How Big of a Tire can i Go? Ninja 650

**jason_999** · 04-24-2012, 01:30 PM

Hey everyone,
I am new to motorcycles so bear with me if this sounds like a stupid question, actually just taking my M2 this weekend.
Anyway love the look of the Super Sport bikes with the fat Rear Tire, but since i am a novice i know they are way out of league, not to mention the insurance is horrible so i am probably going to go with a Sport Touring, something like a Ninja 650r.

My Question is,
-how big of a tire (width) could i go with on a Ninja 650r. There site says it comes stock with 120/70-17 on the Front and 160/60-17 on the back.

-can you go much bigger with keeping the same Rim, or do those need to be replaced?

-i have heard its it little harder to steer with bigger tires, is there any truth to that?

anyway i know it really not that important for someone at the novice level, would just complete the image of the bike i would like to have.

thanks in advance.
jason

120/70-17

**jay-d** · 04-24-2012, 01:42 PM

I think your priorities aren't in order, but I'll oblige to educate.

I'm going to assume you have no idea what the numbers mean so first, let's break that down. 160 is the tire width in millimetres. The next number, 70, is the percentage of the width which equals the sidewall height. So 70% of 160mm = 112mm is your sidewall height. The 17 is your rim diameter.

The problem with going to a bigger tire is that your rim width doesn't change. We'll assume it's 5". So if you put a wider tire on it, say 180 because that's what most Super Sports are at, you're adding 20mm to the width of the tire to a 5" wide rim. What's going to happen is, you're going to increase the height of your tire stance because the rim width doesn't increase in size, so that extra 20mm has to go somewhere and the only place for it to go is up.

This also increases your sidewall height, which increases your tires ability to flex under pressure. The side effects to that is, your tire can, if pushed hard enough, roll over the rim, upset steering because now your height of the bike has increased as well.

The only way to properly do this is if you get a wider rim, that will offset that extra width in the tire. But now you're running in to clearance issues in the swing arm.

So is it worth it? No.

**jason_999** · 04-24-2012, 01:46 PM

Thanks, appreciate the explanation.

**jeffjones** · 04-24-2012, 01:54 PM

Originally Posted by jay-d

I think your priorities aren't in order, but I'll oblige to educate.

I'm going to assume you have no idea what the numbers mean so first, let's break that down. 160 is the tire width in millimetres. The next number, 70, is the percentage of the width which equals the sidewall height. So 70% of 160mm = 112mm is your sidewall height. The 17 is your rim diameter.

The problem with going to a bigger tire is that your rim width doesn't change. We'll assume it's 5". So if you put a wider tire on it, say 180 because that's what most Super Sports are at, you're adding 20mm to the width of the tire to a 5" wide rim. What's going to happen is, you're going to increase the height of your tire stance because the rim width doesn't increase in size, so that extra 20mm has to go somewhere and the only place for it to go is up.

This also increases your sidewall height, which increases your tires ability to flex under pressure. The side effects to that is, your tire can, if pushed hard enough, roll over the rim, upset steering because now your height of the bike has increased as well.

The only way to properly do this is if you get a wider rim, that will offset that extra width in the tire. But now you're running in to clearance issues in the swing arm.

So is it worth it? No.

If your stock tire is 160/60-17 and you want to put a 180 on it your going to go with something along the lines 180/55-17 which will keep the overall height close to the same.
I'm not completely sure what size of rim you have and what is the biggest tire that can fit on it, But it will definitely lower the handling capaibilities by making it sluggish going from side to side and less balanced in the corners.

**djbordie** · 04-24-2012, 01:54 PM

excellent answer Jay

You may want to google this. There are pro's for and against doing such things. Bike specific of course.

For example my bike, going with a 190/55 instead of 190/50 is a fantastic upgrade from the manufacturer's spec. Browsing through all the forums I found alot of info on this fact and why.
I notice a difference for sure, night and day.

Ninja 650? there are probably a but load of different tire config's that work for this or that, and certainly some absolutely DO NOT's...like "do not put a 190mm tire on a ninja 650 if you expect to be able to turn" etc.

check the 650 specific forums, they will have everything you need

**jay-d** · 04-24-2012, 01:59 PM

Originally Posted by jeffjones

If your stock tire is 160/60-17 and you want to put a 180 on it your going to go with something along the lines 180/55-17 which will keep the overall height close to the same.
I'm not completely sure what size of rim you have and what is the biggest tire that can fit on it, But it will definitely lower the handling capaibilities by making it sluggish going from side to side and less balanced in the corners.

So true, completely forgot that you'd decrease your tire profile but you're still going to have that extra bulge. I believe most 180mm wide tires are running on 5.5" rims. The 190mm are running on 6"

Originally Posted by djbordie

excellent answer Jay

You may want to google this. There are pro's for and against doing such things. Bike specific of course.

