oh y'know, just another build thread.

[cbrfxr67]

cool stuff here,...enjoy reading your experiences even if there confounding! 

[iamhiding]

cool stuff here,...enjoy reading your experiences even if there confounding! 

i appreciate it cbr, thanks. confounding, i like that  yeah i tend to get bored with my status quo quite quickly and impulsively change things about

i've been reading back through the thread recently and i kind of laugh at a lot of the stuff i write up here, it's largely for my benefit and keeping track of all the little things, i can imagine it's a bit of a headF**K for a lot people reading or trying to negotiate all the details combined with the irrelevancies in someone else's thought process.  

[iamhiding]

so... i was right, i accidentally used lowering links.

never assume somethings the right part just. 

thunderace on left, standard in the middle and lowering links on the right



i've put the gs back to standard rear height now and left the forks raised through a little. haven't ridden it yet but the static sag isn't too imbalanced, i really need to do something about the rear shock  just don't have the funds to splash on things i don't strictly need at the moment.

so a word on whats going on with my front ride height.

so standard gs tyre's (110/70/17) aspect ratio for height is 70% of 110 = 77mm

the gsxr wheel and tyre (120/70/17) aspect ratio, 70% of 120 = 84mm

so with this wheel i've gained 7mm ride height,
however the gsxr forks are roughly 5mm shorter which makes the front ride height 2mm lower than standard.

i did have the offset differences in the yokes written down with the trail difference but i cant find it now 

long story short i can afford to lower the front height a bit which in turn will decrease the trail.

anyway the forks are raised 11mm through the top yoke and the clipons are mounted 11mm below the top yoke. i was wanting to write the geometry differences down but i'll need to pull everything out the shed to measure the offset again not today 

standard rear height, slightly lowered front 

//

a word on the 16/39 gearing...

booooooooooooooooriiiiiiiing. 

haha nah it's alright, it's nice having slightly longer gears and being slightly more cruise-able again but the bike's lost all of the midrange punch fun factor. i guess it'll do just fine for winter riding.

//

hopefully got a new partworn front tyre arriving today as mine has heavily worn out, down to 0.81mm centre tread... dangerous in the wet and illegal here.

[Ne0n]

I was so jealous for your high rear end (cant use shorter dogbones in my bike, thanks Suzuki for manufacturing tolerances) and now you go back to standard heights? How dare you, hahaha

[iamhiding]

I was so jealous for your high rear end (cant use shorter dogbones in my bike, thanks Suzuki for manufacturing tolerances) and now you go back to standard heights? How dare you, hahaha

that sucks dude, how come you cant use short dogbones? is that like some kind of german TUV thing? and don't worry it's only in preparation for riding on icy and occasionally snowy roads. lower centre of gravity, more stable and less likely to put me on my a*se theoretically so until we hit spring time or until i get bored again

[iamhiding]

so... this is something i've been meaning to document for ages. it's about to get a little geeky if it doesn't interest you but to me it's interesting.

fork lengths, offset, rake, trail and geometry changes. don't take my word for this stuff, do your own research and measuring.

gs500:

fork length - 755mm (centre of axle to top cap)
rake - 25'
trail - 97mm
fork offset - 30mm
wheelbase - 1410mm

gsxr 750 wp:

fork length - 742mm (centre of axle to top cap)
rake - 24.5
trail - 94mm
fork offset - 35mm
wheelbase - 1440mm

-

these are the specs quoted in the manuals but don't account for alternate tyre circumference i.e. from wear front and back, different sizes being fitted like a 120/70 in place of a 110/70 in my case or the difference in individual brands or models, for example not all 120/70/17 tyres will share the same circumference. nor does wheelbase account for gearing changes, chain stretching, sprocket wear or suspension settings. these can all be factors.

-

so my gs500, not taking the above variables into consideration.

fork offset, with the gsxr yokes i've gained 5mm offset.

roughly speaking this 5mm offset translates to - 5.5mm trail and + 4.5mm wheelbase.

-

anyway, with the 25' rake angle, 742mm fork length, 35mm offset and 120/70 (1884mm assumed circumference) tyre. the trail figure is increased 101.346mm which is a 4.346mm increase in trail.

from what i've seen road bikes i.e sports tourers, sport and roadsters tend to fall between 93 and 98mm give or take, with the lesser numbers having less contact patch and being flickier but also more prone to tankslappers with the opposite being more stable at speed.

so really to fall that close to being a healthy trail figure is in part, complete luck.

-

with just the above in mind i'm at 1414.5 wheelbase and 101mm trail with the gsxr wp 750 wheel w/120/70, yokes and forks at standard height

other factors to consider without getting too far into this is how ride height front or back effects the trail figure.

-

for every 1mm raised at the rear end you expect to see -0.4mm trail and -0.2mm from the wheelbase.

and for every 1mm lowered at the front (raising forks through the yoke) you expect to see -0.2mm of trail and -0.5mm wheelbase.

theres a few references backing that up but it's rough theoretical figures i'm talking, so i might be a little out and vary bike to bike.

