Off Roading A few observations with larger tires

Attention: TDR Forum Junkies
To the point: Click this link and check out the Front Page News story(ies) where we are tracking the introduction of the 2025 Ram HD trucks.

Thanks, TDR Staff

Competition puliing truck set ups??

Competition New Times.

As most know I just got through installing a lift and adding 37" tires. This last week I finally got the alignment done and have since added several miles to the truck. The lift turned out nice and I like the extra height, but I thought I would share some interesting observations with you.



The new tires are huge, they weight right around 100lb each without the rims. And trust me there is a huge difference between the aluminum wheels/tire combo and the steel wheels/tire combo i have on the inside rear duals. I just can't imagine all those guys running around with large tires like these on 1500 series trucks, heck I've even seen a few Toyota's with very large tires, it just doesn't make since. That poor engine must be killing itself at each traffic light? Anyhow, It is interesting to note that I see somewhere between 100-150° more EGT's at highway speeds with the new combo. And the automatic seems to also be running alittle more temp, somewhere in the 10-15° more range. The truck still has plenty of go, but I can tell a difference, it was quicker off the line before the swap. What is nice Thu is the transmission feels better suited to the bigger tires then before. I suppose because it has a bigger load on it? But it shifts better, smoother now, and I like the city gear it now has, much better for the stop and go traffic. If you didn't have a transmission cooler on your truck before, I would highly suggest you install one even if you don't tow. In soft soil conditions, mug or anytime they are in a high friction place, they will add alot of heat to the trany, and without help it doesn't take long for the transmission fluid to peek. I sometimes visit the sand dunes and I could see them heating up the trany there.

The Dick Cepeek tires are absolutely quite. I did do alot of looking around and most reports were they are a nice road tire, but you just never know till you try them out for yourself. I would highly recommend them to others, who like big aggressive tires that are not loud on the road.



The higher EGT's are a reflection of load, so with the higher temps I can see the truck has to work harder to push the heavier tires down the road. I just can not see how people would run large tires with small ring & pinions, it just would not be fun (my opinion).

The ride is nice, Not alot different from before. I am still trying to see what it wants in regards to air pressure. I haven't installed the dual steering stabilizer, but I'm not sure it even needs one? I may leave it off so I don't create more load on the steering box then I already have.

I am also going to play with the shock pressures to dial in the ride even better, now I just set them all at 200psi. Till later.
 
I can add that the 37's are a lot more load than 35s but make a very good addition for off roading. We have such large diffs that we have less ground clearance than many smaller rigs. They do use a bit more fuel also.



Bob
 
Braking?

Adding 37's to a 2nd gen would be the equivalent of throwing a Lance on it. Stopping power would definitely be compromised. I had to add an exhaust brake to my '99. It was just too scary trying to stop it.
 
'03 HO Quad Cab. I am interested in running 37's but not interested in a lot of lift. Could I run 37's with a set of longer front control arms? That is, move the front wheels foreward enough for the 37's to clear?



Thank you,

Mickey
 
You will also need a correct lenth rear spring ;). The fit is tight with a stock bed. The tire needs to be centered accurately under compression,the stock leafs won't work,my truck would kiss the front edge with 35s under heavy compression,now with the Carli spring pack it will clear the 37s



Bob
 
Dumped my Toyo M/T 35"s with less than 1000 miles on them and went back to my 33's BFG A/T,The 35's were great for offroading/hunting/deep snow when the larger meats are needed, but for city driving i hated it ,figure i lost about 15-20%(guessimate) take off power,but once you got rolling it was fine---truck looked awsome. PLUS we moved to a large fiver and the thought of doing the change-over every time i wanted to tow was to much for me(tire/rim100lbs+++). Maybe with the 6 speed/ 3. 55 the gearing was wrong,might of been different with 4. 10 rear end but i happier now with my current set-up.
 
Bob,



I am running a mini pac on my truck, they don't change the centering of the rear wheels in the stock bed but my 35's don't rub, and besides, trimming the rear wheel openings should not be a problem! I manage to stuff the front tires (315X70's) into the rear of the wheel well when crossed up off road, so 37's would really tear things up and I don't think I can trim much off the back of the front wheel well. Can I move the front axel forward enough with aftermarket links to let me run 37's ?



