joemud Posted June 10, 2010 Share Posted June 10, 2010 Yes more questions about 31 inch tires. I just cant help but think that 3000 rpms is a bit high for 60 mph. I know that going to a bigger tire like a 31-10.5 would lower the rpms but I wonder if it helps with highway milage at all or if anyone knows a way to get better milage. Link to comment Share on other sites More sharing options...
MY1PATH Posted June 10, 2010 Share Posted June 10, 2010 keep this in mind, -the your engine in stock form is capable of reving to 7k if well maintianed(limter is set arround 6) so using half the rpm aint so bad -the O2 sensor takes greater contorl of your fuel ratio after 2800rpm and povides a much more acurate mixture anyway(if everthings working correct) -being so under powered crusing @ low rpms (where there is less torqe) can use just as much or more gass because the throttle is open wider -20 lbs rotating weight is like ~180 lbs dead weight so if your new tires are 10lbs more each thats like carrying 360lbs everywhere you go theoretically larger diameter, less revoulutions etc... but that larger diameter comse @ the cost of wieght and think about it as a longer lever for the pavment and wind drag to pull against the turning axle. now you can re-gear to overcome these differances but you just wind up in the same place in the end. 31's are nice but I'm gettin some 235/75r15's for my next road trip. I have no concerns about high rpm I ran it @ 4k rpm(I won't say how fast) for over 4 hrs on my last road trip (31's) and it avg'd ~18 MPG for that span. Link to comment Share on other sites More sharing options...
OldSlowReliable Posted June 10, 2010 Share Posted June 10, 2010 you also have to remember that the engine will be working harder to keep the larger tires moving....so if your using an auto it may not shift the same so your engine may be screaming at 4-5k rpms before it tries to lower them... if I fiddle with mine just right on 33's, I can sit @ 65mph (55 on my speedo)at anywhere from 1500 to 2500 rpms (depending on hills and such) on cruise, and I can barely hear the engine! I can't say I've noticed a mileage INCREASE by any means, again, the engine has to work harder due to extra spinning weight... However, if you have/get 4.6 gears, and since 31's were a stock option, you would probably be much happier. Link to comment Share on other sites More sharing options...
joemud Posted June 10, 2010 Author Share Posted June 10, 2010 OK so the speed limit is 70 on the highway I drive to work on and I have a 5 speed so even with the bigger tires I can still keep the rpms up so would it be safe to say I can at least keep the same milage. Link to comment Share on other sites More sharing options...
OldSlowReliable Posted June 10, 2010 Share Posted June 10, 2010 OK so the speed limit is 70 on the highway I drive to work on and I have a 5 speed so even with the bigger tires I can still keep the rpms up so would it be safe to say I can at least keep the same milage. I'll put it this way. Its safe to say you probably won't GAIN mpg...lol, logic says you should loose mpg with the larger size, but I don't think you'll even notice! Link to comment Share on other sites More sharing options...
Tungsten Posted June 10, 2010 Share Posted June 10, 2010 (edited) i cruise at 3000 rpm doing 80 mph without any problems i even buried the needle past 100 mph in some cases and the engine speed was more than 4000 rpm nothing exploded here so you should be fine i have 31 inch tires and get 19.5 mpg Edited June 10, 2010 by Tungsten Link to comment Share on other sites More sharing options...
MY1PATH Posted June 10, 2010 Share Posted June 10, 2010 I often cruise 60ish in 4th instead of 5th just becuase it negotiates traffic better that way, when things speed up enough to keep 5th above 3k rpm then I take 5th more willingly If I really have to I can drop 3rd and will ride that gear up to about 70. It does give a good hard pull compared to 4th and 5th. Link to comment Share on other sites More sharing options...
silverton Posted June 10, 2010 Share Posted June 10, 2010 With bigger tires, you odometer will be off, so when you calculate your mileage, you'll show lower numbers. I notice with my truck, I get about the same with 31x10.5 as I did with 235/75's Link to comment Share on other sites More sharing options...
Tungsten Posted June 10, 2010 Share Posted June 10, 2010 btw my odometer doesn't work lol i track my mileage with a gps Link to comment Share on other sites More sharing options...
Precise1 Posted June 10, 2010 Share Posted June 10, 2010 For a nice balance of mileage and power, install a cone air filter, cat back exhaust system and run 31" tires. My 95 manual tranny Pathy got 20-22mpg on the highway @65-70 mph Link to comment Share on other sites More sharing options...
GrimGreg Posted June 10, 2010 Share Posted June 10, 2010 For a nice balance of mileage and power, install a cone air filter, cat back exhaust system and run 31" tires. My 95 manual tranny Pathy got 20-22mpg on the highway @65-70 mph Same here but with an auto (and MTs). Link to comment Share on other sites More sharing options...
