Raymond Posted October 9, 2023 Share Posted October 9, 2023 2 hours ago, saflyer said: I sent a request for info to Sumitomo via their website. Evidently they forwarded it to a U.S. distributor, TBC Corp. who responded as follows: Mr. Fogle, We are in receipt of your inquiry. We are a wholesale tire distributor of multiple brands of tires, not a tire manufacturer, and we create dedicated websites for each of the brands of tires we distribute; we distribute the Sumitomo brand of tires in North America. Most tire manufacturers only provide us with the maximum psi and maximum load a particular tire can hold, as they cannot foresee where the tire will be installed on; however, Sumitomo has provided a load inflation table which you can find by clicking on the link below: https://tbc.scene7.com/is/content/TBCCorporation/TBC%20Brands/Commercial/Sumitomo%20MRT/Catalog/2022/Medium-Truck-Technical-Data_0322.pdf This information can be found if you return to the website, go to the DEALER RESOURCES section, and under the 2023 MEDIUM TRUCK TIRES catalog, clicking on the third link that reads Medium Truck Technical Data; the information you are looking for is on page 4 of this document. Thank you, Olga Fraga Consumer Relations Tel. (800) 238-6469 Fax. (800) 467-4638 Email: ofraga@tbccorp.com It is obvious there is significant experience contributing information on tires on this thread, so relative to mpg I am interested in any advice on a related matter. I regularly replace my steer tires every 5-years with Michelin Energy X tires, which are considered aggressive tires; I do this primarily because I experience noticeable wear on the edges (steer) after a few years. My suspension is checked annually at JoSams and Barry says “…that’s how these tires wear”. So, in talking to the tire folks at Love’s Truck Center they suggested I use the Michelin XLEZ model on the steer axle which has defined shoulders and are more resistant to wear on the edges. I am wondering if there is any experience out there with the MICHELIN XLEZ. I do not want to diminish my current mpg or handling. Link to comment Share on other sites More sharing options...
Tom Cherry Posted October 10, 2023 Share Posted October 10, 2023 3 hours ago, saflyer said: I sent a request for info to Sumitomo via their website. Evidently they forwarded it to a U.S. distributor, TBC Corp. who responded as follows: Mr. Fogle, We are in receipt of your inquiry. We are a wholesale tire distributor of multiple brands of tires, not a tire manufacturer, and we create dedicated websites for each of the brands of tires we distribute; we distribute the Sumitomo brand of tires in North America. Most tire manufacturers only provide us with the maximum psi and maximum load a particular tire can hold, as they cannot foresee where the tire will be installed on; however, Sumitomo has provided a load inflation table which you can find by clicking on the link below: https://tbc.scene7.com/is/content/TBCCorporation/TBC%20Brands/Commercial/Sumitomo%20MRT/Catalog/2022/Medium-Truck-Technical-Data_0322.pdf This information can be found if you return to the website, go to the DEALER RESOURCES section, and under the 2023 MEDIUM TRUCK TIRES catalog, clicking on the third link that reads Medium Truck Technical Data; the information you are looking for is on page 4 of this document. Thank you, Olga Fraga Consumer Relations Tel. (800) 238-6469 Fax. (800) 467-4638 Email: ofraga@tbccorp.com OK.....This gets confusing. First of all, the table above shows that the ST719 is a Load Range J (18 ply) tire. GO TO THE LAST PAGE or so and scroll down. That is what the spec sheet say on it. BUT, look at the "Secret" as I called it....inflation table says for the 275/70R22.5 ROW. It is a load range H or the Alpha after the Weight. SO, Sumitomo publishes a Load or Inflation table that lists ONLY the 275/70R22.5 in load range H...but does NOT have a row for the Load Range J....which is what the ST719 is. That is interesting. Perhaps Olga could explain this. BUT, curiosity is a horrible vice....so I put together an Excel file with the Published....or what comes from the commonly found table, the link that I posted and the screen shot. Then the SECRET that Olga sent you .... JUST TO COMPARE....here it is... OK....I had to COPY this from an EXCEL file and paste it here and the formatting went crazy. SO, I used THIS for illustration. My CONCLUSION. The Sumitomo tires, regardless of the load