150 170 180 on 15" Rear

[Bushwacker]

So what I have been reading is you can go from a stock 150 to a 170 without any modification. I just want to make sure this is correct and is why Im posting. If you move on to a 180 you will have to modify. "washer-spacer or what ever". I finally got rid of the stock Dunlops and went with the Shinko 110/90-18 61V Frnt & 150/90-15 80V Rear. Very happy with these tires and don't mind if all I get is one summer out of them. Price was great at Revzilla @ $61.90 and $83.94 plus $80 to have them mounted. Anyway back to the question. Is there much advantage to running a wider tire on the back of THIS bike? I would think yes, or does it cause more problems than it's worth? I understand this bike was meant to be a straight line powerhouse, but I find that it goes round corners pretty good for what it is. You just have to find the courage and develop the talent to throw a big bike in the corner and know how to drive it out with some throttle management when the ass gets loose. Not blowing my own horn here guys just telling it how I see it. Would also like to know if anyone has had any luck getting the frontend to settle down and stay a bit more planted at high speed. Ive been thinking or should I say hoping someone has figured out a way to do it aerodynamically with a small fairing up front.

Thanks much!

Bush

 

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A wider back tire looks good. It doesnt really help anything.

Some guys say a wider rear tire diminishes cornering capabilities. Technically, that may be true. However, my practical experience tells me than running a 170 instead of the stock 150 doesnt hurt a damn thing.

Ive not heard of anyone running a 180 on the stock rim. A 170 is a common choice though.

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[Fire-medic]

If you look at what's recommended by the tire manufacturer for the wheel width of a bias-ply tire sized correctly for our 3-1/2" width rear, you will find that a 170 tire is supposed to be on a wider rim, and even more so for a 180. What happens is that the 'warp' of the tire, the way the tire is constructed, or wrapped around the carcass, is designed for certain characteristics with a specific width tire. The way the tire deforms under load and the wrap of the tire around the sides of it, all are designed with specific goals for handling, heat retention in the rubber compound, the 'give' as the tire footprint occurs while underway, its elastic rebound as the footprint unloads, the stiffness of the tire sidewall, the hardness or softness of the rubber, the compound in the rubber as to how quickly it heats to optimal operating temperature, how-easily it can give-up excess heat, because excess heat from flexing that the tire wasn't designed to do due to being too-wwide a tire on a too-narrow wheel; it's all a delicate balancing act.

Running a too-wide tire on a too-narrow rim certainly won't enhance handling, may encourage the tire to overheat and to become 'greasy,' or unstable, and possibly to chunk its rubber under severe use.

Going to a 160 or 170 isn't going to send your handling into the pits of hell, but you're better-off learning how to use what you've got, in the proper size to fit your wheel. Many forum mmbers run a 160 or 170 and have no complaints.

I believe the #1 improvement in handling a VMax owner can take is to run a 17" or 18" X 5-1/2" rear wheel, and a properly-sized radial tire, with a narrow 18" radial up-front. A 100 or 110 is what I'd recommend there, anything wider than that calls for a 3-1/2" wheel width, which is far-beyond what a VMax has stock. You know what a 'muffin-top' female is? Where the tight top above the waist or a tight pair of jeans makes the midriff swell-over the tight clothing confines? Like a muffin browning in the oven swells-over the top of the muffin tin and muffin paper cup? Well, that's what a too-large tire on a too-narrow rim looks like in cross-section. Under load, the tire shifts back and forth, very unstable, and not confidence-inspiring! Anything more than a 180 tire on a widened, larger-diameter wheel will require a widened swingarm, another cost consideration. Sean Morley (Morley's Muscle) can help you with a mod there.

 

[Bushwacker]

Awesome write up Fire-medic. Everything you said makes perfect sense and the best part is I understood the whole explanation. So if I want this beast to handle more like a sportbike it looks like I will have to fork out some fairly serious money to do it right? Or just leave well alone and get another bike. I don't want to ruin the Max by trying to make it into something it was never intended for in the first place. Just leave it as a city street light to light tire shredding monster. LOL

Thanks very much fella's...

 

[Fire-medic]

'Reports of the VMax's poor handling are greatly exaggerated.'

