The Hopefully New And Improved But Still Unofficial and Purposely Disorganized R65 Forum - Looking for factory R65 fork springs, used or?

bob dominguez

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Looking for factory R65 fork springs, used or?
03/06/10 at 01:57:25

Am testing different setups that will let me go at 60-65mph over some of the rough portions of the freeways in SoCal. So, if you've upgraded your setup to progressive or works and your original fork springs is just collecting dust, I'd be glad to take it off your hands.

If none, does anyone know the factory spring rate specs? Or spring measurements such as wire Diameter, Outside Diameter of coil, distance between coils?

Thanks ...
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Bob Dominguez
1983 R65
Cerritos, CA

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Bob Dominguez, '83 R65, Cerritos, CA

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Barry

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Re: Looking for factory R65 fork springs, used or?
Reply #1 - 03/06/10 at 03:43:59

Bob
Original BMW fork springs are dual rate with 66 coils of which 14 are closely spaced. Wire dia 4.25mm, mean spring dia 22mm
During the initial travel of the forks the spring has 66 active coils and a spring rate of 26.87 lb/in. When the 14 closely spaced coils close up there are 55 active coils which gives a spring rate of 34.1 lb/in. I guess from your questions you know how to do the calcs. Mine are based on Rate =(wire Dia to power 4 * 1470000)/(coil dia to power 3*no of coils) Well there is no other way to do the calc only the precise figure used for youngs modulus is up for debate but the possible error is much smaller than manufacturing tolerances. I have all this on a spreadsheet which I can post if you need it.

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« Last Edit: 03/06/10 at 07:04:10 by Barry »

Barry Hodgson, Cheshire, England 79 R45

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Yikes

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Re: Looking for factory R65 fork springs, used or?
Reply #2 - 03/06/10 at 12:43:11

So are the Progressive springs stiffer than the BMW OEM's? I was thinking of dropping some new springs in my '82 because after 50,000+ miles, I figured it was due as a matter of course. I really would not want to go with a stiffer ride. I was considering getting some Hagon springs, but they are quite a bit more expensive than the Progressives and have over a month wait time. Anybody have experience they can impart to us less knowledgeable types? Undecided

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bob dominguez YaBB Newbies Offline Posts: 10 Cerritos, CA	Re: Looking for factory R65 fork springs, used or? Reply #3 - 03/06/10 at 13:35:59 Barry, Thank you very much. Short of actually having OEM springs in my hands, those are precisely what (info) I was looking for. And I've looked for them all over the 'net. And yes, I'd be interested in your spreadsheet.
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Barry

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Re: Looking for factory R65 fork springs, used or?
Reply #4 - 03/06/10 at 16:50:39

Here's a link to some info on aftermarket spring rates. Not so much on our models but it is interesting to see how soft some of the stock rates were on the older airheads compared to ours. Last time I checked progressive springs were 35/50 lbs/in which is quite a bit stiffer than stock http://mysite.verizon.net/vze4dp63/bmwmotorcycleparts/forks1.html

Also spreadsheet of spring rate calcs attached.
I should add that all measurements were taken from my own springs which I am 99% certain were stock.

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Spring_calcs.zip (2 KB | 4 )

Barry Hodgson, Cheshire, England 79 R45

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Ed Miller God Member Online I Love 65 cc! Posts: 1606 Falls City, OR Gender:	Re: Looking for factory R65 fork springs, used or? Reply #5 - 03/08/10 at 13:33:57 I have a spare pair of springs that came with my replacement fork tubes. As far as I know they are still good. Let me know if you want them and I'll try to find them.
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bob dominguez

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Re: Looking for factory R65 fork springs, used or?
Reply #6 - 03/08/10 at 18:36:21

Hi Barry,
Thanks for the zip file. It should help me make sense out of the different setups I've tried. And the website link too. It contains other BMW and aftermarket spring specs that I found hard to find.

Hi Ed,
Yes, I want them!!! Cheesy

Er, I mean, yes, I'll help you get rid of your old, dusty, and discarded springs. Cool

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Bob Dominguez, '83 R65, Cerritos, CA

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Ed Miller God Member Online I Love 65 cc! Posts: 1606 Falls City, OR Gender:	Re: Looking for factory R65 fork springs, used or? Reply #7 - 03/10/10 at 11:50:57 I'll try and dig them out tonight. A spelunking I will go, ....
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dewjantim Full Member Offline If it hurts, you're still alive!!!!! Posts: 142 Ashland, Ky Gender:	Re: Looking for factory R65 fork springs, used or? Reply #8 - 03/15/10 at 13:13:20 Hey Bob, if Ed doesn't find his I have a set. They have 7000 miles on them and I will sell them for $20 plus shipping . Let me know and I will send them on and you can send me a check(American funds only please) . Contact me at dewjantim@msn.com .......
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Ed Miller

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Re: Looking for factory R65 fork springs, used or?
Reply #9 - 03/16/10 at 20:34:54

Bob, I'm sorry. I was mixed up. I don't have spare springs, I have spares of the assemblies that go inside the fork tube. I got them, with my stanchions, from Airhead Salvage and I guess he wanted to sell the springs separately. And that was so many years ago that I got mixed up. All this time I thought I had a spare pair of springs.

Sorry again,

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Ed Miller
'81 r65
Falls City, OR

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bob dominguez YaBB Newbies Offline Posts: 10 Cerritos, CA	Re: Looking for factory R65 fork springs, used or? Reply #10 - 03/17/10 at 01:04:00 Okay Ed, and thanks for poking around your stash. I will now pursue Dewjantim's springs.
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bob dominguez

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Cerritos, CA

Re: Looking for factory R65 fork springs, used or?
Reply #11 - 03/17/10 at 01:13:11

dewjantim wrote on 03/15/10 at 13:13:20:

Hey Bob, if Ed doesn't find his I have a set. They have 7000 miles on them Shocked Shocked Shocked and I will sell them for $20 plus shipping Wink Wink. Let me know and I will send them on and you can send me a check(American funds only please) Tongue Tongue. Contact me at dewjantim@msn.com .......

Sent you a PM.

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Bob Dominguez, '83 R65, Cerritos, CA

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