Has anyone tried this with a GX?

[CNG MOTORS]

In the ongoing quest to increase range on the GX has anyone tried going with a slightly larger or taller tire? This will ultimately change the final drive and bring down the RPMS. I believe the stock tires are 185 wide I know a 195 will fit and in turn would be very slightly taller than stock.

[futuregx]

Re: Has anyone tried this with a GX?

In the ongoing quest to increase range on the GX has anyone tried going with a slightly larger or taller tire? This will ultimately change the final drive and bring down the RPMS. I believe the stock tires are 185 wide I know a 195 will fit and in turn would be very slightly taller than stock.

what yr car do you have because my '09 is fitted with a 195 wide tire

[CNG MOTORS]

Re: Has anyone tried this with a GX?

The older ones I think were 185

[malibu]

Re: Has anyone tried this with a GX?

Does anyone drive the 101 from LA to SF regularly? I am thinking of taking the GX but am somewhat concerned about only having Santa Barbara, San Luis Obispo and Salinias with one station in each.

[Tax Counsel]

Re: Has anyone tried this with a GX?

Does anyone drive the 101 from LA to SF regularly? I am thinking of taking the GX but am somewhat concerned about only having Santa Barbara, San Luis Obispo and Salinias with one station in each.

Malibu ~ Before you make the trip you may need a PG&E Card. Make sure you read this thread for more information:

http://cngchat.com/forum/showthread.php?p=17466#post17466

TC

[larrycng]

Re: Has anyone tried this with a GX?

In the ongoing quest to increase range on the GX has anyone tried going with a slightly larger or taller tire? This will ultimately change the final drive and bring down the RPMS. I believe the stock tires are 185 wide I know a 195 will fit and in turn would be very slightly taller than stock.

Be careful, if you increase the rolling radius too much it can effect the the ABS system and stability control system if the car is so equipped. Also pay attention to the automatic transmission shift pattern because of the difference in the throttle opening (your are increasing the engine load because of the longer lever arm offered by the taller tire) and road speed signal (governor pressure in the old days) you will be shifting at a higher road speed.

Just a couple of things to look for with computer controlled engines and transmissions (assuming an automatic)

The basic idea is sound. An engine is more efficient at wider throttle openings for a given speed because of reduced pumping loss (horsepower that it takes to get air past the throttle valve). The second caviat is that the engine must remain in closed loop (O2 sensor cycling) to maintain a stoichiometric air/fuel ratio. The system tends to go rich in open loop (usually over 80% throttle opening.

As tires get bigger engine load changes and you may have problems passing a loaded mode (dyno) smog test.

Go for it

larrycng

[jetboatjohnny]

Re: Has anyone tried this with a GX?

I had a stock stripped 85 Ranger 2.3 EFI that had 195-70-14. A friend gave me a set of Ford factory alloys with 235-15s and I got worse mileage. The problem was on those models they put a 3.08 axle on it, and I had to drive in 4th gear under 65 (5-speed maunual). I dont think one bigger tire size wil hurt anything, but it will change your speedo readings and may get a slight gain in mileage.

[freedml]

Re: Has anyone tried this with a GX?

LA-SF much safer to take the 99.

[CNG MOTORS]

Re: Has anyone tried this with a GX?

Does anyone drive the 101 from LA to SF regularly? I am thinking of taking the GX but am somewhat concerned about only having Santa Barbara, San Luis Obispo and Salinias with one station in each.

Santa Barb, San Luis Obispo, then San Jose. I've done it a dozen times in a GX

[Kevin Fern]

Re: Has anyone tried this with a GX?

Larrycng, is correct on this point. The one thing that will hurt fuel milage is incresed rolling resistance ie. a bigger tire. It plays to a bigger effect if the load resistance is off, transaxle gearing etc.. it probably would not benifit much to change the tires murf, the biggest improvements you would gain would be intake and exhaust mods and of course driving habits, if you do change the tire size, let me know what happens!

[CNG MOTORS]

Re: Has anyone tried this with a GX?

I had a customer I sold a vehicle to that had 195's and then when she came due for tires Honda recommended that she re-install factory sizes. Afterwards she contacted me concerning her MPG's had gone down. I was wondering if others tried/experienced the same the other way.