Handling of lowered GSA vs standard height, part 2

Yes, I said I believed it would make a difference, I didn’t state whether it would be beneficial - to be honest I thought it might make it feel a bit lazier, but that wasn’t what I found.

Good god man... now you are telling me what I was thinking!
 
Ash700 said:
Yes, I said I believed it would make a difference, I didn’t state whether it would be beneficial -.
Click to expand...

"Many of you will already know that the standard height GS handles slightly better than the standard height GSA. "

..........so you didn't believe the "many" and their anecdotal evidence....

Ash700 said:
to be honest I thought it might make it feel a bit lazier, but that wasn’t what I found
Click to expand...
That I am surprised at...with all your alleged experience and expertise....kinda goes against the laws of physics...but then in your world laws are open to interpretation are they not assuming you are / were a detective in the police?

Ash700 said:
good god man... now you are telling me what I was thinking!
Click to expand...
yeeesss...suggest you read any good anatomy and physiology book and a good neurology book you might then understand the connection between "feeling" and "thinking".
 
Ash700 said:
Firstly, I’d just like to clarify a couple of things. I’m 6’2” and have inside leg of 34” so have no physical need of the lowered height option.
Click to expand...

I’m identical height and leg to yourself and have found that when I’m doing lots of city centre commuting I put the standard seat in the low position as it gives a much better flat foot on the ground when wiggling between cars so have been thinking would it be better with lowered version so I could have the better ergo of the seat in the high position.
I just don’t think I like the slightly squashed look of look of the lowered version.
How did you find it over bumps etc? Is there less travel on the spring with the lowered version?
 
blueranger said:
"Many of you will already know that the standard height GS handles slightly better than the standard height GSA. "

..........so you didn't believe the "many" and their anecdotal evidence....

That I am surprised at...with all your alleged experience and expertise....kinda goes against the laws of physics...but then in your world laws are open to interpretation are they not assuming you are / were a detective in the police?

yeeesss...suggest you read any good anatomy and physiology book and a good neurology book you might then understand the connection between "feeling" and "thinking".
Click to expand...

I actually didn’t know that the standard GS was lower than the standard GSA until I looked into it. The GS with it’s lower height and slightly lighter weight is probably where the difference is made.

Blueranger, I see a forum with a common interest such as motorcycles (especially branded motorcycles) as a friendly place where members can share experiences, pose questions and discuss related issues. You seem to be one of those people who go out of their way to pick holes and discredit what others say. But you are an engineer and know best! Too many people now hide behind a social platform and have absolutely no qualms about sticking their oar in, being confrontational and rude to others at a safe distance - it’s not making for a better world!

The only reason I posted my findings was to hopefully give others a little insight. I’m not Marc Marquez, I’m not Leoarndo da Vinci, I am who I am but can tell the difference between certain things. What I felt was physical, not mental. The result of the detection of physical difference led to a mental feeling. I can assure you I’ve read several books on those subjects, but if I get stuck my good friend and next door neighbour is a teaching neurosurgeon and my wife is a consultant. In addition... one brother-in-law is a Dr of physics as well as a patent lawyer (his Tesla has a very low COG, but that’s another story), the other is a precision toolmaker. So you see, I have many sources of information at hand, I t’s just a shame you don’t live across the road so that I’d be able to consult with you too. Oh well, you can’t have it all!
 
Weird Bob said:
I’m identical height and leg to yourself and have found that when I’m doing lots of city centre commuting I put the standard seat in the low position as it gives a much better flat foot on the ground when wiggling between cars so have been thinking would it be better with lowered version so I could have the better ergo of the seat in the high position.
I just don’t think I like the slightly squashed look of look of the lowered version.
How did you find it over bumps etc? Is there less travel on the spring with the lowered version?
Click to expand...

Bob, I didn’t get to take it over too many bumps so I can’t really say. I did notice that ‘Normal’ ESA felt just slightly firmer than ‘Normal’ on my own bike. From what I’ve read, this is probably down to the spring rate on the lowered version. I think BMW have done a great job of keeping them so similar in feel (I’m talking physical feel here, just in case anyone is confused), they’ve clearly engineered the reduced travel suspension quite well.

Like you, I’m not such a fan of that slightly squashed look. Because of cornering ground clearance and the (to me) slightly squashed look, I’ll probably end up with a standard height bike when I do the deal - although the low one did track nicely... :blast
 
Ash700 well I think your comments are very helpful and I would forget about some of the negative comments. Sorry to say “some” of the post replies ( not often) are from either complete numpties or show offs, but I would like to think most guys on here are bikers not argumentive posers but obviously some fit in that bracket. They certainly wouldn’t be biker guys I would hang or ride out with.
Keep going friend.
 
fishy23 said:
Ash700 well I think your comments are very helpful and I would forget about some of the negative comments. Sorry to say “some” of the post replies ( not often) are from either complete numpties or show offs, but I would like to think most guys on here are bikers not argumentive posers but obviously some fit in that bracket. They certainly wouldn’t be biker guys I would hang or ride out with.
Keep going friend.
Click to expand...

