tire help

[rossi]

everybody is tell me not to put a different tire that suggested on my 99 Katana 750. but it seems that some of you have different sizes on your bikes.

Can I put 150/ 60/17 instead of 150/70/17

suggestions needed please

[Spedee]

160/60/17 rear
120/60/17 front

[The CyberPoet]

STANDARD REPOST (note portions are dated -- I now order from AmericanMotoTire.com normally):

PARTIALLY REPOSTED FROM http://www.katriders.com/forums/viewtopic.php?t=7909 and other threads...

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 straight-line 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, thus last a shorter number of miles). 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). Finally, a larger width tire will also weigh more, which penalizes handling, braking and acceleration some as well.

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).

Avon Cooper does make a 170 that will fit safely according to them on a 4.5" width rear rim.

Here's some more tire stuff I've written gathered together from other threads (so I don't have to re-write it -- and yes, I know some of it repeats):

The stock Michelin Macadam has an gradual arc shape (single apex) that is very poor for handling. Suzuki uses it for a couple reasons -- it's cheap for them in bulk, and it discourages young bucks who have this as their first bike from pushing it beyond their limits (as evidenced by those of you saying you felt as if the back end would give out). This has zero to do with the fact that it's a 150/70ZR17, and everything to do with the fact that it's a Macadam (commonly called Crap-a-damns around here).

Moving to a Metzeler Z6 all around (120/70ZR17 front, 150/70ZR17 rear) will fix this issue, as will switching out to Pirelli Diablos (where you have to use a 160/60ZR17 rear because it's not offered in a 150/70ZR17) or Pirelli Diablo Stradas (which are available in stock size). A pair of Z6's will run you right around $185 - $200 mail order; you may be able to find a local price in that ballpark after you factor in mounting costs (many dealers mount tires they sell cheaper than they mount tires from elsewhere, since they've made their money on the tire as well).

As for running mismatched tires -- don't do it. There are several reasons, including:
The front tire "sweeps" for the rear's tread pattern. Mismatched tread patterns will not permit correct sweeping and may cost you a loss of rear traction on water, sand, etc.
The arc design between the tires is designed to work together, so that as the bike leans, both tires are offering the same surface to the ground in unison rather than exerting stress through the frame due to an imbalance in angles (which again can cause loss of traction).

If you feel the stock tires aren't up to snuff (they aren't), replace them and sell the existing ones on eBay to help offset the cost -- someone will want them.

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).

To read tires, it goes like this:

150/70ZR17 (62W)

Where:
150 is the tire's width left to right across the tread area in millimeters;
70 is the sidewall height as a percentage of the first number (i.e. - in this example 70% of 150mm = 105mm);
ZR is the speed rating (Z) and if required the radial (R) or Bias (B) requirement;
17 is the wheel diameter in inches;
(62W) is the weight rating (62) and any special manufacturer codes (W is often "weight", but they could also have "RR" for road racing only, etc).

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 permits patch 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%).

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,/track use, go 160/60ZR17. Not available in a 150/70ZR17.

2. If you primarily commute, tour, engage in all-weather riding or high-speed highway mile eating, get yourself a set of Metzeler 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. The Pirelli Diable Stradas appear to be exactly the same tire in terms of design (Metzeler builds Pirelli's motorcycle tires for them).

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.

TIPS:

1. When shopping for tires online, always include shipping costs into your calculations. Many firms low-ball tires and then make it up on shipping. I've bought my tires (except for emergency replacements) from chaparral racing ( http://www.chaparral-racing.com/ ); their site isn't always up to date on what they have in stock (call them), but they've always come through cheapest with what I wanted. Other standard sources include DennisKirk. Ask around about reputations -- some standard sources have bad ones when it comes to fulfillment.

2. Double-check with the manufacturer on recommended tire pressure on your bike with a specific tire. Not all tires are supposed to run at the same pressures as the OEM Macadams (the Metzlers and Pirelli's for example run 34 front, 38 rear rather than 32/36).

3. KNOW THIS: Pirelli motorcycle tires are built in Metzeler's factories. Metzeler is the only motorcycle-only tire manufacturer in the world.

4. Balancing is critical. Get the tires balanced at time of install. Also insist the valve is replaced at that time for your own safety.

5. Be cautious: depending on where you live, local dealers & shops may not be willing to mount tires acquired from elsewhere, or may charge an arm & a leg to mount tires they didn't sell you. Shop around for mounting prices before you buy the tires.

6. Most dealerships & shops will charge you half-rate or less if you bring them the wheels already off the bike (saves their mechanic's time). Ask about it.

More next post.
Cheers,
=-= The CyberPoet

[The CyberPoet]

Now it would seem the latest rage is to shoe-horn the widest tire possible onto the bike, because this is what is happening on the R6/R1/GSXR600/GSXR1k/etc. The fact of the matter is that these bike's handling is designed around this fact (or in-spite of it, with extremely aggressive headstock angles to compensate). They would still handle better with narrower tires, but then the manufacturers would open themselves up to a ton of lawsuits from street riders who lost the rear end traction by getting on the gas while coming out of a corner. Thus, it's a trade off between sharper handling and the ability to sucessfully transmit power to the ground without loosing the traction in the rear excessively.

