Choosing Tire Sizes

[tom epp]

hi all,

 

new to the forum and fairly new to track days. i will start with a little background. i have been riding on the street for 20+ years. i did my first track day with css in august at vir after the ama race. since then i've done several more with nesba. i have a total of 8 days under my belt. vir-north with css, vir-full with nesba, 3 consecutive days at road atlanta with nesba, 2 days at barber with nesba and 1 day at cmp with stt. needless to say i'm hooked. i don't even enjoy riding on the street anymore. i'm pretty smooth and consistent on the track. i've got good throttle control. i'm still working on my braking but my main focus on the track is body position. i have no problem getting my butt off the seat but i have a bad habit of counteracting my hanging off with my upper body. each outing gets a little better. i can't wait for next season to get back out there to continue working on my skills.

 

my bike is an 07 zx6r. stock tires are 120/70 front and 180/55 rear. i'm running michelin pilot power 2ct's. i have no complaints whatsoever with the tires but i keep hearing how great the dunlop q2's are. a LOT of the members and control riders on the nesba boards praise the q2's. after reading some of steve's comments in the other tire threads i feel like i should go with the 211gpa's but the price tag on the q2's make them very attractive. my pace is in the upper end of b group or a slow i group with nesba. the only lap times i have would be from road atlanta. my best times that i recorded were 1:50. the bike has a built in lap timer but i find it too distracting to use.

 

my main question is, should i go with a 180/55 or a 190/55? a LOT of guys with much more experience than me recommend the 190/55. i'm just wondering what steve's thoughts on this are. feedback from anyone else is welcome too.

 

my other question is q2's or 211gpa's? i've heard if you don't have warmers you should go with the q2's but it seems like that isn't the case after reading through the tire warmer thread. my wallet tells me to go with the q2's. i got 8 days out of the 2ct's and they still aren't down to the wear bars. i could probably get a few more days out of them but i don't want to push my luck either. should i expect to get the same life out of the q2's or the 211gpa's? i understand that the faster i get the more my tires will suffer. also, i'm still on the stock suspension. i have my sag properly set and it's working very well for me so far. my tires are showing very good wear.

 

sorry for the long post.

 

thanks in advance for the replies, tom

[DUNLOP-RTS]

hi all,

 

my bike is an 07 zx6r. stock tires are 120/70 front and 180/55 rear.

 

my main question is, should i go with a 180/55 or a 190/55? a LOT of guys with much more experience than me recommend the 190/55. i'm just wondering what steve's thoughts on this are. feedback from anyone else is welcome too.

 

tom

 

 

Tom,

 

Good question!

 

CHOOSING THE RIGHT TIRE SIZE

 

When picking a tire for a track day or racing, your tire size choice boils down to what the tire manufacturer recommends for your bike.

 

Not every 180/55 is made the same, neither is the 190/55 or the 200/55.

 

M & P brands make a 180/55 to fit 600cc class bikes with 5.5x17 rims, and do not recommend using their 190/55.

 

Dunlop does not even make a 180/55 race tire. Dunlop recommends using their 190/55 on 600cc class bikes with 5.5x17 rims.

 

As you can see if you were on a 600, using M or P brands the 190/55 would be wrong, but using a Dunlop 190/55 would be right.

 

This does not mean that M & P are wrong, it just means they named their tire a 180/55 instead of a 190/55.

 

Its best to not get caught up in the "will my bike steer slower/quicker?" issue when changing to a different size. As long as the tire is recommend for that bike/rim it should work fine. Trying to figure out the handling attributes of the tire by asking a friend or by looking at the tire while on the stand is counter productive and leads to you having a preconceived bias. Just ride on it and you be the judge of how you like it.

 

If you are going to go on the track, I highly recommend asking the tire guy for your brand what is recommended. For a 600, Dunlop recommends its 190/55x17 D211GPA. That is the same size used in AMA National competition by all the factory teams and riders. This is a winning tire/size, but trying to use the M or P brand in this size on your 600 may have unpleasant consequences.

[DUNLOP-RTS]

my other question is q2's or 211gpa's? i've heard if you don't have warmers you should go with the q2's but it seems like that isn't the case after reading through the tire warmer thread. my wallet tells me to go with the q2's. i got 8 days out of the 2ct's and they still aren't down to the wear bars. i could probably get a few more days out of them but i don't want to push my luck either. should i expect to get the same life out of the q2's or the 211gpa's? i understand that the faster i get the more my tires will suffer. also, i'm still on the stock suspension. i have my sag properly set and it's working very well for me so far. my tires are showing very good wear.

 

sorry for the long post.

