Front tyre profiles and cornering

[TopCat]

Gedday,
Looking for some info from the group if possible.

I have a ZRX12 (and previously a ZRX11) and have mainly used Metzler M1 and now M3 tyres.

One issue I've had with the tyres is that they tend to "fall into" corners and I tend to overcorrect leading to all sorts of jigs and reels as I lean the f*cker.

Reading up on various sites, what I think I've gathered is that the profile of the front tyre can enable the bike to fall quickly into corners (if it has a "triangulated" profile apparantly) but some brands have a more neutral profile. From what I've read the M3 has this "triangulated" profile and therefore "falls into" corners.

Now for the questions -
- how to tell what brands are neutral as distinct from "triangulated" - maybe someone can help point me in the right way;
- is it just or mainly the front tyre that dictates how the bike behaves in the approach to corners or a combination of front / rear;
- I read in a Superbike Mag test from 06 that the Pirelli Corsa tyres are supposed to be more neutral in their handling - anyone found this to be the case from their experience;

I have an M3 on the back that is brand new (brain fart to replace without checking this out first) and the front has 1-2k left. So I'm thinking to get a neutral front and live with the odd combo till the rear is due for replacement.

I'd appreciate any info or where to look to better understand about this.

Thanks for your help.
Cheers,
TC

[hoffy]

try a road 2 front , they dont steer as quick ie fall into corners, but are extremely stable and plenty grippy

There was a massive difference when i changed from powers to road 2

[IsleofNinja]

IMO suspension settings ie how far your forks sit above the triple clamps / rear sag setting and or rear type profile will have far more effect than front tyre profile/cross section ( assuming you are refering to the standard 120-70 17)
Try dropping the forks a few mm and see how you go.

Oh yeah and what Mr Hoffmeister said!!

Can't go past PR-2's as an allrounder IMO

[dave#3]

G'day Tony,

In my experience I've found rear ride height can (does) make a huge difference to how the bike tips in - perhaps try reducing the rear ride height (have you got the eccentric's rollded over? perhaps move them back to standard) to slow down the front. On my 9 I had it well setup with a 190/50 rear (standard) by raising the rear about 6mm - it dropped into corners well but was super stable on it's side. I've recently thrown a 190/55 on it (effectively raising the rear a further 5mm) and it now tips in *really * easily but becomes a bit twitchy on it's ear in real slow (15-25km/h recommended) corners.

I don't like M3's myself and actually found that they didn't seem to tip in as well as the Bridgie's I was accustomed to, which makes me even more confident you should be able to stick with tyres you like/know and adjust the bike to work with them.

Good luck, and let us know how you get on.

[Strika]

You're right in as far as, tyre profile will effect the speed with which the bike goes from full upright to full lean. A more pointed or sharp shaped front tyre will be faster to rotate over on it's side than a more rounded or circular shape. Having said that, the Metzler M1s and M3s are not what I would call an aggressive shape. They are far flatter in shape than say a Michelin Pilot Power. Although others have reccommended a Pilot Road 2, (which I DO really like and currently have about the 3rd or 4th set on my ZRX12 too), I don't think that is the issue somehow. I would have to take a look at your bike before I made further comment about what to do next. But, I think set-up is a more likely candidate than the tyre.

Someone suggested lowering the forks, which I would question as this is going to make it steer slower!! Not what you want really on a 240kg bike which already steers slow as a wet week out of the box.

Has it only happened with this one tyre, or has it happened with previous tyres you've used on the ZRX?

[Phil]

I agree Marty, I wouldnt say the M1's or M3's are an agressive profile, Dungplops, Bridgestones and Michelins I would have thought to be more triangulated. Saying that the M3 is far faster steering than the M1 but still has all the stability I require.

Hard to say what happening with you Tony, you've been riding Rex's for a while too which makes it even more puzzling

[IsleofNinja]

All good advice for you here TC .

as an example ; My 06 ZX10R (different bike by far but same principal)
Original issue when I first got it ; Slow turn in (for litre bike) , somewhat 'twitchy' on apex and a little on the aggresive powering out ie head shake!?
Tyres = Pirelli Diablo Corsa's 120/70-17 front 190/50-17 rear.

