swingarm

[Guest]

I currently have ths stock 150/70 series rear tire, I want to go with a wider tire. Will I have to purchase another swingarm and if so are swingarms universal or would I have to purchase one especially made for the make and model of my bike?

[Spedee]

160/60 max. on stock 98+ rim and stock swing-arm.

[crazyaussie]

I beg to differ...I have a 180/55X17 on my 99' Kat and as far as I know, everything is stock. The rim is J17XMT4.5 DOT.

[Spedee]

I beg to differ...I have a 180/55X17 on my 99' Kat and as far as I know, everything is stock. The rim is J17XMT4.5 DOT.

Please post a pic. Love to see that biggee.

[crazyaussie]

Will do, as soon as I get home from work. It won't look near as clean as yours though Spedee. Damn, do you ever RIDE that thing? I hope its not always that clean.

[The CyberPoet]

I'll just repost:

im pretty sure a 170 will fit, so no, I dont need to "get over" not liking the 150

170 from certain brands will fit. But with only one brand/make exception that I know of, a 170 radial will not fit safely on a pre-98 Kat OEM rear wheel... and that's a crucial difference.

From: http://www.katriders.com/forums/viewtopic.php?t=7909

The rear rim on the 98+ is built to take a 150/70ZR17. Normally you can go up one size by decreasing the sidewall height 10% (160/60ZR17), which gives you an advantage in dry grip, but increases tendency to hydroplane (more surface contact, same weight = less loading per square inch) and will force the tire to deform slightly in response (normally making run a bit hotter than the stock sized tire). The wider tire will also reduce the handling sharpness of the bike compared to a narrower tire with the same tread composite, arc design and tread design (can't compare a 150 Macadam to a 160 Pirelli or a 150 Metzeler -- the Pirelli and Metzeler are just head & shoulders above and have both better tread composites and triple-arc radius designs).

Once you go past that one step-up, you are traditionally setting the angle of the mounting lip on the tire at hard enough of an angle that it can provide stress issues at the first bend above the mounting flange of the rim. The tire also has to distort to compensate for being pulled so tightly at the center, so the arc deforms to compensate, resulting in elevated heat at the carcass. Both of these issue can lead to failure, although it tends to be infrequent. A few companies manufacture wide (170 - 180) tires specifically designed to mount to a 4.5" mounting flange size (the size of the 98+ kats' rear wheel)

...the pre-98 wheel is narrower and has a smaller range of tires that will safely mount to it...

KNOW THIS:
Different manufacturers' specific tires will expand different amounts once mounted and heated/cooled, from as little as 2% on some street tires to as much as 25% on some race tires. Most street tires will expand about 4 - 7%.
When you mount a 160 into a rim designed for a 150, the shape is distorted some, pushing the center arc of the tire outwards further because of the pressure on the sidewalls from the mounting flange angle. This increases the effective circumference above what you would get mounting the same 160 on a rim intended for a 160, and helps decrease the amount of change from a 150. On the other hand, this change in shape also causes the tire to build more heat, resulting in low lifespans than would be the case with the same tire mounted on the "ideal" rim for it.
Pretty much all manufacturers simply lie in their measurements. Theoretically, a Metzeler Z6 150/70ZR17 for example should have a sidewall measurement of approximately 105mm (70% of 150mm). The truth is that it will act as if it were a 150/70ZR17 and safely mount where a 150/70ZR17 will mount. In reality, the real-world sidewall measurement on a Z6 in a 150/70 is closer to 69mm (of which about 50mm is exposed on a 98+ Kat rim -- measure it yourself!), and the full distance from the inner lip to the peak of the center arc is only about 97mm once mounted. This would mean that their claimed 150/70ZR17 is actually closer to a 150/46ZR17

The arc face (edge to edge across the surface) is 190.5mm on a 150/70ZR17 Metzeler Z6, so that would actually make the tire a 190/37ZR17. Now try to reconcile that with the fact that it's labeled a 150/70ZR17 :P

Avon (a subdivision of Cooper Tires) makes a 170 that will fit the 4.5" rim of the 98+ Kats without modification.

KNOW THIS:
Wider tires are only better if you need them to overcome the amount of horsepower being laid down; narrower tires handle more sharply, steer better, cut water and dirt better (i.e. avoiding hydroplaning), and make the thottle & brakes more responsive (as there is less rotational mass to have to spin up & down). Odds are you will not get a positive benefit from moving to a 170 width tire unless your bike is putting out 90+ rearwheel horses (although unless you compare new tire to new tire, you'll never know for sure).

