GS/GSA1150 CHASSIS

[Deleted Member MM]

Since I fitted GS suspension and 17" alloys to my GSA I've been having handling problems with the front kicking, tucking and also experiencing stability issues under heavy braking. Initially thought problem was suspension related but it appears that problem caused by geometry/attitude of bike.

To try and identify cause I need to know following

1/ Is GS1150 rolling chassis (apart from shocks) the same as GSA1150?

2/ Has any GS1150 owner with alloys fitted experienced similar problems?

3/ Has any GS1150 owner who has fitted alloys altered front ride height to compensate for smaller diameter front wheel, possibly by fitting spacer to top shock mount?

 

[CoolCarbon]

Hi MM,

Ques.1.....

I don't know of any differences

Ques.2.....

Mine certainly became more 'Twitchy' with the smaller front wheel, but nothing that felt unsafe...........and nothing that made me feel in trouble when braking.......

It may well have something to do with attitude, when I take Mrs CC out on the pillion, the 'Twitchyness' disappears.......the rear is a wee bit lower!

I've jacked the front shock up one notch and keep the rear as soft as I dare so as not to lose too much travel when solo.....to be honest, the Bike handles fine overall

Ques. 3......A Chap called 'Ricardo' on 'Adventure Rider' did put a spacer in somewhere to lift the front of the bike..........I can't just recall the thread title at the moment........he claimed that this helped the situation..HTH

CC



What Tyres are you running on the alloys?

 

[Deleted Member MM]

[
What Tyres are you running on the alloys? [/B]

Hi Coolcarbon, Currently BT020's, problem same with MEZ3's which I had fitted previously. You may remember that my front wheel has spacer fitted, to eliminate any alignment worries I tried Georgia's R1150R wheels with BT010/020's- no difference same problems.
I going to have a run down to Hadrians and measure various points on his GS1150 and compare them against GSA. If measurements are same I'll fit spoked wheels to see if I regain stability, if that cures prob then it's a case of finding out how to retain standard ride height with alloys fitted,



M.M

 

[andy malton]

Since I fitted GS suspension and 17" alloys to my GSA I've been having handling problems with the front kicking, tucking and also experiencing stability issues under heavy braking. Initially thought problem was suspension related but it appears that problem caused by geometry/attitude of bike.

To try and identify cause I need to know following

1/ Is GS1150 rolling chassis (apart from shocks) the same as GSA1150?

2/ Has any GS1150 owner with alloys fitted experienced similar problems?

3/ Has any GS1150 owner who has fitted alloys altered front ride height to compensate for smaller diameter front wheel, possibly by fitting spacer to top shock mount?

1.Yes I am pretty sure they are apart from shocks.
2.Absolutly not it's brilliant like being on rails
3.I have adjusted my ohlins to give me ride height as if I had a 19rim,but I had no problems with standard shocks either

Perhaps it's got something to do with the longer shocks on the GSA.It would be ashame to lose you from the 17inch club,hope you get it sorted.Andy

 

[Deleted Member MM]

Re: Re: GS/GSA1150 CHASSIS

3.I have adjusted my ohlins to give me ride height as if I had a 19rim,but I had no problems with standard shocks either

Perhaps it's got something to do with the longer shocks on the GSA.It would be ashame to lose you from the 17inch club,hope you get it sorted.Andy [/B]

Andy, If chassis is the same by fitting GS ohlins & alloys to my GSA in theory my bike should have same wheelbase etc as yours.
How did you adjust your suspension to give same ride height as if fitted with 19" rim?




M.M

 

[andy malton]

Re: Re: Re: GS/GSA1150 CHASSIS

Andy, If chassis is the same by fitting GS ohlins & alloys to my GSA in theory my bike should have same wheelbase etc as yours.
How did you adjust your suspension to give same ride height as if fitted with 19" rim?




