Fuel econamy

[Rookiespyder]

Hello all, a friend of mine just recently changed his rear kenda tire out for a car tire General Altimax RT 43 215/60r15. He is finding that he does not get as good fuel mileage as his Kenda. Could this be possible or is he not adding his numbers properly. Oh ya he has a 2016 RTL

 

[BLUEKNIGHT911]

MPG's

Hello all, a friend of mine just recently changed his rear kenda tire out for a car tire General Altimax RT 43 215/60r15. He is finding that he does not get as good fuel mileage as his Kenda. Could this be possible or is he not adding his numbers properly. Oh ya he has a 2016 RTL

If your friend was riding that Kenda with the recommended 30 psi +/- ..... His tire was very HARD .... a hard tire has less rolling resistance and will give better MPG's ........... However it will also not have the traction that the General has if the psi is lower ...Which it SHOULD be ..... so what psi was the General set at ???? ...the more I know the more accurate I can be ..... Mike :thumbup:

 

[2dogs]

Tell your friend to GPS check his speed and distance and he should with in a 1 MPH with that tire. He could have been logging his mileage with the Kenda which had a 4 MPH error.

 

[Peter Aawen]

The OE Spec Kenda was almost certainly smaller in rolling dia & circumference than the General, so as 2dogs mentioned Rookie, your friends speedo AND odometer are now closer to accurate & nowhere as near optimistic as they were with Kendas!! The discrepancy is usually only a couple of %, but it can be as much as 10%, and it's not necessarily identical between vehicles of the same model from the same manufacturer, altho it is pretty much always the OE Spec tires that are small enough to make the readings optimistic! :shocked:

Btw, it's not just the traction improvements which Blueknight/Mike has mentioned that running a non-Kenda/non-OE Spec Car tire at the correct (lower) pressure for the load the Spyder places upon it will bring about; running the lower pressure in any other car tire that's more suitable for the lighter load of a Spyder will also increase the tires potential tread life, improve the ride & handling, reduce the tires susceptibility to damage from road debris, and until you go significantly too low (which is gonna be pretty low under a lightweight Spyder!) you'll also minimise the risk of tire delamination..... but be aware that there is a 'sweet range' in there where going outside it (either up or down) can bring some issues; altho as said, it's gonna be pretty low for a tire capable of carrying a car that's a fair whack heavier than a Spyder, but it's not too much higher than the recommended mid/high teens to low/mid 20's mentioned elsewhere as being close to 'right' for most normal car tires, under a Spyder, especially those running under the rear.

 

[Bob Denman]

Peter is on the trail... :thumbup:
The General is taller, so it "slows down" the speedometer by a little bit.
(The actual percentage can be figured out...)
Since the bike is registering fewer miles travelled per fill-up: the mileage will seem to drop...


EDIT: I just ran the Math...
ON PAPER: there is a 5.47% increase in tire circumference. The Speedometer (and Odometer) will be slowed down by that amount.
If (on paper): he's travelling 5.47% fewer miles per tankful; that's how much his fuel mileage should drop.
If he is seeing a change in his fuel mileage that is different than that: we have other factors coming into play...

 

[JayBros]

A cursory look at the mpg results from the last long trip I took with a Kenda rear tire, 5,347 miles, and two trips with my General Altimax, 6,343 total, tells me it would be a waste of time to try to compute a difference in mpg between the two tires. There are just too many variables that were different on the three trips. The one thing I did notice was that on my trip to the D3WR, which included a mix of interstate travel and US/State/Local roads, my mpg for the trip, 4,262 miles was 36.2 which just happens to be the mpg I have achieved since Day 1 on the bike. The big difference, of course, is the General looks like it's been barely ridden while the Kenda would have been well on its way to half bald.

 

[Easy Rider]

I think your friend needs to ride more and worry less. :thumbup:

 

[ARtraveler]

The subject comes up from time to time. Many, many variables involved. Changing tire sizes or brands adds more possibilities to the mix.

The guys who are into the math and specs are definitely on the right trail.

Bottom line, (average (and that's a whole new subject) reported) by most--

998's--29 to 31 mpg. 1330's--39 to 41 mpg. WARNING, WARNING, WARNING--YOUR MILEAGE MAY VARY.

Advice given above about not worrying to much about mileage is right on. Most of us bought them for the fun, and not the economy.

There are many, many mileage and oil threads. Fun to jump into from time to time. The regulars may complain, but good information for "newer" members. :yes:

 

[RudyB]

Re fuel milege

Hello all, a friend of mine just recently changed his rear kenda tire out for a car tire General Altimax RT 43 215/60r15. He is finding that he does not get as good fuel mileage as his Kenda. Could this be possible or is he not adding his numbers properly. Oh ya he has a 2016 RTL

What do you call good fuel mileage I got the General Altimax RT43 I checked my fuel mileage 37.5 on an Imperial gal