THINGS TO KNOW:
1. Bias (non-radial) tires generally are 1/4 wider at each lip than comparable-sized radials because of how the lip is formed;
2. Front and rear tire treads and crowns are designed to work together to sweep water or loose debris out of the way; the front tire clears for the rear tire's tread pattern, and is the reason manufacturers all recommend using the same brand & model tires front and rear together as a pair.
3. Front and rear crown apex designs are designed to work together to provide a consistant lean angle for the bike, to reduce unnessary flexing from mis-matched lean angles; this is the other primary reason that all tire manufacturers recommend matching brand & model front & rear tires.
4. Of all the manufacturers, only Dunlop officially supports patching of punctured tires, and then only certain models of rear tires, single patch, and when patched, the speed rating drops to 70 mph.
5. All tires "grow". Typical street tires grow in size about 5% - 8% during the first 10 days of ownership from being under pressure and heating cycles; race tires grow even further (as much as 22%).
[/quote]

i've got a 160/60 rear tire on my pre98, and i've read this is bad, why is that?

The reason it's normally considered "bad" is really to say it's "not perfectly safe" because the width of the tire on the stock pre-98 rear rim causes a less than ideal mating between the rim flanges and the tire bead lip, and exerts excess stresses onto the junction between the tire bead reinforcement and the sidewall (as well as deforming the actual arc radius of the tire, causing it to run hotter than intended). Most riders who try it may like it, but are missing the fact that the squeeze is making the tire act more like a 150/70 than a 160/60. Switching rear rims to a 98+ Kat rim will set everything right again, since the 98+ rim is wide enough to take a 160 safely without too much distortion.

Here's my age old recommendations, based on actual back-to-back tire swaps on late model katana's (one set a week, a few hundred miles inbetween):

1. If you primarily rail, live in a dry area (think desert, etc) and wet-grip isn't critical (buy dry-grip is), get yourself a set of Pirelli Diablos. Best dry surface grip and great triple-apex design. For street, go 150/70ZR17. For primarily track use, go 160/60ZR17.

2. If you primarily commute, tour, engage in all-weather riding or high-speed highway mile eating, get yourself a set of Metzeler Z4's or their follow-on replacements, the Z6 Roadtechs. They have a good triple-apex design, about 95% of the dry-weather grip of the diablo's, about 140 - 200% of the wet-weather grip, and quite a bit longer lifespan in them. Go 150/70ZR17 for best handling.

3. If you for some reason insist on having the biggest, widest damn tires you can squeeze in (which negatively impacts handling, but it seems to be bling-bling right now), Avon, a Cooper Tire subsidiary, makes a 170 that will fit the stock rear rim of the 98+ Kats. They also have a limited road-hazard warrantee in Canada & the UK & the USA (covers the tire, not the labor, valid for the first 3.5mm of tread depth wear).

4. Or, if you have the $$ and time to try it, do what I did and simply order yourself a whole variety of suitable tires (you can get quantity discounts this way, both from the vendor and from the local shop that will install them each week). Compare them back-to-back and sell the barely used ones on eBay -- if you shop wisely, you'll make back every penny you spent on tires when you resell them (at least I did). Keep the ones you like the best
I compared: stock Macadam 90x's, Dunlop 205's & 207's, Metzeler Z4's, Pirelli's Diablo's, Chen-Shins (never again!), plus rode other people's Avons and Bridgestones during that same timeframe. You can pick your own tires for your own comparo...

Notes:
Chen-Shins, aka Barracuda's, aka JC Whitney no-name house-brand, aka Maxxums: the crappiest, cheapest tires ever. Use only if you are showing threads and are in starving college student mode; expect no handling or stopping capabilities. Worst tire I've ever tried.
Macadam 90x: Broad, single apex design makes for wallowy, slow handling but decent breaking performance. Ran into scalloping, uneven tire wear. I suspect high road-surface temps in Florida, combined with my highspeed (100 mph+) style of riding played into the tire tread wearing unevenly.
Dunlop 205's & 207's: Dual-apex design, better than the Macadams, but advantages wore away within 1200 miles. Same type of uneven tire wear as the Macadams. I suspect high road-surface temps in Florida, combined with my highspeed (100 mph+) style of riding played into the tire tread wearing unevenly.
Pirelli Diablos: Triple-apex design, superb dry-weather grip, unfortunately grip nose-dives on wet surfaces, especially at first mist and in torrential downpours.
Metzeler Z4's: My tire of choice; been through 3 sets of them so far (almost 30k miles) between two late model Kat 600's. Triple-apex design, more grip than a stock Kat 600 can break loose railing as hard as possible; hyper-reliable grip in the rain (which we get a ton of in Florida). I liked the fact that when locked, the rear bunny-hops a couple times before sliding out...
Metzeler Z6's: I haven't ridden them yet, but Metzeler's engineers tell me that they are the Z4's with a smaller initial bead compound (10% more grip in the dry, 18% more in the wet, and 8% longer lifespan) and a modified tread-pattern for supposedly better heat & water dissipation. Others here on KP have tried them -- all have loved them.
Avons: Seem to be the Canadian tire of choice. Not sure why, but I suspect that road-hazard warrantee plays into it. I liked them, but they still weren't quite up to the spec of the Pirelli's and Metzelers, plus I got an uneasy feeling about the belt construction (can't recall the exact why's anymore -- perhaps bias tires?)...
Bridgestones: Longlasting, single and double-apex designs, but took quite a while to warm up and never were as grippy as the Pirelli's and Metzeler's.