M.M

Yes in theory thats right.To adjust the ride height just turn up your bottom rings on your ohlins and this pushes the front of the bike up hey presto ride height returned.Mine is slightly higher than standard as I don't want things touching down.If I had the rings halfway up the bottom collar normal ride height would be achieved If you want to scrape your pegs just return rings to the bottom.Your only looking to make up that inch you have lost by fitting the 17 inch rim.This is something you can't do with the CG125 front shock that these bikes come with.Take it off throw it away or use it for target practice and do yourself a favour and get a set of ohlins and find out how a real shock works,It's money well spent ask anyone who has them.Look I even took a picture to show my ring ooer mssus.Andy

 

[Deleted Member MM]

Andy, I've already got GS ohlins fitted and understand how you've adjusted suspension, unfortunately I'm still a little puzzled as to what affect this would have on steering angle. I'll pm you with my query,
Thanks M.M

 

[Steptoe]

Re: Re: Re: Re: GS/GSA1150 CHASSIS

Yes in theory thats right.To adjust the ride height just turn up your bottom rings on your ohlins and this pushes the front of the bike up hey presto ride height returned.Andy

doing this doesn't make the damper unit longer, how does it increase the height, surely it just compresses the spring, making it firmer.

 

[Deleted Member MM]

Re: Re: Re: Re: Re: GS/GSA1150 CHASSIS

doing this doesn't make the damper unit longer, how does it increase the height, surely it just compresses the spring, making it firmer.

Maybe I need to explain in a bit more detail. GSA has longer shocks which actually decrease wheelbase and give steeper steering angle compared to GS1150, I've fitted GS1150 ohlins to GSA so IF chassis is the same would expect I've now got GS wheelbase and steering geometry.
Next step was to fit alloys which in effect would lower front of bike but also give steeper steering angle ??
The only way I can see that would increase front ride height would be to fit a longer front shock (forget bike attitude and lowering rear) but surely this would steepen steering angle further?
Problem I have is that I believe steering geometry on my bike is too steep and I can't think how I can change it without re-fitting 19" front wheel which would also give back the ride height.
Hopefully Andy will shed a bit more light on ride height effect and ride quality as I really DON'T want to put the spoked wheels back on

 

[andy malton]

Re: Re: Re: Re: Re: GS/GSA1150 CHASSIS

doing this doesn't make the damper unit longer, how does it increase the height, surely it just compresses the spring, making it firmer.

Don't be as it's fairly simple winding up the bottom collar does push damper unit at the top of the unit up the damper rod it does actually make it longer = higher ride height sorted, if it don't how come I can adjust mine.Think about it the top part of the shock is not attached to the bottom it slides on the rod wind the rings up it pushes the top part up.Wind it down the weight of the bike pushes it down=lower height of the bike.Andy

 

[Steptoe]

well well , i've got ohlins on my bike, i'm going to try that tomorrow, more adjustment to confuse myself with.

 

[CoolCarbon]

Re: Re: Re: Re: Re: Re: GS/GSA1150 CHASSIS

Don't be as it's fairly simple winding up the bottom collar does push damper unit at the top of the unit up the damper rod it does actually make it longer = higher ride height sorted, if it don't how come I can adjust mine.Think about it the top part of the shock is not attached to the bottom it slides on the rod wind the rings up it pushes the top part up.Wind it down the weight of the bike pushes it down=lower height of the bike.Andy

Will that not be the same as me 'Notching up' the front standard Shock??

CC

 

[Deleted Member MM]

well well , i've got ohlins on my bike, i'm going to try that tomorrow, more adjustment to confuse myself with.

I'm off to the garage now So if this takes some weight of the front and let's hope it works as I really don't want a 1200

 

[Den]

Try a higher profile front tyre. I had a 70 profile front and just fitted a 60. Its a loy twichier than it was.
Fitted spacers under the top mount, raised it about an inch maybe. Never noticed the difference.
You will get used to it.

 

[andy malton]

ride height

Right just been down the workshop and done a little fiddling.
Picture shown here is with the bike on centre stand,using two pieces of strong wire tape one to the fork leg the other to the inside of the beak mark a line.

 

[andy malton]

pic 2

bike off the centre stand with shock in highest position,you can see it's just level with the bottom of the fork bridge.

 

[andy malton]

pic 3

Bike off centre stand on the lowest setting,you can see it's lower than pic 2.The difference between pic 2 & pic 3 is your adjustable ride height it does not look much but makes a big difference.Andy