-

my previous rear ride height of plus 50mm would have decreased trail by 20mm and decreased wheelbase by 10mm.

so 81mm trail and 1395.5mm wheelbase

-

with my front end fully lowered by the 28mm i have adjustment for before hitting the clipons allows a further 5.6mm  decrease in trail and a further 14mm decrease in wheelbase.

-

so if i were to raise my rear 50mm and drop the front 28mm it'd decrease the trail by 25.6mm and the wheelbase by 28mm. which is actually pretty crazy, definitely delving into the realms of you really shouldn't be doing that on the road.

that would take it down to 73mm trail and 1382mm in wheelbase from the standard gs500 97mm trail and 1410mm wheelbase.

by no stretch am i suggesting doing such things.

-

so right now with standard rear height and the front dropped by 11mm is 98.8mm trail and 1409mm wheelbase, which is fairly conservative to be fair.

-

this is completely ignoring changes in swingarm geometry, weight bias to the centre of gravity which 1. i'm not too concerned about the swingarm geometry as its a low powered bike so what little effect these changes have on squat characteristics aren't a massive concern and 2. i simply don't have the tools to deal with weight bias and CG. in terms of weight bias, it's beneficial for me to have it slightly more forward to put more weight onto the forks to get them moving a bit more balanced with the overly soft rear but ideally it would be sprung for the bike. another thing to consider is that forward bias can create poor traction when getting on the throttle on corners but once again the gs is a low power application and i'm running a tyre which gives me a larger contact patch anyway.

i've probably mistyped some numbers knowing me but thats the gist of whats going on. by no means are my deductions evident, they're just my rationalisations, i have no means to measure weight balance and at what point the rear tyre breaks traction. do your own research and get your head round it if it interests you having a basic understanding of this stuff can only benefit you.

to me it's just interesting to see what kind of effect just making one change to your bike geometry can have, for example if you're throwing the common sv650 shock swap on the bike.

[Ne0n]

I was so jealous for your high rear end (cant use shorter dogbones in my bike, thanks Suzuki for manufacturing tolerances) and now you go back to standard heights? How dare you, hahaha

that sucks dude, how come you cant use short dogbones? is that like some kind of german TUV thing?

nah, as I said, it's because Suzukis manufacturing tolerances. I tested it once with a buddy, but my rear shock would hit against my swingarm. This is pretty common for some gs500, as the German wiki states.

[Ne0n]

sry, double post by mistake

[iamhiding]

I was so jealous for your high rear end (cant use shorter dogbones in my bike, thanks Suzuki for manufacturing tolerances) and now you go back to standard heights? How dare you, hahaha

that sucks dude, how come you cant use short dogbones? is that like some kind of german TUV thing?

nah, as I said, it's because Suzukis manufacturing tolerances. I tested it once with a buddy, but my rear shock would hit against my swingarm. This is pretty common for some gs500, as the German wiki states.

ahhhh i get you. trying to think but off the top of my head i'm sure i ground down the swingarm previously trying to fit the thunderace shock so when it came to the shorter dog bones i didnt have that clearance problem 

what about picking up a cheap early sv650 shock and using that to lift the rear? from what i remember reading it doesn't require grinding the swingarm. the lifted rear really does transform the bike so i can only imagine what a better shock is going to do.

[Ne0n]

hm, no bad idea.
Maybe I could do that over the winter, if I find a place to do it.
Don't wanna do it on the frontyard while it's snowing haha

[iamhiding]

hm, no bad idea.
Maybe I could do that over the winter, if I find a place to do it.
Don't wanna do it on the frontyard while it's snowing haha

oooooohhhhh i know the feeling!  working on bikes in winter is a nightmare, it's always dark by the time you get anything finished as well 

[iamhiding]

new tyre day!  think my old tyre is fried! the diameter difference is comical as well in comparison to the old 120/70.



my absolute favourite tyre and weapon of choice. dual compound Michelin pilot road 3 in 120/70/17 

fitted totally hassle free! love when that happens. wooooop! a tyre i actually trust 



investigated my jumping speedo and its definitely the speedo itself not the drive at the wheel or cable.

[iamhiding]

pic update showing how it's sitting with the front just dropped 11mm in comparison to the the various stances it's had recently.

i can absolutely feel the change in trail. it requires noticeably more effort at the bars to counter steer at 98.8mm trail vs the sketchy 81mm it was running before it's not bad it's just so much more effort to flick side to side. it's like more slow smooth and stable. it honestly felt like i had a flat tyre with the effort i needed.

when i get round to sorting the rear height and/or shock i'll dial it all in so that i've got a little more forward weight and try get the trail set up to 94/95 territory.