Fix 1 - align rear axle/wheel properly (via string method) and re check adjuster marks. ----- made a suprising amount of difference as was a fair way out!?
Fix 2 - Once rear tyre was due (again!?)- changed to correct 190/55-17 profile (taller / correct for this bike )
Fix 3 - Finally extract the digit and set the suspension sag properly

I realise that what I was trying to acheive is the complete opposite to what you are looking for but the steps I used turned my bike from a fairly lethargic steerer to something a bit closer to the mark for what I was looking for . You may be able apply in reverse for yours .

This sorta info may give you a bit of insight into cause / effect if nothing else as with the above posts by some of our resident guru's .

NB; What tyre pressures are you running TC?

Hope it helps

[Phil]

NB; What tyre pressures are you running TC?

And are they Hoff approved ??

[hoffy]

NB; What tyre pressures are you running TC?

And are they Hoff approved ??

I charge a $37 consultative fee on Tyre Pressures, if required..

[jonoZRX]

Is this for a road bike? My experiences with road tyres for heavier bikes are as follows:

Michelin Pilot Power - super pointy triangle
Dunlop Roadsmart - nice and neutral
Pirelli Somethings (can't remember which ones, probably Corsa III) - nice and neutral

Track tyres:

Bridgestone BT002 Race (treaded) - pretty fast tip-in
Pirelli Supercorsa Pro (treaded) - pretty fast tip-in
Pirelli Superbike (slicks) - surprisingly neutral

[TopCat]

Firstly, thanks guys for the advice! More experience here than you can shake a stick at!

More details about the bike - standard tyre sizes, back end (Ohlins shocks) raised up by ~1" with risers, eccentrics in stock position, tyre pressures 36fr 38rr, low and narrow handlebar, steering damper fitted, front forks in std position on yokes, probably run the forks much softer than most (otherwise found that they lost grip as they jarred from bump to bump), sag set for my weight.

Hoffy, never had a road2, had a PP and that felt much worse than the M3.
Isle of Ninja - been the same, no diff whether rear tyre was new / shot.
Dave #3 - I like the fact that it turns faster than stock, just not the speed that it "falls" into corners. No problem in fast corners but in slower ones its a pig.
Strika - agree on the PPs. Not just this tyre but any of the M3s on the 12. Can't really remember back to the 11 (2 yrs ago). Although the one set of PPs on the 11 were worse than the M3s.
Isle of Nija - I'll check the wheel alignment (article in this issue of AMCN) next. Pressures are 36/38. Are you still using the Pirellis?
Phil - not Hoff approved. I'll try the alignment first.
Hoffy - bargain! - cheaper than $50 shipped.
Ausjc - tyres are for a road bike. A posting a couple of years ago on this site said that Pirellis were recommended by a particular performance shop for heavier bikes but I can't find the thread now. Don't know if the shop just sold Pirellis or what, just remember the thread. As in the opening posting - Perfomance mag's compo found Pirellis to be neutral.

I'm going to check the alignment at the weekend (will do a mate's ZX6R at the same time).

Again, I appreciate the advice and time taken to respond. I'm trying to separate the quick turning which I like (from a raised rear end) from the speed of falling once you start to lean over. Bloody hard I tell you.

All and any advice welcome.
Cheers,
Tony

[Phil]

I run 36/42 in the pressures, give that a try as well.

[IsleofNinja]

Isle of Nija - I'll check the wheel alignment (article in this issue of AMCN) next. Pressures are 36/38. Are you still using the Pirellis?Tony

Yep - for some reason they don't seem to last very long though those following me have often reported a bit of illegal road marking of the dark and aromatic variety!?

Hoffy - bargain! - cheaper than $50 shipped.

$37.00 plus GST = $40.70 plus ---- the $9.30 Aust post fee gets you bang on your $50.00 posted - (he ain't as green as he is cabbage looking )