C vs. E loads and the BS (not back spacing!).

[Jeff Allan]

A steel wheel has less rolling resistance yet but there comes a point of diminishing returns. We were never talking rolling resistance, we were talking 'ride'. I would only be worried about less rolling resistance than a C has if I were driving a Prius and trying to achieve an extra .1 mpg to satisfy some overactive quest for some green-related thing. The last thing I am going to be worried about when I choose to drive a Wrangler is mpg. If that was high on my list, I sure wouldn't be driving a Wrangler. That's like worrying about ground clearance on a Porsche Carrera or 1/4 mile times on a Prius.

Are you even commenting in the right thread? Steel wheels (?) were never mentioned by me. I said a bunch how smooth/easy it drives with less rolling resistance and bumps feel a little more distant! That's the whole point of the thread.. Sorry Jerry, seems like you didn't read any of what I have been saying.

On that mileage comment, Nothing wrong with a little balance. Not everybody crawls rocks or wants to. Saw a guy with 37's on his, said it gets 9 mpg. Screw that, I got better things to spend/save my $ on.

So after the experiment, I'm happy about my results and yet I have to argue with everybody about it!! lol..

 

[Jeff Allan]

This thread is the most fun to date on TJ Forum.
Thanks for chiming in Jeff.

No doubt the differences between C & E are there. Buy what appeals to you. Me, I'm buying 15" Rims this spring so I can buy something like 33x10.50x15 KO2s. Tired of the brutal ride over washboard and rocky roads with the 255/85R17 MTs I now have or the 245/75R16 MTRs which came on my TJR. Just wish there was more selection of C Ratings in 16" & 17" sizes.

My winter grips are C Rated Yokohamas. Absolutely love changing over every fall. Night and day ride difference. No difference is gas mileage tho.

Love the donkey balls comment. Should win a prize

That was the whole deal, I spent so friggin' much time reading and trying to find a C tire for these 16" rims. Because I kept reading E's are too rough and kill mpg... every tire's different and I learned a bit about rolling resistance. All I know is after this comparison, I preferred the smoothness and beter mpg of the E,... for the KO2's. Maybe a different brand/style of tire, and I'd prefer the C. That's why I say, I don't think there should a blanket like there is and everyone saying how bad the E is for a jeep. In this case, the C's just were so noticeably soft/spongey and that much friction created more tire noise, made the ride less comfortable, and really killed mpg. I can't believe some like that, it felt like I was closer to the road and every line/bump/hole was noticed as the jeep would jiggle and bounce. I'd see the steering wheel move a lot with those bounces!!

I don't calculate mileage, but since my daily driving routine is exactly the same for many years, I noticed on the first tank with these E's, I got 4 days more driving on one tank over the stock MTRs. the ride is world's better, smoother. That's all a huge unexpected improvement, and I went a size bigger as well.

 

[mrblaine]

Are you even commenting in the right thread? Steel wheels (?) were never mentioned by me. I said a bunch how smooth/easy it drives with less rolling resistance and bumps feel a little more distant! That's the whole point of the thread.. Sorry Jerry, seems like you didn't read any of what I have been saying.

On that mileage comment, Nothing wrong with a little balance. Not everybody crawls rocks or wants to. Saw a guy with 37's on his, said it gets 9 mpg. Screw that, I got better things to spend/save my $ on.

So after the experiment, I'm happy about my results and yet I have to argue with everybody about it!! lol..

I think you're being a bit more defensive than is warranted. No one is arguing with your results, just the inability to reproduce them across the board with all tires. That and some of your analogies and comparisons are almost the exact opposite of what you think they mean.

 

[Jeff Allan]

I think you're being a bit more defensive than is warranted. No one is arguing with your results, just the inability to reproduce them across the board with all tires. That and some of your analogies and comparisons are almost the exact opposite of what you think they mean.

Read above and I said, maybe with another brand/tire I'd prefer a C, and why it seems a blanket statement is out there with all E's and I found it ain't necessarily true. That's all.

As for comparisons, we already seen we have different views on that stuff, so no problem there.

 

[mrblaine]

Read above and I said, maybe with another brand/tire I'd prefer a C, and why it seems a blanket statement is out there with all E's and I found it ain't necessarily true. That's all.

There is a reason for that and it's because 99.99% of the E tires suck donkey balls when compared to the similar tires in a C.

As for comparisons, we already seen we have different views on that stuff, so no problem there.

