Squared-off tires, or is it tyres?

[Metastable]

I guess this is more along the lines of survival maintenance....

It has been quite a long time since I've ridden a sportbike on the road (circa 2007). However, recently I sold by track bike and bought a 2008 R6. I have decided to do a road trip with a mate before making the R6 a track machine ..... and he coincidentally bought a 2009 R6. Both bikes have less than 8000kms, are stock, and aside from a bit more preload on my friend's bike the settings were put to factory stock settings for everything else. Both machines are in essentially mint condition. I did basic maintenance on both bikes (adjusted chain, tire pressure etc...), with mine I also lubed up all the suspension bits while changing out the previous owner's lowering linkages.

My bike came with brand new tires. I took it for a shakedown ride and it felt great. Then I hopped on my friend's bike and did the same shakedown ride (he lives quite far away, but there was a good deal near my place, so when he was here for work, he bought the 2009 R6).

<-- my expression at the first corner I got to.... very low speed. At first the bike was reluctant to turn in, then it turned in like a bastard. Same thing on some other corners and if I touched the brakes mid corner and didn't keep strong input on the inside bar, it would shoot back up. On faster corners and while doing quick left/right transitions it was a lot less noticeable.... but at slow speeds ..... BUGGER ME!!!

I must say I have never ridden a bike with tires as squared off as this one. When I checked the tire pressure (before ever riding it), they were super low.... 18 psi rear 21 psi front.... which to some part explains the excessive centre tire wear. The pressures were adjusted before the ride.

So what's the point. I guess it's obvious that new tires usually feel better than used ones; however, I never realized how totally buggered up a bike feels with tires that are extremely squared off. The transition between flat and round is so pronounced, that slow corners are plain scary.

Anyway - peeps can ride what they want, but if you have squared off tires and your bike feels like crap, maybe consider a simple change that will make your riding a lot more enjoyable and safe too.

[Drew]

Most people don't notice the extent that squared tyres hinder performance, because it's a gradual transition as they stack up k's. When they replace tyres they all make the same revelation you just have.

[george formby]

Yup, the only bit of the bike that touches the road should be in top condition.

Tire reviews that start with "I've just changed from blah blah old tires to blah blah new tires and the new blah blah's are a huge improvement...." immediately lose my attention.

Good point with the slow speed handling, anything untoward becomes very apparent doing tight, slow speed, turns. You get instant feed back.

[Drew]

I wanna troll the tard that's using the brakes mid turn!

[Jin]

Why would he set the pressure so low? I have seen in the US forums they set their pressures super low like 30-35 in the rear which is stupid when manufacturer recommended is 42.

[Metastable]

Oh I'm pretty comfortable applying brakes mid-corner..... and I'm not going to get into a where to brake debate..... I've explained myself lots on here before. Anyway, during the shakedown ride I was trying all sorts of stuff (cornering, braking, going over bumps on purpose, fast, slow...shakedown) .... I never did need to touch the brakes mid corner.... but I did it on purpose to see how the bike reacted.

As for the low pressure - I think the dude was just clueless.... about checking his tire pressure. For a sec I thought my gauge gave me a false reading. Also - FYI, for the track some tires like Dunlops actually have fairly low recommended rear tire pressures..... low 20s. (I know it's the track, just an FYI... they are street legal race tires)

[jellywrestler]

I wanna troll the tard that's using the brakes mid turn!

try riding a z1300 without doing this and you die

[george formby]

I wanna troll the tard that's using the brakes mid turn!

I decided not to mention it... I've had incidents were, er, em, other riders have caused me to hit both brakes in a corner. Maybe I was to close, maybe they just spotted a dollar coin on the road. Dunno. Even my Exxon Valdez with wilted celery sticks for forks and a playdoh shock stands up sharpish if I touch the front brake tipping in. Most disconcerting.

[swbarnett]

Most people don't notice the extent that squared tyres hinder performance, because it's a gradual transition as they stack up k's. When they replace tyres they all make the same revelation you just have.

I commute about 100km of motorway every week day. As a result my tyres do eventually square off before they get replaced. I've never had the problem of "not noticing it". A weekend twisty ride on old tyres soon has me wanting new ones. Having said that it also depends very much on what "rubber" I'm running. The Conti Road Attacks (1 & 2) were terrible when squared off but the BT45s were less of a problem. The PR4s I'm running now don't seem to square off nearly as much. After 16,000km there was a noticable but not huge difference once the new rear went on (22k now and I've yet to change the front).

[Kickaha]

Why would he set the pressure so low? I have seen in the US forums they set their pressures super low like 30-35 in the rear which is stupid when manufacturer recommended is 42.

42 is more likely the maximum pressure at maximum load

[Drew]

Why would he set the pressure so low? I have seen in the US forums they set their pressures super low like 30-35 in the rear which is stupid when manufacturer recommended is 42.

Bridgestone say 40 something in the S20 rear hoop. I run 32. NZ supplier agrees with me, he knows how I ride and what I ride.

It is a safe guideline. Not the perfect number. There is no perfect number, too many variables.

[5ive]

Most people don't notice the extent that squared tyres hinder performance, because it's a gradual transition as they stack up k's. When they replace tyres they all make the same revelation you just have.

Yep, I had that same exact experience myself. Racked up some serious k's commuting every day, then didn't ride for a month over the Christmas holidays. Jumped on the bike for my regular commute, and found that my bike wasn't handling as well as it should around a long, smooth, but tightening corner in a 100km zone.

Asked the workshop to check out my bike during the next service that was due a few days later, and they couldn't find anything wrong with the bike.

I had a good look at the tyres myself, and found that even though there was still enough tread left on both, a combination of side wear on the front tyre, and enough of a flat spot on the rear made the bike unstable at high speed whilst cornering.

I wouldn't of noticed if I'd not taken a break from riding.

A New set of tyres fixed it right up.

[Jin]

R6, R1, fireblade, cbr600rr all have recommended pressure of 42 rear for the street. Going lower you might get slightly better grip but you are giving up handling and tire wear. I dont baby my bikes and have tried lower pressures but hate the squishy feeling of a lower pressure. Guess its a more a personal preference but these are sport bikes not commuters keep that in mind why the recommended pressure is 42.

[Kickaha]

R6, R1, fireblade, cbr600rr all have recommended pressure of 42 rear.

Recommended by who and where?

[neels]

Had the same thing when I stuck new boots on one of my bikes, turn in improved so much I almost chucked it on it's side at the first corner, huge difference that definitely took me by surprise.