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Posted

Keep in mind that tyre size is general. A 180 tyre is not exactly 180mm wide. It can be anywhere within about 10mm either side. Dunlop, Avon tend to be wider. Pirelli and Metzler tend to be narrower. Michelin in the middle.

 

As measured, my 180/55 Pilot Power on a 5.5 inch rim is 16mm wider and 6mm taller than my 160/60 Pilot Power on my 4.5 inch rim.

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Guest ratchethack
Posted

who are this pair of droids? Are these these blokes from that silly TV show?

 

Pete

[. . . sob . . .] :(

 

Yes, I'm afraid so, Pete.

 

They've become yet another horrific eyesore among wot vast swaths of humanity have come to accept as icons of "American Values". :homer:

 

See link here:

 

http://www.v11lemans.com/forums/index.php?...st&p=123069

Guest drknow
Posted

May I be small voice of opposition in these hallowed ranks? While I would agree on principle with the general consensus that the 160 on a 4.5 inch rear rim is likely the best handling combo, I go the other direction. Yes, that's right folks, I run a <gasp> 190 on my 5.5 inch rear rim. If I may be so bold as to give my reasons why...

 

1. I like the way it looks. Yes, I know that is a very unmanly statement, something only Harley owners might appreciate, but there it is. The V11 is a large scale bike, and the skinny tire just doesn't look as muscular, nor does it fit the bikes somewhat "generous" proportions. While my particular V11 didn't come with a 4.5 inch rim, if it had, I would have swapped with one of you in a heartbeat (which reminds me, I will have a 4.5 inch rim in shortly, and will be looking for someone with more sense than me to do exactly that). Furthermore, look into your hearts a moment. We ride air-cooled 550lb bikes. If we had to maximize our sporting experience to the degree many of you seem to suggest, we'd all be riding R6s or GSXR750s. I ride Guzzis because they're fun to ride, they make slower paced stuff exciting, and they work much better than they have any business to. Yes, i know that there are roads where a Guzzi doesn't give away anything to anyone, but face it, those are not all we ride on. Even when we set out to ride in a sporting fashion we ride smooth roads, roads with big sweepers, etc. I know a few of you have kept your K&N pods even in the face of evidence that the airbox setup makes more horsepower, just because you like the way it looks and sounds!

 

2. I'm cheap. I know that at least the 180 would be a better handling tire than the 190 I run, but alas, I'm a racer that races open class bikes, and have a practically inexhaustible source of 190 DOT take-offs, and I'd rather run those than pay to run something "better." Besides, I can wear the 190/55s all the way to the edge, so I think I'm getting my moneys worth anyway. RichPugh, if you buy one, I'd go with the following sizes in order of preference: 180/55, 190/55, 190/50. The 190/50 is a pretty awful profile, so stay away from that one if possible. The 190/55 really won't look appreciably bigger on there, and is designed for a 6 inch rim, so it won't be quite as great, and isn't available in very many places yet, but all the Big 4 make a hyper street bike tire in that size now. Or, call me, I'll sell ya some take-offs cheap!

:bbblll::D

 

dk

Posted

dk,

 

I think we probably see eye to eye on a lot of things LOL. The airbox/pod filter point is a wonderful argument. I know a million VW guys that argue that a VR6 engine in a Mk2 chassis Golf handles terribly but they still run their over oiled, heat absorbed cone filters because it looks and sounds cool.

 

The bike I just bought has all the 'balls' I could ever want in a bike... it should have a rear tire to represent it :) Thats not too much to ask for it is? I resent anyone remotely attempting to compare me to a member of OCC so I hope that asnt anyones intention. While I love choppers and what they represent to the american culture, I happen to prefer an Italian sports cafe bike with class and character. God forbid me wanting a wider rear wheel and tire haha.

 

I'm surely interested in a simple swap 4.5 for 5.5 wheel if anyone wants to downsize in the off season! (My off season is late November thru early March.

Posted

May I be small voice of opposition in these hallowed ranks? While I would agree on principle with the general consensus that the 160 on a 4.5 inch rear rim is likely the best handling combo, I go the other direction. Yes, that's right folks, I run a 190 on my 5.5 inch rear rim. If I may be so bold as to give my reasons why...

