[SDM!]

Being new to racing there are a lot of things I am still learning. i bought the original size tire for the race. 150/70 I couldnt get comfortable during practice, the bike felt really heavy and I was having to force the bike into the turns. It didnt feel natural. At first I thought since I just got my new cartridges installed maybe they were not set properly. So I took the bike back to the paddock and had our master suspension guy reset everything sag from the bike and rider sag. Everything was correct after checking. I had just bought the set 2 days before the race. $310.00 a lot to spend on tires. Our mechanic told me to stop complaining and buy a 140/70 tire and try it out, he was getting frustrated as I made him check the suspension again. So I bit the bullet and spent another $215.00 for a 140/70 rear. More expensive since I am at the track already. We got the new tire on warmed up the bike took it out on the track and couldnt believe the difference going to a smaller tire made. It was like the bike was on rails, it dropped into the turns with ease. I guess sometimes you need to learn so you never forget. What I should have thought about was I used my N300 140/70 on the bike when I went for my track days. I just couldnt get it in my head that 10mm would make that much difference. TRUST ME IT DOES.

Here is the 150/70 tire after 5 outings in 1 day. No matter how hard I tired I couldnt get to the edge with out the bike feeling like it wanted to fall over.





My 140 tire after 5 outings, 2 practice, 1 qualifying and 2 races. As you can see all the way to the edge.

 

[Kiwi Rider]

All very interesting. Can't argue with the results.
Looking at the tread pattern they appear to both be Pirelli Diablo's?

Funny you should bring this up because although I find the N400 turns in OK and is generally very stable, I have been finding it hard to get right over comfortably for some reason. I was also surprised I hadn't ground my hero knobs once yet. Maybe I need to try the 140 when I buy my next rear hoop.
Thanks for sharing.

Late edit: Your tyre wear pattern looks really good BTW, your suspension set up must be pretty good.

 

[Engine-R]

@SDM! one thing I remember from a German Aprilia-Forum is, that the guys over there in the race use the following combination
150/60 rear then the best for the front is the 120/60 (the standard rims are 3 inch front and 4.5 inch rear and yes, even when the standard-rim for the 120/60 is 3.5 inch, the 3 inch is also ok and even allowed from the German TUV, if you know what that means).
The 120/60 lowers the front by 5 mm.
140/70 rear then the better solution is the 110/70 in the front, but all of them say that this combination cannot compete against the series 60 tires.
But at least it depends on you what you like better.

 

[SDM!]

@SDM! one thing I remember from a German Aprilia-Forum is, that the guys over there in the race use the following combination
150/60 rear then the best for the front is the 120/60 (the standard rims are 3 inch front and 4.5 inch rear and yes, even when the standard-rim for the 120/60 is 3.5 inch, the 3 inch is also ok and even allowed from the German TUV, if you know what that means).
The 120/60 lowers the front by 5 mm.
140/70 rear then the better solution is the 110/70 in the front, but all of them say that this combination cannot compete against the series 60 tires.
But at least it depends on you what you like better.

Bro your full of information. Thanks for sharing your knowledge. If the tires were cheaper I would try that set up 150/60 & 120/60, that of course will depend on if they are here in country. There is only 1 place that stocks tires for racing and they keep in stock what the racers are using. The other places special order the tires in and its really expensive as they do not offer a racers discount.

 

[jonfonts]

I guess this would be a good place to ask then, if I went 120/60 with stock rear size is that ok?

 

[Engine-R]

I guess this would be a good place to ask then, if I went 120/60 with stock rear size is that ok?

My 2 cts...

I would recommend this, but also want to say since the bike becomes more stable it's not turning into the corners that nimble way like it does with the 110/70 tire.
So to keep this or even make it better at my bike I'd lower the front fork by additional 5 mm (5 mm comes from the 120/60 tire already) and so have the front lowered by 10 mm with the rear shock length extended by 5 mm, which gives a raised rear by 10 mm (please keep in mind that with the uni trak rear suspension there is a transmission ratio from 1:2*).
My rims are 3.5 inch front and 4 inch rear with 120/60 front and 150/60 rear tires.
Please keep in mind that what works for me or what I like must not be valid for you.
And at least everything in case of suspension, like tires, depends on testing, testing and testing until you turn crazy or find the right setup...

