Upsizing Rear Tire to 190/55 (w/ pics)

[Aasland]

Thinking about this a little more .. the rim width remains the same, so how is the tire "wider"? I understand that the distance across the surface of the tire, from edge to edge, is 190mm (i.e. 10mm more than 180) but is the distance from the bead to the edge actually increased too?

I would think that on the same rim width, the wider tire would just bow out more.

 

[CA G-Man]

Thinking about this a little more .. the rim width remains the same, so how is the tire "wider"? I understand that the distance across the surface of the tire, from edge to edge, is 190mm (i.e. 10mm more than 180) but is the distance from the bead to the edge actually increased too?
I would think that on the same rim width, the wider tire would just bow out more.

I’m no expert but I suspect the answer is something like this:

When you look at a motorcycle tire profile there is a “protrusion” of the tire outside the plane of the rim (more so than with a car tire). I think you could conceivably have significant variation in tire width (measured at the maximum width) all while leaving the bead in exactly the same place. In other words, yes, the lateral distance from bead to edge will vary.

In reality, I suspect a 190/55 will be a bit wider than a 180/55 (but not necessarily 10 mm) and it will be a bit taller (larger diameter) and the diameter difference will probably exceed the 11 mm difference that the simple math would suggest due to some “pinching” or “bowing.”

Again, just my layman’s “common sense” guess.

 

[SLK50]

Actual width in this case is determined by the rim.

Height, as indicated by aspect ratio, is not affected

by rim width. Tires do not "bow out" when pinched

at the bead. Circumference is held in check

by the belts.

 

[FJRat]

I am thinking of a 200/50 which will make the width 100 (multipying 200 x .50). The stock 180/55 calculates at width 99 (multipying 180 x .55)

Am I correct on these calculations?

If I am, then a 200 hardly seems worth it since I ll probably lose a bit on the pinch of the rim.

I would not be a fan of the 55 since I am not interested in making the bike taller. Though another option might be a 200/55 then use a lowering link...a lot of trouble and at a width of 110, I am not sure that a 200/55 would be a good choice for this OEM rim

 

[SLK50]

First set of numbers is the width in millimeters.

200 being 20 millimeters wider than a 180.

Second set of numbers is height as a percentage:

55 % of 180 = 99; 50 % of 200 = 100, etc.

A 200, IMO, would be a poor choice for an FJR rim

although it is the same height as a 180.

 

[FJRat]

SKK,

Dont keep the secret to yourself, do tell: why do you think the 200 would be a poor choice for the FJR?...I am listening...

 

[art miller]

Fairlaner is running a 190/55 on his Gen III and claims no negative issues. He has not commented specifically on the TCS but I would expect he would have commented if the change caused the TCS to become inactive. he claimed the bike is easier to get up on the centre stand and the speedo (mph) is dead on. As I recall, he had no negatives regarding handling.

I'm going with a 190/55 PR2 as soon as the Factory 180/55 hits the wear bars.

 

[FJRat]

To me, a higher rear end with a 190/55 mean a lower front end--with the change in geometry.

Sure, you are quickening the transition on curves, but at high speed on the freeway, you are also taking away some of the stability of the OEM design.

If you lower the rear of a bike, you gain some stability on the straight away at high speed and lose maneuverability on the twisties. The bike will sit on the freeway better at the higher speeds. The opposite happens when you raise the rear....resulting in a lower the front.

Anyways, that what it seems to like. If it doesn't to you then, ok.

 

[Top_Speed1]

My last follower to do this was "Wine Guy" this past Sat (6/7/13). He just had it done, so his report should be forthcoming.

TBH, I have not had one peep say they would go back to the 180/55. I'm sure it's coming but so far they were a great upgrade to my FJR. My BMW has the 190/55 by default. I'm not fatsiding it so it's staying that and I'm overly happy with the whole package. Remember that *Aspect* ratio number also for you 200/50 seekers.

For you newbies, read WAY back in this thread, I have pics and such of when I first did this (I stole the idea after I test drove a Beemer K16 with them on it).

 

[Top_Speed1]

To me, a higher rear end with a 190/55 mean a lower front end--with the change in geometry.
Sure, you are quickening the transition on curves, but at high speed on the freeway, you are also taking away some of the stability of the OEM design.

If you lower the rear of a bike, you gain some stability on the straight away at high speed and lose maneuverability on the twisties. The bike will sit on the freeway better at the higher speeds. The opposite happens when you raise the rear....resulting in a lower the front.

Anyways, that what it seems to like. If it doesn't to you then, ok.

Again, all this was discussed earlier

<----------------

 

[palerider]

To me, a higher rear end with a 190/55 mean a lower front end--with the change in geometry.
Sure, you are quickening the transition on curves, but at high speed on the freeway, you are also taking away some of the stability of the OEM design.