 

thanks in advance for the replies, tom

 

see this post to answer your question:

 

http://forums.superb...indpost&p=20491

[spthomas]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

[tom epp]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

 

thanks, steve.

 

the sizes available for the q2 is what really prompted my question. i'm pretty sure that steve will tell you to run the 190/55. i've got a feeling that the only reason they offer the 180 is for dealers or shops that will NOT install a 190 tire on a bike that the manufacturer calls for a 180. i'm interested to see what steve has to say about this.

 

also, if you're heading down south at all for a track day next season, let me know and maybe we can ride together. i will be trying to do vir as much as possible and i plan on heading back to road atlanta too. another on my to do list is summit point, which probably isn't TOO far for you.

which track day orgs. do you ride with?

[tom epp]

steve,

 

thanks for boiling all this down for us. this is really some good stuff. your knowledge and reputation really makes this a no brainer for me. i'm leaning towards the 211gpa. i'm thinking the q2's would give me roughly the same amount of track days as the 2ct's i ran. i understand that there are a lot of factors involved but can i expect the same longevity from the 211gpa's if track conditions and riding style were equal?

 

thanks, tom

[DUNLOP-RTS]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

 

thanks, steve.

 

the sizes available for the q2 is what really prompted my question. i'm pretty sure that steve will tell you to run the 190/55. i've got a feeling that the only reason they offer the 180 is for dealers or shops that will NOT install a 190 tire on a bike that the manufacturer calls for a 180. i'm interested to see what steve has to say about this.

 

 

Tom,

 

 

See Dunlop's fitment chart for the Q2 here: http://www.dunlopmot...tire.asp?id=108

 

As you can see the Q2 180/55 and the 190/55 will fit both a 5.5x17 and 6.0x17 rims (600,750 and 1000's). Forget the 190/50x17 Q2 for performance riding, its a flatter center and better suited for regular urban street riding and not aggressive cornering.

 

Q2 on a 600, I would start with the 180/55. Since it will be closest to your stock chassis settings. If you are willing to make small chassis adjustments (and looking for a future in track riding or racing), I would go with the 190/55. The 190/55 Q2 is the same width and height as the 190/55 D211GPA race tire, thus making the transition easier from Q2 to D211GPA.

 

Both are good choices in the Q2 for track days.

[tom epp]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

 

thanks, steve.

 

the sizes available for the q2 is what really prompted my question. i'm pretty sure that steve will tell you to run the 190/55. i've got a feeling that the only reason they offer the 180 is for dealers or shops that will NOT install a 190 tire on a bike that the manufacturer calls for a 180. i'm interested to see what steve has to say about this.

 

 

Tom,

 

 

See Dunlop's fitment chart for the Q2 here: http://www.dunlopmot...tire.asp?id=108

 

As you can see the Q2 180/55 and the 190/55 will fit both a 5.5x17 and 6.0x17 rims (600,750 and 1000's). Forget the 190/50x17 Q2 for performance riding, its a flatter center and better suited for regular urban street riding and not aggressive cornering.

 

Q2 on a 600, I would start with the 180/55. Since it will be closest to your stock chassis settings. If you are willing to make small chassis adjustments (and looking for a future in track riding or racing), I would go with the 190/55. The 190/55 Q2 is the same width and height as the 190/55 D211GPA race tire, thus making the transition easier from Q2 to D211GPA.

 

Both are good choices in the Q2 for track days.

 

 

steve,

 

i'm definitely going with the 190/55. i'm still on the fence with regard to the q2 or the 211 gpa. of course i want the best tire for little money and i want it to last forever...lol...i know there are a lot of variables involved but how many track days can i expect to get out of the q2's or the 211gpa's? i do have a spare set of wheels so i am tempted to try both. if the life expectancy is fairly close i will just go with the 211's. would one tire be better than the other for the colder temps at the beginning and end of the season verses the heat of the middle of summer? what chassis adjustments would you recommend for the 190/55?

 

thanks again for being available here for us to pick your brain. i really appreciate it.

 

tom

[DUNLOP-RTS]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

 

thanks, steve.

 

the sizes available for the q2 is what really prompted my question. i'm pretty sure that steve will tell you to run the 190/55. i've got a feeling that the only reason they offer the 180 is for dealers or shops that will NOT install a 190 tire on a bike that the manufacturer calls for a 180. i'm interested to see what steve has to say about this.

 

 

Tom,

 

 

See Dunlop's fitment chart for the Q2 here: http://www.dunlopmot...tire.asp?id=108

 

As you can see the Q2 180/55 and the 190/55 will fit both a 5.5x17 and 6.0x17 rims (600,750 and 1000's). Forget the 190/50x17 Q2 for performance riding, its a flatter center and better suited for regular urban street riding and not aggressive cornering.

