41mm or 39mm front end choice...

[scratch]

After years of gathering parts, I'm about to start reassembling a GS850g to replace my daily 850g.
I have 2 front ends a 41mm from a GS1100GK and a 39mm from a 850G and wondering which one would make for a better ride?
Don't mind the extra weight as I like a heavy/smooth ride... I ride with a passenger quite a bit but our combined weight is just under 300 lbs but, not anticipating a heavy touring fairing to go on the bike
Are there advantages/disadvantages to the beefier 41mm front end?
Thanks a heap in advance!

[Redman]

When you say front end, do you mean the entire front end?

the 41mm front end is also wider apart, so requires a different fender. And the 41mm from a GK had a big fairing with headlight in fairing. So all the headlight mounting stuff from your 850g (nor an 1100g) will not fit on the 41mm stuff.

[scratch]

Thanks for the reply. Have a set of headlight mounts, an 8" light and 2 nice GK front fenders. Wiring is no prob... In general fitment is not the issue; I'm wondering if the 41mm front end will be to harsh as the springs are meant to carry that large front fairing...
I'd prefer the heavier duty 41mm unit if it wasn't going to be too harsh due to the lighter load (no fairing).

When you say front end, do you mean the entire front end?

the 41mm front end is also wider apart, so requires a different fender. And the 41mm from a GK had a big fairing with headlight in fairing. So all the headlight mounting stuff from your 850g (nor an 1100g) will not fit on the 41mm stuff.

[Grimly]

I'd suspect the original fork springs (if those are still there) will be sagged out by now anyway, so might fall into the range you would like on an unfaired bike. Otoh, they might be too far gone with no life in them at all.
Those who've fitted GK forks to their GSs seem happy enough with them. If any were available here cheaply enough, I'd go that route.

[LAB3]

Realize that a Glowing isn't the same bike but here's my experience. My Wing was in need of new springs and I replaced them with Progressive which where meant for a fully faired bike. Mine doesn't have a fairing and I'm quite pleased with how it rides. I'm a shade under 200lbs and carry about 100lbs of gear a good part of the time, take that for what it's worth.

[TeamDar]

Gs850’s use 37mm forks not 39mm just saying.

[RichDesmond]

Thanks for the reply. Have a set of headlight mounts, an 8" light and 2 nice GK front fenders. Wiring is no prob... In general fitment is not the issue; I'm wondering if the 41mm front end will be to harsh as the springs are meant to carry that large front fairing...
I'd prefer the heavier duty 41mm unit if it wasn't going to be too harsh due to the lighter load (no fairing).

the stock GK springs won’t be too stiff.

[scratch]

I'd suspect the original fork springs (if those are still there) will be sagged out by now anyway, so might fall into the range you would like on an unfaired bike. Otoh, they might be too far gone with no life in them at all.
Those who've fitted GK forks to their GSs seem happy enough with them. If any were available here cheaply enough, I'd go that route.

Thanks, guess once I've committed I can change the springs if I find them to stiff, soft or whatnot...

Gs850’s use 37mm forks not 39mm just saying.

I just checked and stand corrected, thanks

Realize that a Glowing isn't the same bike but here's my experience. My Wing was in need of new springs and I replaced them with Progressive which where meant for a fully faired bike. Mine doesn't have a fairing and I'm quite pleased with how it rides. I'm a shade under 200lbs and carry about 100lbs of gear a good part of the time, take that for what it's worth.

Noted

the stock GK springs won’t be too stiff.

Right on & thanks everyone... then the GK front end will be the choice

[bobgroger]

Gen 1 Bandit 1200 forks make a good upgrade, if only for the brakes....

[salty_monk]

The GK forks would be a good choice... The Twinpot brakes fit on that front end if you want to upgrade brakes. You'll have to also change the triples so although of course the bearings will fit you'll have to make sure the steerer stops, ignition & gauge mounts are the same or fabricate something. I believe the wheel is the same but you'll need a different spacer pack I think....

[scratch]

Gen 1 Bandit 1200 forks make a good upgrade, if only for the brakes....

Interesting... Does that cause a change in rake?

The GK forks would be a good choice... The Twinpot brakes fit on that front end if you want to upgrade brakes. You'll have to also change the triples so although of course the bearings will fit you'll have to make sure the steerer stops, ignition & gauge mounts are the same or fabricate something. I believe the wheel is the same but you'll need a different spacer pack I think....

Have this mod on my radar and have acquired one of the required discs, hunt on for disc 2. The only beef I have with my current 850 is stopping power not quite on par with modern stuff... Just rode my friends big new vstrom and was amazed at the difference.
Otherwise, I have literally 2 of everything need to swap gauges, stems, fenders, etc...

[RichDesmond]

Interesting... Does that cause a change in rake? ....

It will if the fork length is different. Or more correctly, if the distance from the bottom of the lower triple to the center of the axle is different.
If, as I suspect, the Bandit forks are shorter you’ll end up with less rake.
The other big variable is triple clamp offset, which directly affects trail. And it’s trail that matters, rake is important only insofar as it impacts trail.

[scratch]

I'm a decent wrench but, I'n no engineer so....41mm front end that was on the GK sounds like a better plan ; )

It will if the fork length is different. Or more correctly, if the distance from the bottom of the lower triple to the center of the axle is different.
If, as I suspect, the Bandit forks are shorter you’ll end up with less rake.
The other big variable is triple clamp offset, which directly affects trail. And it’s trail that matters, rake is important only insofar as it impacts trail.

[bobgroger]

I'm a decent wrench but, I'n no engineer so....41mm front end that was on the GK sounds like a better plan ; )

Bandit forks are 775mm, same length as stock and 43mm diameter. Use a RF900R lower Triple and the Bandit upper, geometry is correct at least on a GS1100e. Gen 1 Bandit forks also retain the speedo drive. Use the Bandit swing arm and wheels too and you can swap to modern radial tires and save 50-ish pounds. Not sure why I can't link photos right now...

http://network-pros.com/bike/80/80-19.jpg

[tas850g]

• I’ve tried to keep my ‘79 stock but I’m really thinking about changing some things up. The shaft drive is one main reason stopping me.

I really like that front and rear setup bobgroger!