[iamhiding]

so after all that... i picked up a WOODSCREW  in my back tyre  at least it wasn't the new front but the rear is pretty much at the end of it's life span and i'm not one for repairing tyres if i can avoid it. if it had been a newer tyre i would've repaired it though.

so i was put in the position of shell out money i don't have to spend on a rear tyre new or partworn or... work with what i've got and chuck the almost dead TKC80 knobblies back on for winter 

no regrets, forgot how good this thing is with big bars, stacked bar risers, jacked up rear and knobblies.

i wasn't really enjoying the standard rear height and imbalance front to rear it gave because of the shock and leverage ratio, so i'm back to having super short trail. with the bars and geometry changes it's very lively, very fun at the low-mid speed stuff, it'll be ideal for the slower riding over winter i think.

it's back to being a bit of a wheelie machine with the big raised bars, not as mental as its geared standard again but sitting clutch ups in 2nd at 25-30mph is decent enough.











chain was rubbing off the sprocket cover again, also heavy running on the rubber chain guide. both due to the angle of the swingarm with it being lifted so much.



inner marks are the chain guide rub and the outer marks off the sprocket cover



got ye old faithful angle grinder out and notched the fouling area out the sprocket cover



increased the throttle tube pulley size again    to 36.2mm with a 2nd cable tie. with them superglued i physically cant pull them off by hand so its plenty secure, with the toothed side facing up it allows the cable to groove in slightly giving it a nice channel/guide to sit in. it's roughly just over 1/4 turn throttle.



so yeah... once again a total change of flavour  dang... she fun!  slow and geared boringly... but fun.

[ShowBizWolf]

Your updates and pics make my day!!!

So what setup is on your bike right now to achieve that tail height? Do you have the raising links + a different shock? I lost track over time lol and I'd love to scroll back thru all the pages but I'm at work and I really should be working lolol

[cbrfxr67]

+1 "Your updates and pics make my day!!!"

[Bluesmudge]

Love the TKC80s. I have them on my GSF too.

[iamhiding]

Your updates and pics make my day!!!

So what setup is on your bike right now to achieve that tail height? Do you have the raising links + a different shock? I lost track over time lol and I'd love to scroll back thru all the pages but I'm at work and I really should be working lolol

+1 "Your updates and pics make my day!!!"

  shucks haha

yeah showbiz i'd have lost track if i didn't document stuff here too 

so the rear is about 47-48mm taller, call it 2''.  standard rear shock and thunderace dogbones, the dogbones are 165mm eye to eye so 15mm shorter than the standard gs ones 

i couldn't put another shock in with the dogbones being this short as it would be far too stiff due to the change in leverage ratio, i could however put the original dogbones in and swap shock out.

i kind of geek out when it comes to stuff like this but this is a decent overview of leverage in the shock linkage - http://www.promecha.com.au/leverage_linkages.htm

basically playing with dogbones doesn't just change ride height, it alters the way in which the suspension works. also changes wheelbase and trail... and swingarm angle but i don't fully grasp the swingarm part of it yet but i understand enough.

the firmness it gives me on this setup actually balances up quite well with the stiffness of the front. for the time being the standard gs shock is actually not a mooshy mess like it would normally be and it's doing what i need to in that it's creating a balance of weight front and rear. ideally i'd like to throw a gsxr 750 wp shock in the rear with standard gs dogbones i think.

the bike feels like a slightly heavier supermoto and feels similarly in height. so flicky and turns in so sharp when you want it to, i really do wish i could give some of you's a shot, it's barely recognisable as a gs in the way it handles. i mean, well set up standard forks sprung correctly with cartridge emulators. a decent brake and a decent shock would respectfully outperform my gs in stability, feel, outright corner speed and ability at fast road/track but it's just a totally different feel this way, on a gokart track it would be a different story i guess it's a bit like a supermoto... parallel twin without the ground clearance. it's just too much fun and totally effortless just wish it had a little more grunt, the mental gearing i had before really did help it feel more punchy.

[iamhiding]

Love the TKC80s. I have them on my GSF too.

they're so good aren't they! i don't know about you but a lot of riders sneer at them in a way of ''oh i wouldn't ride them on the road'' but really in the dry they have more grip than most people need, i've pushed them harder than i should've and they just take it... it's actually scary as theres little to no feedback at the edge i feel.

in the wet it's a different story, have to go super cautious as it doesn't take much to put them sideways or light up the rear... which is fun when you're expecting it.

rode them on a vfr 750 as well, dead impressed by them but i think i'm going to try a Mitas E10 on the rear next as a cheaper alternative to the TKC80.

[ShowBizWolf]

hiding, I really appreciate your reply!!

I've been playing around with dogbones and just swapped in the R6 shock on my GS a few months ago. Right now I have raising links to give the rear a 1" lift but was thinking about going taller... but I know I can't do that unless I go back to the stock shock because I had to grind the swingarm just to install the 1" raising links WITH the R6 shock.

So I have been debating whether or not to just do the SV650 shock conversion and go back to the stock dogbones... OR buy the 2" raising links and go back to the stock shock. The SV650 shock swap is actually cheaper than buying more raising links. Crazy!! But buying the 2" raising links would be less work (cuz of the trimming and re-drilling of the SV shock).

I know it's not much work at all but I don't wanna do any more than I have to if I'm not gonna like it.

So you'd say that the raising links almost totally transform the stock GS shock into something good? Can I ask what your weight with gear is? I'm about 145-150lbs.