I know that a tires weight can affect centrifugal forces and play a part in acceleration, braking, and handling. It's rotating mass, just like installing BST wheels or an aluminum rear sprocket can reduce this rotating mass. However, I'm wonder how much a heavier tire will affect top-speed ability?

I ran 196.4 mph in the 1.5 mile on the stock Metzler Sportec M5 tires about half-worn, and the OEM 42T steel rear sprocket. Next week I'm installing a Vortex aluminum 40T sprocket and new Michelin Pilot Road 4 tires on my 14R. I know the PR4's are heavier than the M5's, but by how much I do not know. Can't find tire weights online anywhere...

Will my top speed ability decrease because of the heavier tires at the furthest outward location, even with the small reduction in sprocket mass closer to the hub?

* Last updated by: Bradley427 on 3/26/2015 @ 1:59 PM *

Heavier tyres are more likely to affect handling (if at all) rather than top speed. More weight at the rim would mean a greater gyroscopic effect due to centrifugal force so the bike would be harder to lean over, in theory at least and there would be more unsprung weight. Back in the day when the Exup 1000 was top dog one of the bike mags did a track test with various tyres culminating in the fitting of lightweight racing slicks. The grip was obviously better but the handling was rubbish. According to the tyre guys involved in the test this was because the suspension was built and setup for road tyres which were far heavier. Suspension and tyres have come a long way since then but the theory is still the same. JMO

I have run the Pilot Road 4 over 200 many times. Will it reduce your top speed by a small amount? Yes. But is it the most well constructed tire for confident operation AT those speeds? Yes. I believe so. It is stable and planted at full tilt. Thats important. Its a trade-off. I will take the tire that will perform safely every time. The Road 4 has fantastic grip for such a versatile tire. Very predictable and confidence inspiring. I pay close attention to pressure and run accordingly.
Just my 2c.

* Last updated by: Cblast on 3/26/2015 @ 4:23 PM *

What rear sprocket was used for the 200+ runs C?

I have no doubt the tire is built for war! So much technology and engineering in these new tires, I'd wager they're some of the best on the market right now. I'm glad I snagged a set when I did for a song! I went with the standard PR4 front and the PR4 "GT" version on the rear since my fully loaded touring mode adds some junk to her trunk. Bet I would've been fine with a standard rear tho.

On my crappy bathroom scale I show the rear tire around 16lbs and the front around 10lbs. Anyone have more accurate weights than that? Or how it compares to other tires?

IDK if this will be of much help but the Pirelli Super Corsa was one of the the lightest among the bunch in a brand comparison test. A 190/55 is 13 lbs, 11.6 oz. The front 120/70 is 9 lbs, 6.1 oz.

* Last updated by: Rook on 3/27/2015 @ 4:53 AM *

Yeah Bradley, that GT is a heavy rear, I have never run that compound, I was using a 41 tooth rear for the top speed stuff. Little over-rev helps.

^^

In the recent Motorcycle USA test, the Super Corsa had the second lightest front and lightest rear.

http://www.motorcycle-usa.com/545/21928/Motorcycle-Article/2015-Sport-Motorcycle-Tire-Shootout-Conclusion.aspx

Don't think tire weight would have any noticable difference for the average person.

If you go to gear commander you can plug in sprocket changes, both front and rear, and see what your theoretical speeds will be in each gear. Unless you modify your clutch you need to subtract 3-4% for slippage.

Because to me it's easier, I changed from a 17 to an 18 countershaft sprocket. Theoretical top speed with stock tires and 11,500 rpm redline is 222.7, subtract 4% and you end up with 213.7.

Changing to an 18 means you have to slip the clutch a "little" more on starts but not much, sure gives you a lot longer legs which is what I wanted for myself.

In the recent Motorcycle USA test, the Super Corsa had the second lightest front and lightest rear.

