Kawasaki Z125 Forum banner
1 - 12 of 12 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter · #1 ·
What size tires are people running in the front and rear? I'm having a hard time finding stock sizes without mixing brands.
 

·
Registered
Joined
·
464 Posts
What size tires are people running in the front and rear? I'm having a hard time finding stock sizes without mixing brands.
I too am finding it IS a real problem. Since I value nimbleness in my motorcycles, I am always looking for tires that not only offer high traction (for safety and confident handling), but also low weight. But for both my current bikes, my Yamaha R3 and my Z125, I am having trouble even FINDING the weights anywhere in the manufacturers' available specs. When I email them, I either get no answer at all, or I often get an answer that is clearly erroneous (e.g. a smaller front tire that the reply says weighs more than its matched larger rear tire). Sometimes I get told that the manufacturer makes a rear tire, but no matching front tire for that rear tire, which seems ridiculous.

Then, there is the availability problem. Even if you find a matched set that supposedly exists, finding it actually in inventory, or available to order, anywhere at any dealership too often becomes the problem.

For what it's worth the DennisKirk.com site does the best job of actually showing full tire specs, including weights for most of the tires they offer, and their website also does a good job of filtering the availabel tires down to ones that should work with your specific motorcycle. You might have a look there. Then, even if Dennis Kirk does not have a specific tire in inventory at the moment, you at least have the data to do a Google search for that specific tire or pair of tires.

Jim G
 

·
Registered
Joined
·
464 Posts
In fact, just to prove the point, here is an actual email exchange I am having currently with the Technical Department at Avon Tires (A British tire company that is at LEAST 50 years old, so not a newbie):

To: Motorcycle Technical
Subject: Website enquiry

*****External Email: Please use caution before opening attachments or clicking on links. Forward suspicious messages to [email protected] *****

Please select an option
Motorcycle technical

Full name
James Gnitecki

What is your make, model and year of bike?
2018 Kawasaki Z125 Pro
What are your tire sizes?
Rear 120/70-12 51L and front 100/90-12 49J or 110/70-12 (the 110/70-12 has been successfully used by others despite lower load rating)
Message
I want to buy the lightest weight Avon tires suitable for sporty street riding on my Kawasaki Z125 Pro. The motorcycle is a project bike where low static weight and rotating moment of inertia are important. The motorcycle is only very rarely ridden in rain.


Hi,

Thank you for the below email.

Unfortunately we do not produce the below two sizes and therefore do not have a recommended fitment for this bike.

Many thanks,

Avon Motorcycle Technical



Actually, you DO make tires in the correct size. They are in your SCOOTER offerings. The Kawasaki Z125 uses scooter tires because of its 12” wheels. I have seen your scooter tires in the correct size being advertised at tire dealers. It is the WEIGHT of those tires that is missing in the technical data available to me. I need the weights of the tires.

Jim Gnitecki



Hi,

Apologies we do produce the rear size in our scooter range.

Please see below weight of the below sizes in our Viper Stryke range;
120/70-12 – 3kg

With regards the front sizes we do not produce them in our Scooter range.

Many thanks,

Avon Motorcycle Technical



The 3.0 kg = 6.6 lb weight of the 120/70-12 is very attractive to me, and does not surprise me, as I have used Avon tires a LOT in the past, and generally found them to be responsive lightweight tires! But why would you produce ONLY a rear tire and not a matching front tire??

Jim Gnitecki



You DO make a front scooter tire: AM63 VP2 Viper Stryke Front Scooter Tire
Tire Size 110/90-12

I found it for sale, in stock, on a dealer website.

What does that front tire weigh?

Jim Gnitecki



Hi,

Thanks for the below reply.

We do produce a 110/90-12 in our Viper Stryke range and this weighs 4kg. But unfortunately we do not produce either of these two sizes - 100/90-12 or 110/70-12.

Many thanks,

Avon Motorcycle Techincal



Thank-you. That 110/90-12 front tire weighs 4.0 kg?? That is 33% heavier than the larger 120/70-12 rear tire, so seems inconsistent! Are you sure it weighs 4.0 kg?

Jim Gnitecki



Hi,

Apologies, I stated the weight of a different size. Weights are:

110/90-12 – 3.4kgs
120/70-17 – 3.15kgs

Regards

Avon Motorcycle Technical



Uh, why are you now giving me the weight of a 17” rear tire??

And, if you simply mistyped 120/70-12 as 120/70-17, why did the weight change from the 3kg stated in your earlier email to 3.15 kg now??

Jim Gnitecki



I have not yet received a reply to that last email . . .

Jim G
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #4 ·
I know these might not fit your weight requirement but seems like the Kenda KD1 are available online at some places in stock sizes. I just went with 110/90 front and 130/70 rear Michelin City Grips. Pretty grippy so far but the spikes rub on the front fender (should go away after a while).
 