For example my bike, going with a 190/55 instead of 190/50 is a fantastic upgrade from the manufacturer's spec. Browsing through all the forums I found alot of info on this fact and why.
I notice a difference for sure, night and day.

Ninja 650? there are probably a but load of different tire config's that work for this or that, and certainly some absolutely DO NOT's...like "do not put a 190mm tire on a ninja 650 if you expect to be able to turn" etc.

check the 650 specific forums, they will have everything you need

I wanted to go 190mm from my 180mm, but the benefits aren't worth it

The tire wouldn't even look as "wide" because the rim width stays the same.

I think OP wants that wider look, which will require a wider rim!

**jason_999** · 04-24-2012, 02:12 PM

hey guys, thanks again.
definitely sounds like it would be a project that would require a lot more thought.
i will put that one on hold and just focus on getting my Ninja first

I actually wanted to do something similar with my car (Dodge Challenger) and ran into a similar sort of problem, if the tire is to wide for the Rim, the edges kind if bow, and in the end you dont get to really take advantage of the increased width of the tread. sounds like the problem is a lot more complicated on the bikes, and the last thing i would want would be to make the bike sluggish and less balanced.

Looks like i will be sticking with Stock Tires on my Challenger and whatever Bike i get.
Thanks Again!

**jeffjones** · 04-24-2012, 02:20 PM

Here is a good read that should help you out about the geometry of a tire.

http://www.sportrider.com/tech/tires...ize/index.html

**RockerGuy** · 04-24-2012, 02:22 PM

narrow tires are better, easier turn-in

**slogan** · 04-24-2012, 02:29 PM

Well, I think it is better to stay within manufacturer's specs unless you really know, what you do.

The tire size is not made for design...

wider you install the tire wider you make the contact surface of your wheel => reducing wheel pressure to the ground => will change traction/gripping properties.

my $0.02

**taximan62** · 04-24-2012, 03:07 PM

I look at it this way. The engineers at the factory have designed the bike and chose the tire size based on many factors. Why second guess the designers, stick with the stock size.

Just because it looks cool does not mean it makes it better!

**D23** · 04-24-2012, 04:46 PM

The 650r has a 636 wheel conversion kit available that lets you use the proper width wheel for a 180 tire.

From what I remember you can do this and drop some MM off the front forks (lowering them in the clamps slightly) and get better handling from your bike.

Probably something you do when you need it but people do things for looks as much as performance. I get that.

Info's probably old so a 650r specific forum vs. a General Motorcycle forum would be best to ask on about this. If you are still looking for something like this. Not that the above wasn't good info but this is specific to what you wanted.

.....kit was the wheel (obviously) and these bits.......

Kit is (was?) from BRP in the US.

**mongol777** · 04-24-2012, 05:17 PM

Here you go - you are welcome

http://toronto.kijiji.ca/c-cars-vehi...AdIdZ374318858

**Emerald94** · 04-24-2012, 06:30 PM

I got stuck behind one of these monsters when running the Dragon.

(

Originally Posted by mongol777

Here you go - you are welcome

http://toronto.kijiji.ca/c-cars-vehi...AdIdZ374318858

**Gryphon** · 04-29-2012, 02:51 PM

160/60-17 is nice, big, chubby tire on Ninja650.
Looks "generous" size (lots of rubber there).
180/55-17 will have same rolling radius, but you don't really want one - the stock size is perfect.

In 1979 a 100 HP+ six-cylinder CBX came with 120/90-18 rear!
(We would of course immediately over-size that, to 130/80-18, heheh.)
So the big 160mm radial on the back of the little Kawi twin looks like all kinds of meat, to me...
L8R

**RicoChet** · 04-29-2012, 03:05 PM

Originally Posted by Gryphon

160/60-17 is nice, big, chubby tire on Ninja650.
Looks "generous" size (lots of rubber there).
180/55-17 will have same rolling radius, but you don't really want one - the stock size is perfect.

In 1979 a 100 HP+ six-cylinder CBX came with 120/90-18 rear!
(We would of course immediately over-size that, to 130/80-18, heheh.)
So the big 160mm radial on the back of the little Kawi twin looks like all kinds of meat, to me...
L8R

My 1982 cb900f has a 110 on the back I think or maybe the 120 but it's a blast to ride and turns like its on rails

love that bike

**Gryphon** · 04-29-2012, 03:30 PM

Hi RicoChet,
I had a (brand-new) CB900F in 1981...
You can go 130/80-18 rear on that; it's considered the "proper" size.
Tires had just changed from Imperial sizes (ie. 4.00-18; 4.25/85-18; 5.10-18 etc.) and there were some creative translations, heheh...
On CBX / CB750F / CB900F of that era, it's more critically important to keep the 100/90-19 front size!
You'll find people with 110 fronts installed - and this is a major no-no.

**Riceburner** · 04-30-2012, 04:22 PM

stick to stock. But if you must, you can go up to a 170 on the stock rim. A 180 will "fit" on the rim, but will be pinched and the tire may rub on the chain, etc.