range...are DIFFERENT from the Original Goodyear 670 tires. That is TOTALLY weird...based on doing comparisons for many members over the years. The same size tire & Load Range in a Michelin, Goodyear, Toyo, and several different other brands were all in the SAME range or ballpark. BUT, your Somitomo's are "DIFFERENT"....so again, you rely on the Manufacturer....and NOT on what is posted on some random site. Bottom line....if it were ME, I would run 95 PSI in the FRONT....and 100 PSI in the rear. The additional 5 pounds should NOT cause any issues...but IF it does...then, from an interpolation standpoint....you could run probably 97 in the rear and be just fine....the front is OK at 95. BUT, I would NOT run 90 in the front....the Olga SECRET chart does NOT even list a value for 90 PSI....so run 95 up front....and 97 if you want the smoothest ride in the rear. That is WAY too precise...but we Engineers tend to be a little OCD... That's it. I think you are fine here...but as to the Fuel....I think you need more data. If it continues to be an issue....then talk to the folks. The Rev's per MILE would be a minor issue...but very minor. The tires are close to the same....unless the load range J ST719 looks like it is totally underinflated and looks like a "FLAT"...but, seriously....that is a physical impossibility. NOW....the lower the pressure...the LOWER the tire will be pumped up....and the wider the tread patch or surface contacting the road. That DOES provide more resistance. I could see the difference, maybe 0.1 MPG between towing a lighter H3 Hummer with fatter tires as compared to a heavier Yukon with somewhat "less aggressive tread". BUT that was based on a few years of data for each to compare. CERTAINLY not halving... That's it. Let us know when you have more data. OR you can have the engine scanned....to see if there are any codes....it would take a tremendous blockage of the air filter to reduce your mileage by half..... ST719 PSI 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 Publish Single NA NA NA NA 4920 5160 5400 5645 5880 6130 6355 ---- 7000 (H) Dual NA NA NA NA 4590 4815 5040 5270 5490 5720 5940 ---- 6395 (H) Secret Single NA NA NA NA NA NA 5400 5630 5850 6070 6290 6510 6730 --NA-- ---- 6940 (H) Dual NA NA NA NA NA NA 4980 5180 5390 5590 5800 6000 6200 --NA-- ---- 6395 (H) 56 minutes ago, Raymond said: It is obvious there is significant experience contributing information on tires on this thread, so relative to mpg I am interested in any advice on a related matter. I regularly replace my steer tires every 5-years with Michelin Energy X tires, which are considered aggressive tires; I do this primarily because I experience noticeable wear on the edges (steer) after a few years. My suspension is checked annually at JoSams and Barry says “…that’s how these tires wear”. So, in talking to the tire folks at Love’s Truck Center they suggested I use the Michelin XLEZ model on the steer axle which has defined shoulders and are more resistant to wear on the edges. I am wondering if there is any experience out there with the MICHELIN XLEZ. I do not want to diminish my current mpg or handling. Call Michelin. Ask their tire gurus or send them an Email.... Link to comment Share on other sites More sharing options...
saflyer Posted October 10, 2023 Author Share Posted October 10, 2023 13 hours ago, Tom Cherry said: OK.....This gets confusing. First of all, the table above shows that the ST719 is a Load Range J (18 ply) tire. GO TO THE LAST PAGE or so and scroll down. That is what the spec sheet say on it. BUT, look at the "Secret" as I called it....inflation table says for the 275/70R22.5 ROW. It is a load range H or the Alpha after the Weight. SO, Sumitomo publishes a Load or Inflation table that lists ONLY the 275/70R22.5 in load range H...but does NOT have a row for the Load Range J....which is what the ST719 is. That is interesting. Perhaps Olga could explain this. BUT, curiosity is a horrible vice....so I put together an Excel file with the Published....or what comes from the commonly found table, the link that I posted and the screen shot. Then the SECRET that Olga sent you .... JUST TO COMPARE....here it is... OK....I had to COPY this from an EXCEL file and paste it here and the formatting went crazy. SO, I used THIS for illustration. My CONCLUSION. The Sumitomo tires, regardless of the load range...are DIFFERENT from the Original Goodyear 670 tires. That is TOTALLY weird...based