Squared-off tires, or is it tyres?

[SVboy]

Interesting thread. In the OPs first post he said he had returned both bikes to std suspension settings, apart from a little more preload. Good place to start, but a better place would be setting sags for each individual rider. Why would factory rebound settings be right with fork and shock oil that is now years and Kms old?
Tyre pressure is an individual thing. The factory says 42 for a rear S20, yet Drew runs 34? He is an experienced rider and probably used prior knowledge and experimentation to get to where he feels the tyre is working for him. AllanB is an experienced rider with a sophisticated bike, but he didn't just accept the manuals suggestions, he experimented to find what works for him.
I run 25 f 29r on my motard on the road. Works for me. Search the net for Dave Moss, it will be worth your while.

[Drew]

Hahahah there were lots of excuses for sure! One of those offs with a 'WTF' why did that happen situation.


Now - look you'll have everyone wanting advice on tyre pressures to hit that 60 degree lean now .......... is that how you get rid of the chicken strip - it's all about the tyre pressure.

Fuck yeah. 50psi to get rid of yer chicken strips. Every time.

[R650R]

42 PSI is suicidal for any sportsbike... that's asking for a cold tyre highside or lowside for that matter.
The GSXR 750 I run at 34 front and 36 rear in summer, maybe couple psi lower in cold conditions. The DR on80/20 tyres runs as low as 24/28 F/R but typically 28/32 F/R. When it came back from an absurd 33 PSI after the dealer first service when new I could feel it letting go too easy.
Don't brake thru corners and tyres should wear fairly evenly.
Yep nothing like a fresh front tyre to transform handling....
I regard 20psi as dead flat for sportsbike but have ridden home with 6 spi in rear tyre, it was near end of its life so didn't mind BBq ing it vs breakdown/recovery late ona sunday....

[Drew]

42 PSI is suicidal for any sportsbike... that's asking for a cold tyre highside or lowside for that matter.
The GSXR 750 I run at 34 front and 36 rear in summer, maybe couple psi lower in cold conditions. The DR on80/20 tyres runs as low as 24/28 F/R but typically 28/32 F/R. When it came back from an absurd 33 PSI after the dealer first service when new I could feel it letting go too easy.
Don't brake thru corners and tyres should wear fairly evenly.
Yep nothing like a fresh front tyre to transform handling....
I regard 20psi as dead flat for sportsbike but have ridden home with 6 spi in rear tyre, it was near end of its life so didn't mind BBq ing it vs breakdown/recovery late ona sunday....

20psi is far from dead flat. I've run SC2 supercorsa rear that low many times.

So stop making sweeping statements when there are too many variables to make a hard rule.

[george formby]

Yeah, to low a pressure causes bad wear. Flat tire on the local roundabout. The whole tire tire looked like that. A can of tire weld and a slow trip home before the photo. Tire is still going strong with a plug in it.

Attachment 323711

[Jin]

42 PSI is suicidal for any sportsbike... that's asking for a cold tyre highside or lowside for that matter.
The GSXR 750 I run at 34 front and 36 rear in summer, maybe couple psi lower in cold conditions. The DR on80/20 tyres runs as low as 24/28 F/R but typically 28/32 F/R. When it came back from an absurd 33 PSI after the dealer first service when new I could feel it letting go too easy.
Don't brake thru corners and tyres should wear fairly evenly.
Yep nothing like a fresh front tyre to transform handling....
I regard 20psi as dead flat for sportsbike but have ridden home with 6 spi in rear tyre, it was near end of its life so didn't mind BBq ing it vs breakdown/recovery late ona sunday....

Fuck off


10char

[onearmedbandit]

Fuck it's another 'what oil' thread...

[AllanB]

Fuck it's another 'what oil' thread...

Full synthetic surely. Only the best will do.

[scumdog]

Fuck it's another 'what oil' thread...

Add it to the KB Wave thread and we'd really have something!

[ellipsis]

...'bin riding on shit tyres for eons...they were fucking nearly built square for some of the shit I've owned...did a few seasons on IRC's on a post classic, sometimes they had enough air, they only let go once without rider instruction...you cunts are all dependents...sticky expensive tyres only last for about ten smiles whenever I own a set...

[AllanB]

I was in at the local Suzuki dealer a few weeks back - a M109R had a new tyre on the rear - a 240 something 18 I think. Bloody new tyre profile was not very curved compared to what I usually look at they must be shit when worn. That's one wide rear though.

[swbarnett]

...sticky expensive tyres only last for about ten smiles whenever I own a set...

16k out of a PR4 rear. Front's on 22 and still going strong.

[Gremlin]

While the thread has touched on factors such as the factory manual and a riders personal preference, remember that the tyre itself probably makes as big a difference, if not more. Different tyres are constructed differently with different compounds. You have single compound, dual, triple and and varying compound. Some tyres have a stiff carcass, others have a soft one and obviously some are sticky, some not so sticky, silica content etc etc and so on.

A tyre with a stiffer carcass will handle a lower pressure and retain it's shape better than a tyre with a softer carcass. Indeed, a stiffer carcass may need the lower pressure to deform and perform in certain environments, where a higher pressure would be detrimental. You also need to remember what the max pressure for a tyre is, some can't handle more than say, 36psi.

So, just because you run one model of tyre at a pressure, doesn't mean a different tyre will be great at the same pressure. Couple that with rider preference, and basically the best thing to do is educate people and let them make their own decision.

[caspernz]

Amusing reading this stuff. My Busa manual says 42 psi front and rear. Well mmmm, if I crank the pressures up to that, it just plain sucks!

Do a bit of research and find it's all to do with manufacturer of bike not being sued by some dumbass Yankee doodle who can't work out that when he puts a pillion on the back, along with his luggage, the tyre pressures need to go up a little.

Experience with various tyres, 38 front and rear is a good starting point one up. Day at the track? 36/32 is a good set of numbers. Two up? Well funnily enough, 40/42 works quite nicely under those conditions...

[rastuscat]

The issue is that as tyres wear we as riders simply adapt to them over the life of the tyre. When we get new tyres the difference is normally stark.

I'm always reluctant to get rid of a set of tyres until the last of the life is out of them. It's a money thing.

This morning I'll be scrubbing in my Metzler Z8s. When I rode the bike home from the shop the tip in had me grinning from ear to ear.

The bike is a R1200RT. It's 300 kg ish. I run 36 front and 42 rear. It's the manufacturers recommendation. I don't know better than him, so I'm okay with that.

Tyre pressures always make for good debate. Track experiences cause people to raise or lower their road tyres for normal use. Despite the fact that on the road tyres are expected to be a jack of all trades, dealing with lots of different surfaces and conditions.

I look forward to new tyres when the time comes.