If you lower the rear of a bike, you gain some stability on the straight away at high speed and lose maneuverability on the twisties. The bike will sit on the freeway better at the higher speeds. The opposite happens when you raise the rear....resulting in a lower the front.

Anyways, that what it seems to like. If it doesn't to you then, ok.

Theory and practice: Perhaps at the very top end there is more instability, but at the speeds I travel--seldom more than 90mph--there is no practical loss of stability; and the practical benefits are significant--faster turn-in, more stability in turns, more-accurate speedometer, higher weight loads, better mileage, easier center-stand lift, and lower heat.

 

[SLK50]

<blockquote class='ipsBlockquote'data-author="palerider" data-cid="1153768" data-time="1402337574"><p>

<blockquote class='ipsBlockquote'data-author="FJRat" data-cid="1153762" data-time="1402336444"><p>To me, a higher rear end with a 190/55 mean a lower front end--with the change in geometry.<br />

<br />

Sure, you are quickening the transition on curves, but at high speed on the freeway, you are also taking away some of the stability of the OEM design.<br />

<br />

If you lower the rear of a bike, you gain some stability on the straight away at high speed and lose maneuverability on the twisties. The bike will sit on the freeway better at the higher speeds. The opposite happens when you raise the rear....resulting in a lower the front.<br />

<br />

Anyways, that what it seems to like. If it doesn't to you then, ok.</p></blockquote>

Theory and practice: Perhaps at the very top end there is more instability, but at the speeds I travel--seldom more than 90mph--there is no practical loss of stability; and the practical benefits are significant--faster turn-in, more stability in turns, more-accurate speedometer, higher weight loads, better mileage, and lower heat.</p></blockquote>

And let's not forget the four-hour erections! JS

 

[SLK50]

<blockquote class='ipsBlockquote'data-author="FJRat" data-cid="1153754" data-time="1402334468"><p>

SKK,<br />

<br />

Dont keep the secret to yourself, do tell: why do you think the 200 would be a poor choice for the FJR?...I am listening...</p></blockquote>

The 200 is intended for a rim that's 20mm ( or two full sizes ) wider than

an FJR's.

Since there would be no net gain I see no reason to choose a 200/50

over the 180/55.

What I'd like to see is a 180/60 in a long-lasting compound like a PR2.

THAT would be something I'd be interested in.

I've pounded enough hard parts into the deck to appreciate the

extra height.

 

[Spud]

My last follower to do this was "Wine Guy" this past Sat (6/7/13). He just had it done, so his report should be forthcoming.
TBH, I have not had one peep say they would go back to the 180/55. I'm sure it's coming but so far they were a great upgrade to my FJR. My BMW has the 190/55 by default. I'm not fatsiding it so it's staying that and I'm overly happy with the whole package. Remember that *Aspect* ratio number also for you 200/50 seekers.

For you newbies, read WAY back in this thread, I have pics and such of when I first did this (I stole the idea after I test drove a Beemer K16 with them on it).

Again, this has been done for a while....

https://www.fjrforum.com/forum//index.php/topic/148260-upsizing-rear-tire-to-19055-w-pics/page-7?do=findComment&comment=1090926

Although your write up has popularized it recently.

As for the high-speed stability question, my bike with a 190 Angel GT is on a rail at one-forty plus, so I wouldn't worry about that concern. I'm on my second 190. Just don't go chasing chicken strips--I think you'd lose. I use to get my 180's to the edge on occasion, not even close on the 190's.

 

[Wine Guy]

Just changed mine out to a 190/55 this past weekend on my 2013. Only have a couple of hours on it so far but it's seems great. No traction control or ABS issues or warnings. It's brought my speedo closer to reality as well. It was 10% optimistic before the tire change and now is down to 5%. No complaints from me at all.

 

[CA G-Man]

Just changed mine out to a 190/55 this past weekend on my 2013. Only have a couple of hours on it so far but it's seems great. No traction control or ABS issues or warnings. It's brought my speedo closer to reality as well. It was 10% optimistic before the tire change and now is down to 5%. No complaints from me at all.

That's exactly what I'm expecting/hoping for with my tire change this week (esp. the 10% to 5% correction). I'll post up if it turns out otherwise.

 

[FJRat]

so, how much higher is the sitting postion with a 190/55?

 

[Wine Guy]

As far as I know, it's just about a half inch taller. 1 inch in total diameter but just half on the radius. I didn't measure it and I really don't notice a difference.

 

[RadioHowie]

The difference in tire height, I believe, would be 5.5 millimeters....and with the center point of the rider's seat well in front of the vertical center point of the tire, the answer would be "damn little".

Edt: Well, Wine Guy got his answer in before I did, and I'm not sure if his math is right or mine is, but regardless, I think my final conclusion is correct, i.e. "damn little".

 

[Spud]

It's enough that on a Gen II the center stand is a little easier....