Repeat this (above) often, it's true. Worn tires, leaky fork seals, shot wheel bearings, loose or tight steering head bearings, without grease; worn-out shocks, loose swingarm pivots, any, some or all of these can cause poor handling. Because a VMax has some decent HP, these afflictions are more-quick to appear if you are one to twist the throttle. You can get into trouble a lot more-quickly on a 110 RWHP bike than you can on a 30 RWHP bike.

The VMax was designed with early 1980's suspension technology and tire technology. You can update each significantly. Some 'cures' aren't cheap, but they are effective. Making sure what you have is in good shape to begin is step #1. If you don't run Progressive Suspension fork springs, run air pressure in your forks.

That's the lesson for today.

 

[Bushwacker]

Couldn't agree more and I am currently on my way to addressing all things mentioned above. Some are just plain old basic maintenance issues. Ive only had the bike a short time, but knew when I bought it the first thing to be done would be to get it mechanically sound again and make upgrades as I go. First thing I did was to give it a tune-up then the front end. Seals - springs - head completely done - breaks front and rear. Just got tires put 61 miles on them yesterday. I can tell you after doing just these few things it has made a huge difference. No more speed wobble at any speed from the front end, no wondering at any speed, stops way better and sticks to the road so much better. Still have much much more to do, but I'll get there. Need to grind that pesky little kickstand foot assist (or whatever you call it) off, I keep scraping it. Not sure what to do with the rear end yet need to do more research. Thats why what you posted above was so helpful. Thanks again for that.

 

[davesax36]

You can also check your swingarm bearings if things feel funny. Plenty of wandering, wobbles, and other odd handling things have been fixed by doing those. Also just checking torques on driveline bolts can be eye-opening on a newly acquired max.

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[sdt354]

With all the mods available, a gen 1 Vmax can be made to handle beyond many riders abilities now. Best to start with making sure everything is maintained and adjusted correctly. Head bearings, swing-arm bearings for a start. Stickier tires next. Lowering the bike does wonders. Radials on wider wheels, incredible upgrade.

 

[Bushwacker]

Which sticky tires are you recommending and when you say incredible upgrade when switching to radials can you be more specific please.

 

[Fire-medic]

First, let me mention a new correct speed-rated performance bias ply tire will give you good service, it's what Yamaha specified from the factory. A new correct bias ply tire (preferably a pair of tires) will be much safer to operate than a worn-out-radial, or bias ply tire.

Lots of guys on here like the Shinkos because they are relatively inexpensive, and we have a relatively powerful bike (600 lbs & ~110 RWHP). Any quality tire should be good, really. The trade-off is soft tread compound vs. tread wear, which will be worse for better grip. Longer-lasting, harder tread compound means less grip, and the rear end will feel loose if you grab a handful of throttle on a curve for instance. That's good if you like leaving a strip of rubber on the pavement exiting corners, but couple that with wet or greasy pavement, (or both!) and you are facing a possible spill if you aren't ready for it.

So I would say, sport compound rather than touring or sport-touring compound, but you'll not get 6000 miles out of a rear tire. Maybe half that. It's 'pay to play.'

Radials I feel are the best handling mod you can make to our bikes, I've had mine 24 years.

 

[ShawnD]

First, let me mention a new correct speed-rated performance bias ply tire will give you good service, it's what Yamaha specified from the factory. A new correct bias ply tire (preferably a pair of tires) will be much safer to operate than a worn-out-radial, or bias ply tire.

Lots of guys on here like the Shinkos because they are relatively inexpensive, and we have a relatively powerful bike (600 lbs & ~110 RWHP). Any quality tire should be good, really. The trade-off is soft tread compound vs. tread wear, which will be worse for better grip. Longer-lasting, harder tread compound means less grip, and the rear end will feel loose if you grab a handful of throttle on a curve for instance. That's good if you like leaving a strip of rubber on the pavement exiting corners, but couple that with wet or greasy pavement, (or both!) and you are facing a possible spill if you aren't ready for it.

So I would say, sport compound rather than touring or sport-touring compound, but you'll not get 6000 miles out of a rear tire. Maybe half that. It's 'pay to play.'

Radials I feel are the best handling mod you can make to our bikes, I've had mine 24 years.

Which bias tires have the best grip? I barely manage 1K miles a year between 2 bikes as it is so mileage is a non-issue.

 

[Traumahawk]

I've found shinko to have the best grip. I tend to get maybe 4K out of the rear tires.

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