Rook you don't happen to know the weight of the OEM Metzlers by chance do you? I know you usually weigh OEM parts coming off and the aftermarket parts going on, but if I remember correctly you put the Pirellis onto your busa...

I had the Pirelli Diablo Supercorsa SP's on my CBR1000RR and can vouch for how amazing they are. Best grip I've ever felt - bar NONE. But that bubble-gum like grip comes at the cost of longevity. I kept them when I replaced em with a fresh set. The worn-out carcasses are in the garage waiting for me to make an end table or something out of them.

NOpe, no weight on the OEM 14r tires. Those Pirellis went on the busa. My 14 is and 08 so I had OEM BT-014s anyway. Long gone now.

The worn-out carcasses are in the garage waiting for me to make an end table or something out of them.

I think this is kinda nice. How about a Super Corsa Spittoon?

I would say, yes. Not only the weight of the tire would effect performance but traction of the tire as well. But, I would think if you were doing like LSR Bonneville type stuff a heavier tire wouldn't hurt. But if you're doing like a mile race or something it would. A heavier rotational weight will hurt in a shorter distance. But on the longer, higher speed races I think traction comes into play a little more than rotational weight (just tire weight difference). Cause, at close to 200mph your back tire is fighting against the wind and will actually be spinning faster than what you're actually going. If you're doing the mile or 1.5 I would say a heavier but stickier tire would be better. And run as much pressure as you can in both your front and rear.

Yes, my question is in regards to top speed LSR type conditions. For all other street riding these tires will be no problem.

I just hope that the extra weight being thrown around at that speed won't hinder my ability to reach my target. The lighter sprocket should offset a small amount of that weight, but I don't have an accurate enough scale to know how much exactly.

I'm also on the fence about how to balance the tires (if at all). In the past I've mounted motorcycle tires and not needed to balance them, but granted those bikes weren't set up for this level of speed. Static balance on bearings/cones/rod setup or Dynamic balance on a tire machine at my favorite dealer, or no balance at all?

I just hope that the extra weight being thrown around at that speed won't hinder my ability to reach my target. The lighter sprocket should offset a small amount of that weight, but I don't have an accurate enough scale to know how much exactly.

Static balance on bearings/cones/rod setup or Dynamic balance on a tire machine at my favorite dealer, or no balance at all?

Can't tell you if you could go without any weights on a unbalanced tire. I doubt it matters a lot for most sport riding but if your doing 200, might be a safety factor. IDK.

You might want to have a look at the opening of this. I'm not a tire expert but it's based on a little research I did.

http://zx14ninjaforum.com/messages.cfm?threadid=FD889E3A-1372-66AE-3BF245423CB4CA83

You're awesome Rook! Thanks for all your help and info! And that's correct my Vortex sprocket is only 40T with their new black HardCoat finish. What does stock steel sprocket weigh compared to your aluminum Vortex 45T?

I think I might just make a balancer at home using the rear axle itself. Not as nice as your Bike Master rig but it's probably a safer bet than running with no balance.

This would be a good argument for running a 180 on the rear.

I can'r post pics right now because my Acrobat is screwed but here;s links if you want to view pics.
Vortex Aluminum 45T
19.3 oz

http://s461.photobucket.com/user/Rookzx/media/2008%20ZX-14/Sprockets/vortex45Tweight.jpg.html?sort=3&o=3

AFAM Aluminum 45T
20.4 oz

http://s461.photobucket.com/user/Rookzx/media/2008%20ZX-14/Sprockets/weightAFAM45T.jpg.html?sort=3&o=5

OEM 41T
32.0 oz

http://s461.photobucket.com/user/Rookzx/media/2008%20ZX-14/Sprockets/OEM41Tweight.jpg.html?sort=3&o=4

about 33% is a nice weight reduction.

I think I might just make a balancer at home using the rear axle itself.

