[Mustfire]

I just changed to a 205-50-ZR17 car tire......ok before anyone tells me how dumb I am (and you may be right, but so far I love it. I can drag the pegs in 2nd gear, hammer the throttle, and it will not slide out from under me), I have another question. Since I put this tire on, my low fuel light comes on at about 80 miles. The only other things different are (a.) I put my modified stock exhaust back on. I cut the y-pipe where the front and back pipe join and welded a 2 1/4 inch collector pipe on, then that goes out to a Magnaflow straight-thru muffler. Sounds great, but I digress. (b.) I've been teaching my wife and son to ride so I have been doing a lot of slow and easy riding as I follow them. Could any or all of these changes made that much difference? The tire does weigh about 4 pounds more than the Continental I took off.

 

[Shawnzilla]

Well, aside it being a bad idea, in my feeble head, to put a car tire on a bike, the one big problem you're facing is 4 extra pounds of *unsprung weight* that your bike now has to try to spin. Unsprung weight is MUCH more detrimental to a vehicle's performance than Sprung Weight.


Just a quick lesson on Unsprung Weight: In a ground vehicle with a suspension, the unsprung weight (or, more properly, the unsprung mass) is the mass of the suspension, wheels or tracks (as applicable), and other components directly connected to them, rather than supported by the suspension. (The mass of the body and other components supported by the suspension is the sprung mass.)


The amount of movement is inversely proportional to the weight - a lighter wheel which readily moves in response to road bumps will have more grip when tracking over an imperfect road. For this reason, lighter wheels are often sought for high-performance applications. In contrast, a heavier wheel which moves less will not absorb as much vibration; the irregularities of the road surface will transfer to the cabin through the geometry of the suspension and hence ride quality is deteriorated.
Pneumatic or elastic tires help by providing some springing for most of the (otherwise) unsprung mass, but the damping that can be included in the tires is limited by considerations of fuel economy and overheating.


Anyway, in theory, your heavier car tire is hindering your motorcycle's overall performance, including your fuel consumption.

 

[monstrddg]

What was your milage before the changes?


Im currently running a BFG g-Force T/A 225/45/17. My milage has been in the 30's for years and thats where its been since August when I installed it. 33-38 MPG.


While I agree with Shawnzilla to an extent, I think my wrist has much more to do with my milage than my sprung and unsprung weight.

This is the tire before I used my driveway to create a more rounded profile. Before anyone asks....No it wont stand up without the kickstand!

 

[dmonty]

This is not the 1st time I have heard of someone using Car tires on a MC. It's done by a good number of touring bike owners where I live. This is however, the 1st time I have heard of a tire causing poor milage. I'm thinking the issue is to be found elsewhere.

 

[dmonty]

So... does it stan................

Before anyone asks....No it wont stand up without the kickstand!

.............. doh!!!

 

[BOSSMAN2677]

Any pix with it on the bike?? Down here in Florida, we dont have twisties. That tire looks like it would last forever.

 

[mdfdwarrior]

I recently read somewhere a little known fact that on a motorcycle tire your contact patch when leaned over is relatively larger than when you are upright. I can see this being the opposite when you put a car tire on it.....

 

[monstrddg]

I read that as well however I don’t feel I have any less traction than I did with a bike tire and the group I ride with will tell you I’m no less aggressive in the corners. This is the stickiest tire Ive ever run on especially when its been warmed up a bit. I tapered the edges a bit by putting a smiley inthe driveway and it gave the front brakes a bigger workout than a bike tire ever did in the process.

You can see the remains of my lastrear tire if you look closeat my tail light


http://mcdarksiders.forumotion.com/yamaha-f9/2007-yamaha-warrior-1700-t1543.htm

 

[07midnite]

I read that as well however I don’t feel I have any less traction than I did with a bike tire and the group I ride with will tell you I’m no less aggressive in the corners. This is the stickiest tire Ive ever run on especially when its been warmed up a bit. I tapered the edges a bit by putting a smiley inthe driveway and it gave the front brakes a bigger workout than a bike tire ever did in the process.

