68RFE+3.73+35" tire = ???

[ronr]

Im going to try a different slant on an earlier post. I interested in hearing from anyone who is running 34-35" tires on a 6. 7 3. 73 6speed auto truck. I'd like to know how well it runs empty on the flat and in the hills - What is your experiance when you start to load it up and do you ever wish you had the 4. 10s in it to bring your overall gearing lower? Thanks for any insight you can provide.

 

[Jeff_K]

I have 35" toyo m/t's on my 68rfe and 3. 73's. It basically changes the speed by 10% over stock. Empty driving is fine, but if I was towing I would probably only use 5th at most. With the 6-speed auto, I think this is the perfect gearing. Below is the new rpm vs. speed vs. gear table cut and paste from Klengers gear-speed-calc. xls file.



Gear 1 2 3 4 5 6

RPM 3. 231 1. 837 1. 410 1. 000 0. 816 0. 625

1000 9 15 20 28 34 45

1100 9 17 22 31 38 49

1200 10 18 24 33 41 53

1300 11 20 26 36 44 58

1400 12 21 28 39 48 62

1500 13 23 30 42 51 67

1600 14 24 32 45 55 71

1700 15 26 34 47 58 76

1800 16 27 36 50 61 80

1900 16 29 38 53 65 85

2000 17 30 39 56 68 89

2100 18 32 41 58 72 94

2200 19 33 43 61 75 98

2300 20 35 45 64 78 102

2400 21 36 47 67 82 107

2500 22 38 49 70 85 111

2600 22 39 51 72 89 116

2700 23 41 53 75 92 120

2800 24 42 55 78 96 125

2900 25 44 57 81 99 129

3000 26 45 59 84 102 134

3100 27 47 61 86 106 138

3200 28 49 63 89 109 143

3300 28 50 65 92 113 147

 

[ronr]

Thanks for the reply Jeff. I take it you feel the gearing is "perfect" even with your 35s and you never feel like 4. 10's would improve your truck.

 

[Jeff_K]

If I was pulling a trailer all the time I would get the 4. 10's, but if you drive around empty most of the time, than 3. 73's will be fine IMO.