on doing comparisons for many members over the years. The same size tire & Load Range in a Michelin, Goodyear, Toyo, and several different other brands were all in the SAME range or ballpark. BUT, your Somitomo's are "DIFFERENT"....so again, you rely on the Manufacturer....and NOT on what is posted on some random site. Bottom line....if it were ME, I would run 95 PSI in the FRONT....and 100 PSI in the rear. The additional 5 pounds should NOT cause any issues...but IF it does...then, from an interpolation standpoint....you could run probably 97 in the rear and be just fine....the front is OK at 95. BUT, I would NOT run 90 in the front....the Olga SECRET chart does NOT even list a value for 90 PSI....so run 95 up front....and 97 if you want the smoothest ride in the rear. That is WAY too precise...but we Engineers tend to be a little OCD... That's it. I think you are fine here...but as to the Fuel....I think you need more data. If it continues to be an issue....then talk to the folks. The Rev's per MILE would be a minor issue...but very minor. The tires are close to the same....unless the load range J ST719 looks like it is totally underinflated and looks like a "FLAT"...but, seriously....that is a physical impossibility. NOW....the lower the pressure...the LOWER the tire will be pumped up....and the wider the tread patch or surface contacting the road. That DOES provide more resistance. I could see the difference, maybe 0.1 MPG between towing a lighter H3 Hummer with fatter tires as compared to a heavier Yukon with somewhat "less aggressive tread". BUT that was based on a few years of data for each to compare. CERTAINLY not halving... That's it. Let us know when you have more data. OR you can have the engine scanned....to see if there are any codes....it would take a tremendous blockage of the air filter to reduce your mileage by half..... ST719 PSI 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 Publish Single NA NA NA NA 4920 5160 5400 5645 5880 6130 6355 ---- 7000 (H) Dual NA NA NA NA 4590 4815 5040 5270 5490 5720 5940 ---- 6395 (H) Secret Single NA NA NA NA NA NA 5400 5630 5850 6070 6290 6510 6730 --NA-- ---- 6940 (H) Dual NA NA NA NA NA NA 4980 5180 5390 5590 5800 6000 6200 --NA-- ---- 6395 (H) Call Michelin. Ask their tire gurus or send them an Email.... Interesting side note about lower inflation. When I purchased this coach 12 years ago Ibelieve it had Michelins but not absolutely sure. Driving it home from Michigan I thought I had made a big mistake. It drove terribly. Wandered all over the road. I was constant turning the wheel left and right wearing myself out. I was driving 60-65 and when trucks passed it scared the begeebers out of me. Got it home and had the alignment checked. It was good. Then I looked up the inflation tables. The dealer had the tires at something over 120 psi, exactly how much I don’t recall. The inflation tables were more like 95 rear and 100 or so steer. I was leary of lowering the pressure as I thought that could only worsen the drifting problem since the sidewalls would be less stiff. To my surprise that wasn’t the case. The new pressures improved the driving of the coach immensely. Still didn’t drive like a car but far better than before. I realize some of the improvement may have been muscle memory but I’m sure the inflation was a big part. To get better steering I switched from the Shephard steering box to a TRW one but didn’t notice any improvement with that. Link to comment Share on other sites More sharing options...
saflyer Posted October 14, 2023 Author Share Posted October 14, 2023 Re: previous post about lowered mileage with new tires. Just did a fill up with the new Sumitomo ST719s. The last one had 124 miles on the old tires so this one is more representative. My last fillip on the Michelins gave 7.6 mpg. The last six fillups gave an average of 6.8 mpg. This fill up was after driving 309.8 miles mostly at 65 mph. Fuel used was 69.651 so about 4.5 mpg! Ouch! My mileage dropped by fully 1/3! I filled at the same station and pump so the coach level the same on both fills. I did squeeze more fuel in the second time so that dropped my mileage. But even applying a huge fudge factor of 5 gallons the mileage is still less than 4.8 mpg. Next week I’ll take the motorhome to a shop to find out if there could be any drive train problem causing the change. Ed ‘05 HR Ambassador Link to comment Share on other sites More sharing options...
