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Barkleymut
01-27-2001, 12:47 AM
I have a 98 Ram 1500 that I love except that it has always looked kind of wussy because it had 225/75 R16 tires. Recently while shopping the local trading post paper I saw a guy who had rims + tires that he had taken off of a 96 Ram 1500. The tires are 245/75 R16. They do make the truck look better but they sure do make a lot of noise. Also I realize they will make my speedometer/odometer run at about 90% of what it actually should. Is there a way I can have the speedometer/odometer modified to acurately reflect the true mileage? Any thing else I should look out for? By the way the rims/tires are Kelly/Springfield and they came with the standard rims, have 75-80% of tread left and only cost me $85 for all 4.

lawrence stone
01-27-2001, 08:01 AM
Good deal. It's nice to have a complete set of extra wheels and tires up north so you can switch from snow tires to highway tread.

Now about the odometer how much taller is the 225 vs. 245?

[Edited by lawrence stone on 01-27-2001 at 08:39 AM]

Greenkeepers
01-27-2001, 08:14 AM
I have a 99 2500 that I just put BFG 265's on to try to fill up the wheel wells a little. It looks alot better. My dad has a 1500 that he put the 265's on as well and it looks fine and rides really good w/ minimal noise. I think he said that his speedometer was off about 2mph's so no big deal.

Barkleymut
01-27-2001, 10:12 AM
Stone, I know what your getting at with the height of the wheels but wouldn't the circumference be the only issue? Anyways the tires are just minimally taller. And Greenkeepers, how can he tell that they are off by just 2 mph, and wouldn't that be proportional to the speed you are travelling? If the tire is 10% bigger then wouldn't the speedometer/odometer reflect 10% less than actual? Am I going insane and in my own little world?

BCLawncare
01-27-2001, 10:51 AM
barkleymut, all you have to do is go to your local dodge dealer and tell them what size tires you have and order a new speedometer gear for the transmission to get your spedo.to read rite for the tires you have. my dodge 2500 has 255/85 tires tall & skinny i love em

Premo Services
01-27-2001, 12:43 PM
Barkleymut:
The tires that you have are probaly hard tread tires,to get less noise you would need a radial tire that has a soft tread. The hard tread tires get more miles on them before wearing out and are quite noisy, and the soft tread tires are much more quiet but wear out faster. I had the hard tread tires on my truck and the noise was unbearable and as they wore out the noise got worse,also when less tread was on them I didn`t get the traction as with soft tread tires.As for the size of tire it does change the mph,mine were 15 inch tires instead of 16 inch tires so I had my wife follow me and she told me when I was going 60 mph, the speedometer said 65 so I drove 5 miles per hr. faster until I got sick of the noise and bought new soft tread tiresthat were the right size for my truck.

nlminc
01-27-2001, 03:58 PM
I was told not to change the tire or wheel size (from factory)at two different shops because it would screw up the ABS and 4x4 on the truck.

Chris

thelawnguy
01-27-2001, 04:09 PM
It wont affect the abs on a Dodge, unlike the GM products with a separate box behind the glovebox.

Most Dodges I have seen, the speedos already read high so taller tires will most likely bring it closer in line with reality.

I went from 245/75 to 235/85, 2 inch taller, and the clock still runs 3 mph fast at a indicated 60. Per radar a la police dept.

KirbysLawn
01-27-2001, 04:30 PM
My truck has 265/75/16's, I'm going with 295/75/16's next time to fill wheel well space. I've spoke to several folks who have done this and they say it's a better ride. Here are a few links with information about getting larger tires. The first one shows you how much your speedodmeter will be off.

Remember, if you change tire sizes make sure you get the speedometer calabrated.

http://www.miata.net/miata/garage/tirecalc.html

http://pw1.netcom.com/~sgalaba/tiresize.htm#ustires

http://pw1.netcom.com/~sgalaba/mph.htm#GearSpeed

John DiMartino
01-27-2001, 04:41 PM
My Dodge camewith 245/75R16 E range Michelins,I put 285/75/16 BFG all terrains on the stock rims,they looked perfect for the truck,they were 32.7" tall,and that wheelwell is huge,so they dont even look that big on the truck.I think 245/75R16 is 29.6" tall average height.265/75/r!6's are 30.6",225/75R16 are 28.7.Sizes vary,but these are real close with new tires,and full tread.

lawrence stone
01-27-2001, 06:02 PM
I just put a set of 30.5 x 9.50 x 15 on my c1500 on the factory steel wheels.

That's a full 2' height increase over the p235 suv tires I had. They ride great and helped drop some highway rpm's with the 4.10 posi gearset.

In the rear I have gas shocks with overload springs. I tow class two with no trailer brakes with a 2" receiver box hitch off the factory step bumper.

klite
01-27-2001, 10:47 PM
I have an old Dodge Ram Charger and it came stock with 275+ 75+15 tires. Since they wore out I have run 33+11+15 with no ill affects except for the speedomitor, it's about 5 MPH more and who cares anyway. I just go 5MPH less and have never gotten stopped for speeding.

KirbysLawn
01-27-2001, 11:43 PM
Klite, it can effect the shift patterns on some trucks, especially the newer ones.

rdh
01-28-2001, 08:10 AM
i put bigger and wider tires on anew ford in 1997 steering
felt funny didnt like it didnt have the ruturn to center
like the factory tires

John DiMartino
01-28-2001, 08:28 AM
Ray,it will affect the shift pattern on any truck,it has to,taller tires will space the shifts further apart,since every time it shifts RPM;'s fall back more with taller geaing,so shift stacking is spread out.This is not a problem on newer vehicles.The only problem is when you install taller tires on one axle only of a 4 wheel ABS system,mostly on the rear of 2wd trucks.This drives the ABS nuts,it thinks the rear tires are locking up every time you touch the brakes,since it only knows wheel speed,it knows the rears are turning slower when you touch the brakes.So it releases pressure to the rears until they speed up to meet the speed of the front wheels,which they never will with tall tires,so its a never ending process that results in little or no rear brake bias,and dangerous stopping,and high wear on the ABS actuator.Taller tires will not hurt 90% of the vehicles on the road,the other 10% will get bruised fenders and wheel wells from rubbing.

KirbysLawn
01-28-2001, 09:51 PM
John, I didn't want (or know exactly how) to explain all the details, my point was "with the newer ones" was the newer ones with the ABS. Thanks for the detailed answer.

moonarrow
01-28-2001, 10:01 PM
Paul just go to the dodge dealership and tell them what size tires you have changed to and they will give you a little gear to put in the transmission where the speedometer cable ties in and it will corect everything

Alan
01-28-2001, 10:35 PM
I swapped from 225 to 245 on an 89 GMC. Tire place gave me all manner of BS, right to the point of telling me that THEY could be held liable if there were problems with the ABS (rear only) in the event of an accident. Finally called GM and they laughed. There is more variation between brands in a given size than between those two tire sizes. The odometer catually was closer with the 245s than it had been with 225s, so I would assume the speedometer was as well. For what it's worth, a 3% change in diameter will make the difference of about 1 1/2 mph at an indicated 50.