Pilot powers and pilot roads

[fulcrum]

Hi all,

I'm (hopefully) getting my bike back Saturday morning (yay!!!).

While I'm over that side of town I'm going to get some new tires popped on.

My wife just got some pilot powers on her bike and loves them.

I asked for them, but the guy said they don't make the right sized rear power and recommended a pilot power for the front and a pilot road for the rear.

I asked about a 160 rear power and he suggested that the 150 rear road would be better, and just fine with the front power. He said the 160 wasn't made for it and would be too slippy whatever that meant.

I don't care if they don't last forever, and I don't do a lot of touring. I mainly ride through nice twisty roads and want something that will instill a lot of confidence (currently using the default tires - dunlops I think, but they aren't macadams). I'd prefer more stick and less life I guess. And I rarely ride in the rain - mainly because it doesn't rain much here and I'm only a weekend rider.

[fulcrum]

I noticed in some other posts that people are also going for 120/60 front and 160/60 rear.

The default sizes for the K4 750 (I thought) are 120/70 front and 150/70 rear.

How does dropping from 70 to 60 affect the bike? And what about the 150 to 160 change?

Are there any problems with doing this? And if there is a 120/70 in the range why would people get a 120/60... is it because they got a 160/60 rear?

[The CyberPoet]

I noticed in some other posts that people are also going for 120/60 front and 160/60 rear.

The default sizes for the K4 750 (I thought) are 120/70 front and 150/70 rear.

How does dropping from 70 to 60 affect the bike? And what about the 150 to 160 change?

Are there any problems with doing this? And if there is a 120/70 in the range why would people get a 120/60... is it because they got a 160/60 rear?

Dropping the sidewall height improves the road feedback and reduces the amount of flex in the sidewall, but also makes the suspension work harder and doesn't flex over surface imperfections as well, reducing tire contact times on bumpy surfaces.

Yes, the default sizes are 120/70ZR17, 150/70ZR17 for the 98+ models.

You can push the rear one width size up by dropping the sidewall height by 10% (i.e. a 160/60ZR17 will fit without safety concerns on a 98+), which improves dry weather handling but decreases the speed at which the bike will hydroplane, plus the other considerations mentioned above. A lot of riders are taking 160/60's because some brands (the Diablos for example) aren't available in a 150/70 and they want that brand. Note that the broader arc of a 160/60 will also slow the handling characteristics some.

If you can have the tires of your choice in the stock size, take them.

Cheers
=-= The CyberPoet

[fulcrum]

Thanks cyber

I was sure there had to be some trade-off when changing from the 150 to the 160.

[OtLa]

I was just curious, what impact on speedometer readings would there be by going from stock to a 160...In the Diablo for example. (I did this last fall, and speedo seems a tad more innacurate)

[Black_peter]

Dave,
Whats up with the tires?

[The CyberPoet]

I was just curious, what impact on speedometer readings would there be by going from stock to a 160...In the Diablo for example. (I did this last fall, and speedo seems a tad more innacurate)

I'd ball park it around a 10% change if you're on a 98+ Kat (which take the reading off the front sprocket, not the front wheel).

KNOW THIS:
Different manufacturers' specific tires will expand different amounts once mounted and heated/cooled, from as little as 2% on some street tires to as much as 25% on some race tires. Most street tires will expand about 4 - 7%.
When you mount a 160 into a rim designed for a 150, the shape is distorted some, pushing the center arc of the tire outwards further because of the pressure on the sidewalls from the mounting flange angle. This increases the effective circumference above what you would get mounting the same 160 on a rim intended for a 160, and helps decrease the amount of change from a 150. On the other hand, this change in shape also causes the tire to build more heat, resulting in low lifespans than would be the case with the same tire mounted on the "ideal" rim for it.
Pretty much all manufacturers simply lie in their measurements. Theoretically, a Metzeler Z6 150/70ZR17 for example should have a sidewall measurement of approximately 105mm (70% of 150mm). The truth is that it will act as if it were a 150/70ZR17 and safely mount where a 150/70ZR17 will mount. In reality, the real-world sidewall measurement on a Z6 in a 150/70 is closer to 69mm (of which about 50mm is exposed on a 98+ Kat rim -- measure it yourself!), and the full distance from the inner lip to the peak of the center arc is only about 97mm once mounted. This would mean that their claimed 150/70ZR17 is actually closer to a 150/46ZR17.

Cheers
=-= The CyberPoet

[fulcrum]

Thanks for the advice everyone.

I am getting the power/road combo put on tomorrow morning. I'll let you know how they are after my ride on Sunday.

[crazymofo]

the power road is a good tyre, i had one on the rear of the kat done 3000 km from it with still 2mm of tread left (i like to ride hard :P)

ive opted for the powers front and back now. cant wait to test the babies out on the kat.

cheers.joe.

[fulcrum]

I just got back from my ride. They are nicely scrubbed in now.

These tires definitely feel different from the standard ones, but they are great.

Still getting the confidence back on the twisties, and the bike feels completely different (working front brakes and a noisy pipe as well as the new tires). But I can feel they are a definite improvement. I had a look at my speed through a couple of corners and was impressed. I thought I was taking it easy and was about 20km/h faster than I used to go through some of them.

And there is one sharp uphill right hander (you guys who drive on the wrong side fo the road think uphill right hander) where when I put the power on the back used to skip across the road. That doesn't seem to happen anymore.

[fulcrum]

ive opted for the powers front and back now. cant wait to test the babies out on the kat.

I went with what the guy at Brisbane Motorcycle Tyres suggested. He said it'd be best not to put a Power on the rear as they don't make the 150. He had to get the Road in, so I know he wasn't just trying to clear stock. Seems like a really knowledgeable guy.

Anyway, it does feel fantastic. Might go for Powers front and back next time too (unless I get a new bike before then... it appears that Triumph have finally released the new Sprint ST in Australia (drool, drool)).

[crazymofo]

ive run the 160 profile on the rear's since day one of owning the kat, so going the powers isnt that big of a step :P

ive never had once problem with the 160's.

ive even had a tyre dealer offer to fit up a dunlop 208. 170 wide at that! i decided against it as there would have been less then 3mm of clearence between tyre and swing arm.

cheers.joe.

[duff daddy]

hummm im looking at thoes pilots also

[1FunnyGuy]

If you guy's don't mind my 2 pennies worth .. here's what I did to my 89 Red/Gold 600 Katana.
I installed a set of the wider rims from a 2002 600 Kat. Wrapped them with a 160-60-17 Mich Pilot Power on the rear and a 120-70-17. Seems to handle very well....