DavidL Posted October 14, 2023 Share Posted October 14, 2023 Because you are saying that you are trying to squeeze every drop into the tank, indicates you aren't calculating mileage correctly. You should be long term tracking how much fuel goes into the tank, independent on the capacity of the tank or fullness. Across time, the errors with each fill will normalize. If your calculations are indeed correct (after monitoring for several more fuel fills / documenting how many gallons across miles), and you are getting consistently low mileage, then you have a motor problem. If it's running well, then you probably aren't having motor problems. But no way is changing tires going to affect mileage to the degree you are saying. 2 Link to comment Share on other sites More sharing options...
saflyer Posted October 14, 2023 Author Share Posted October 14, 2023 (edited) 10 minutes ago, DavidL said: Because you are saying that you are trying to squeeze every drop into the tank, indicates you aren't calculating mileage correctly. You should be long term tracking how much fuel goes into the tank, independent on the capacity of the tank or fullness. Across time, the errors with each fill will normalize. If your calculations are indeed correct (after monitoring for several more fuel fills / documenting how many gallons across miles), and you are getting consistently low mileage, then you have a motor problem. If it's running well, then you probably aren't having motor problems. But no way is changing tires going to affect mileage to the degree you are saying. I fully understand the concept of calculating mileage. But two points. One, it was my first opportunity to update. Two, as I said it’s not likely I made a difference in filling of anywhere near 5 gallons but factoring that my mileage is still horrible. Edited October 14, 2023 by saflyer Link to comment Share on other sites More sharing options...
Ivan K Posted October 14, 2023 Share Posted October 14, 2023 If you changed tire size and use odometer for calculation, it would make some difference but not that significant. I would check hub temps, brake drag, assuming no ECM parm updates. 1 1 Link to comment Share on other sites More sharing options...
DavidL Posted October 14, 2023 Share Posted October 14, 2023 2 minutes ago, Ivan K said: If you changed tire size and use odometer for calculation, it would make some difference but not that significant. I would check hub temps, brake drag, assuming no ECM parm updates. Agreed, but if brake drag, the pads would have melted off by now. Even slight drag adds very significant heat across a mile. Time will tell. Thanx for the updates Saflyer. Link to comment Share on other sites More sharing options...
JDCrow Posted October 14, 2023 Share Posted October 14, 2023 32 minutes ago, Ivan K said: If you changed tire size and use odometer for calculation, it would make some difference but not that significant. I would check hub temps, brake drag, assuming no ECM parm updates. Yep 1 Link to comment Share on other sites More sharing options...
The Hales Posted October 14, 2023 Share Posted October 14, 2023 New Sumitomos 2 1/2 years ago. Replaced old Michelins. Have run about 10,000 miles. 97 psi all the way around. All in the Southeast. About 7 mpg. Rides a tad firmer. ‘04 Monaco Knight 34PDD. Happy especially with price point. 1 Link to comment Share on other sites More sharing options...
saflyer Posted October 14, 2023 Author Share Posted October 14, 2023 3 hours ago, Ivan K said: If you changed tire size and use odometer for calculation, it would make some difference but not that significant. I would check hub temps, brake drag, assuming no ECM parm updates. Same tire size. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted October 14, 2023 Share Posted October 14, 2023 4 hours ago, saflyer said: it’s not likely I made a difference in filling of anywhere near 5 gallons but factoring that my mileage is still horrible. If the pavement is tilted the wrong way and I tilt the coach the other way I can often add a lot more fuel. I have tilted my coach after it appeared full then added 30 gals. So I figure a difference of 5 gals would be pretty easy for me to make. IMHO Link to comment Share on other sites More sharing options...
Steven P Posted October 14, 2023 Share Posted October 14, 2023 I've been watching this w interest. Recently installed larger tires just on the front of my coach and did not notice any mileage differences. @saflyer, were you checking mileage leading up to the tire change? Or had you stopped watching mileage for some time, then restarted after the change? Any other work done on the coach before the mileage change? Have you talked to the people who did the work w your observations? 1 Link to comment Share on other sites More sharing options...
saflyer Posted October 14, 2023 Author Share Posted October 14, 2023 40 minutes ago, Steven P said: I've been watching this w interest. Recently installed larger tires just on the front of my coach and did not notice any mileage differences. @saflyer, were you checking mileage leading up to the tire change? Or had you stopped watching mileage for some time, then restarted after the change? Any other work done on the coach before the mileage change? Have you talked to the people who did the work w your observations? My start of this thread had my last fill-up on the Michelins give 7.6 mpg. Average for the last 6 fill-ups before the new tires was 6.8. 49 minutes ago, Ray Davis said: If the pavement is tilted the wrong way and I tilt the coach the other way I can often add a lot more fuel. I have tilted my coach after it appeared full then added 30 gals. So I figure a difference of 5 gals would be pretty easy for me to make. IMHO I made it a point to use the same fueling lane both times so the lean would be minimized as a factor. Even if I apply a 10 gallon difference that only gives 5.2 mpg a 23.5% reduction in mileage. 1 Link to comment Share on other sites More sharing options...
