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So...fuel economy...


VtwinStorm
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30 minutes ago, p6x said:

According to certain tire manufacturers, tire pressure and tire construction play a role in fuel consumption. I am yet to verify this on my motorbike. Maybe these statements are applicable to automobile tires.

 

 

My 2010 Chevy HHR gets ~31mpg highway with the tires inflated to 44psi. It doesn't change any, until you get down to about 35- then the mileage slips down to 28-29. It's possible that this is also an artifact of weather, since the only times my tires have been so low on pressure is in cold weather which is rare for me.
For both cars and bikes, I tend to the pressure that gives the greatest mileage rather than road feel. I've never had a street bike (that is, never ridden one so hard) on which the pressure had any effect on traction. 


Anecdotally, Metzeler gave a few of us 'cheater' tires at Daytona '96, after proving that Dunlop was using F1 compounds in DOT molds for their contracted riders. 
On a 65hp, 450lb H-D 883, there was no physical way to slip those tires; the engineers had us all the way down to 17psi to get them up to the rubber temps they wanted. Simply amazing. And probably not as good as the store-bought tires we all use today. 

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When I commute, almost all freeway, I'm averaging 33/34 mpg running mostly between 80-95 mph when the traffic allows, with some slogs between 35-50 mph, on Road 5's at 35 p.s.i. front and rear. My Ducati DS1100 bike gets around 38/40 mpg in the same conditions.

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5 hours ago, Pressureangle said:

Until you reach the margin of adhesion, the age of a tire doesn't make a difference in handling. But I've found that Italian bikes- 2 Tontis, the Sport-i, and a '74 Aermacchi 350- are all exquisitely sensitive to tire profiles. I ran 30psi in the front Bridgestone T30 because it had a nebulous, imprecise feel in hard cornering and I wanted more rubber on the road to maximize traction. (it never slipped even once in it's life) The Pirellis I replaced them with had much sharper cornering, but felt drifty on fast straight bits where the Bridgestones were boxcar-stable. I did notice with the Pirellis at the Spine Raid (Tail of the Dragon) that higher pressure, 38psi made fast corner dumping and transitions easier and didn't affect traction at any speed I ride. 
Also, any new tire has a perfect profile so replacing a tire with any visible wear will make handling changes you can feel.
There is some ethereal feel to brand new rubber that defies description, something you sense but can't isolate. Maybe just in the head. 

Well if the Tonti spine frame is sensitive to tire profiles, then which profile would suit it best? is there a thread on this? I mean, other than which tire brand and model do your recommend?

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14 hours ago, Pressureangle said:

Until you reach the margin of adhesion, the age of a tire doesn't make a difference in handling. But I've found that Italian bikes- 2 Tontis, the Sport-i, and a '74 Aermacchi 350- are all exquisitely sensitive to tire profiles. I ran 30psi in the front Bridgestone T30 because it had a nebulous, imprecise feel in hard cornering and I wanted more rubber on the road to maximize traction. (it never slipped even once in it's life) The Pirellis I replaced them with had much sharper cornering, but felt drifty on fast straight bits where the Bridgestones were boxcar-stable. I did notice with the Pirellis at the Spine Raid (Tail of the Dragon) that higher pressure, 38psi made fast corner dumping and transitions easier and didn't affect traction at any speed I ride. 
Also, any new tire has a perfect profile so replacing a tire with any visible wear will make handling changes you can feel.
There is some ethereal feel to brand new rubber that defies description, something you sense but can't isolate. Maybe just in the head. 

It's not only the tread that wears and degrades but the carcase as well. New tyres feel and steer nicely because the carcase isn't fatigued and degraded through millions of flex cycles and is it's true shape and stiffness.

Ciao 

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7 hours ago, Lucky Phil said:

It's not only the tread that wears and degrades but the carcase as well. New tyres feel and steer nicely because the carcase isn't fatigued and degraded through millions of flex cycles and is it's true shape and stiffness.

Ciao 

While that's probably true, it can't happen without changing the profile at the same time. The definitive answer will never be known because you can't buy identical tires ten years apart; and if you could, I defy anyone to tell the difference while street riding. 

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15 hours ago, p6x said:

Well if the Tonti spine frame is sensitive to tire profiles, then which profile would suit it best? is there a thread on this? I mean, other than which tire brand and model do your recommend?

When my LM1000 came to me it had the 16" front wheel and was shod with Metzelers (15 years ago, and the tires weren't new) The front end felt totally untrustworthy. After reading a lot of anecdotes, I swapped on a 18" LM3 wheel, with new Metzelers. The front then was extremely stable, but heavy and slow. I ran through 3 sets of tires subsequently, Metzeler x2 and most liked Michelin Pilots. But where it all went right, was while restoring it I put the 16" front back on, added longer rear shocks, dropped the forks in the trees 1/2" and it turned magical wearing Pirelli Road Demons. The Mille GT is wearing some Shinkos, or other no-name tires; they're old, a bit scary looking but not worn. They are very neutral handlers on that bike, with only the slightest tip-in in turns. 
I do recall on the LM that when the rear center wore, it tended to drift on fast straight roads (which are all I have at home)
I always tend to 'sticky' tires, because I imagine I'll go ride some nice roads far more than I actually have opportunity. 