 

Q2 on a 600, I would start with the 180/55. Since it will be closest to your stock chassis settings. If you are willing to make small chassis adjustments (and looking for a future in track riding or racing), I would go with the 190/55. The 190/55 Q2 is the same width and height as the 190/55 D211GPA race tire, thus making the transition easier from Q2 to D211GPA.

 

Both are good choices in the Q2 for track days.

 

 

steve,

 

i'm definitely going with the 190/55. i'm still on the fence with regard to the q2 or the 211 gpa. of course i want the best tire for little money and i want it to last forever...lol...i know there are a lot of variables involved but how many track days can i expect to get out of the q2's or the 211gpa's? i do have a spare set of wheels so i am tempted to try both. if the life expectancy is fairly close i will just go with the 211's. would one tire be better than the other for the colder temps at the beginning and end of the season verses the heat of the middle of summer? what chassis adjustments would you recommend for the 190/55?

 

thanks again for being available here for us to pick your brain. i really appreciate it.

 

tom

 

 

Tom,

 

Its really hard to tell you exactly how many days you would get from each tire. there are just to many variables. It is like asking someone how long it takes to clean their room.

 

The best thing to do is try it and compare. I know that may not help you when you might be on a budget, but if you are going to play this game, you are going to use tires. So try both and gauge the tire usage for yourself, on your bike, with your riding style and your suspension settings. Only then will you know which is best for you.

 

On you question for what to change on the 190/55. let me ask which tire are you going from and which are you going to. Give me that data and I will talk about how to change the ride height in another thread.

[tom epp]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

 

thanks, steve.

 

the sizes available for the q2 is what really prompted my question. i'm pretty sure that steve will tell you to run the 190/55. i've got a feeling that the only reason they offer the 180 is for dealers or shops that will NOT install a 190 tire on a bike that the manufacturer calls for a 180. i'm interested to see what steve has to say about this.

 

 

Tom,

 

 

See Dunlop's fitment chart for the Q2 here: http://www.dunlopmot...tire.asp?id=108

 

As you can see the Q2 180/55 and the 190/55 will fit both a 5.5x17 and 6.0x17 rims (600,750 and 1000's). Forget the 190/50x17 Q2 for performance riding, its a flatter center and better suited for regular urban street riding and not aggressive cornering.

 

Q2 on a 600, I would start with the 180/55. Since it will be closest to your stock chassis settings. If you are willing to make small chassis adjustments (and looking for a future in track riding or racing), I would go with the 190/55. The 190/55 Q2 is the same width and height as the 190/55 D211GPA race tire, thus making the transition easier from Q2 to D211GPA.

 

Both are good choices in the Q2 for track days.

 

 

steve,

 

i'm definitely going with the 190/55. i'm still on the fence with regard to the q2 or the 211 gpa. of course i want the best tire for little money and i want it to last forever...lol...i know there are a lot of variables involved but how many track days can i expect to get out of the q2's or the 211gpa's? i do have a spare set of wheels so i am tempted to try both. if the life expectancy is fairly close i will just go with the 211's. would one tire be better than the other for the colder temps at the beginning and end of the season verses the heat of the middle of summer? what chassis adjustments would you recommend for the 190/55?

 

thanks again for being available here for us to pick your brain. i really appreciate it.

 

tom

 

 

Tom,

 

Its really hard to tell you exactly how many days you would get from each tire. there are just to many variables. It is like asking someone how long it takes to clean their room.

 

The best thing to do is try it and compare. I know that may not help you when you might be on a budget, but if you are going to play this game, you are going to use tires. So try both and gauge the tire usage for yourself, on your bike, with your riding style and your suspension settings. Only then will you know which is best for you.

 

On you question for what to change on the 190/55. let me ask which tire are you going from and which are you going to. Give me that data and I will talk about how to change the ride height in another thread.

 

ha ha, i got a good chuckle from the cleaning your room analogy. i hear what you're saying.

 

as far as tires, i'm coming from michelin pilot power 2ct in the 120/70, 180/55 flavor. i was able to get 8 days out of them at about 1k track miles. see my first post for the tracks i rode. the front still has quite a bit of rubber on it but the rear is getting close to the wear bars on the edges. going to the q2 and or 211gpa in the 190/55.

[DUNLOP-RTS]

First, Tom, welcome to the forum! You've asked a really good question!