Martinvz Posted October 14, 2023 Share Posted October 14, 2023 This is both interesting and concerning. However, one question not asked so far is, what type of terrain are you currently in that could affect your current fuel consumption? Is it level or are there a lot of grade changes? Also do you have a lot of head and/or side wind to deal with? Link to comment Share on other sites More sharing options...
Steven P Posted October 14, 2023 Share Posted October 14, 2023 7 minutes ago, saflyer said: My start of this thread had my last fill-up on the Michelins give 7.6 mpg. Average for the last 6 fill-ups before the new tires was 6.8. Oops, I should have reread the post. Thanks for clarifying. Were there any other changes made around the time of the new tires? Bearings, brakes, etc.? Link to comment Share on other sites More sharing options...
saflyer Posted October 14, 2023 Author Share Posted October 14, 2023 14 minutes ago, Steven P said: Oops, I should have reread the post. Thanks for clarifying. Were there any other changes made around the time of the new tires? Bearings, brakes, etc.? That’s OK. No changes to anything I can think of including our travel weight. 17 minutes ago, Martinvz said: This is both interesting and concerning. However, one question not asked so far is, what type of terrain are you currently in that could affect your current fuel consumption? Is it level or are there a lot of grade changes? Also do you have a lot of head and/or side wind to deal with? Good question. The first fill-up with most miles on the new tires was mostly level across central Oklahoma and north central Texas with a slight tailwind. The second fill-up was over slightly hilly but mostly level north central Texas with a 15-25 mph quartering headwind for the second third of the miles. 1 Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted October 15, 2023 Share Posted October 15, 2023 Another aspect might be the fuel itself, the % of biodiesel may play a part. I have thought I experienced a decrease in power and MPG with some fuels. However, I doubt it would make as much difference as Ed ( op ) experienced. Link to comment Share on other sites More sharing options...
jacwjames Posted October 15, 2023 Share Posted October 15, 2023 I battled headwinds across Kansas last week, it was brutal, had to have the steering wheel point between 1 & 2 o'clock and my mileage dropped to 6 or less. That segment of my trip will definitely impact my mileage along with my climb over the rockies. Now it Utah and the grades are all over the place with miles and miles of rolling hills but then get into an area of grades. I probably won't average 7 mpg this trip. Link to comment Share on other sites More sharing options...
Solution saflyer Posted October 16, 2023 Author Solution Share Posted October 16, 2023 MODERATOR EDIT. Please do NOT start a NEW TOPIC with an "UPDATE". Continue to use the same topic. Thanks END OF EDIT Mea culpa time, maybe. After fueling yesterday I moved the coach a few feet to a spot where it tilted a little to the right. Got out to find fuel pouring out of the right hand side. I quickly opened the fueling door to find the tank cap off and hanging from its lanyard. In most cases I fuel on the left side almost always but I guess I fueled on the right side in June which was the last time before the new tires. Now this doesn’t necessarily explain all of the mileage loss but it does explain some, possibly. Confounding factors: (1) I found the right side of my toad covered in fuel after one but only one refueling. (2) I would think after the loss of a few gallons fuel would no longer come out the open fill line. I did check for leaks multiple times and found no evidence of any. I won’t have a chance to do another mileage test until our next trip in February. Will update then. Ed I thought I was wrong once but I was mistaken. 2 Link to comment Share on other sites More sharing options...
Tom Cherry Posted October 16, 2023 Share Posted October 16, 2023 44 minutes ago, saflyer said: Mea culpa time, maybe. After fueling yesterday I moved the coach a few feet to a spot where it tilted a little to the right. Got out to find fuel pouring out of the right hand side. I quickly opened the fueling door to find the tank cap off and hanging from its lanyard. In most cases I fuel on the left side almost always but I guess I fueled on the right side in June which was the last time before the new tires. Now this doesn’t necessarily explain all of the mileage loss but it does explain some, possibly. Confounding factors: (1) I found the right side of my toad covered in fuel after one but only one refueling. (2) I would think after the loss of a few gallons fuel would no longer come out the open fill line. I did check for leaks multiple times and found no evidence of any. I won’t have a chance to do another mileage test until our next trip in February. Will update then. Ed I thought I was wrong once but I was mistaken. Hate to admit it….but did that once. A trucker flagged me down. Bottom line, you were lucky. I had filled and had the habit (now broken) of tilting. Never again. Go back to basics, at least my basics and advice of others. Pull in. Level the MH….not precisely, but close. Fill until the auto pump shuts off. You, most likely can force in up to 5, maybe more, gallons. OR let it shut off….look at the level, and bring it up to a known “distance” (eyeballed) from the end or bottom of the neck or tube. Verify other fill cap in place. THEN….start MH and push the travel button, if you have that on your air bags. Let it air up and level. Then leave. If the fuel pad is really out of kilter, make sure you get it to where each side is “equidistant” or the same height as the pad. You don’t want one side totally raised or one corner…. That’s it…. It happens….LOL Link to comment Share on other sites More sharing options...
