lowering front vs raising rear

[colinginger]

just curious of the differences of lowering the front vs raising the rear, then what the knock on effect of either would be?
hoping Zeno or Terry might give me some insight!

[frostyscurse]

ground clearance??? I would think......

[Wattie]

i'd say ground clearance too.

if your scraping fairings, you dont wanna go dropping the front.

[*Oggy*]

In laymans...bullet item terms.....

Lowering front end is free... just involves loosening the tripple clamps, Whilst raising the rear end will involve adding/modifying the shock or linkage..

Lowering Front = less ground clearance... Raining Rear = more ground clearance.

Lowering front does not change the characteristics of the forks actions, whilst raising the rear will have changed the geometry of the linkages..

As for what you should change for the internals, then I'll leave that to the experts....

[Wattie]

you can put a spacer above the shock, its free and doesnt change the linkages... :)

[colinginger]

sorry, should have been more explicit in the question... meant in the feel of the bike (i.e. turn in, mid corner and corner exit) and traction (i.e. front and rear)
Cheers C

[Marshy]

Colin has spacers above the shock.... As many as would fit. Not sure if he knows that :D

Valid question though.

[Big Lunt]

Dropping front (this is the only one I have done)

Faster turn in
Can get on the gas more as can keep tighter line
Higher corner speed from my experience from the above
But sometimes if you do drop too much makes the front feel like its going to tuck

Try only couple mm's at a time as I have been advised in the past

[zenodamper]

(no spacers on top of Unit Prolink possible)

Lowering the front (or rear) will have some affect on everything – of course the trail and rake do change, but not by a massive amount, you would need to slide through around the entire 25.4mm there to alter that by much.. (sag will often do that, as will poor damper control)

Lowering the front will load up the front more with weight however and this will alter the trail’s median position during operation if other things are not done (and even then the wrongs or rights can outweigh each other). It will also alter the amount of leverage you and the motor have on the front (locked arms or bent arms ditto). As a side effect your rear geometry will shallow out, shallow rear-arm angles can be bad, causing the bike to exit wide. (however, some affected worse; but due to their design) Usually a lower front will allow for a tighter corner entry (though you need to be able to hold it up properly or it will plough straight ahead)

Raising the rear will affect the front by moving some more weight onto it; but the effect will affect the rear better usually, because the rear’s arm angle has steepened; though horses for courses of course, some machines will not benefit from being raised (too steep already, or swing-arm rubs on chain etc..). Also some design of components will on some bikes benefit one way and not the other. Usually a steeper arm angle (depends where u start from) will allow for a tighter exit line... (so is more common)

When a bike gets lower (overall) you’ll require more lean angle for the same road velocity, but it pitches less; vice versa for when getting taller. The C of G for the ‘96 600F was an inch or so more than the SRAD600 of a similar period, it went round corners with less lean at the same 80kph; so if the mid-speed of the turn sees both bikes on the edge of the tyre with no more to use, then one will be going quicker.... CX500s had good corner speed as compares CD200’s – one took more muscling than t’other however!

[colinginger]

thanks for that Zeno... still a little confused, but thats hardly surprising :)

so raising the rear is more advisable than the lowering the front?

basically I am trying to get better turn in, but also more front end grip in mid-exit corner, as the bike feels like it is oversteering.
when at Oran Park and EC i was strugglin to turn in and hit the apex, then wasn't holding line on corner exit and drifting.
when mid corner at EC turn 1 it felt like the front wasn't planted (like on old bike!)

note: I now have marshys old bike gsxr600K7

[Fezz]

Hmm, are you trail braking at all?

Wierd as the owner before Marshy was very quick on it.

Obviously the same settings don't work for everyone but.

[colinginger]

jordy was exceptionally quick on it, but am also 15kgs heavier :(

yeah i do trail brake into corners

was going all right for the first time out at EC on the bike (47s), but front end just felt not quite planted (i.e. grippy)

[Captain]

I assume you're familiar with the best mod anyone can make to a Blackbird Jim? I talk of the mighty shim (which raises the rear by 6mm). Having done it, I can attest to it's wonders ... but I do wonder why they don't simply lower the front instead? I think it's possible, isn't it?

[zenodamper]

I willl have to go and work in a minute; so I expect this will go on and on - but to re-iterate for your EG Capt'n: If you lowered the front on the B'bird it would make the rear sw-arm even shallower - plus on some RWU fork designs there simply is not sufficient room between the bottom clamp and the dust boot on the fork (i.e. they might slam into each other) - I am not a wrecker (nor that sort of anorak), just to say it can be so with some bikes in some ...

Colinginger: for that Suzuki I will need a lot more infomation - it sounds like the front has insufficient spring controle (the feeling of) - what is to say it could be over-preloaded, or the oil could be too thin; the rebound amount not enough - or just set "not how you need it" (toes not tread on ok/).

K6-K9 all lack enough rebound damping in the fork - they also frequently suffer shock issues. And what is done to the shock will affect the story a lot @ front...

Right, I must work now: no employees earning me $ - but will look at this tonight...

to really help yourself though, pick one person, trust them and keep it all straight-forward - putting it out in the public domain with insufficient data-specifics will likely see every form of advise possible and confuse you further... (sorry, a pragmatists response that)

[colinginger]

Thanks zeno. You're right, putting the question on the public domain is probably asking for trouble. Just wanted to get a starting point for further research.
Am new to the adjustment thing and was hoping I could get some insight into changes without actually having to do the work myself.
But best way is to pick a ride day and change one at a time to feel the effects for myself!