305/50r20 Or 305/55r20 Decisions, Decisions, Decisions...

mrkln · September 23, 2010

Thought I would bug the forum for some opinions. I have a white GMT900 and am having a hard time deciding which size tire to buy. I put a 3" Zone body lift on over the weekend and have a set of black XD Monsters (20X9 +18mm offset) sitting in the garage waiting for rubber but I can't convince myself of one size over the other. I am leaning towards the 305/50R20s due to cost and difference in size from stock. The tires I am looking at are the 305/50 Cooper Zeon LTZs and the 305/55 Nitto Trail Grapplers. The LTZs make more sense as the spare tire would be much more usable in a pinch than the Grapplers and they would make the wife much happier due to how quiet they would be compared to the Grapplers. The LTZs should also help on fuel economy. However, the Trail Grapplers will most likely cost me about $425 more than the LTZs and assuming that I can get five years out of the tires, the additional cost for the larger tires would be a whopping $7.13 per month. Throw in an additional $10 per month for gas and you are just under $20/month for the bigger tires. I know that if I put on the Trail Grapplers I will have to level the truck or trim (I would choose leveling which adds a few more dollars).

Bottom line, do you think it is worth the additional money for a tire that is just one inch taller? I'm having a hell of a time convincing myself one way or the other (and no the wife won't let me buy both sets. I've still gotta figure out how many days I'll be sleeping with the dogs for just one set!) I initially thought I wanted the bigger size but I really wonder if it is really worth it now.

Two more questions, does anybody have a picture of LTZs on a GMT900 in the larger size as that is a possiblity as well and how bad would it be to run the stock spare if I suffered a flat with the larger tires. The difference would be 1.5" in diameter which I would think would freak out the Stabilitrack and ABS.

One more thing to consider is that I need some sort of side steps so the savings going with the smaller tire would pay for the steps as well.

Thanks in advance.

sab316 · September 23, 2010

Matt_ has 305/50/20 Cooper Zeon LTZ's with a 3" BL also. Dunno about backspacing and all that jazz... His truck looks good with them on there.

http://www.gm-trucks.com/forums/index.php?showtopic=118896

http://www.gm-trucks.com/forums/index.php?...6763&hl=305

http://www.gm-trucks.com/forums/index.php?...5810&hl=305

Matt_ · September 23, 2010

I ALSO ran 305/55/20s and had to trim a lot of metal to get them to fit on a 3" body lift with the same wheel width&backsapce you're looking at: http://www.gm-trucks.com/forums/index.php?...5&hl=gmt900

So if you want to run 9" wide wheels with +18mm offset on a 3" body lift, and dont want to trim metal, the decision is easy, get the 305/50/20s.

mrkln · September 23, 2010

I was hoping and figured you would chime in Matt. I don't mind putting a leveling kit on the truck. I think I would like it a little better with a 1" leveling kit installed. My question is more about aesthetics. And this is for Matt directly. Do you regret going from the 305/55s to the 305/50s? In a perfect world if both tires were the same price, I know I would be going with the 305/55s. However, they are not the same money and logically almost everything tells me to go with the 305/50s. I would like to save the money but as I mentioned earlier, if they are gonna last me 5 years (or even longer) and you take the additional cost over that amount of time, it's not a deal breaker.

Anybody have any idea which tires will ride better. The XL rated 305/50 with a shorter sidewall or the E rated 10-ply taller 305/55?

Thanks.

Matt_ · September 23, 2010

dude i got ya covered... here's the answers to all your questions;

If you're willing to get a leveling kit, get the 2" RC. With the 3"BL + 2"RC, 305/55/20s fit perfectly on with 9" wide +18mm offset wheels. Might actually need to trim a small amount of plastic depending on variables like actual tire size. but regardless, thats a very popular combo for members on this site and plenty of pictures floating around.

Do i regret getting the 305/50?? NOT AT ALL. As a matter of fact, i think this size tire would look even better if i had a 2" leveling kit added to my truck (i wouldnt run this combo on stock or high offset wheels though). I'll probably stick with the 305/50 tire for a few reasons.... the next answers another question of yours...

The XL rated 305/50s ride a lot softer/nicer than the E-rated 305/55s. They're also about 20lbs lighter per tire which plays a huge roll in not only performance, but ride quality as well (unsprung weight affects how the spring/shock performs)

given the same price, the only reason id go with the 305/55s again is to get a specific tread pattern that i like (like the ATZs for example) since there arent many mud terrain tires available in 305/50/20. With that said, im damn near possitive that my next set will be the 305/50/20 Grabber AT2s (i just put them on my wifes jeep and they look awesome. cant wait to see how they handle snow this winter)

sab316 · September 23, 2010

So semi-hijacking this here.... How is that Jeep turning out Matt? Weren't you looking at putting a lift on it?

Also it sound like you've made up your mind on the tires really. 305/50's still look good and you can put some money towards your steps. Sounds like a good plan to me

Matt_ · September 23, 2010

the jeep turned out awesome. i put a 2" RC lift on it with some black XD Spys and 245/70/17 General AT2s. it looks like a completely different jeep.

sab316 · September 23, 2010

the jeep turned out awesome. i put a 2" RC lift on it with some black XD Spys and 245/70/17 General AT2s. it looks like a completely different jeep.

Sounds awesome. Don't be like Steven here.... put up some pictures!

Matt_ · September 23, 2010

i didnt start a thread talking about how awesome it turned out... but if i do, i promise to post pictures (unlike some...)

mrkln · September 24, 2010

dude i got ya covered... here's the answers to all your questions;

If you're willing to get a leveling kit, get the 2" RC. With the 3"BL + 2"RC, 305/55/20s fit perfectly on with 9" wide +18mm offset wheels. Might actually need to trim a small amount of plastic depending on variables like actual tire size. but regardless, thats a very popular combo for members on this site and plenty of pictures floating around.

Do i regret getting the 305/50?? NOT AT ALL. As a matter of fact, i think this size tire would look even better if i had a 2" leveling kit added to my truck (i wouldnt run this combo on stock or high offset wheels though). I'll probably stick with the 305/50 tire for a few reasons.... the next answers another question of yours...

The XL rated 305/50s ride a lot softer/nicer than the E-rated 305/55s. They're also about 20lbs lighter per tire which plays a huge roll in not only performance, but ride quality as well (unsprung weight affects how the spring/shock performs)

given the same price, the only reason id go with the 305/55s again is to get a specific tread pattern that i like (like the ATZs for example) since there arent many mud terrain tires available in 305/50/20. With that said, im damn near possitive that my next set will be the 305/50/20 Grabber AT2s (i just put them on my wifes jeep and they look awesome. cant wait to see how they handle snow this winter)

Awesome. Thanks for the advice. Treadepot.com has the 305/50 LTZs for $164 a corner. Did you day that you had a guy that had some good pricing on tires too? I may have to check out the AT2s also. Thanks again for the help. I appreciate it.

Matt_ · September 24, 2010

yeah man, shoot ryan(at)eastcoasttires.com an email. tell him you got his contact from me. he can get you prices for almost any tire/wheel.

mrkln · September 24, 2010

Pulled the trigger on the 305/50 LTZs. Got them from Treadepot.com for $752 shipped to my door. Interested to see if they will fit without rubbing or if I can run mud flaps with the +18mm offset.

Thanks again.