willbo777 Posted October 16, 2023 Share Posted October 16, 2023 I tilt almost every time. But I have air leveling, easy peasy and gets another 20 gallons or so. The only time I don't is if I am going to go into a campground directly after fueling. 1 Link to comment Share on other sites More sharing options...
jimc99999 Posted October 16, 2023 Share Posted October 16, 2023 On 10/14/2023 at 4:39 PM, saflyer said: Good question. The first fill-up with most miles on the new tires was mostly level across central Oklahoma and north central Texas with a slight tailwind. The second fill-up was over slightly hilly but mostly level north central Texas with a 15-25 mph quartering headwind for the second third of the miles. I've gone from 3 tanks at 8+ mpg (not much headwind) to a tank at 5.8 mpg (150-200 miles of 20+ mph quartering headwind) to 3 more tanks at 8+ mpg, on the same tires, on the same trip. I was also going somewhat slower into the headwind than on the other tanks because the wind was pretty tiring and I was at the West Texas part of a FL -> Tucson, AZ non-stop trip. That headwind will have a lot more effect than you think. 1 Link to comment Share on other sites More sharing options...
Tom Cherry Posted October 16, 2023 Share Posted October 16, 2023 24 minutes ago, willbo777 said: I tilt almost every time. But I have air leveling, easy peasy and gets another 20 gallons or so. The only time I don't is if I am going to go into a campground directly after fueling. So did I, UNTIL, I almost stressed the frame at an ugly stop. As LONG as you return to level….or travel…..and ALWAYS, without fail, do that. Otherwise, HOPE you have a low deductible for a windshield replacement. I really thought that I had somehow bent something on the frame or got the body warped. I had a tire wear down very suspiciously about 100 miles from that stop. A lot of folks here and Barry at Josam’s helped diagnose….a BAD tire….and I had no issues. However, most of our experienced, as well as suspension and such minds, suggested that tilting for a few gallons more and forgetting to level or achieve travel height could be false economics if i stressed to the point of breaking windshield mount(s) loose or stressing the windshield. So, I quit cold turkey. I never fully understood the delicate installation of the front brackets for a windshield. YES….some years were better but we repeatedly have seen issues….but for the general membership, the words of caution about tilting and such to get in the last 10 gallons in is something that we, the “Moderators or Staff”, advise NOT TO DO. Forgetting to undo something….at a fuel stop…with folks backed up behind gets me into a hurry and we know what usually happens….. So, now, I don’t put the Camelot at risk and depend upon my steel trap mind to be perfect…. LOL. 1 Link to comment Share on other sites More sharing options...
Frank McElroy Posted October 17, 2023 Share Posted October 17, 2023 On 10/8/2023 at 4:44 PM, saflyer said: Just installed a new set of Sumitomo ST719s on my coach in place of my Michelins.I haven’t done a rigorous check yet but they appear to be delivering about half the fuel mileage as the old tires. Maybe 3-3.5 mpg vs. my former 6.5-7, which was nothing to write home about. I can almost see the fuel gauge move as I drive. It’s so bad I checked for a fuel leak. Is this possible? The installers put 115 psi in all tires. I gat the Sumitomo numbers and the table ssid 95 psi so I lowered all 6 to 105 psi for this trip. Will update st my next fill up. Ed ‘05 HR Ambassador It simply is not possible that changing tire brands alone, inflated at the correct pressures, caused a 50% drop in fuel economy. Either something else happened with this engine or his fuel economy calculations, based on gauge readings, are wrong. Please no more debate on this until the OP posts his actual fuel economy after at least 2 full tank fill-ups. 1 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now