19.5 and spare

[Wertles]

I just got my Ricksons delivered today and put them on. Awesome tires and love how they fill out the wheel wells so much better than stock. I only got to put about ten miles on them but the Bridgestones definitely sing a little to me while on the highway but I haven't really noticed any harsher ride. I have yet to find some railroad tracks yet though. My question is, will my spare tire work on the front in a pinch as long as I don't use 4WD or should I just put it in the shed with the other stock tires?

 

[HBarlow]

I don't own one but my understanding is that Dodge 4x4 front differentials are always engaged so I believe you'll be spinning the front axle shafts at different speeds and spinning the spider gears in the differential at significant rpm even though fwd is not engaged.

You might be able to get away with it to drive 10 miles into town at 20-30 mph in the event of a ruined front tire but it would probably not be a great idea.

 

[Barry]

Somewhere in the cobwebs of my mind, I think I remember that the OEM tires are around 31" tall and the 245/70/19. 5s are just a hair over 33" tall... ...



But like Uncle Harvey said, it will be something to limp into the next town... .

 

[smitty3500]

The reason I went with the 225/70/19. 5's. I wanted the same height as OEM setup. I kept my stock spare. If I ever have a issue I will just mount spare until repair can be made.

 

[Barry]

Smitty,



I ran almost 150,000 miles on OEM tires and wheels. My speedo was always 3 mph fast... ... ... ..... until I installed the Ricksons with USED 225/70/19. 5s. Then the speedo went dead on... ... ... ..... now the speedo, the GPS and the roadside radar all agree.



Therefore, it leads me to believe that even the 225s are just a hair taller than the OEM tires.



Did it change your speedo any?

 

[Road Dog]

If you rear diff is limited slip then the tires should be the same size. In the front the diff is open so they can be different sizes. I blew out a tire hunting and ran 1,000km with the original smaller spare on the front (highway & gravel) pulling a trailer and loaded with deer. No issues at all. It even tracked straight.

 

[Wertles]

Barry,
225's are the closest 19. 5 you can get to stock. The 265/70-17 Toyo AT specs are diam-31. 6, rpm-658, wt-3195. The Bridgestone 225/70-19. 5 is diam-32. 5, rpm-639, wt-3970. I went with the 245's for the additional max weight. Those tires are diam-33. 4, rpm-622 and wt-4940, almost a ton at additional capacity on a srw and now closely matches the capacity of the rear axle. My speedo was always 1-2 mph fast at 65 and now reads 3-4 mph slow at the same speed.
Road Dog,
Thanks for the info. I do have limited slip in the rear and in event of a failure was planning on swapping a front to the rear with my spare going on the front. It would only be on there for a few miles until I could get to a safe place. I just wasn't sure if it would ruin the front drivetrain with the different sizes. I guess the spare will go back under the truck this weekend.

 

[fest3er]

Smitty,



I ran almost 150,000 miles on OEM tires and wheels. My speedo was always 3 mph fast... ... ... ..... until I installed the Ricksons with USED 225/70/19. 5s. Then the speedo went dead on... ... ... ..... now the speedo, the GPS and the roadside radar all agree.



Therefore, it leads me to believe that even the 225s are just a hair taller than the OEM tires.



Did it change your speedo any?

The 225/70/19. 5 is around 8% larger than the OEM 245/75/16. At 70 MPH, my tach dropped from about 2000 RPM to about 1850. I used a TruSpeed to dial in the odo. Record the mileage at mile marker X, and at mile marker X+100. Subtract the start mileage from the end, then divide by 100. That'll tell you almost exactly how far off the odo/speed are.



I dialed mine to where it was 1-1. 5% over with new tires. As the tires wore, the odo would be 1-1. 5% under. On average, the mileage would be correct. The speedo, OTOH, rarely matched the roadside radar, even when the odo was dead-nuts on. It's been better in recent years, though.



The loaded radius of the 225/70/19. 5 was around 3/4" larger than that of the OEM 245/75/16.

 

[smitty3500]

Smitty,



I ran almost 150,000 miles on OEM tires and wheels. My speedo was always 3 mph fast... ... ... ..... until I installed the Ricksons with USED 225/70/19. 5s. Then the speedo went dead on... ... ... ..... now the speedo, the GPS and the roadside radar all agree.



Therefore, it leads me to believe that even the 225s are just a hair taller than the OEM tires.



Did it change your speedo any?

The 225/70/19. 5's are a hair larger then my stock tire/wheels. I would only use my spare if I had a flat while loaded and towing. I would remove once repaired/replaced. A few miles to get to a safe location off a highway is important to me.



My speedo is dead on with road side radar with my 19. 5's.