For several reasons but some of them are you tend to ignore counterpoints that have an impact on the discussion like my question to you about running a C and E on the same rig at the same time in two different rim sizes which you clearly sidestepped. You also seem unable to use language that is not confusing to most folks. You use words like stiff to define good ride quality and soft to define bad ride quality. Even your shoe analogy is counterintuitive to what most understand about how things feel.

I think if you go back and read your descriptions that will become evident. Any time you are confused by something, take it to the extremes. Solid steel wheels like you see on a train are the stiff end of the spectrum. Big soft mushy turf tires on tractors and the old 3 wheelers are the opposite end. Somewhere in between those is what we like for our rigs. You don't use words like stiff to define a good ride and soft to define a bad ride if you expect to be taken at a credible level.

 

[Jerry Bransford]

Are you even commenting in the right thread? Steel wheels (?) were never mentioned by me. I said a bunch how smooth/easy it drives with less rolling resistance and bumps feel a little more distant! That's the whole point of the thread.. Sorry Jerry, seems like you didn't read any of what I have been saying.

I guess my comment about steel wheels was too subtle for you. It was saying that a solid steel wheel (no rubber) would have even less rolling resistance yet... but as said above, there comes a point of diminishing returns where less rolling resistance becomes less important than other more important tire characteristics.

 

[Jeff Allan]

I guess my comment about steel wheels was too subtle for you. It was saying that a solid steel wheel (no rubber) would have even less rolling resistance yet... but as said above, there comes a point of diminishing returns where less rolling resistance becomes less important than other more important tire characteristics.

No,I get the wheel thing, but lets stick to what I wrote in the post as I guess you missed all as you said we weren't talking rolling resistance, yet it's all over my first post and how I preferred the way they rode so smooth.. It's not so much diminishing returns as is more about balance between what qualities someone prefers or needs. We all ain't climbing rocks or doing extreme. If I was, I'd put more importance on other features, like the extra friction/traction the C's seemed to have for ex..But they sucked gas big time.

No matter what you think, bottom line is with these tires my jeep rides better than ever, better mpg, and that's good enough for me.

 

[mrblaine]

No,I get the wheel thing, but lets stick to what I wrote in the post as I guess you missed all as you said we weren't talking rolling resistance, yet it's all over the first post... It's not so much diminishing returns as is more about balance between what qualities someone prefers or needs. Balance. we all ain't climbing rocks like you think.

No matter what you think, bottom line is my jeep rides better than ever, better mpg, and that's good enough for me.

You seem like you have a big chip on your shoulder when it comes to other folks who wheel differently than perhaps you do. You've made reference to "real jeepers" and now climbing rocks like somehow any of that is a bad thing, just something that makes you defensive and disingenuous. Are you doing that on purpose or you just can't help yourself?

 

[Serbonze]

Interesting discussion that once again points out just how much I don't know. I had no idea that there was a preferred load rating for Wranglers. After reading this I went out to the garage to see what I've got, and sure enough the 305/70/16 Cooper Discoverer STTs are an E. Oh well, I guess I'll switch to Cs when these where out in like ten years.

 

[Serbonze]

I was thinking about this last night. In many forums, you see people ask how they can get a smoother ride. Inevitably someone days to replace the springs then the veteran posters reply that springs have nothing to do with ride comfort and that they should look at tire pressure and shocks.

I can't recall ever seeing someone ask about the tire load rating of the posters tires.

 

[Jeff Allan]

Interesting discussion that once again points out just how much I don't know. I had no idea that there was a preferred load rating for Wranglers. After reading this I went out to the garage to see what I've got, and sure enough the 305/70/16 Cooper Discoverer STTs are an E. Oh well, I guess I'll switch to Cs when these where out in like ten years.

there are lots of threads on Jeeps/load ranges if you did a search. But same here, I never paid much attention until I started reading up on which tires to get, many were saying C load because that's what they have or read. The TJ Rubicon did come with E load MT tires, and I never minded it, until the end when they were really worn. The reason I went with E originally was that the BFGs come with a 3 ply sidewall, the C load is 2 ply. Sometimes I encounter some sharp terrain and like the security of having a tougher tire, especially when I can improve the ride and mpg too! Talking with BFG, they confirmed what I had been saying on the rolling resistance, tho' they were surprised that I noticed that much mpg diff due to friction.

BFG also told me the new KO2 is a made with a different compound from the KO. which makes it ride softer. Funny I read a few negative reviews on Tire Rack from die hard KO users who run E loads on their big pickups, and they gave the KO2 a lower rating because they said the tire was not as firm in handling as the KO's they ran religiously. That's why I was saying I didn't like the blanket statement out there on E's vs. C. Tires are changing and one brand might not be same as another, etc.. Like I always say, you really don't know... until you know. gotta try for yourself.