Precise1 Posted June 10, 2010 Share Posted June 10, 2010 I have no idea how you get 20+mpg out of an auto with MT tires... B Link to comment Share on other sites More sharing options...
adamzan Posted June 10, 2010 Share Posted June 10, 2010 I get 20 mpg out of an auto with AT's. I found that with the legos and 31's i get better mileage on the highway than the 235/75/15s and the steel rims. Link to comment Share on other sites More sharing options...
Tungsten Posted June 11, 2010 Share Posted June 11, 2010 legos are lighter than steelies Link to comment Share on other sites More sharing options...
GrimGreg Posted June 11, 2010 Share Posted June 11, 2010 (edited) I have no idea how you get 20+mpg out of an auto with MT tires... B Best I got was 24mpg, between here and Washington D.C., it was right after I changed plugs and swapped to a cone filter. (I even had my roof rack on it at the time!) You have to figure, once you get to cruising speed and the TC locks in, it's a very smooth power transition. Edited June 11, 2010 by GrimGreg Link to comment Share on other sites More sharing options...
joemud Posted June 11, 2010 Author Share Posted June 11, 2010 Wow thanks for all the gret info guys, I just got my tires today and will be doing a full tuneup this weakend. I will look into the cone filter and since I am looking for better milage, and of corse its byproduct, I guess the exhaust will be my next project. Does anyone know how to get the speedo and odometer to work right with the bigger tires? Link to comment Share on other sites More sharing options...
silverton Posted June 11, 2010 Share Posted June 11, 2010 I'm getting about 20mpg with mixed city and highway driving with an AT and 31s. Right now I'm running some stock Toyota steelies. Link to comment Share on other sites More sharing options...
tmoore4512 Posted June 12, 2010 Share Posted June 12, 2010 Gotta disagree...the lego's are heavy as crap compared to my Frontier steelies... I am waiting on my wheels to get here, then going to put some 33's on there...then cry when my mpg's fall through the floor...but she will be the tallest pathfinder in my area...lol Anyone lookin for some legos? LOL I have four ready to go. Link to comment Share on other sites More sharing options...
Precise1 Posted June 13, 2010 Share Posted June 13, 2010 Wow thanks for all the gret info guys, I just got my tires today and will be doing a full tuneup this weakend. I will look into the cone filter and since I am looking for better milage, and of corse its byproduct, I guess the exhaust will be my next project. Does anyone know how to get the speedo and odometer to work right with the bigger tires? You replace the gear on the sender unit IIRC. Not hard and someone did it recently and did a write up. Let me know if you cant find it with search. B Link to comment Share on other sites More sharing options...
joemud Posted June 13, 2010 Author Share Posted June 13, 2010 You replace the gear on the sender unit IIRC. Not hard and someone did it recently and did a write up. Let me know if you cant find it with search. B Thanks precise1 but I cant get the search tool to work. Im sure I can figure it out though I assume your just talking about replacing the gaer in the peice on the tranny. Im also guessing I would have to get that from a dealer. I got my tires mounted yeasterday and Im going on a good road trip this weak so I will figure out my milage and let yall know friday when I get back. milage aside I love the tires and no rubbing whatsoever. BFG 31-10.5 at Link to comment Share on other sites More sharing options...
Daves94XE Posted June 16, 2010 Share Posted June 16, 2010 for you guys with an auto, going to 31's from 235's did you notice a change in low end? sometimes i pull a small boat with mine and don't want to mess with my low end too much. Link to comment Share on other sites More sharing options...
GrimGreg Posted June 16, 2010 Share Posted June 16, 2010 for you guys with an auto, going to 31's from 235's did you notice a change in low end? sometimes i pull a small boat with mine and don't want to mess with my low end too much. Not enough of a difference that I noticed. Link to comment Share on other sites More sharing options...
ANDY Posted June 16, 2010 Share Posted June 16, 2010 i went from 31x10.5 to 33x10.5 on my yota and i noticed it a lot so gas mileage aint nothing im used to 15 mpg but i kinda want to get rid of 31x15 on my pathy and maybe going smaller but not sure Link to comment Share on other sites More sharing options...
tmoore4512 Posted June 17, 2010 Share Posted June 17, 2010 Just went to 33's today...honestly...it rides like a freakin hay wagon. I wish I would have gotten A/T tires instead of the M/T's. Looks good, but I can clearly feel a power loss...guess it is time to do gears...Or go back to 31's. Dont know about mileage yet...certainly cant help... Link to comment Share on other sites More sharing options...
joemud Posted June 22, 2010 Author Share Posted June 22, 2010 OK so I drove right at 200 miles going by the mile markers on the interstate and the milage is exactly the same as it was before the tire swap. However before leaving I changed the oil and checked the air filter and the thing ran great on the way down but when I got to the first light off the interstate the motor died. Started right back up but idled realy low. The next time it died I did some checking and it turns out when I checked the air filter I must have knocked the plug loose for the air flow sensor. Not to sure what difference that would make for milage but as long as it dosnt get worse milage im happy as can be with the bigger tires. Link to comment Share on other sites More sharing options...
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