Front OEM shock spring specs for '79 GS850G

[sarathchandars]

For my ever ongoing rebuild of my GS850G, I'm looking to get the front fork sorted with progressive springs. However, I don't know the OEM spring specs. I'm getting a good deal on Progressive Suspension PS1145 but not sure if it will work for the '79 GS850G forks. Can anyone help?

 

[bwringer]

Looking at an application list, I'm pretty sure those Progressive springs (if you have a set of 11-1145 springs) are intended for much larger forks with a 41mm outside diameter (for example, they fit most years of the SV650). Your bike's forks have a 37mm OD, so they'll need much skinnier springs to fit inside.

After some assorted poking around in dark corners, I turned up this Progressive part number for Progressive fork springs for all years of the the 850G/GL. 1000G/GL, and 1100G/GL: 11-1129

It appears to be in stock here:
https://www.jpcycles.com/product/pr...uki-yamaha-bmw-ducati-1976-2009?sku_id=903064


If you are large and/or ride fast (guilty on both counts), you'll want straight-rate springs. Race Tech and some other suppliers have these. The Progressive brand springs are a good all-around choice for the more average-ish rider.

 

[sarathchandars]

Thanks bwringer. Fortunately, I'm not guilty on both counts So I guess I shouldn't get too excited about the great deal that turned up for the what would be useless set of springs.

 

[salty_monk]

I think I might have a set of progressives I bought off someone here & never used... They would be for a 1000 or 1100 so will be the same for an 850G I would think. I can take a look on the shelf if you're interested. PM me an email or cell phone number & I can send pics.

 

[bwringer]

I think I might have a set of progressives I bought off someone here & never used... They would be for a 1000 or 1100 so will be the same for an 850G I would think. I can take a look on the shelf if you're interested. PM me an email or cell phone number & I can send pics.

That sounds like a great deal, Dan! There's no telling what's hiding in garages all over GS-land...

 

[sarathchandars]

DM’ed you with my contact details salty_monk

 

[salty_monk]

If you're much heavier you can always cut the close wound springs off the progressives & replace it with a solid spacer. That turns them into about a 52lb straight weight spring from memory. Somewhere between 0.9 and 1 kg mm.

A lot of heavier guys kind of effectively do that already by really loading preload onto the spring (although cutting is better because it allows you to then still adjust preload at the new spring rate), there is really only so much preload you can practically add.

Straight weight springs make the biggest difference when combined with Cartridge Emulators.