Thank you,

Mickey
 
Bob,



I am running a mini pac on my truck, they don't change the centering of the rear wheels in the stock bed but my 35's don't rub, and besides, trimming the rear wheel openings should not be a problem! I manage to stuff the front tires (315X70's) into the rear of the wheel well when crossed up off road, so 37's would really tear things up and I don't think I can trim much off the back of the front wheel well. Can I move the front axel forward enough with aftermarket links to let me run 37's ?



Thank you,

Mickey

With my Carli front arms the 37's have not touched sheet metal yet,It has seen some air time and 600miles of Baja driving so far.



Bob
 
I would not have liked 3. 55 gears ither, and with 37" tires it would have been a real dog



Second gen trucks are no different then third gen trucks with respect to lifting of using larger tires, both will do just fine if the work done was done right. Don't kidd yourself into thinking the third gen trucks have any sort of advantage.
 
:-lafThe 3rd gens do have advantages... ... ... ... . stiffer frames and will fit bigger tires with less lift. I have both and the difference is noticeable.



Bob
 
I am running 37 Goodyear GSAs on a 2nd gen truck with no rubbing. The GSA is not a big 37 by any means, but the 2nd trucks(Dana axles) have a little more ground clearance than the 3rd gen trucks. They are much better offroad than even 35's. Around town they are fine. Brakes still seem fine, but towing heavy loads would probably be a little tougher to stop with. Exhaust brakes and trailer brakes are a huge benefit.



Be careful using longer control arms. At full bump, you can end up having interference problems with your axle housing and steering components. Each truck varies slightly, so pay careful attention to this. Cycle the suspension without the springs, and see what it does with the longer arms before committing to them. I have read that Carli's control arms are only a half inch longer than stock, and this should be fine in most cases. We have seen trucks that could not use longer arms at all without limiting bump travel.



KP
 
I run 37" Pro Comp Mud Terrain 3 Ply's on mine (with a 5" lift).

Mud Terrain 3 Ply

I was a bit hesitant to upgrade from my old 35's because I wasn't changing the gearing. I can honestly say I think the gearing is about right now. I have 4. 10's and at 70 mph, I sit at 1900 RPM. That seems the sweet spot. Anything over 2k RPM, my mileage goes to crap. Still start out in 2nd (6 speed) and no problems with braking or power whatsoever. The 3 ply sidewall really seems to help with sidewall flex. Just wish they weren't so damn expensive to replace.
 
Remember not all 37's really are 37 " tall. You can find the actual dimensions on the tire company's web sites.

On another note the GSAs seem to work very good in the sand,I will find out about the Toyo mts this wk end. Hopefully better that their ats.



Bob
 
GSA's

I've seen the GSA's on Jason's truck and they do look sand friendly. Toyo needs to come out with an "E" rated 35" for us high wt. guys in a 17" AT tread design.
 
I have wheeled with Toyo mt equiped trucks at Glamis in 35s,but till I drive them it is hard to compare. Diff driving skills power and weight levels etc



Bob
 
I've seen the GSA's on Jason's truck and they do look sand friendly. Toyo needs to come out with an "E" rated 35" for us high wt. guys in a 17" AT tread design.



Mt bro has an H1 that had the GSAs not much power but he could cruise up OLds even if it was at 15mph :-laf



Bob
 
Remember not all 37's really are 37 " tall. You can find the actual dimensions on the tire company's web sites.

On another note the GSAs seem to work very good in the sand,I will find out about the Toyo mts this wk end. Hopefully better that their ats.



Bob



Years ago I had a Toyota Tacoma prerunner and I got some of the GSA race tires. Same tread pattern as the street but different compound and sidewall. I really didn't like them. I then switched to the Baja T/A KR's and I never looked back. I really liked the BFG A/T's too. Maybe BFG will finally make a A/T that works on our trucks.
 
Back
Top