 

Steve, I'm in a similar situation with Tom except I have a CBR600, and the original tire sizes are 120/70R17 and 180/55R17, the same as Tom's Kawasaki. I currently have Qualifiers and you mentioned in another post a few weeks ago of trying Q2's next. Unlike the race tire, the Q2 is made in a 180/55 size, but it sounds like I should still use the 190/55- is that right?

 

thanks, steve.

 

the sizes available for the q2 is what really prompted my question. i'm pretty sure that steve will tell you to run the 190/55. i've got a feeling that the only reason they offer the 180 is for dealers or shops that will NOT install a 190 tire on a bike that the manufacturer calls for a 180. i'm interested to see what steve has to say about this.

 

 

Tom,

 

 

See Dunlop's fitment chart for the Q2 here: http://www.dunlopmot...tire.asp?id=108

 

As you can see the Q2 180/55 and the 190/55 will fit both a 5.5x17 and 6.0x17 rims (600,750 and 1000's). Forget the 190/50x17 Q2 for performance riding, its a flatter center and better suited for regular urban street riding and not aggressive cornering.

 

Q2 on a 600, I would start with the 180/55. Since it will be closest to your stock chassis settings. If you are willing to make small chassis adjustments (and looking for a future in track riding or racing), I would go with the 190/55. The 190/55 Q2 is the same width and height as the 190/55 D211GPA race tire, thus making the transition easier from Q2 to D211GPA.

 

Both are good choices in the Q2 for track days.

 

 

steve,

 

i'm definitely going with the 190/55. i'm still on the fence with regard to the q2 or the 211 gpa. of course i want the best tire for little money and i want it to last forever...lol...i know there are a lot of variables involved but how many track days can i expect to get out of the q2's or the 211gpa's? i do have a spare set of wheels so i am tempted to try both. if the life expectancy is fairly close i will just go with the 211's. would one tire be better than the other for the colder temps at the beginning and end of the season verses the heat of the middle of summer? what chassis adjustments would you recommend for the 190/55?

 

thanks again for being available here for us to pick your brain. i really appreciate it.

 

tom

 

 

Tom,

 

Its really hard to tell you exactly how many days you would get from each tire. there are just to many variables. It is like asking someone how long it takes to clean their room.

 

The best thing to do is try it and compare. I know that may not help you when you might be on a budget, but if you are going to play this game, you are going to use tires. So try both and gauge the tire usage for yourself, on your bike, with your riding style and your suspension settings. Only then will you know which is best for you.

 

On you question for what to change on the 190/55. let me ask which tire are you going from and which are you going to. Give me that data and I will talk about how to change the ride height in another thread.

 

ha ha, i got a good chuckle from the cleaning your room analogy. i hear what you're saying.

 

as far as tires, i'm coming from michelin pilot power 2ct in the 120/70, 180/55 flavor. i was able to get 8 days out of them at about 1k track miles. see my first post for the tracks i rode. the front still has quite a bit of rubber on it but the rear is getting close to the wear bars on the edges. going to the q2 and or 211gpa in the 190/55.

Changing the ride height when you switch to different tires.

 

Assuming everything is perfect on your setup (which generally it is not, but we will assume this for this drill), you may need to adjust the ride height when changing from 1 style of tire to the other.

 

First find out the tire you have now, the tire you are going FROM. Find the diameters of these tires.

 

Then find out the diameter of the tires you are going TO. Subtract them, then divide by 2 (because radius is 1/2 of Diameter) and that is how much ride height you need to change.

 

Lets walk through this simply:

 

Michelin 2CT-

120/70x17 is 606mm in Diameter

180/55x17 is 640mm in Diameter

 

Dunlop D211GPA-

120/70x17 is 605mm in Diameter

190/55x17 is 643mm in Diameter

 

Now do your math-

FRONT: 606-605 = 1 mm in diameter (this is how much larger one tire is than the other), Divide by 2 for radius (this is because you are concerned with, from the axle to the ground height, the radius) = +0.5mm ride height

REAR: 640-643 = -3mm. 1/2 of -3 = -1.5mm

 

The results are-

+0.5mm front

-1.5mm rear

 

In a perfect world you would then raise the front 0.5 mm, and lower the rear 1.5mm and the bike will have the same ride height as it did with the old set of tires.

 

In my opinion, taking into consideration most riders do not have a perfect setup, its easier to not make a change if its only a couple of mm different. Put the tires on and ride, then make small changes as is needed for the chassis.