Says the £12 wanker who likes to derail threads with nonsense
 
+1. Ash, just ignore the sanctimonious pricks - they’ve got nothing better to do!
 
To fredaroony At least I’m not a sarcastic numptie like you. I can’t be that bad as I once stopped some crew chucking a numptie with your attitude overboard.
 
fishy23 said:
Ash700 well I think your comments are very helpful and I would forget about some of the negative comments. Sorry to say “some” of the post replies ( not often) are from either complete numpties or show offs, but I would like to think most guys on here are bikers not argumentive posers but obviously some fit in that bracket. They certainly wouldn’t be biker guys I would hang or ride out with.
Keep going friend.
Click to expand...

Thanks Fishy, that’s very heartening.
 
fishy23 said:
To fredaroony At least I’m not a sarcastic numptie like you. I can’t be that bad as I once stopped some crew chucking a numptie with your attitude overboard.
Click to expand...

I can just imagine you are some geriatric know it all pompous douchebag. You really are a cretin...

You can't even work out how to quote properly in this forum
 
Ash, enjoying this thread, yes interrupted by Mr :blagblah but the thread has a genuine purpose.

When I started to reading it I thought well if the COG is lower its got to handle better. But there is a bit more to it than that.

Keep up the good work :beerjug:
 
SteveC glad to see and read normal helpful comments your obviously a biker, yeh back to the point of COG just now winterwise I ride with a sheepskin seat cover a very thick one and that’s just about puts me into the danger zone of on tippy toes if not carefull.
 
The lowered suspension presumably affects wheel travel and ground clearance on the limit. Does it also affect the Telelever geometry? Does it brake dive more or less with lowered springs?
Wunderlich sell a (very expensive) modified Paralever arm that lowers the back end. Something less silly money might be an idea.
 
Ash700 said:
Blueranger, I see a forum with a common interest such as motorcycles (especially branded motorcycles) as a friendly place where members can share experiences, pose questions and discuss related issues.
Click to expand...

I agree completely.......

Ash700 said:
You seem to be one of those people who go out of their way to pick holes and discredit what others say.
Click to expand...

I can see why you perceive this as you do...it's actually intrest in the subject matter not trolling for it own sake.....

Am I a bit of a keyboard warrior...probably...but not because I just want to piss people off for the sheer fun of it.....what I care about is knowldege and discerning fact from opinion...as a detective something I expect you would also cherish?

I'm trying to work out whether your knowldege and experience is accute enough to take it (on face value) that the lower GS does handle discernably better and whether you are self ware enough for placebo not be a factor....so in the abscence of repeating the test with a more competent and consistent rider than myself with a datalogger and under double blind conditions......your simple test is all we have to go off...but all credit to you for actually doing it and not just posting a wooly question hoping to get a clear answer..more than some manage.

I actually get completely where your coming from with the low speed wobble...the funny thing is I find the LC GSA to be significantly better balanced than say the 1150GSA. I also do a lot of filtering with a large top box with 2m worth of 16mm chain in there.....

Considering both generations have a similar fully fuelled weight..truth be known by the time I'd ditched the ABS module, the CAT and changed the end can the 1150 was probably lighter...but still felt less stable.

I speculatively put this improvement down to them lowering the COG on the LC and possibly even moving it forward...one thing is for sure the LC feels to me much more sure footed and stable off road, riding ruts was always a challenge for me where as on the LC I feel like I can ride them quick enough to track the centre with confidence.

I did notice too that the 12LC is harder to get on the centre stand for me.

Interestingly, I note that the steering angle on the 1150GSA is 26.2, the hexhead is 25.7 the LC GSA is reduced to 25.5......

The steeper steering angle my well explain why at walking speeds it wobbles all over the place?
Would also be interesting to weigh the LC;s wheels vs the 1150's wheels as well to see if the angular momentum of the wheels is any different.

