Heavy, Overpowered Bike And More Slab Than I Like To Admit

[Chev]

OK, so here is a new twist on the old tire thread. I really don't want to hear I like XXXXX on my 5th gen, or I like XXXX on my 600RR. I have a special case here, more weight and less width than a Viffer and more torque/hp than a 600RR.

I'm about to order a set of tires in 120/60-17 and 160/60-17 for my F2 wheels. My bike is about 575 lb wet and 120-125 hp almost 70 ft-lb of torque. What kind of tires would you suggest, and why based on the bike requirements?

I do want some good performance in the twisties, but I'm slow (compared to HS anyway) and I'm fine waiting for them to warm up. I also hang off pretty proficently, so ultimate traction all the way to the edge is not really a concern.

I will say that I have recently lost all confidence in Dunlops. I scorched a set of 205s that looked fine 1000 miles ago and started wearing out really fast all of a sudden.

I'm hoping to get 3-4,000 miles out of the rear tire and I would like to think I could get close to double that out of the front.

/duck and cover.

[martinkap]

Metzler M3 ... rear tire on less heavy bike does about 5k miles. Good tracktion. Reasonable in the rain...

Martina

[zRoYz]

Diablo Road or a Pilot Road.

I have a friend that rides a Blackbird & has spare rear wheel. He has one wheel fitted with a Pilot Power for when he likes to play & the other wheel fitted with a Pilot Road for touring with his wife. He did this due to eating Pilot Powers like candy & the Roads give him great mileage & still great grip.

I only use my bike for play so fit sticky tyres because I can & my fav 2 are Pilot Power & Diablo Corsa but I tend to wear a rear out at about 4000kms. We pay allot more than the US for everything & at $300AU a rear tyre I have to cut down my riding.

[Veefer800Canuck]

I think any modern radials will outperform the original bias ply tires of the day by a wide margin.

But why the /60 front tire?

Your original 120/80-16 front tire was 23.55" in diameter.

a 120/60-17 is 22.66" in diameter. That's 4% smaller.

A 120/70-17 is 23.61" in diameter, that's only 0.23% larger in diameter than stock. Just about spot-on I'd say!!!

Speedo drive up front? Should still be accurate provided the CBR speedo drive gears are the same.

Don't worry about losing steering quickness going from a 16 to a 17" wheel. The radials will gain that back for you Vs the bias ply tires.

IMO, trying to compensate by using a /60 profile tire isn't necessary. The radials alone will be like adding power steering to the bike!

Now on the rear, you had a 140/80-17 as stock. That's 25.81" diameter.

A 160/60-17 is 24.55" which is almost 5% shorter. AND, it'll lower the rear end by 0.63 inches, slowing your steering.

How about a 160-70-17? It's EXACTLY 25.81" diameter. Gearing and ride height will be maintained perfectly where they are now.

Avan Azaros are made in a 160/70 rear, as are the BT020 Bridgestones, maybe more, I didn't look further. Have a boo yourself.

If it helps in your search, the 160/70-17 rear is the stock size for a BMW K1200LT And the ST1100, and the BMW F650CS.

If there's ever been a big heavy bike, it's the BMW Light Truck. And again, any tires built in the modern era for that bike will be worlds better than the 1985 technology hoops your bike was sold with.

Anything that fits the 1200LT will run circles around the (what were they, K-155 bias plys?) that came on your bike from the factory.

SUMMARY: MODERN SPORT-TOURING COMPOUND TIRES WILL DO EVERYTHING YOU'VE LISTED AND MORE, YOU DON'T NEED DIABLO CORSAS OR PILOT RACE, ETC.

Avon Storm ST, Michelin Pilot Roads, Dunlop D-220s, Pirelli Diablo Stradas, etc, etc, etc.

ANd the BMW-LT specific fitment tires will of course have extra reinforcing belts to deal with the weight of the bike, which is applicable to your situation (as per your OP details).

Just checked:

Metz RoadTec Z-6 comes in that size.

And the new Bridgestone BT-021

I'm guessing a 160 is about the widest you can fit without mods? A 170 won't go? is that right?

[Guest]

Try the Conti Attack as they have a thicker tread for a longer life and plenty of grip.. 6,800 miles out of my last rear tire convinced me...Thats highway/twisties use and alot of 2 up riding..9,300 miles on the front tire and it will be getting replaced in a month or two...

[Chev]

First, thanks everyone for keeping this on track. I really hate to see just another tire thread where everyone says that the tires on their bike are the greatest in every size and for every bike. :thumbsup:

Rob, jebus man talk about information overlaod. Processing all that is going to take some time. I mentioned those sizes because those were the stock sizes for the F2. From what I gathered on the CBR board, a 70 in the front will slow down the steering, but give some more stability. That is fine with me. They also said that a 170 will technically fit on the back, but the profile gets squashed. I will have to seriously consider the 70 front and rear, though.

I should mention that I am coming off of a set of Dunlop 205 Radials. The rear seems fine, but the front never really felt good to me. I liked the Metzler Lasertec Bias Plys far more on my 700 than these 205s...... weird thing to say, I know.

So, I feel pretty comfortable with the choice of a sport touring rear tire, but I leaning towards Pilot Roads, Avon Azaros (or whatever they call them now), M3 (I loved my Lasertecs afterall) and Stradas right now.

What are your thoughts on a sport tire (Power, Corsa, ect.....) for the front?

Thanks again everyone for avoiding just another tire thread.

[Veefer800Canuck]

Rob, jebus man talk about information overlaod. Processing all that is going to take some time. I mentioned those sizes because those were the stock sizes for the F2. From what I gathered on the CBR board, a 70 in the front will slow down the steering, but give some more stability. That is fine with me. They also said that a 170 will technically fit on the back, but the profile gets squashed. I will have to seriously consider the 70 front and rear, though.

Don't worry about what will or won't work on an F2. Ideally, you want to maintain the same diameter (and therefore, rolling circumference) of your stock 1000R tires as closely as possible.

The benefits are: chassis attitude isn't changed, speedometer reading is still close, and final drive gearing stays the same.

As far as slowing the steering, yes, a /60 profile tire will steer quicker than a /70 profile tire, all else being equal.

BUT, and this is a big BUT, your bike came stock with an /80 profile front.

So, a /70 profile front will already steer quicker than your stock /80 tire PLUS, changing from bias to radials is like adding power steering or losing 100 LBS off the bike.

You'll be amazed! I was when I changed the wheels on my '86 VFR750. Losing the 16" front tire and going to a 17" did nothing to slow the steering as it was more than offset by the lighter feel of the radial tires Vs the stock bias tires.

Look at the math again and you'll see a 120/70 and 160/70 are perfect for your bike.

Also, measure your existing clearance on your rear tire and see how much room you have for a bigger (wider) tire beyond what you have on there now. 170 perhaps?

Any more Q's, just shoot, I've done this swap already myself. '86 VFR750 with CBR F2 wheels.

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