You can see the remains of my lastrear tire if you look closeat my tail light


http://mcdarksiders.forumotion.com/yamaha-f9/2007-yamaha-warrior-1700-t1543.htm

YIPES!!!!!!!!!!!!! That just ain't right. It looks like a Bourget that was the first "phat tire" bike.Rogerused a 230 car tire. I think I'll stick with a bike tire.


It SHOULD cause lower gas mileage. It makes more contact with the road than a regular motorcycle tire therefore you also would have more drag on the bike. You would have to use more gas because the tire would slow you down due to a much larger contact patch. Simple!

 

[arizonawarrior]

Notice how this comesaround in cycles every year or so

. Unsprung weight will cost you a little MPG but most of your loss of mileage is due to other factors, possibly even one too many

while calculating your mileage (lol). Friction in corners, and the sprung weight of having to crunch-lean that tire for every left or right turn, well that's another story. Still, you should look at your exhaust mod as a possible MPG culprit.


Now, about that car tire. The problem of loss of traction doesn't manifest itself during most normal riding. Its emergency riding that tells the tale. Just do us all a favor and think way ahead down the road. If you have a problem in the corners including a flat tire, you will go down. Some bikes are made for a squarish profile tire, the Warrior was built to apply a sport tire profile to the road. The car tire will be good going straight but you will loose the ability to push-left-go-left (or right of course) in an emergency maneuver to swerve at speed around an obstruction. Plus wet roads in corners won't leave you with any traction. Be careful!

 

[Scoper50]

I was at a biker bar about a month ago and there were a bunch of these bikes. I think hey were called Boss Hoss or something. They are bikes that have small block chevy V8's in them and they are frieken huge. There had to be at least a dozen of them there. And every one of them except for one was running a car tire. Those bikes are made for straight line riding obviously, but on occassion they do have to turn, and I noticed that all of the tires had excessve wear on the edges from cornering, which leads me ot believe that a car tire doesn't last very long on a bike.


As for the gas milage with the tire, It has to be from a larger contact patch and the extra weight of the tire. Extra contact vs a motorcycle tire causes more friction, which causes more drag. Plus you have more rolling mass. It doesn't surprise me at all that your fuel milage sucks.

 

[arizonawarrior]

Could you imagine a Boss Hoss with a sport bike tire? It wouldPOP the instantit came down off the jack!


Avon 200/50ZR17 = 853# max capacity


Avon 120/79ZR18 = 536# max capacity


Boss Hoss: GVWR 1,675# (ouch!)


Engine - TypeLiquid Cooled V-8
Horsepower - 355 @ 5250 rpm
Torque - 405 Ft.Lbs @ 3500 rpm
Block - Cast Iron 4 bolt main
Cylinders - Aluminum (58cc)
Valvetrain - 1.94"Int / 1.5"Exh.
Size - 350 c.i. (5700cc)
Compression - 10:1
Fuel Injection - Holly 680 cfm Throttle Body
Exhaust - 2.5" with dual mufflers
Transmission - 2-speed semi-auto w/rev.
Final Drive - Belt, Gates- Polychain


Dimensions
Overall Length 106"
Wheel Base 80.0"
Seat Height 28.0"
Rake 33.0 degrees
Grd. Dlearance 4.5"
Frame Width 28.0"
GVWR 1675 lbs. <-------------------
Dry Weight 1110 lbs.


Tires/Wheels
Front 130/90-16, 3.50"x16.0"
Rear 230/60, 7.0"x15.0"


Suspension (Adj. Preload)
Front 63mm inverted forks, 3.5" travel
Rear Dual 13.0" coilover shocks


Brakes
Front Dual four-piston calipers, 12.6" floating disc
Rear Single four-piston caliper, 12.6" floating disk


Fuel
Tank 8.5 gal.
Reserve n/a
High/Low MPG 25/20

 

[Mustfire]

I never ride in the rain, unless I just get caught unexpectedly. As far as manueverability, I found a large parking lot over the weekend and did some emergency swerves to test the tire differences. In a quick swerve, the bike did everything I asked it to do. I tried every kind of manuever I could thnk of as below:


High speed stop using rear brake only - no surprise here, it's like throwing out an anchor!


Hard turn, hard rear brake - controllable slide, it does want to stand up at the end of the slide, counter-steering corrects easily


Easy lane changes and course corrections - no change noted


Roadspeed curves - slight hesitation on initial turn-in.