Incidentally, if you assume that the bike is not perfectly in balance between left and right side when perfectly vertical and ignoring the effect of the cylinder position in balance and flywheel rotation, I would estimate that the lower GS would have around a 5% reduction in the overturning moment as a result of the 50mm reduced height....which in simple terms would flip to a 5% reduction in force required to lift the bike back to vertical from leaned over...so if very crudely we then said that 5% in overturning moment translated back directly to kg, you be at about 13kg for a fully fuelled GSA...I'd say you probably notice a light difference like that if you were riding flat out, or if you were carrying 13kg of luggage...nearly a bag of sand and gravel or small child...but I think the wide bars of the GS mask that effect to degree.

Also, the Wheelbase would be reduce by about 1.5%....not big numbers but definately discernable.

I am still intrigued by thought process behind thinking the lower bike would be slower steering....
 
I have to confess that I’m assuming that BMW have reduced both ends of the bike by the same amount, but I don’t know if this is a fact. If it is, the trail, rake and castor angles would remain the same (please correct me if I’m wrong). The wheelbase, in theory, would be ever so slightly less, but that would be virtually impossible to detect. A bit like tightening the chain on a bike, lengthens the wheelbase - imperceptible done in increments. I suppose what I’m saying is, apart from the COG being lower, I’m not sure what else would make the difference, as not much else seems to have been changed. Although 263kg (578lbs) sitting 50mm lower is significant.

I’ve learnt that both bikes bottom out at the same height, which means the lowered one has less suspension travel. That being the case, the spring compression rates and internal damping will have been changed to still allow for the same max load weights. I know that suspension set up is a science and can be a nightmare... which is why I think that BMW have done a brilliant job in getting both bike options to feel so similar. What did I notice... discount the fact that the bike is physically lower and a very slightly firmer ride, the thing that I did notice was a slightly better turn in and tracking in corners. It felt a bit easier to change line mid bend. It was just easier when pushing on in the twisties - less drama if that makes sense?!

Shame it looks a bit squashed and drags its pegs. Don’t get me wrong, the standard bike is incredible and during times when I’ve had it on track days it has impressed me much more than I thought it would; and that was after getting off my S1000RR. Obviously two bikes in different leagues, but the GSA is a lot more capable than it ought to be. Having ridden nothing but radical sports bikes for past 30 odd years and going straight to a GSA and not being bored with it after nearly 4 years is testament to how good they are. What the hell did they introduce a lowered version for? :hammer
 
The other thing to consider is that the Centrifugal force during a turn will obviously compress the suspension, if the lower bike has a more rapid rise in spring rate then proportionally it will compress less in actual mm (hence feeling firmer) depending on the mass balance between front and rear wheels will also affect how much the front or rear compresses.

I'd wager the front and rear were dropped equally, otherwise you'd have to change steering angle and if I recall when doing my outfit 1" equates to roughly 0.5 degrees, so in dropping the front by fitting a 17" wheel and raising the rear by 1" I effectively adjusted steering angle by 1 degree.

For simplicity, I'm more inclined to think its easier to have a different shock length for each respective version than change steering geometry.

As for changing direction mid bend....assume thats by adjusting bars only on constant throttle? is that in tightening and extending the turn radius?

Edit:

Would say that on a GSA as your sat upright you'd tend to put weight on the rear more so than a sports bike which would put your weight forward, therefore in theory on a bike with a longer spring, the rear would drop more increasing the steering angle making it feel "heavier"...the lower bike would possibly sit more neutral making the bike feel more "flickable".
 
blueranger said:
I agree completely.......



I can see why you perceive this as you do...it's actually intrest in the subject matter not trolling for it own sake.....

Am I a bit of a keyboard warrior...probably...but not because I just want to piss people off for the sheer fun of it.....what I care about is knowldege and discerning fact from opinion...as a detective something I expect you would also cherish?

I'm trying to work out whether your knowldege and experience is accute enough to take it (on face value) that the lower GS does handle discernably better and whether you are self ware enough for placebo not be a factor....so in the abscence of repeating the test with a more competent and consistent rider than myself with a datalogger and under double blind conditions......your simple test is all we have to go off...but all credit to you for actually doing it and not just posting a wooly question hoping to get a clear answer..more than some manage.

I actually get completely where your coming from with the low speed wobble...the funny thing is I find the LC GSA to be significantly better balanced than say the 1150GSA. I also do a lot of filtering with a large top box with 2m worth of 16mm chain in there.....

Considering both generations have a similar fully fuelled weight..truth be known by the time I'd ditched the ABS module, the CAT and changed the end can the 1150 was probably lighter...but still felt less stable.

I speculatively put this improvement down to them lowering the COG on the LC and possibly even moving it forward...one thing is for sure the LC feels to me much more sure footed and stable off road, riding ruts was always a challenge for me where as on the LC I feel like I can ride them quick enough to track the centre with confidence.

I did notice too that the 12LC is harder to get on the centre stand for me.