* I guess the EX400 is equal to the EX300 and EX250, but for a real value please take the measurement.

 

[Topaz]

The 140/70 also raised your rear by .8" That may have changed your feeling on the bike as well.

I've just known about this tire dimensions calculator:
https://tiresize.com/calculator/

It's intended for cars, but I guess the maths are the same.

 

[Tuscani451]

The 140/70 also raised your rear by .8" That may have changed your feeling on the bike as well.

I've just known about this tire dimensions calculator:
https://tiresize.com/calculator/

It's intended for cars, but I guess the maths are the same.

Yeah you also need to think about how much height you lose or gain with different size tires. I used the 150 without any complaints (SC2). The track I run has lots of heavy acceleration corners so the extra meat is nice for me.

 

[jonfonts]

Sorry, don't mean to hi-jack, but I think I decided on the Power RS 120/60-17 & 150/60-17. I was looking at different category tires, and I kind of wanted the Road 5's as I don't do track days yet and the confidence in rain might push me to them again, but I'm not to set on them either. Idk, what do you guys think? Has anyone ridden in the rain with the Power RS before?

 

[Topaz]

^^ I like Michelin as well. I have a set of Pilot Road 3 right now.
The Pilot Road is designed for rain. If you like riding in the rain (I love it, no sarcasm), go for the Pilot Road.
I never used the RS. They are supposed to have mote grip on the dry.

I ride mainly street, and some track. I think I'll go for the new Pilot Road 5.
There is no 150/60 though. They make it in 150/70 for the rear, so a bit taller.
And there is no 110. There is a 110/80 but it's a 'trail' tire, which I'm not sure what it is. And maybe 110/80 would be too tall. I don't know.
But for the 120 you have the two options: 120/60 and 120/70

 

[Apis]

@SDM! one thing I remember from a German Aprilia-Forum is, that the guys over there in the race use the following combination
150/60 rear then the best for the front is the 120/60 (the standard rims are 3 inch front and 4.5 inch rear and yes, even when the standard-rim for the 120/60 is 3.5 inch, the 3 inch is also ok and even allowed from the German TUV, if you know what that means).
The 120/60 lowers the front by 5 mm.
140/70 rear then the better solution is the 110/70 in the front, but all of them say that this combination cannot compete against the series 60 tires.
But at least it depends on you what you like better.

My 2 cts...

I would recommend this, but also want to say since the bike becomes more stable it's not turning into the corners that nimble way like it does with the 110/70 tire.
So to keep this or even make it better at my bike I'd lower the front fork by additional 5 mm (5 mm comes from the 120/60 tire already) and so have the front lowered by 10 mm with the rear shock length extended by 5 mm, which gives a raised rear by 10 mm (please keep in mind that with the uni trak rear suspension there is a transmission ratio from 1:2*).
My rims are 3.5 inch front and 4 inch rear with 120/60 front and 150/60 rear tires.
Please keep in mind that what works for me or what I like must not be valid for you.
And at least everything in case of suspension, like tires, depends on testing, testing and testing until you turn crazy or find the right setup...

* I guess the EX400 is equal to the EX300 and EX250, but for a real value please take the measurement.

Personally I haven't elaborated with tire height, just with different tires, tires size, cold and hot pressure etc. Could you perhaps describe what would be the advantage, and the disadvantage, of going for more OR less height in a tire?

My thought is that it's just rider preference and the style of the rider that determines. Given mine style - broader lines, fast corner speed and lean angle (rather than massive braking, point and squirt from apex) - which in theory would be "better"? The 60 or 70?

 

[Warp12]

I am sure most of you guys know, but you can't just do some math to calculate the installed height of a tire. With equal "paper sizes", there is a big variety of actual sizes, when installed. Some tires will have a reputation as being "short" or "tall". Same goes with tire weight...big variances.

A 140/70 is, on paper, a 98mm sidewall height.