* Last updated by: Rook on 3/28/2015 @ 5:01 PM *

Weight doesn't decrease or increase top speed, it affects rate of acceleration. How it all factors exactly in I'm not really sure. But it could be something like this. Increase a vehicles sprung weight 1%, it will slow the acceleration rate 1%. Unsprung weight (in this case only wheels/tires) is factored by 3. A bike weighs 500 lbs. You add 5 lbs of sprung weight, it slows the bike's rate of accerlation 1%. If you changed tires and added 1.33 lbs to them, effectively that would be equal to adding 5 lbs of sprung weight.

Changing direction is an entirely different thing. Consider that when you are changing direction, you are constantly accelerating that rotating mass in the direction of change. Therefore yes, handling is directly affected by weight.

In the same way suspension actuation is affected. As suspension is moving, it's a directional change and the same laws of physics apply as turning.

Awesome data rook! It's a very nice weight reduction indeed.

As for the balancing, I'll do something about it but I'm not sure what yet. I need to take the tires somewhere to use a mounting machine, so I'll ask around to find if they also balance on a machine. If no luck there, I'll make a rig in the garage to do it by hand statically. I have a couple ideas to reduce the friction on the axle to find that heavy spot.

Also worth mentioning, tires usually come with a yellow/red dot painted on the sidewall. On cars and trucks we always used to position that dot across from the valve stem (180 degrees around) since it meant that was the heavy spot in the tire. With the extra weight of the valve stem, the heavy spot in the tire would cancel itself out and get you closer to balanced by doing this. I can't recall if my PR4's have a dot, but if they do should I position that AT the valve stem or ACROSS from the valve stem? I recently read that folks put it right at the stem (and I started wondering which method was right).

Bradley the yellow dot indicates the light point ,so mount by valve stem

^^^Usually mount by the valve stem. To be precise, mount the dot so it is aligned to the heaviest spot on the rim. Where is the heaviest spot on the rim? What is "the location of the valve," Alex? DING DING DING!!! the heaviest spot is usually where the tire valve is located in the rim. Not necessarily exactly on the tire valve. My Carrazzeras don't seem to have a heavy spot on the rim. That wheel is exceptionally well balanced from the factory. I would check the balance of the rim after the tire is removed and mark the heavy spot before you choose a location for the tire dot. Line the dot up wherever the heavy spot on the rim is. This is no guarantee that the the wheel will be balanced after the tire is installed but it might just help you use less weights. For one thing, a tire stretches an awful lot when you install it and it's pretty unlikely that dot will remain where you positioned it. The dot will probably migrate a few inches by the time you get the second side of the tire pulled over the rim and you might have a tough time pulling back where you wanted it. Oh, when you check the balance of your rim without the tire, leave the rotors/sprockets on because those coould have an effect on wheel balance as well.....if you are being precise which it seems you are.

Check out this tutorial. It's really long but there's a lot of links to other valuable info throughout. All you really need is the link at the beginning to Adam Glass's Motorcycle Tire Changing. It tells how to make a wheel balancer and how to mount tires with irons and home made tools. In my tutorial, I'm just parotting what he says but there may be a few nuggets of info that might be gleaned from looking over what I have written + I have some good illustrations in there I think....and actual pictures of ZX-14 wheels.

HOW TO REMOVE AND MOUNT TIRES

The dot on my Pirellis was very hard to see. I think it was 3 dots [...] in transparent pink so you have to look closely. I did not see them at first. They might have been printed on the bead if I recall--instead of the sidewall.

Are you mounting your own tires with tire irons......... ? think twice. $25/wheel is a steel if they don't scratch up your wheels. That's MHO. Full days work and pretty stressful and a little dangerous by yourself. Could result in some real PIA damage to rims which you will need to fix. You will probably scratch the inside of the wheel if it goes tough but one scratch on the bead of the rim and the bead won't seal. Don't forget you have to take the old tires off and they can be very hard and stubborn if they are old. i had to cut my old tires off the busa. It was just impossible to pull off with irons. Dremel and cutting wheel. Wound steel cable around the tire beed. pop poioop pop...had to cut it one strand at a time....in several locations....then you have sharp barbs of steel sticj=king out and you sure don't want to have those touch the rim.