 

1. I like the way it looks. Yes, I know that is a very unmanly statement, something only Harley owners might appreciate, but there it is. The V11 is a large scale bike, and the skinny tire just doesn't look as muscular, nor does it fit the bikes somewhat "generous" proportions. While my particular V11 didn't come with a 4.5 inch rim, if it had, I would have swapped with one of you in a heartbeat (which reminds me, I will have a 4.5 inch rim in shortly, and will be looking for someone with more sense than me to do exactly that). Furthermore, look into your hearts a moment. We ride air-cooled 550lb bikes. If we had to maximize our sporting experience to the degree many of you seem to suggest, we'd all be riding R6s or GSXR750s. I ride Guzzis because they're fun to ride, they make slower paced stuff exciting, and they work much better than they have any business to. Yes, i know that there are roads where a Guzzi doesn't give away anything to anyone, but face it, those are not all we ride on. Even when we set out to ride in a sporting fashion we ride smooth roads, roads with big sweepers, etc. I know a few of you have kept your K&N pods even in the face of evidence that the airbox setup makes more horsepower, just because you like the way it looks and sounds!

 

2. I'm cheap. I know that at least the 180 would be a better handling tire than the 190 I run, but alas, I'm a racer that races open class bikes, and have a practically inexhaustible source of 190 DOT take-offs, and I'd rather run those than pay to run something "better." Besides, I can wear the 190/55s all the way to the edge, so I think I'm getting my moneys worth anyway. RichPugh, if you buy one, I'd go with the following sizes in order of preference: 180/55, 190/55, 190/50. The 190/50 is a pretty awful profile, so stay away from that one if possible. The 190/55 really won't look appreciably bigger on there, and is designed for a 6 inch rim, so it won't be quite as great, and isn't available in very many places yet, but all the Big 4 make a hyper street bike tire in that size now. Or, call me, I'll sell ya some take-offs cheap!

:bbblll::D

 

dk

 

dk,

You know how I can tell you made your bike handle worse? You only have a 114 post count.

Posted

I'm all for differences in opinion. Different riding styles demand different settings, I know that. The thing is that in my experience, which I freely admit is more limited than some, most if not all *modern* Guzzis are over tyred as a fashion statement rather than as an ajunct to performance enhancement. I find that V11's in particular actually handle better and are more ENJOYABLE to ride with smaller rear tyres than the factory recommends. I've found the same thing, too a lesser extent, with my Griso.

 

Having a bottomless supply of cast off race tyres helps :grin: . Rob runs a whole variety of race bike knock-offs on his street LeMans 'cos they're cheap, he has them and they do hold the road a lot better than almost any street tyre even when they are virtually f#cked!. BUT he still preffers a 110/90-100/90 combination on the road if he's got them handy.

 

I find that fat rears make turning the bike, especially in a *spirited* manner an absolute chore. I also couldn't give even the tiniest of shits about what other people think of my bike aesthetically. I love it for it's form as part of it's function. Not as a suplementary side issue. But that's me. Lesser men etc. Greg :grin: .

 

Pete

Posted

 

Now I know that it's a Popular Kulture "bling exercise" to have that big fat black meat protruding as conspicuously as possible out back. kinda like 10 lb. of bologna stuffed into a container designed to hold 5 lb.

 

You mean like this?

sparetyre.JPG

Posted

You mean like this?

 

This Mike, is NOT a good look. In fact I might go as far as to say it is a conspicuously BAD look. Even if the poor girl wasn't on a motorbike it's a bad look! Doesn't anybody have a mirror at home nowadays? (Not that I'm any oil painting.)

 

Pete

Guest ratchethack
Posted

You mean like this?

YEEEEEEFFFFFFTTTT!!!

 

Did someone say there's no accounting for taste?! <_<

 

With something like THAT waving in one's face on the road, it'd be an easy matter to evaluate the wear pattern -- whether you want to look or not . . . :o:homer:

Posted

Hahaha... that pic is priceless!

 

FWIW, The bike I own has very low aftermarker clip-ons, putting me into a very forward, very sporting riding stance. Perhaps a 180 or 190 rear tire on a 5.5" wide rear wheel would not affect the handling as much with my bikes riding position? Perhaps still LOL...

Guest drknow
Posted

dk,

You how I can tell you made your bike handle worse? You only have a 114 post count.

