that ships with the BMW shock, and how that wll affect the ability of the shock to work correctly...When bolted to an NC30 linkage, who's ratio will be differnt from that of the stock BMW set up.

Any suspension/engineering experts out there care to help us work this out?

I'd rather get the BMW shock rebuilt before fitting it.

Buy an HRC link from Rick you Pikey, it will cost you almost the same to get the BMW revalved and with a heavier spring.

I probably will do

But i just wanted to try and understand the mechanics of whats going on... (oh, and i'm not a pikey btw! )

[jetblack]

[quote="Timon"]Thought I would post up a quick guide as the question seemed to be asked alot recently. Rick - I hope you dont mind, used a few of you pictures. Mods - feel free to modify/delete

How to: fit a BMW s1000rr rear shock to a VFR 400 nc30
2.
With your new BMW shock you will have to slim the top of the shock down to fit into VFR frame, to aprox 38.4mm across. (alternatively you can widen the inside of the frame to suit the shock- I chose not to do it this way to keep the frame standard)



How did you slim the top of the shock down? file? Dremel?

Got mine here in front of me and not sure of the best way to get a good, even finish.

[porndoguk]

file by hand

[jetblack]

Thanks Rick. i've got a dremmel with a large, flat grinding stone attachment (same size as the bushing face that needs to be ground down so i'm gonna try that first and if that fails i will revert to doing it by hand - Did you take the bush/insert out to file it or leave it in the shock body?

tried tapping it gently with a hammer but it doesn't look like it wants to move...

[iDemonix]

I'm not sure it comes out the shock, just get a hand file and file it for 30 seconds, see if it fits yet, if not - repeat. That's what I did :)