* Last updated by: Rook on 3/30/2015 @ 10:42 AM *

Well if anyone is curious I've contacted both Metzler and Michelin and submitted inquiries for the exact weights on their tires. I just got last email, so the results are as follows:

Metzler Sportec M5 120/70ZR17 E (Front tire on OEM ZX14R) weighs 9.60 lbs
Metzler Sportec M5 190/50ZR17 E (Rear tire on OEM ZX14R) weighs 14.77 lbs

Michelin Pilot Road 4 120/70ZR17 (My new front tire) weighs 9.35 lbs
Michelin Pilot Road 4 GT 190/50ZR17 (My new rear tire) weighs 15.13 lbs

If I had gone with the standard rear and not the GT it may have even been lighter than the M5 rear. The front PR4 is in fact lighter by 4oz. The PR4 GT rear is only 5.76oz heavier than the stock M5 rear. (All these tires listed are OEM sizes)

That means with the 40t Vortex sprocket (minimum of 12.7oz lighter than OEM, but possibly a tad more based on Rooks measurements above) my rear wheel/tire assembly has lost at LEAST 6.94oz overall. Sweet!

I had planned on mounting them myself, and I still might. I called around today and the cheapest place was $60/pair, most expensive was $160/pair. And I would bring them just the wheels and tires! Turns out dealers don't like installing YOUR brand new Michelin tires, only the ones you buy from them at or above MSRP. Meh. I've done several of them myself before, the last 2 rears for my stunt bike just out in the front yard with some irons on a hot day...soft rubber is much easier to work! I'll let you know how it goes once I'm all finished.

* Last updated by: Bradley427 on 4/2/2015 @ 12:48 PM *

Used to have an old Chevy rim mounted on a pedestal with 1/2 heater hose split along the length around the edge.a friend of mine was spooning off a tire and slipped,he didn't damage the rim but his dental bill was pretty expensive

* Last updated by: darryle on 3/30/2015 @ 5:13 PM *

I got the new tires and sprocket mounted. I decided against installing the ariete valve stems this time, did a ton of reading and there's some mixed results with sealing properly and the nut being on the inside has me worried. Anywho, I borrowed a mounting machine and balancer after hours and did all the work myself, just the way I like it. Took longer than a 17-year olds at the shop could have done it, but there's not a scratch on 'em ANYWHERE. Perfect mounting and I got a helluva static balance on them to boot, using the spindle on the balancing machine. As it turns out there was NO YELLOW DOT on either of my Michelins...go figure. So I just made sure they're turning the right way and then over to the balancer.

Mounted the 40T sprocket, looks great on the bike. I had to adjust chain slack for it obviously, but it ended up being pretty far back. It's at 4.5 'notches' back if looking at the adjustment lines on the swingarm itself. (There's only 6 notches total). I did a short 5 mile slow-ish ride to get the new tires scuffed and shake down the bike to make sure everything is tight and settled in. Chain slack is great and no noise or issues with shifting so I'm going to run here for a while, and just monitor it for any more stretching. Here's some pics:

* Last updated by: Bradley427 on 4/2/2015 @ 9:44 PM *

I decided against installing the ariete valve stems this time, did a ton of reading and there's some mixed results with sealing properly and the nut being on the inside has me worried.

I've used 90° stems on the busa and the 14. Bridgeport (looks like that is another name for Ariete) and Bikemaster. I even had to dremel the base of the stem right up to the O ring so it would fit on the Carrazzeria rims I have. I've had no problems with sealing. The bridgeports worked great on the OEM rims. They seal just as good as OEM stems did. The nut on the inside also concerned me but I did not read of any problems and I've had none of my own. Just use a drop of lokTite. One bad thing about aluminum valve stems is they weigh a bit more than rubber so I guess you made out there.