 

[CasterTroy]

Wow...so much hostility and defensiveness. Feels like I walked in on my wife watching some reality show. I'm like Billibob though in the sense it WAS kinda exciting.

I'm forced to run E on my dually because of what it's "capable of" but if I had my choice I'd slap some C's on that bad boy to reduce the level of fornication my spine attempts with the base of my skull while rolling down the road. I've dropped the pressure to 50Fr and 45Rr which helps a bunch, but man....I can't imagine the teeth I'd lose running full pressure E's on my TJ. Hell I run 28/25 in the C's I have on there now (chalk tested, wifey approved)

I had some buddies that use to run 47 LTBs on their yoyota rigs. They'd pull the valve stem out and leave it at camp when wheeling (sidewalls so stiff it didn't need air) and never break a bead.

 

[Jeff Allan]

50 psi?!!! that's insane. I'm at 32 and it's beautifully smooth.

Just this morning, we went to our daughter's Christmas show for school, my wife says, "jeep rides nice with the new tires".

The jeep is riding so smooth, noticing mileage is WAY better. So far, I'm saving about one tank a month!! Nothing like saving $35-40 a month and getting to move up to a bigger tire..and these ain't even broke in. If I had stayed with the C's I'd bet it'd be at least an extra tank a month, I could physically feel that I had to push the gas pedal down further to get moving. 10 years driving the same vehicle with same tires, same routes, I really noticed it to be a big change.

Screw the letter rating, go by the actual tire's design and how it rides. I'm very grateful for DT and how they were very understanding and helpful.

 

[CasterTroy]

50 psi?!!! that's insane.

Door sticker has 75psi Fr and 60psi Rr for proper towing pressures

 

[Jeff Allan]

Door sticker has 75psi Fr and 60psi Rr for proper towing pressures

For E loads on a Wrangler? Unlimited? ..wow, didn't know that. Seems real high. BFG told me I should be at 35 according to their charts and my vehicle but mine's short wheel base I guess.

 

[CasterTroy]

I'm forced to run E on my dually ....... I've dropped the pressure to 50Fr and 45Rr which helps a bunch

 

[_swede]

For E loads on a Wrangler? Unlimited? ..wow, didn't know that. Seems real high. BFG told me I should be at 35 according to their charts and my vehicle but mine's short wheel base I guess.

That sounds like a C load pressure spec. E's are typically run in the 80 psi range on full size trucks. I have E's on my Tacoma and run around 45-50 psi. I'm on my third set now and even have a set of snows too. The snows I run higher pressure.

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[Jeff Allan]

That sounds like a C load pressure spec. E's are typically run in the 80 psi range on full size trucks. I have E's on my Tacoma and run around 45-50 psi. I'm on my third set now and even have a set of snows too. The snows I run higher pressure.

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I bet, I thought we were talking about Wranglers here. that makes sense now. 35 is what BFG recommended for my jeep/E load, but I like it at 32 seems to ride nice.

Nice truck! CasterTroy.

 

[Serbonze]

Back to this...I've been running 28psi in my 305/70/16 Cooper Discoverer STTs (which are an E load) based on recommendations from several posts. The load capacity of the tire was never brought up, it more along the lines of "for 33" tires you should be around 28psi".

Is that still the case with the stiffness of an E rated tire?

I'm still trying to wrap my head around all of this, and I think I'm just overthinking it.

 

[_swede]

Back to this...I've been running 28psi in my 305/70/16 Cooper Discoverer STTs (which are an E load) based on recommendations from several posts. The load capacity of the tire was never brought up, it more along the lines of "for 33" tires you should be around 28psi".

Is that still the case with the stiffness of an E rated tire?

I'm still trying to wrap my head around all of this, and I think I'm just overthinking it.

I disagree that one size fits all for pressure to diameter relationship. In general I have found that E rated tires require higher pressure to achieve the true diameter, low rolling resistance and correct tread contact patch than the equivalent C rated. Depending on the weight of your vehicle and personal preference, you may be well under the rated tire pressure. For instance, I have E load KM2s which are rated to 80psi but I've never kept it at that because then my mid size truck would ride like a wagon cart on wooden wheels I'm at about half that most of the time.

Post a couple pics of what your tires look like at 28psi and we can maybe give our opinion if they "look" properly inflated.

Perfect world would lend to pressure being the same on all four corners but that never seems to happen for me. Some people run less up front for a softer ride.

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