 

So to keep it real, there is no need to make these small changes, immediately, if you are not riding on the track record. As a track day rider or amateur racer, don't think your setup is so perfect that you need to make a 1mm change, instantly. ask yourself how many times you made a ride height change with your old tires and you will soon realize you would be splitting hairs. After you make the tire change and ride, then you can make small changes to see if it helps or not. (just because your ex girlfriend was blond doesn't mean you must always date a blond, add some flavor, try different things)

 

Certainly if you were a seasoned rider and had street tires and race tire you want back and forth with, you would be familiar with your ride height changes and if it made a difference to you, then you would make those every time you swapped back and forth, if you felt the need.

[khp]

M & P brands make a 180/55 to fit 600cc class bikes with 5.5x17 rims, and do not recommend using their 190/55.

Just a sidenote here on the Pirelli Diablo Supercorsa 190/55 vs 180/55 size on a 5.5" 600cc rim: if you put a 190/55 on a 5.5" rim, you will be unable to use the very edge of the tire: Danish racer Thomas Rebien (whom I'm talking to from time to time) tried this on his YZF-R6 2008 last year in search of higher grip when fully leaned over, but found it did buy him anything.

 

Thomas is a former winner of the German Yamaha R6-Cup and was by far the fastest Supersports guy not on Dunlops last year (only two other were faster than him by ~1-2 seconds; both on Dunlops NTecs).

[maxpr1]

 

Tom,

 

 

See Dunlop's fitment chart for the Q2 here: http://www.dunlopmot...tire.asp?id=108

 

As you can see the Q2 180/55 and the 190/55 will fit both a 5.5x17 and 6.0x17 rims (600,750 and 1000's). Forget the 190/50x17 Q2 for performance riding, its a flatter center and better suited for regular urban street riding and not aggressive cornering.

 

Q2 on a 600, I would start with the 180/55. Since it will be closest to your stock chassis settings. If you are willing to make small chassis adjustments (and looking for a future in track riding or racing), I would go with the 190/55. The 190/55 Q2 is the same width and height as the 190/55 D211GPA race tire, thus making the transition easier from Q2 to D211GPA.

 

Both are good choices in the Q2 for track days.

 

Steve,

I've just purchased a set of Carrozzeria wheels for my R6. I had been running Q2 180/55 on the rear of my stock 5.5" wheel. I see from the fitment chart that this size in the Q2 will fit both a 5.5" and a 6" rim.

Would you recomend I stick with this size or should I move up to the 190/55 for a 6" Rim

 

Thanks in advance for your suggestion

[DUNLOP-RTS]

Steve,

I've just purchased a set of Carrozzeria wheels for my R6. I had been running Q2 180/55 on the rear of my stock 5.5" wheel. I see from the fitment chart that this size in the Q2 will fit both a 5.5" and a 6" rim.

Would you recomend I stick with this size or should I move up to the 190/55 for a 6" Rim

 

Thanks in advance for your suggestion

 

I would go with the 190/55x17 Q2 on the 6.0" rim.

 

But I must ask; With a special rim that is wider than stock, why would you not step up to a higher performance tire like the D211GPA? You have upgraded the rims, why not the tires? If you paid for special rim, why not get better tires. Consider it.

 

Steve

[bradvanhorn]

I would go with the 190/55x17 Q2 on the 6.0" rim.

 

But I must ask; With a special rim that is wider than stock, why would you not step up to a higher performance tire like the D211GPA? You have upgraded the rims, why not the tires? If you paid for special rim, why not get better tires. Consider it.

 

Steve

Well I didn't ask, but you have me convinced nonetheless. I'm going to the 211GPA for my newly acquired track bike when I next replace the tires.

[maxpr1]

I would go with the 190/55x17 Q2 on the 6.0" rim.

 

But I must ask; With a special rim that is wider than stock, why would you not step up to a higher performance tire like the D211GPA? You have upgraded the rims, why not the tires? If you paid for special rim, why not get better tires. Consider it.

 

Steve

 

Well, I just assumed you have to be one of those "Fast Guys" to appreciate the GPA's!!!!

 

Truth of the matter I have less than two days on my new set of Q2. I was just going to follow Keiths' advice and stick with the Q2 as he seemed to be a big fan. Having said that, I need to buy a new set regardless so I will give the GPAs' a try. Thanks for your great feedback on the forum, you've shed quite a lot of light on this VOODOO subject

max

[bradvanhorn]

Well, I just assumed you have to be one of those "Fast Guys" to appreciate the GPA's!!!!

 

Truth of the matter I have less than two days on my new set of Q2. I was just going to follow Keiths' advice and stick with the Q2 as he seemed to be a big fan. Having said that, I need to buy a new set regardless so I will give the GPAs' a try. Thanks for your great feedback on the forum, you've shed quite a lot of light on this VOODOO subject

max

Please let us know how you like the GPAs when you get around to trying them. I'd be interested to hear what you think.