 

Yeah, I'm an underachiever in that category. ^_^

 

Pete, with regard to the 170/60 on a 5.5 rim. I think a good sport 180 will be just as quick to turn, and allow you to explore the tires limits all the way to the very edge. When you spread a 170 (designed for a 5.0 rim) the extra 1/4 inch on each side, it tends to make it feel funny when at the very edge of the tire. I think that may be contributing to the unused portion on the front you're describing. It's the opposite of running the 190 on a 5.5. Many racers do it, some prefer the way they drive off the corner, but all notice the difference at full lean. I would think you may consider trying other 180s to find one that has a better profile than that metzeler. However, considering that I run tires that aren't ideal I'd say take that with a grain of salt (the fact that I own a Race Tire distribution business and sell and tune them constantly should be ignored).

 

Incidentally I recently went to a 170 section on the back of the Griso and it has made it a lot more whippy! Onl;y problem is I don't use as much of the front tyre now so all the poofter dags are still in the edges! With the first set of Rennsports, (A dreadful tyre! Deafeningly noisy!) I managed to wear the elephants off the edges anigrin.gif (Which for a scaredy-cat slowpoke like me is really quite impressive!)

 

dk

Posted

While I mostly agree with narrower tire handling better concept, I would just like to add that from my limited experience, a bigger tire will go a few more miles, and provides a more comfortable ride.

Because I am not out to win races, I too, would happily swap my 4.5 for a 5.5 so that I can switch from the 160 to the 180.

Guest ratchethack
Posted

Look, I'm not the least bit interested in participating in the "I've got the Biggest Schwanstupper Here" contest.

 

Having said that, ;)

 

Does Size Matter?

Squeezing a wide tire onto a narrow rim can be a big mistake.

Here's why.

 

Sport Rider did a comparison test of exactly the sizes we're talking about here.

 

Anyone thinking of going to a wider rear wheel and tire without also knowing how OEM engineers and/or knowledgeable racing teams properly match up appropriate front wheels and tires to rear wheels and tires will no doubt be interested in this.

 

As discussed on this Forum three years ago this week. The illustrations make it pretty clear what causes the less-than-favorable symptoms noted in the comparo:

 

http://www.sportrider.com/tech/tires/146_0...size/index.html

 

Does Size Matter

Squeezing a wide tire onto a narrow rim can be a big mistake. Here's why.

By Andrew Trevitt

 

Those low-profile 190-series tires sure look gnarly on the back of a sportbike, and we've seen them pinched onto all sizes of rims. But in reality, a 190/50-17 fits properly only on a 6.0-inch rim, and cramming it onto anything smaller severely changes its profile.

 

As an experiment, we mounted a 190-series Metzeler Rennsport onto our F4i's 5.5-inch rear wheel and took some measurements. Compared to the correctly sized tire on the same rim, the 190's profile closely matches the 180's near the edges of the tread, but is much lower in the center area-equivalent to about a 6mm change in ride height. Effectively, the wider tire will give more rake and trail when the bike is vertical, while keeping close to the original geometry when the bike is leaned over. Accounting for one (by changing ride height) will unduly affect the other.

 

Following our test with the Metzeler Sportecs, we slipped a 190/50 rear Sportec onto the F4i and rode a portion of the test loop for a practical comparison. With no changes to suspension or geometry, the F4i felt substantially different with the wider tire. With the bike straight up and down, steering was slightly sluggish in comparison, but just off vertical, the F4i was quite tippy and darted into corners. The light, neutral steering of the Sportecs was completely changed and the bike lost its balanced feel. The sensation was very much like riding on a tire squared off from too many freeway miles. At higher lean angles, performance was less affected, although making transitions from side to side was unpredictable. And, contrary to the popular myth that the wider tire puts down a bigger footprint and gives more traction, we felt no improvement in that department from the properly sized tire.

 

We've experienced similar changes with a 180-series tire on a 5.0-inch rim meant for a 170-series bun. Tire engineers work hard to design and match front and rear profiles for characteristics that we sometimes take for granted. Upsetting that balance is surprisingly easy and you should think twice before sacrificing your tire's performance for appearance's sake.

 

Sport Rider's bottom line:

 

Tire engineers work hard to design and match front and rear profiles for characteristics that we sometimes take for granted. Upsetting that balance is surprisingly easy and you should think twice before sacrificing your tire's performance for appearance's sake.

The above only addresses different tire sizes on the same wheel. Of course this begs the question:

 

What might be expected when front and rear wheel widths aren't correctly matched? :huh2:

 

Slaves of "fashion" will make their choices, as will those who favor performance, comfort and safety. Too bad they're mutually exclusive and opposite directions here WRT mfgr's recommended applications. :whistle:

 

Ain't it just a wonderful thing that in a Free Market Economy, we all have freedom of choice?! :thumbsup:

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