Excessive Front End Sag?

[nikos]

The R1200GS road tester in MSL (page 55 of "The Quality Monthly" dated March 2010) complained about the crudity of the repeated bobbing when coming on and off throttle: he suggested that the telelever front end has excessive sag with the suspension topping out on accel and sitting back on the spring on decel.

Isn't this a simple matter of pre load adjustment (front and/or back)?

Was he riding the bike on planet bollox where g=2.5?

 

[Mr K]

Sounds like he's talking bollox: How does excessive sag relate to topping-out?

Topping-out is normally due to excessive preload. Bobbing may mean damping adjustment is required.

Ham-fisted hack at work?

 

[Giles]

The Job RT's we ride at work are terrible for this. I regularly have cars infront of me pulling over because they think I'm flashing them. When we first got them (after the pans were taken off the road) one bloke took the bike straight round to workshops saying he thought there was a fault with the suspension! We can alter the preload on the rear shock, but can't alter the front end at all, and it does bob on and off the gas terribly.

 

[Toad]

Reminds me of a girl I used to know

 

[Giles]

Sounds like he's talking bollox: How does excessive sag relate to topping-out?

Topping-out is normally due to excessive preload. Bobbing may mean damping adjustment is required.

Ham-fisted hack at work?

If you're suspension is so soft that it's diving on a shut throttle and rising on power, then I would say that that too much static sag is exactly the problem. Excessive preload on your forks would give you a harsh stiff uncompromising front end, but I don't think it would cause your suspension to top out.

 

[Yonkyo]

I'd agree that the front Pre-load needs to be increased.
You use a 'C' spanner to tighten the shock to reduce the Static Sag.

 

[teamwimp]

too much preload leads to topping out, too little to bottoming out - bobbing up and down is too little damping

 

[London Mole]

The Job RT's we ride at work are terrible for this. I regularly have cars infront of me pulling over because they think I'm flashing them. When we first got them (after the pans were taken off the road) one bloke took the bike straight round to workshops saying he thought there was a fault with the suspension! We can alter the preload on the rear shock, but can't alter the front end at all, and it does bob on and off the gas terribly.

Have your mechanics come up with any kind of "home-made" solution or can nothing be done at all?

 

[Giles]

Have your mechanics come up with any kind of "home-made" solution or can nothing be done at all?

These are BM's 'factory made' bikes. They come off the production line as a fully kited out police bike complete with slimline panniers, all the lights and two tones single seat conversion etc etc.
The benefit to the police is the waranty. Bm deal with anything that is a (major) problem. The get out clause Honda had with the wobble and weave on the Pan was that the standard had been police specced, and not by them (lights, radios, extra batteries....). So Honda were able to wash their hands of the problem and say, 'but you've tinkered with an otherwise reliable bike, its not our problem'.
I can't tweek the suspension on the telelever on the RT, and any home made solutions would probably invalidate the warranty.


Re the original thread, I think you're being blinded by science! The bottom line is that the journo complained that the bike was bobbing on and off the Gas. (as our RT's do). It needs more preload! Don't be blinded by damping and rebound, the front is just to soft.

 

[Packer]

If the GS suspension tops out on acceleration I'd reduce the preload to give more sag. With 7½" of travel you've got plenty to play with.

If the adjustment front and rear is in balance won't the bike rise and fall evenly at both ends as my 1150 does when accelerating/decelerating?

Perhaps the damping is inadequate for the extra kit on the force RT machines. and they have less travel in the first place.

 

[Giles]

Who knows! I'm certainly no expert on suspension settings; I do quite a bit of mountain biking so understand all the principles of setting up your static sag, preload, rebound, damping... And yes, your bike should be balanced on both front and rear settings so it doesn't see-saw.
I do think people over complicate things though, and look for hi tech answers, when usually its something pretty simple!

 

[Yonkyo]

If the adjustment front and rear is in balance won't the bike rise and fall evenly at both ends as my 1150 does when accelerating/decelerating?

The 1200’s don’t suffer with the rear end rising under acceleration like the 1150/1100’s, due to reduced torque reaction form the revised Tele-lever.

Anyways. Since I fitted the Accelerator wire, my 1200GSA tends to lift the front end….and keep on lifting till the anti-wheelie electronics interveneaugie

 

[GSmonkey]

I've reduced the front preload on my GSA and jacked up the rear to get more weight over the front end. It improves the handling of the bike no end.

And, more preload = less sag = less upper spring range = more likely to 'top out'

 

[Giles]

Good grief Thats not the girl Toad used to know it it?

 

[Engineer]

The R1200GS road tester in MSL (page 55 of "The Quality Monthly" dated March 2010) complained about the crudity of the repeated bobbing when coming on and off throttle: he suggested that the telelever front end has excessive sag with the suspension topping out on accel and sitting back on the spring on decel.

Isn't this a simple matter of pre load adjustment (front and/or back)?

Was he riding the bike on planet bollox where g=2.5?

MSL is hardly "The Quality Monthly" - the journalism is amateurish, the spelling is as bad as the Grauniad, the type-setting appalling, the photography dire and it is as biased and subjective as all the other mags - which wouldn't be so bad if it was entertaining, but it is the most boring read ever!!

So, in summary I wouldn't much notice of anything that they say.

 

[Brian ROSEN]

MSL testers

Having been riding a couple of 1200GS's over 5 years I read this article and wondered how far it would go before the 'analytical motorcycle tester' (as he calls himself) found a fault that I had never noticed. Sure enough I have never experienced this bobbing about as you come on and off the throttle - BUT I don't ride like that, nor do I drive my car like that. In any case as he doubts that these faults will be really noticeable to anyone other than him I don't think I will ever notice them.

 

[Dusty10 bikes]

Titman

No not the reveiwer.........Beetee are all Alex Harvey fans titmen,that must be where I get it from.

 

[London Mole]

The 1200’s don’t suffer with the rear end rising under acceleration like the 1150/1100’s, due to reduced torque reaction form the revised Tele-lever.

Anyways. Since I fitted the Accelerator wire, my 1200GSA tends to lift the front end….and keep on lifting till the anti-wheelie electronics interveneaugie

Yonkyo,

What do you mean by "anti-wheelie electronics interveneaugie"???

Because last week I nearly sh*t myself when the front lifted in second gear.

And I mean "proper" lifted!!!!!

... nearly lost it ...

I need to learn how to be careful... or lift it safely!

 

[GSmonkey]

London Mole: The anti-wheelie electronics is ASC, if you have it fitted. It detects the rear wheel going faster than the rear wheel and cuts the power. Useful if you've got the bike fully loaded, but spoils the fun when on a spirited ride.

 

[Yonkyo]

Yonkyo,

What do you mean by "anti-wheelie electronics interveneaugie"???

Because last week I nearly sh*t myself when the front lifted in second gear.

And I mean "proper" lifted!!!!!

... nearly lost it ...

I need to learn how to be careful... or lift it safely!

London Mole: The anti-wheelie electronics is ASC, if you have it fitted. It detects the rear wheel going faster than the rear wheel and cuts the power. Useful if you've got the bike fully loaded, but spoils the fun when on a spirited ride.

Correctomundo.

ASC = Anti Social Control? Auto Sensible Control?


You go steady now London Mole. It sounds like you could benefit from some ASC on your bike.