Cheers,
=-= The CyberPoet

[crazyaussie]

Pictures of crazyaussie's Rear Tire

Enjoy!

[crazyaussie]

Some more Pictures

For your reference...

[Spedee]

Thanks. I am very surprised at the room left between the swing-arm and tire.

[Evader]

I'm running a 170/60 Z6 Rear tire and no problems at all. Not a fan of the tire tho, I'll go back to bridgestone after. got stuck with a flat and didnt' have a choice.

[stevnmd]

And that is why you don't run a 180 on a 4.5" rim...

Compare swingarm clearance.JPG and size of tire.JPG

Pay attention to the edge of the rim and the amount of space between it and the sidewall of the tire. The tire isn't even centered on the rim anymore due to the gross distortion of the profile. I'm guessing you have a TINY strip of bead seated around that rim. I wouldn't ride on that tire, that's for sure...

Look folks, there's the right way to do something and the half-ass, no concern for safety way to do things. If you want to run a 180 tire, buy a different bike. Tire manufacturers do not state that the widest tire you can safely run on a 4.5" rim is a 160 for no reason. I truly do not understand this obsession with wide rear tires. WTF is the point? It slows steering. It distorts the profile of the tire. It creates a safety issue. If you're willing to sacrifice safety for a "cool in your mind look", you're nuts. What would happen with a drop in air pressure? Run over a nail and you could die. A drop in air pressure and I could see that rim spinning free from the tiny tire bead quite easily.

[crazymofo]

And that is why you don't run a 180 on a 4.5" rim...

Compare swingarm clearance.JPG and size of tire.JPG

Pay attention to the edge of the rim and the amount of space between it and the sidewall of the tire. The tire isn't even centered on the rim anymore due to the gross distortion of the profile. I'm guessing you have a TINY strip of bead seated around that rim. I wouldn't ride on that tire, that's for sure...

Look folks, there's the right way to do something and the half-ass, no concern for safety way to do things. If you want to run a 180 tire, buy a different bike. Tire manufacturers do not state that the widest tire you can safely run on a 4.5" rim is a 160 for no reason. I truly do not understand this obsession with wide rear tires. WTF is the point? It slows steering. It distorts the profile of the tire. It creates a safety issue. If you're willing to sacrifice safety for a "cool in your mind look", you're nuts. What would happen with a drop in air pressure? Run over a nail and you could die. A drop in air pressure and I could see that rim spinning free from the tiny tire bead quite easily.

+1!!!!!!

well said

cheers.joe.

[Black_peter]

I beg to differ...I have a 180/55X17 on my 99' Kat and as far as I know, everything is stock. The rim is J17XMT4.5 DOT.

It's true!!!
I've seen it

It still turns too

That tire is waaaaaay fat !!

[Waltari]

And that is why you don't run a 180 on a 4.5" rim...

Compare swingarm clearance.JPG and size of tire.JPG

Pay attention to the edge of the rim and the amount of space between it and the sidewall of the tire. The tire isn't even centered on the rim anymore due to the gross distortion of the profile. I'm guessing you have a TINY strip of bead seated around that rim. I wouldn't ride on that tire, that's for sure...

Look folks, there's the right way to do something and the half-ass, no concern for safety way to do things. If you want to run a 180 tire, buy a different bike. Tire manufacturers do not state that the widest tire you can safely run on a 4.5" rim is a 160 for no reason. I truly do not understand this obsession with wide rear tires. WTF is the point? It slows steering. It distorts the profile of the tire. It creates a safety issue. If you're willing to sacrifice safety for a "cool in your mind look", you're nuts. What would happen with a drop in air pressure? Run over a nail and you could die. A drop in air pressure and I could see that rim spinning free from the tiny tire bead quite easily.

I agree 100% with Steve on this. Being someone who has spent ALOT of time measuring, fitting, and modding things, I cant tell you first hand that a 180 on a proper sized rim meant for a 180 will not provide sufficient clearance within the stock kat swingarm. Cram one onto a stock 4.5" rim, yeah it'll go in but as Steve said you'll be running a tire with a questionable bead seat and something that is MUCH more likely to fail under stress. BE safe...period

[Black_peter]

In crazzyaussie's defence:
He bought the bike with this tire.
This is his first bike.
He realizes it is over sized and affecting his handling.
He is planning to replace it..

He did not add this tire for bling....