On a bike like the typical Kat 600 or 750, there simply isn't the horse power to overwhelm the stock tire size coming out of the corner with a good compound on there (this may change if you've modded heavily, changed gearing radically, or dropped in a bigger engine/etc).

When you look at race bikes, they use the narrowest tire they can readily get away with, because narrower tires handle better -- they weigh less (so they brake easier, accelerate faster and change direction quicker), and their arc shapes are sharper (making it easier to drop the bike into the turn).

Finally some new additions:
CycleGear stores mount tires for something $12 - $15 a wheel. That's dirt cheap...
EDITED:
All of the major MC tire manufacturers are concentrating all their R&D on 120/70 front tires, thus buying a 120/60 (or a 110/80, etc) means that you are effectively buying older technology. See related thread here http://www.katriders.com/forums/viewtopic.php?t=12680 (includes Q&A session with a former tire rep). You'll find the 70 profile is also where virtually all the R&D in sports-touring tires goes for rears (because most sports-tourers use 70 profile tires as spec).

Cheers
=-= The CyberPoet

[rossi]

All, I need is when I lean the bike, I won't fall. seems like the 160 would help better than 150...right

[The CyberPoet]

All, I need is when I lean the bike, I won't fall. seems like the 160 would help better than 150...right

wrong.

Cheers,
=-= The CyberPoet

[paradoxmd]

cyber knows his stuff. if i remember correctly, a narrower tire will be better for corners because it won't have to mushroom to fit the rim. maybe mushroom isn't the word i'm looking for, but if you put too big of a tire on a narrow rim, it was distort in a way that could be unsafe.

[rossi]

after hearin all that it seems like Metzelers M6 120/70/17 and 150/70/17 are my number one choice now. thanks guy.

I will still be considering other opinions though

thanks guys

[The CyberPoet]

No problem. Check out www.americanmototire.com as one of the cheapest sources for tires in general. Also check out DennisKirk.com.

Cheers,
=-= The CyberPoet

[JamesS]

Cyber should set up a referal from AMT and get a small kickback :P

[WildKat]

americanmototire is a great place. I would have ordered from them if HS2020 didnt give me such a great deal.

Everybody posted up great information. There will always be a debate on this topic. What's safe, what isnt, why this tire is better than that one, why a 160 is better or worse than the stock 150, etc. It's a never ending debate but suffice it say many of us run a 160/60/17 on the rear and a 120/60/17 on the front like spedee mentioned. Works awesome ! others prefer to stick to the standard recommendations and enjoy just as confident riding as the others.

[DooD]

Can't somebody PLEASE sticky one of these tire size threads, so we don't have to reply to a new one every second day?

Edit the title and sticky this one - it's got all the info anyone could ever need! The current stickied tire thread kinda sucks, and I think that's why we're seeing tire size posts every 12 hours....

[Grimmy]

Tires is such a big thing... everybody hates to pay for em... but everyone needs em. Up here in Canada - dealers have a real monopoly on tires. When calling around, one gets quoted either MSRP or a special on a tire in house, which likely has been on the shelf for 2 years or more, or they try and sell you a tire that wont even work!!!! (ie. bias ply, 180, etc).

In the end - I run 120/160.

SV650 tire size.

Sorry, but I cannot bring myself to pay $390.00 CAD plus taxes for a set of rubber at the dealer.

I would rather shoe horn 160 on the rear end, and pay $200 even for a set of new take-off's.

No one up here stocks 150's!!! its all special order, and all regular, through the roof prices.

-Grimmy

[suzukisportrider2004]

also try www.shadetreemotosports.com if you still need tires

[iwannadie]

Now it would seem the latest rage is to shoe-horn the widest tire possible onto the bike, because this is what is happening on the R6/R1/GSXR600/GSXR1k/etc. The fact of the matter is that these bike's handling is designed around this fact (or in-spite of it, with extremely aggressive headstock angles to compensate). They would still handle better with narrower tires, but then the manufacturers would open themselves up to a ton of lawsuits from street riders who lost the rear end traction by getting on the gas while coming out of a corner. Thus, it's a trade off between sharper handling and the ability to sucessfully transmit power to the ground without loosing the traction in the rear excessively.

On a bike like the typical Kat 600 or 750, there simply isn't the horse power to overwhelm the stock tire size coming out of the corner with a good compound on there (this may change if you've modded heavily, changed gearing radically, or dropped in a bigger engine/etc).

When you look at race bikes, they use the narrowest tire they can readily get away with, because narrower tires handle better -- they weigh less (so they brake easier, accelerate faster and change direction quicker), and their arc shapes are sharper (making it easier to drop the bike into the turn).

Finally some new additions:
CycleGear stores mount tires for something $12 - $15 a wheel. That's dirt cheap...
EDITED:
All of the major MC tire manufacturers are concentrating all their R&D on 120/70 front tires, thus buying a 120/60 (or a 110/80, etc) means that you are effectively buying older technology. See related thread here http://www.katriders.com/forums/viewtopic.php?t=12680 (includes Q&A session with a former tire rep). You'll find the 70 profile is also where virtually all the R&D in sports-touring tires goes for rears (because most sports-tourers use 70 profile tires as spec).

Cheers
=-= The CyberPoet

the cyclegear near me wanted 30$ Per tire ; \