Wheel conversion of '04 CTD

I am going to convert my 17" wheels to 22.5" Alcoa's. This will increase my tire height 6". Is it possible to recalibrate the speedometer 15%? Any help
will be appreciated. Steve
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Roy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Roy wrote:

It will probably help if he has 4.10s. 4.10s are way too low.
--
Ken



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

certain rpm range. I have no problem with the 4:10's in my truck.
Roy
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Roy wrote:

We really don't know what the final drive ratio will be until he picks out a tire profile. If it ends up being the 15% difference that he quoted, it will make it drive like it had 17s and 3.48:1 rear gears. That's pretty close to the gears that I have. If he were using it for heavy hauling the 4.10s would be a better choice, but I don't think he'd be putting 22.5s on it then.
--
Ken



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Roy, That will change my 4.10s into 3.55s or 3.65s. Effectively putting 70MPH at 1800 rpm, which will save a lot of fuel. It will make the ride smoother, quieter and increase tire life to more than 200k miles. Additionally, it will add significantly more life to the truck. We are fortunate to have both the brakes and the suspension to handle the mod. The GM product cannot without extensive suspension changes. Unfortuately, it also adds 25lbs in unsprung weight at each wheel, so the shock absorbers should also be changed to gas type. This change will set me back about $5,000 all in though. Steve

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mike, Good question. The answer is "I think so." Let's assume I keep the truck for 200k miles, I will save 3 sets of tires for $1,000 plus say a 10% fuel savings, which is 11,560 gallons at 17.3 mpg verses 10,526 gallons at 19 mpg with the difference being 1,000 gal + at say $2.50 a gallon for about $2,500. So, without the cool factor, the better ride, the better gearing, the lower stress on the motor and chassis, potentially yes. But, I think the key to the answer is "How long will I keep the truck?". Steve

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You may save tire wear but I'm betting you will use more fuel. Take into account that the tires and rims are heavier than stock, with the increased ride height you will have a lot more drag on the road. Plus those larger tires will take more fuel to get them moving as well as your ratio change is higher than you have. You will be looking at closer to a 3.00 ratio. Lower RPM isn't always a good thing. I have never seen any 22.5 tire that will give a good ride on a light weight vehicle either. Hope you know a good dentist. If you have ABS your going to have lot's of fun getting it to work correctly with that much rubber as well. Good Luck.
--
Steve


"Steve Lusardi" < snipped-for-privacy@lusardi.de> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Steve, I have done my homework correctly, depending on the tire size, my height change will be between 3.5 and 6.0 inches. I am running 31s stock. Worst case is 265/70 at 37", but I will run either 245/70 or 2.55/70 at 34.5 and 36" respectively, which is either a11.3% or 14% gear change. I have 4.10s, so the effective gear change will be either 3.649 or 3.530. Please remember that 3.73 is the standard Dodge gear. However, your word of caution will be heeded because both the wheels and tires in that size are not always round and any imbalance or eccentricity will get my undivided attention. On the fuel issue, I have queried others that have made this change and the fuel savings is substantial. Their stated change in consumption is far greater than I'm planning on. In actual fact, the rolling resistance is less with the big wheels as the tire width is only slightly wider than stock, but with a much harder compound. Steve

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.