High speed slalom - nothing that decreased confidence


Straight line traction - fantastic


If I lived in the mountains I might be of a different opinion, but here in the flat-lands, this tire works well. This was a financial desision, I figured out that it was costing me $.10 a mile in rear tires!

 

[Mustfire]

Before I was getting about 110 miles before the fuel light came on. If I got gas within 3 or 4 miles, it would take about 2.6 gallons.That works out to about to 42 mpg. Now its closer to 30 mpg.

 

[Dice]

Well, you could always do what us hypermilers do on our hybrids, and pump your air pressure up to 50 lbs, this will decrease the rolling Resistance, giving you better millage. On my hybrid it will gain me 5-10% increase in mileage. Do know if I don't go with the right tire on my Insight, I'll loose about 5mpg. Also will take about a 3mpg hit till the tires are broke in.





Don't Know how it was costing you $.10 a mile in rear tires unless you were replacing them every 1500-2000 miles. That statement makes know sense to me.

 

[Judge2008]

He said it cost him .10 a mile not $10.

 

[the_CADFather]

One of the things that I've noticed running on the darkside is that I tend to accellerate a lot faster and more often, thus reducing my fuel mileage. I've been on the darkside since April of this year, actually just a week before WFIII I put the tire on. It is a Toyo Proxxes T1R in 245/50R16 and grips like SHlT to a blanket, it has only broken traction on me one time and that was this past weekend while decellerating for a corner while braking and down shifting the rear chirped a little. Yeah I ride like a granny in the corners but that is more because of my crash than the bike's handling, basically I'm scared shitless, but I am getting better. I've ridden in the rain with my tire and it has never offered to step out even while leaning. As far as contact patch goes, if more of your tire is off the pavement than there is on it, you need to lower your pressure. Normally I run 29 - 31 PSI in my rear tire on the Rocket, and that seems to feel the best for me on that bike, although on the Blood Mtn trip that we took this past weekend I had it at 42 just to feel the difference.



Watch some of this guys footage on youtube, yep that is a supercharged Rocket on the Darkside, I've ridden with this guy, he has no problems keeping up with sport bikes on this thing. Search for more of his videos if you don't believe me "RiderRocketMan"

http://www.youtube.com/watch?v=twWOL2ceP4s

 

[arizonawarrior]

When I read that I did the math too. For me its about 6,000 miles and about $300 for a rear AV56 with freight mount and balance, injust round numbers. That's a nickle a mile for one rear tire and its still an eye-opener. Doing the same math for the big top-end 50k tires on our truck its just a under penny a mile mounted and balancedfor all 4 tires, not just one tire. This is aninteresting way to look attire cost. Its not enough to get me into a car tire on my Warrior, but for other bikes who knows what the future holds, maybe some 'crossover' tire will come along.

Don't Know how it was costing you $.10 a mile in rear tires unless you were replacing them every 1500-2000 miles. That statement makes know sense to me.

 

[INJEKTER]

When I read that I did the math too. For me its about 6,000 miles and about $300 for a rear AV56 with freight mount and balance, injust round numbers. That's a nickle a mile for one rear tire and its still an eye-opener. Doing the same math for the big top-end 50k tires on our truck its just a under penny a mile mounted and balancedfor all 4 tires, not just one tire. This is aninteresting way to look attire cost. Its not enough to get me into a car tire on my Warrior, but for other bikes who knows what the future holds, maybe some 'crossover' tire will come along.

Don't Know how it was costing you $.10 a mile in rear tires unless you were replacing them every 1500-2000 miles. That statement makes know sense to me.

try a "z" rated tire on your truck, I'm sure you will find the cost goes up. the only reasonable comparison if we are talking cost per mile is tires of the same durometer.

 

[Mustfire]

Well, with mounting and balancing, my rear tire replacement cost would be right in the $200.00 range. And I was only getting about 2200 miles on a tire. I tried Continental, Metzler, Dunlop, and a Michelin. Not much difference in any of them. I kept the tire pressure right at 42 psi on all of them. I don't do burnouts, but I do like to take off hard. Someone mentioned that the gravel in the asphalt in my area, which is limestone fossilized sea shells is particularly abrasive. I don't know if that is true or not. So, not quite $.10 per mile but close enough!