Progressive fork springs

[simplemind]

Sorting the r80 basic out for next summer's grand tour. I will have a pillion plus camping kit etc. I was thinking about fitting these 'progressive fork springs with a thicker viscosity oil to cope with the extra load. Seen some on ebay marketed under the name 'hyperpro' Anyone have any experience on this modification. I am not looking to modify for its own sake. Would I be better changing to a thicker oil ?
Regards mark

[Carl P]

I can't comment on your model or make of springs, but I fitted a pair of uprated springs from Motoworks in my 78 R80 & it was very much worth the cost & effort, much less diving under braking & I think better handling.

[colebatch]

Progressive suspension in any format is worth the change vs linear. Thats why manufacturers of modern bikes put in link mechanisms in rear suspension, progressive damping in top of the line shocks etc. Its all about making the action of the suspension progressive. Ideally suspension should be soft and supple to absorb bumps in the road, riding over gutters etc, but if it is soft and linear then you run the risk of bottoming out when you have a big hit or jump - you want the suspension to be supple for small movements, but you do NOT want it to be soft and supple for major suspension movements. Progressive suspension is a way to deal with that juggling act.

So a change to progressive fork springs will help. Hyperpro are the leading brand of progressive springs for bikes in the world.

But bear in mind, in your case, the weight of your pillion and luggage will make little different to your forks (front end). At least 95% of that additional 100 kgs or so of weight will go through to the rear suspension, and that is the priority for you to take care of.

I recommend you talk with a guy I know who is one of the leading Hyperpro technicians in Holland who also happens to be an R80 (airheads in general) enthusiast, and a former BMW dealer head mechanic. He has 12 airheads, some as dirt / trials bikes, some as off road touring bikes, some as highway touring bikes, some as round town bikes, some as choppers and some as sidecars. All have modified suspension at the back, many have different forks at the front, but some have modified versions of BMWs OEM forks. He is probably one of the best guys in the world to talk to regarding airhead suspension in general, and definitely the best guy you could possibly talk to about airhead suspension as it applies to adventure touring.

Call Bas on +31 172 417171 during office hours.

[Roboyobo]

Don't expect too much from the upgrade. I have progressive springs at the front and Ohlins at the rear on an R100GS PD. It's still extremely primitive. I did also have thicker oil in the forks, but that didn't seem to make any difference. Have since been advised not to do that, as it's not so good for the seals. The Ohlins helps a little, but I still make sure I don't overload the back with weight (i'm a bit heavy anyway).

To put it into perspective, I travel with a friend who has an R1100GS with the paralever. He is able to ride tight twisty roads much faster than me. Where the R100 is diving, drifting wide and becoming unstable, he is able to go fast, using the brakes in the corners.

More important has been fork maintenance. Have an expert do it and make sure everything is tight as specified, that makes a big difference to stability. I don't get the bars wobbling and threatening a tank slapper anymore.

[Carl P]

Originally Posted by Roboyobo

To put it into perspective, I travel with a friend who has an R1100GS with the paralever. He is able to ride tight twisty roads much faster than me. Where the R100 is diving, drifting wide and becoming unstable, he is able to go fast, using the brakes in the corners.

In reality that doesn't put anything into perspective as the bikes are chalk & cheese in the handling department.
You shouldn't be able to keep up with him (if he's a competent rider), him being on a telelever bike, especially where braking & corners are concerned as they excel at that.

[Walkabout]

Originally Posted by Carl P

In reality that doesn't put anything into perspective as the bikes are chalk & cheese in the handling department.
You shouldn't be able to keep up with him (if he's a competent rider) on a telelever bike, especially when braking & corners are concerned as they excel at that.

While I totally agree with your main point, it's the 1100GS that has both the telelever and paralever suspension, fore and aft.

https://www.google.co.uk/search?q=pa...w=1330&bih=602

The 100GS has just the paralever, last time I looked:-
https://www.google.co.uk/search?q=r1...w=1330&bih=602

[dc lindberg]

Originally Posted by simplemind

Sorting the r80 basic out for next summer's grand tour. I will have a pillion plus camping kit etc. I was thinking about fitting these 'progressive fork springs with a thicker viscosity oil to cope with the extra load. Seen some on ebay marketed under the name 'hyperpro' Anyone have any experience on this modification. I am not looking to modify for its own sake. Would I be better changing to a thicker oil ?
Regards mark

Yes!
Better / stronger springs will give you better front-end operation.

No!
Do -not- use thicker oil!
You will get dissapointed.
I tested Omega 699 automatic gear oil. It is by far the best fork"oil" that I have tested during 20 years and over 300 000km on beemers.
The Omega 699 http://www.magnagroup.com/products/o...re/odis699.pdf
http://www.magnagroup.com/ is a 5W/20 non-foaming automatic gearbox oil. Its damping ability is non changing between cold and warm, which is great!
You will most likely find that any automatic gear oil will work better than fork-oil.
Adding Omega 917 is strongly recommended: http://www.magnagroup.com/products/o...re/odis917.pdf

And the rear shock?
Condition?

You -must- balance the front and rear shocks! If they are not working well together you will find that your investment made roadhandling less good (not reliable / predictable / consequent ).

[Carl P]

Walkabout,

I can see how you're confused, it could have been read either way so I've stuck a "him being" in the post to make it clear as to which bike I'm referring to as a telelever bike.

[Roboyobo]

My point is it is a very rudimentary suspension system on an ancient design.

It will never be good, no matter what you do.

I just live with it.

[Magnon]

I think I must be missing something here. I have had my 1989 R100GS from new and I also had a 2002 R1150GS for three years.

The R100 has either a WP or Technoflex rear shock fitted (depending on use) and the front forks are standard. It may be antiquated but I find it handles well. On very twisty road it needs a certain technique but is as quick as most bikes of the same type including R11xxGSes and quicker than some. If you're into the GS bit and have TKC or similar tyres fitted these can be a bit of a limitation. I've often been tempted to try progressive fork springs in the hope that small potholes may be absorbed a little better.

The 1150 with it's telelever front suspension was a horror. I spent a lot of time fiddling with both front and rear preload only to conclude that the OEM suspension was real rubbish and the spring rates were completely wrong. I'm about 95kg so would have expected the preload to be a little above the middle settings but the best settings I could get was with the front on the lowest and the rear on the highest and it was still hopeless. I contemplated fitting Wilbers but sold the bike instead.

I agree the telelever does reduce the diving but then the R100 hardly has enough braking to cause the forks to dive anyway, so you just learn to ride in a different way.