·
Registered
Joined
·
464 Posts
I know these might not fit your weight requirement but seems like the Kenda KD1 are available online at some places in stock sizes. I just went with 110/90 front and 130/70 rear Michelin City Grips. Pretty grippy so far but the spikes rub on the front fender (should go away after a while).
I finally found a "mix" that would work, after reluctantly abandoning the stance of insisting on same brand and model of tire front and rear, and giving up on getting actual weights from tire manufacturers and depending instead on Dennis Kirk's website which has always been accurate to-date. I ordered:

Rear tire: Avon Viper Stryke rear 120/70-12 = 3.15kg = 6.93 lb

and

Front tire: Pirelli EVO 21 110/70 = 6.0 lb

IF these weights prove to be accurate (From past disappointing experiences, I never assume they are), the total tire weight will be 12.93 lb, which is about 1.3 lb lighter than the OEM combo, and the tire traction and handling should be notably better.

The 110/70 Pirelli has 2 things I don't like. One is that it is 10mm wider than OEM, but I am assuming that the front fender and its mounts can clear the extra 10mm. The other is that the load rating is slightly lower than OEM - 386 lb versus 408 lb, so about 22 lb lower rating, but that is not enough to be concerned about. I'm sure Kawasaki was pretty conservative on the tire loading, and the Z125 is remarkably tail heavy (Note that Kawasaki recommends 29 psi rear and only 22 psi front).

I like the low weight, the lower visual profile, and the 13mm (half inch) smaller radius which will quicken the steering a bit more, especially with the short wheelbase of this bike.

I've used both Pirelli and Avon tires multiple times in the past, because they are typically SO responsive compared to some others. I'll see how well they work on this bike.

Jim G
 

·
Registered
Joined
·
464 Posts
I know these might not fit your weight requirement but seems like the Kenda KD1 are available online at some places in stock sizes. I just went with 110/90 front and 130/70 rear Michelin City Grips. Pretty grippy so far but the spikes rub on the front fender (should go away after a while).
That 110/90 front is going to slow down your steering and also raise the front end visually and make it look "heavier". Here's why:

A 110/90 tire has a nominal sidewall height of 110mm x 0.9 = 99mm.

The OEM tire has a nominal sidewall height of 100 x 0.9 = 90mm.

So, you are raising the front axle by 9mm = 9/25.4 = 0.35 inch!

You have already discovered that the extra 0.35 inch of sidewall height also raises the top of the tire to where it starts to get pretty close to the fender.

And the extra 0.35 inch x 2 = 0.7 inch increase in total DIAMETER makes that front tire look very tall and "heavier".

On the plus side, the bike will feel more "stable" at highway speed because of the altered rake.

Jim G
 

·
Registered
Joined
·
27 Posts
Discussion Starter · #7 ·
That 110/90 front is going to slow down your steering and also raise the front end visually and make it look "heavier". Here's why:

A 110/90 tire has a nominal sidewall height of 110mm x 0.9 = 99mm.

The OEM tire has a nominal sidewall height of 100 x 0.9 = 90mm.

So, you are raising the front axle by 9mm = 9/25.4 = 0.35 inch!

You have already discovered that the extra 0.35 inch of sidewall height also raises the top of the tire to where it starts to get pretty close to the fender.

And the extra 0.35 inch x 2 = 0.7 inch increase in total DIAMETER makes that front tire look very tall and "heavier".

On the plus side, the bike will feel more "stable" at highway speed because of the altered rake.

Jim G

Yep I have noticed the steering change slightly. My rears also increased 7mm by going to 130/7 but it all seems to be a welcome change. Cornering is much better since my previous rear tire was basically squared off. Hope your tires work out!
 

·
Registered
Joined
·
464 Posts
Yep I have noticed the steering change slightly. My rears also increased 7mm by going to 130/7 but it all seems to be a welcome change. Cornering is much better since my previous rear tire was basically squared off. Hope your tires work out!
Ah, very good, by installing a larger rear tire, You compensated for most of the height increase at the front,
AND gave yourself more ground clearance. You probably added a lb or 2 to the rotating weight, which makes the bike a little less nimble, but again steadier.

Jim G
 

·
Registered
Joined
·
875 Posts
So where's the advantage??

Options without mix 'n matching. Kenda KD1 seems like the only reasonable option in a stock size... but those appear to be a more race oriented tire. It would be nice to have a good dual compound for street hooligan use.
 

·
Registered
Joined
·
464 Posts
Options without mix 'n matching. Kenda KD1 seems like the only reasonable option in a stock size... but those appear to be a more race oriented tire. It would be nice to have a good dual compound for street hooligan use.
Yeah, you're right if you want to stay with "matched' tires front and rear. I've given up on that and now trying to select the best tires separately for front and rear without doing anything drastically different between the two.

Jim G
 
1 - 12 of 12 Posts
Top