A 150/70 is, on paper, a 105mm sidewall height.

A 150/60 is, on paper, a 90mm sidewall height.

All of this is theoretical, though, until you mount the tire, inflate to operating pressure, and load it. This is not ultra-critical on the street. But in racing, in can affect your desired gearing choice. Also, rim width plays a part in what you can expect, as well.

 

[Apis]

The answer or to say 'magic word' is Geometry and for this let me give you 2 links to read about
Motorcycle Geometry 101
https://lifeatlean.com/teach-me-suspension-simple-geometry/

Well this looks just bloody brilliant! I thank you and salute you, good sir! :clap: :grin:

 

[Eagleracer]

I’m a Pirelli guy.

I’m running 120/70 sc1 front
160/60 sc2 rear

Bike handled great with this set up. The rear tire started to tear after about 100 laps but that’s because I’m still in the stock shock and the rear was moving around a bit


Currently have 150+ laps on a 1.7 mile track on these tires

 

[Kiwi Rider]

I’m a Pirelli guy.

I’m running 120/70 sc1 front
160/60 sc2 rear

Bike handled great with this set up. The rear tire started to tear after about 100 laps but that’s because I’m still in the stock shock and the rear was moving around a bit


Currently have 150+ laps on a 1.7 mile track on these tires

Tyre wear looks good. Interesting that you find the 160 set up good and SDM prefers the 140. Quite a contrast in opinions.

Hey in what way was your rear moving around? I have a similar sounding problem with my SV race bike. It wags it's tail on corner exit under power. tempting to back off when it is bad. Harder you push the worse it gets. Any thoughts?

 

[SDM!]

Tyre wear looks good. Interesting that you find the 160 set up good and SDM prefers the 140. Quite a contrast in opinions.

Hey in what way was your rear moving around? I have a similar sounding problem with my SV race bike. It wags it's tail on corner exit under power. tempting to back off when it is bad. Harder you push the worse it gets. Any thoughts?

Im using 140/70 I think he is using 160/60. I looked they dont sell it here wanted to see the difference between the tires.

 

[Kiwi Rider]

Im using 140/70 I think he is using 160/60. I looked they dont sell it here wanted to see the difference between the tires.

Looking at it on paper I would err towards the 140 because of the quicker turn in and, more importantly on a low HP bike, the lesser unsprung weight of the narrower tyre.
But you cant beat real world testing. :grin:

 

[mdabyo]

anyone race with a 120 front 160 rear? I just picked up an 18 ninja and am about to do my first weekend on it. i had an R3 and an RC390 before it, i ran 120/160's on both of them and liked the feel. wondering if anyone ran it on the ninja 400? i assume i will be fine.

 

[Texas]

Im using 140/70 I think he is using 160/60. I looked they dont sell it here wanted to see the difference between the tires.

Looking at it on paper I would err towards the 140 because of the quicker turn in and, more importantly on a low HP bike, the lesser unsprung weight of the narrower tyre.
But you cant beat real world testing. :grin:

anyone race with a 120 front 160 rear? I just picked up an 18 ninja and am about to do my first weekend on it. i had an R3 and an RC390 before it, i ran 120/160's on both of them and liked the feel. wondering if anyone ran it on the ninja 400? i assume i will be fine.

I can confirm 140 rear feels a lot better on track than 150. I have not tried 160 yet.

 

[Doc-Ram]

anyone race with a 120 front 160 rear? I just picked up an 18 ninja and am about to do my first weekend on it. i had an R3 and an RC390 before it, i ran 120/160's on both of them and liked the feel. wondering if anyone ran it on the ninja 400? i assume i will be fine.

my recommendation is to check what the local fast guys are running and use that. Our local fast guys are running 110 front / 140 rear on Pirelli and whomever is running MotoAmerica, uses whatever Dunlops gives them

I ran 110/140 on the R3, felt really comfortable, and am staying with the same combination on the N400 race bike as well. Previously, I had 150 rear and didn't feel good for turn in, so switched to a 140 rear and that felt great right from the start. After dialing in the suspension, the 140 rear felt the best by far.