Interestingly, I note that the steering angle on the 1150GSA is 26.2, the hexhead is 25.7 the LC GSA is reduced to 25.5......

The steeper steering angle my well explain why at walking speeds it wobbles all over the place?
Would also be interesting to weigh the LC;s wheels vs the 1150's wheels as well to see if the angular momentum of the wheels is any different.

Incidentally, if you assume that the bike is not perfectly in balance between left and right side when perfectly vertical and ignoring the effect of the cylinder position in balance and flywheel rotation, I would estimate that the lower GS would have around a 5% reduction in the overturning moment as a result of the 50mm reduced height....which in simple terms would flip to a 5% reduction in force required to lift the bike back to vertical from leaned over...so if very crudely we then said that 5% in overturning moment translated back directly to kg, you be at about 13kg for a fully fuelled GSA...I'd say you probably notice a light difference like that if you were riding flat out, or if you were carrying 13kg of luggage...nearly a bag of sand and gravel or small child...but I think the wide bars of the GS mask that effect to degree.

Also, the Wheelbase would be reduce by about 1.5%....not big numbers but definately discernable.

I am still intrigued by thought process behind thinking the lower bike would be slower steering....
Click to expand...

I appreciate the need for things to be engineered and designed - I’m a huge fan of fine engineering. But once it is engineered it then has to be ridden/driven/flown etc., in order to know how it handles and feels. That is all I was doing. It wasn’t a huge scientific test, it was a fairly simple test ride, on the best roads I could find at the time (and they were cold roads too).

You have thought about flywheel rotation and vertical balance, things I admit I hadn't considered. Accumulatively, I suppose many small factors make a difference, but it is worth repeating that it wasn’t a huge difference I found.

I have always had a natural interest in mechanics and how things work. I’ve taken many things apart over my lifetime and put them back together, the only thing that eluded me was a typewriter - should’ve made more notes on that one! My profession honed my desire for accuracy, and when I have the time I can be quite pedantic. As well as discerning between opinion, fact and belief.

I don’t know why I thought that the lowered one would steer slower? Maybe because the one in the shop looked like a chopper in comparison to the standard one I’m used to seeing and assumed it would steer slower because it looked lower at the back than the front. I haven’t a clue what BMW have done to the fork internals, but when I looked closer (after I’d ridden it) there is a difference in the gap between the front mudguard and the beak between the two bikes, so they’ve clearly lowered the front too, which is less obvious visually. Hence the surprise when I rode it - it steered very nicely.

I’m not actually convinced that such a small percentage change in wheelbase would be that noticeable because these were things I used to play with on track and I personally don’t think that I’d notice such a small change, it’d have to be a slightly bigger percentage change to start feeling a difference. Other things, like steering angles I would notice.

Ultimately, like most things, it’s horses for courses... but there are very few bikes on the planet that will do what the GS & GSA can do - a horse for lots of courses!
 
blueranger said:
The other thing to consider is that the Centrifugal force during a turn will obviously compress the suspension, if the lower bike has a more rapid rise in spring rate then proportionally it will compress less in actual mm (hence feeling firmer) depending on the mass balance between front and rear wheels will also affect how much the front or rear compresses.

I'd wager the front and rear were dropped equally, otherwise you'd have to change steering angle and if I recall when doing my outfit 1" equates to roughly 0.5 degrees, so in dropping the front by fitting a 17" wheel and raising the rear by 1" I effectively adjusted steering angle by 1 degree.

For simplicity, I'm more inclined to think its easier to have a different shock length for each respective version than change steering geometry.

As for changing direction mid bend....assume thats by adjusting bars only on constant throttle? is that in tightening and extending the turn radius?

Edit:

Would say that on a GSA as your sat upright you'd tend to put weight on the rear more so than a sports bike which would put your weight forward, therefore in theory on a bike with a longer spring, the rear would drop more increasing the steering angle making it feel "heavier"...the lower bike would possibly sit more neutral making the bike feel more "flickable".
Click to expand...


Yes, totally agree centrifugal force and compression. It does also seem that the front and back were dropped by the same amounts. I think whether it’s sit-up-and-beg or a sports bike, once the rider is on the bike, weight doesn’t move too much forwards or backwards. The mass of the rider is always on the bike so I’m not sure how it would effect compression of suspension whilst cornering - this is definitely where telemetry would come into play.

I noticed the effects of steering through the bars to change a line mid bend. On track days we teach steering ‘mid bend’ can be done on the throttle, on any bike. Close the throttle to tighten your line, open the throttle to push you wider - nice when you use it. I would have loved to have taken both bikes on a track to get a real back-to-back feel.
 
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