I think the Tonti is less affected by the profile than the geometry- 'feeling the difference' is not the same big change as setting the geometry correctly. But you *can* feel the difference, where I really never noticed on the Asian bikes I had. The Sport-i is far more sensitive to tire profile than the Tonti, which is a function of tire width probably.

FWIW, the Mille GT will get Michelin Pilots if they're still available when the time comes.

*the above statements are not paid endorsements, nor are the opinions expressed valid beyond the skull of the author*

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I had pretty crappy fuel economy till i discovered a nasty crack in my mistral crossover.  It was right next to the lambda sensor too.

Actually i’ve only just last week had it repair welded and popped it back on the bike.  

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On 4/22/2022 at 10:21 AM, Pressureangle said:

There is some ethereal feel to brand new rubber that defies description, something you sense but can't isolate. Maybe just in the head. 

 So much of motorcycling impresses me as ethereal.

"In the head?" Unquestionably, motorcycling is a heady experience. And an emotional one. These aspects certainly can cloud our methods and technical impressions.

We are not the first to allow the heart and feel and head to cloud the technical matters . . .

"A skittish motor-bike with a touch of blood in it is better than all the riding animals on earth, because of its logical extension of our faculties, and the hint, the provocation, to excess conferred by its honeyed untiring smoothness. Because Boa loves me, he gives me five more miles of speed than a stranger would get from him." – T. E. Lawrence

telcrop1.jpg

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Here's a recap of using Ethanol free fuel from Buc-ee's.

Usage from April 18th was mixed city and highway.

I refilled with Ethanol Less at Buc-ee's once more yesterday. I still have not noticed any blatant difference between Ethanol and Ethanol free. However, I don't think I was running on pure gas just yet. I have not checked what is the density difference of both fuel. They probably mix and dilute, not separate.

IMG_0406

 

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For sure adding non-ethanol fuel into a tank that is already half full of ethanol fuel is going to result in a tank of fuel with half the ethanol in it the ethanol fuel had. The two fuels are 100% mixable.

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  • 4 weeks later...

I reverted to using typical gas ethanol baptized. I don't want to specifically seek Ethanol free gas station.

42 mpg is a mixed city highway.

44.5 mpg is highway 59 to Lufkin and back, max rpm 4500. Conservative riding, no hard acceleration.

IMG_0467

 

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  • 3 weeks later...

More fun fuel usage math:

My office commute is 18 miles (round trip). The Toyota 4Runner (LandBruiser) gets about 1/2 the fuel "economy" as mySport (17.6 vs 36.5 USmpg), yet the round trip commute to&from the office is more like 43 miles on mySport (more than double the straight-shot distance, but takes in some lovely hollows, creek roads, and ridge climbs).

On top of that the fuel cost for the Sport's *premium* versus the 4R "regular" is about a US dollar more per gallon.

So, today, taking the (fun) long way to the office on the (fun) Sport cost me an extra $1.96 over scowling my way down the highway in the LandBruiser .

I showed up, and came home, a happier man. Where else can you get that for two bucks?

 

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  • 1 month later...

Took the 'Sport out the past 2 days, about 120 miles each day. Hot and sunny, in the 90s. First day was all 35-55mph, leisurely tooling without a lot of stops or traffic. I was very surprised to find on the fill-up the next morning it returned something over 50mpg- I did note that the fuel warning lamp came on at 102 miles. It has always come on at about half, ridiculously soon, so I noticed the distance. The second day, same weather but mostly 50-65mph, light traffic and a little town. My fuel lamp didn't come on until 120 miles of 127. Next fill I'll report the exact mileage. 
The notes here are that in ~15k miles the best mileage I've ever seen before is about 45, and that was also in very hot weather with steady open 55-70mph roads. 
I haven't done anything at all to the fuel system, nor changed the spark or fuel maps from previous rides. Unfortunately I did make more than one change since at once so I can't be specific as to cause. I installed the Caruso cam gears, and I will attribute the majority of the increase in mpg to them as the bike runs so much better at all speeds that it proves better efficiency. It has brand new Dunlop SS Road IVs at sidewall pressure. I changed the trans and bevel lubricant to Chevron Delo ESI 85-140. The last bit is worth watching, as the transmission seems quieter than with the RedLine shockproof although I changed the location of my camera microphone which makes objective measurement impossible. We'll do a temperature check at the Spine Raid to see if there is a meaningful reduction from other oils.

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So the exact mileage for the previous post- noting that I never fill all the way to the vent, so a little ~. 44.8mpg. Today's ride of 150 miles, 45-65mph with light traffic got the fuel lamp right on 121 miles again, so I'll assume it's right in the low-to-mid 40's as before. What I see here compared to before the Caruso gears is a big improvement in mileage around town, low mph/low speed, and consistently as good as ever before- which was not consistent. I'll eventually be testing whether I can cut fuel at these cruising speeds. 
Today's food for thought; my roomie's Enfield Himalayan, just across 2k miles today, quit twice. Both times while hot and stopped at lights in town traffic. The RE's EVAP system is pointed to in anecdotes elsewhere. The second time, I pulled over and shut mine off. When I got her down the road, mine backfired and blew the RH throttle body off the manifold. That's never happened before (a backfire) and I'm blaming both bikes' issues on the increasing crap factor of the sewage they sell out of the gas pumps. Meh. 

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