R100GS fork upgrades

[DA KLIXTER]

What kind of low-buck improvements will help stock R100GS forks for moderate off-road use?

[Jabba]

maintain the same fluid level- but ramp up the fluid weight. stiffens 'em up nicely. Increasing the level will lead to blow outs, DAMHIK!

[Possu]

I think stronger springs are needed, stock items are a bit soft.

On my girlfriends 80GS, I used slightly heavier oil with a slight increase in the quantity to reduce the airgap to increase damping. If going this route, don't add too much or you'll blow the seals.

I also turned a couple of 12mm aluminium spacers on my lathe to place on top of the stock fork springs & spacer tubes to increase preload. I made them them in the shape of an upside down top hat. The narrower section slots inside the stock plastic spacer tubes & prevents the new spacer from sliding away when you apply presure to bolt up the fork tops - saves skinned knuckles.

All of the above made a difference, worthwhile because cost was negligible.

[Stagehand]

I found that a pair of Progressive fork springs and 10w oil (less than $100 for me) made the front end a joy and a pleasure to steer. I didnt change the spacer size, just kept that stock. Did the work myself to save some dough, too, not that it's much work, or much dough.

[RubberDown]

I believe it was CC Products that used to make a nice fork brace for the R100GS and I'd definitely look into springs. You might call Bob's BMW to see if they have or can locate some parts.

[TxDieHart]

Originally Posted by DA KLIXTER

What kind of low-buck improvements will help stock R100GS forks for moderate off-road use?

I just installed progressive springs in my 94 gs, big improvement, about $60.00 and twenty minutes of work. Well worth the effort, the front end doesn't dive like it did prior to installation. I had just replaced the fork oil about a month ago so I didn't change it just took the old spring out and put the new spring in, they can be made even stiffer if I put in heavier oil.

[Gringo]

ditto - $60 progressive springs and 10wt oil made a new beast of my '92 PD. may be the best bang for the buck of all the upgrades I've done to the bike.

[sstodvictory]

"Low buck" means different things to different people. I had progressive springs for a while and then went to Race Tech gold valve emulators. I don't remember the price but I think they were less than $200. They're so much better that I now consider the Progressive springs to have been a needless expense. With the Race Tech's you use the same weight and volume of fork oil as the original spec.

I bought mine from California Triumph/BMW and I believe they modify the valves specifically for the airhead GS, so talk to them if you consider this an option.

Steve

[Stephen]

Progressive Susp springs improved my old GS front end immensely, but no comparison to what RT emulators did for the KLR. Based on that, and on theoretical considerations, if I had it to do again I'd go with the emulators.

Or some WP forks. And a shitload of work to bring the rest of the thing to that level. Hmmm, think I'll just ride the 950 instead.

Yeah, you should get the emulators and go ride.

[cat]

> Race Tech gold valve emulators.
...[SNIP]...
> They're so much better that I now consider the
> Progressive springs to have been a needless
> expense.

and...

> Progressive Susp springs improved my old GS
> front end immensely, but no comparison to what
> RT emulators did for the KLR. Based on that, and
> on theoretical considerations, if I had it to do
> again I'd go with the emulators.
> Or some WP forks.

We hear this a lot. Bear in mind that the stock springs on an early model GS are likely to be stuffed. They probably sagged out in the first year or two, anyway. The Race Tech emulators are basically the equivalent of a tuner re-valving your stock valves. You still need good springs.

Progressive Suspension fork springs are about the cheapest around - and there's probably a reason. (Like they might sag out quickly.) I got WP springs from www.wuedo.de . If you don't want to get them shipped from Germany, there's a Wudo USA website and there's Lindemann Engineering www.le-suspension.com . The other good ones are Hyperpro and Technoflex.

afaik, the WP springs are the only ones that are longer so that you don't need a spacer. (I think spacers are a waste of space - that could be used by springs, especially if it's progressive / dual rate springs.) I don't know about the length of the Hyperpro and Technoflex springs.

[sstodvictory]

Originally Posted by cat

Progressive Suspension fork springs are about the cheapest around - and there's probably a reason.

I had never heard this viewpoint but at $100/pair it makes sense. I had forgotten - my springs were also replaced when the valve emulators went in, so its not as simple as my original message implied.

Steve

[Gringo]

OK I've been wondering about this for awhile and it sounds like there is some experience here - is it true that you cannot use Progressive springs with the cartridge emulator? I know the progressives are a bit longer than the stock springs, had to cut down the spacers - I presume the emulator is going to take the place of a spacer - so what is the recommended route if you want to get a cartridge emulator - get new stock springs? Is there another alternative? I'm just wondering how this will go. I put the progressives in a few years ago and have been pretty happy, but am in the process of doing a big upgrade on the front brakes, and think it would be very useful to stiffen the front suspension some more - all reports of cartridge emulators are that they are the best way to go.

Also is it true that you need one emulator, but that they are sold in pairs? I know that compression is on the right tube, and rebound on the left in R100GS forks, so assume you need an emulator for the right fork only - correct? If they're sold in pairs only, anyone want to go in on a pair?

[norton73]

Hey Gringo,
If you want to go in on a pair, I'd be interested. There are some threads around about it, I don't have time to do a search right now, but maybe this evenin'

[Gringo]

Norton73-
Good, let's do it. I looked into it awhile ago, am not gonna be able to put time into this right away, but it's something I've been wanting to do for awhile...

Still need to find out if I'm gonna want new stock springs (hate to put those old noodles back in the bike, but I think I kept 'em). Prolly have to order the springs at my dealer in advance... Hope someone with some experience on this project will reply to my earlier thread, whether or not you can use progressives with the cartridge emulator.

[Stephen]

The emulator is, IIRC, 14mm. So that's 14mm less spacer you need.

And yes, I would have replaced my springs even with emulators -- the stock ones were NFG before 10,000 miles. Hmph. The ProgSusp worked fine, although a shorter spring with a bigger spacer -- or a better spring -- might be better, as the spring rate for the progressive part is so soft that many coils bound just putting the caps back on. That's more wasteful than a long spacer. But I'm not gonna diss ProgSusp. They worked with a buddy to get just the right springs into his R69US, and the result is brilliant.

Also IIRC, Right is Rebound. Whatever. Good luck, gents.