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190 Vs 200 Rear Tire What's The Difference


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I want to say thanks for the advice I got on my "cornering jitters". Now I feel much more confident coming through the turns and was even able to realize that I was a victim of early corner entry because of them. Granted it has only been a couple of days it seems like a totally different experience now I am trying to fine tune the process and pick my speed up. Once again thanks .............but I have two more questions. The more speed you carry into a turn it, why do it seem like you body position changes so? Should I be resting my chest and outside arm more on the tank? Also I changed my tires and put a 200 on the back versus 190 one of my friends says I won't notice the difference, while another on says I am going to reduce my contact patch when leaning. Wouldn't a bigger rear tire give me more drive out of the curves? Which one is right?

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Hi J-mal

 

Can't tell you about the body position as that is not my expertise - there are people here far better than I but I can offer some light on the tyres.

 

What size wheel rim have you got? If you've got a 5.5 inch then you can't really go over a 180. You can squeeze a 190 section on but if anything, it has a negative effect. If you've got a 6 inch rim then you can go for 190 section tyres. 200 section? Why? Is this an asthetic selection? Does it make it look better? It won't go faster - my race can makes it go 'louder'... What is it that you want to achieve? What's your unit of measure? lap times? Straight line times? Looking mean? What success are you after?

 

Why go no larger? Because by squeezing on a larger tyre, the tyre will deform to fit the rim. It will deform first in any weak spots and secondly, it will make the tyre profile peak and look pointy. And it gets too tense. As it was designed with a certain profile in mind and now you're changing it there is no real benefit 'cos the tyre wasn't designed to work that way. It can play a little mind trick on you thinking that if it's peakier then it must turn faster but it won't. Only you can turn the bike faster. Maybe relax your arms, slouch over the tank and turn the bars on their pivot point. That'll make it turn faster. Or maybe if it's a bigger tyre then I can go faster because I can get more power to the rear wheel because it's got a bigger contact patch but it isn't, it doesn't and you won't.

 

If a tyre deforms on it's weak spots - and there is at least one somewhere, it's all a matter of degree - then you are not going to have a uniform tyre. It's going to bulge, it's going to have more flex in some places. Consistancy is the key.

 

It will potentially slow down your turning speed as there is more rubber for the bike to get over. The more rubber there is then potentially, the more resistance to change and that means turning speed. There is a time when you want that resistance - it's called grip but we want to use it to our benefit, not put up with what we are given. Quick to turn and the right amount of grip when we get there. I want to say 'low resistance' and 'high resistance' but that is incorrect. It's about getting the 'right' amount of resistance. Too much and too little are both bad things. Go for the 'right' amount of grip. Thin tyres typically turn faster than fat ones. It's all about balance.

 

Contact patch. If you want a bigger contact patch then lower your tyre pressures. it won't give you any more drive - your right hand does that bit so basically, the contact patch will pretty much remain the same. There isn't any real benefit to fitting a larger tyre than the one your bike was designed to go with.

 

Finally, I fitted a 190 section onto my bike and i've got a 5.5 inch rim. It looks better. I took it to the track and got to about 2 mm from the edge of the tyre. Consistantly. I didn't go any lower, the bike didn't go any faster. The only thing preventing any changes - going lower, going faster, turning quicker etc was the size of my confidence. I don't think that the size of my tyre had much to do with it. And I'll be going back to a 180 section tyre when this one is done.

 

Hope it helps!

 

FT

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Changing a rear tire size from stock without analyzing and having GOOD data on the entire chassis geometry AND making appropriate changes, is a BAD IDEA...

 

If the bike was not engineered to run a 200 (or in some cases a 190, 180, etc), you're not going to benefit from slapping one on and doing nothing else.

 

Instability can/will result, as will crashing when you run out of front tire long before you're over to the edge of the larger rear...

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If the bike was not engineered to run a 200 (or in some cases a 190, 180, etc), you're not going to benefit from slapping one on and doing nothing else

 

I ride/race a Suzuki TL1000R which is running standard rims, which come fitted with a 190. Everyone anywhere will tell you to fit a 180 to (supposidly) sharpen up the steering. Ok, so this does sort of work, but the advice above is still corect! The 180 tyre walls become exactly vertical, they stop sloping in from the tyre tread to the rim, the tyre edge become flush with the rim. Therefore, for the side wall to change angle, the treaded area must have deformed also.

 

I went in search of something better and stumbled upon a Bridgestone 190/55 race tyre. A 190 tyre with a 180 profile. This seems to me to be a much better (and safer) option than a deformed 180! I also like the confidence boost that it gives me knowing I have a bigger contact patch!

 

The bikes suspension and chassis was rumoured (by the previous owner) to be set up to take the 180. How much truth or BS is there is setting up the chassis/suspension to deal with tyre width?

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The bikes suspension and chassis was rumoured (by the previous owner) to be set up to take the 180. How much truth or BS is there is setting up the chassis/suspension to deal with tyre width?

There's absolute truth to altering setup/geometry to deal with a different size/shape/profile tire. I do it all the time.

 

Now, whether the previous owner of your bike made these adjustments, and made them correctly, is something I cannot answer...

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Now, whether the previous owner of your bike made these adjustments, and made them correctly, is something I cannot answer...

 

Indeed, many of the things I have been told about this bike I have proved to be inaccurate!

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some other things to consider when making even the slightest changes to tire profile/measurements...

 

first it helps to know what the heck we are talking about...

 

in this case, the metric measurement of 180, 190, 200 refers to the width of your tire measured in millimetres (mm). just as important is the next number such as 60, 70, 80, 85, 90 etc. which is the height of the tire expressed as a percentage of the width. this percentage can be expressed as a fraction which we all know is a ratio ...aspect ratio. too much info?

 

ok. bottom line, how tall your tire is has a BIG effect on how fast things are turning at a given speed. taller tire equals bigger circumference equals less revolutions per given distance. ie. you will need to change your gearing to maintain redline at a given place and gear...i'll let you extrapolate as to all the permutations of that fact.

 

and as mentioned previously, big changes in geometry will result from seemingly small (8.5mm) change in height. also, different brands, different models with same numbers will NOT measure the same. maybe different profile, maybe, maybe, maybe... when changing tire style or brand of equal size (supposedly)measure for yourself. the molded number ain't the reality.

 

now, it is possible to calculate all sorts of things with basic math here. and whole new worlds open up with a little right triangle trigonometry. i'm sure everyone knows that the circumference of your tire divided by (fraction/ratio) the diameter is one of those beautiful transcendentals...um...tmi again. anyway, tune in next time for the secret code to figure out everything from the brew date, to compound, to what country your tire may have been molded in.... ;)

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  • 13 years later...

Recently Joe Roberts did a day of practice on one of our school bikes which he is familiar with. He had always rode it with a 200/55 rear but this time he used the new 200/60. As suspected the bike turned in very well due to the higher rear. The 200/60 is 10mm taller than the 200/55.

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Guest Bromson

I'm so glad you posted this! At my last track day the Dunlop tire vendor was recommending the 200/60 and said it would make the bike "turn better" but I didn't really understand why, and I was wondering. This info was very helpful.

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