Posts by jonzjeepyj

Just when I thought I had my mind made up, you threw that in. LOL
I guess I have a decision to make. Very Good Advice. If I intend to eventually build this into a toy, Why do things twice. I really do like the 4" on 31's. Damn ! Decisions Decisions.

I have to replace my leaf springs due to bad sag and wanted to go a little taller. I posted in an earlier thread that I liked Yankee19934"s jeep before he put on his 33's

It was Yankee19934's 92YJ / 4"lift on 31" tires that I liked. The taller stance off the "stock" look.
Mine being a 92 YJ also, this is the look I'm trying to achieve.

Yankee's 4" on 31's
Mine would be 2" on 28s

Here is a shot of Yankee's 92 YJ and the look I'm trying to achieve

With that said, I bought the 4 banger for it's fuel mileage. A get to work and back rig that I can enjoy driving. I want to keep my fuel economy and don't want to regear at this time so I guess I'll down size one tire size from what I have now (235/75/R15) and get a 2.5" lift instead of a 4" lift. I'm now thinking of ....

2.5 RC lift on 215/75/R15's

This will give me a little better stance and still keep my 5Th gear and fuel economy for my highway driving to work. I read that any thing over a 3% diameter change in tire size is when you will notice a difference in performance. This will keep me under that threshold. I think eventually this will become a toy and will be built that way but for now it's a highway rig.

Now I need to pick out a tire, which should be easy in that size range. Again, a good beefy tire but good on the highway.

Recommendations ?

John

OK, I have been thinking about this and I think I got it.

Before I start, I'm not trying to tell everyone somthing they already know, I'm trying to work this out and in the proses, maybe some other members might get a better understanding of how this works as well as me.

If you were to take two tires with the same width and weight but different heights and apply them to the same gears, the difference in the equations would be revolution of tire per axle turn. Isn't that what ratios are all about. Picking your tire size and then selecting the correct gears to effectively put your motor in the proper power band to operate your vehicle. Keeping everything else relatively the same except height (weight and friction changes this a little and contributes some) your ratio changes from lets say 3.73-1 to 4.10-1 due to the longer revolution of the taller tire. This effectively changes the ratio without changing the gears and puts the motor out of it's power band. This is why it performs sluggishly and gives poor gas mileage.
As 2000Sahara said...

Quote

Adding Bigger tires without regearing takes the engine out of its optimal power range. For example, you will have to bring your rpm's up a bit more to get the tire moving from a dead stop due to its larger diameter and weight. By bringing the rpm up you are taking the engine above its power band, causing it to feel sluggish. On the other hand once you are moving down the highway at speed your engine may be running at a lower rpm which would usually mean better mileage however, because of the larger diameter and weight and improper gearing you need a bit more throttle to get moving...Hence poor gas mileage and wear and tear.

I think I'm starting to understand this now. Rolling resistance/friction and additional tire weight does play a small part and only makes this worse, but is not the main culprit.

How am I doing so far?

I was told that the 4cyl stick YJ's came with 4:10 gears, Is that true?

LOL!

No really, I didn't take anything. I just need to take a break. I went for a good soak in the Hot Tub.

Ok, I'm back
CAPTAIN

1) How does it ride?
2) Is your jeep a 4/6cyl?
3) Did you regear?
4) What was you loss in MPG?
5) What tire is it, The BFG AT KO?
6) Is there any other brands in that size?
7) Would a 31x9.5x15 kill it much more from a 235/75/R15--(29x9.25x15)?
Who makes 31x9.5x15's other than Interco and BFG?

John

I'm sorry if I came across wrong. I didn't mean to come across so strong. I guess it did sound like I was paranoid about people out to get me, LOL I didn't get you link to work. I'll try it again. I guess my kids are driving me crazy today and I took it out on you. I'm not looking for conformation, Just honest answers. I'm tired of getting the same answer without a reason. Some of the members gave me good input, and I'm starting to understand why and how this works. but there has got to be more. Like I said, I'll try your link again.

And by the way, When I said the kit was complete, It had everything in it I spoke about for that price.

I guess I'll go take a valium now and check back in awhile. Maybe I'll have a better perspective.

John

Quote

Do some more research before you just go and add a 4 inch lift, as you will find that there is more involved than just new springs.

Is it me or is everyone coming across like their aggravated with me.

Yes I know about all the other things. I have had my hard core wheeling days when I was younger.
Yes there is more then just throwing larger springs on like Pitman arms for steering correction, T/case lowering kits for proper drive shaft angles, Brake line relocation brackets or longer brake lines, longer shocks, bump stops bushings wedges for the rear leafs etc etc etc Blah Blah Blah Blah Blah. I'm talking about one issue, power loss due to larger tires and I wanted to discuss it with people who care about finding out the truth rather then just accepting the same old answers. Yes in short

Quote

Lifting=bigger tires= Poor gas mileage=Need for regearing=$$$.

This is not my first lifted Vehicle. Try my 7Th. I have learned a lot about how this work by asking questions and getting honest answers. I have lifted everything from a fords to Chevy's, Toyota's and now this is my third jeep. There is a hurricane blowing out there and I just wanted to talk to other jeepers and find out some info to make some tire decisions. That's what I'm trying to do. As I talk and discuss more ideas with members in this forum, I'm learning more. I'm not interested in beating my chest and being king of the sand box, just wanting some honest answers.

Nothing more, Nothing less.

Please stop trying to slam me.

First of all

Quote

No but he is.

Can't we as fellow jeepers talk about somthing without "slinging mud" at each other. No pun intended. I said I'm not claiming to know what I'm talking about, just trying to figure things out. Sorry if the conversation got too deep for you.

LOL vbquick1 I know what you mean. HMMMMMMMMMM, That explains it a little more. I knew there had to be something else going on. A difference of 16lbs, in my eyes wouldn't do it. There are probably more factors we are not thinking of. I do believe that by keeping the width down and minimizing the rolling resistance/friction will help with power loss!

Anyone else have any Theories?

OK but how would the motor know? Weight is weight,Yes No? So A tire with the same footprint lets say 9.5x15 but the only difference being the height 30 -33 and the weight.

30x9.5x15_______________38lbs each (total of 152)
33x9.5x15_______________42lbs each (total of 168)

Difference of...
***_ 16lbs total weight_***

Wouldn't that just prove "my theory" Rolling resistance / friction across the wider tire has more of an impact then tire weight? 16lbs of total weight compared to 500lbs of cargo/fuel weight/passengers would make that big of a difference?
I'm no expert and I don't claim to know what I'm talking about. I'm just trying to figure things out. LOL

Tire weight Info gathered from link below

http://www.tirerack.com/tires/…+T%2FA+KO&tirePageLocQty=

OK, I have been doing a lot of research and digging. Please help me out.

I want a taller tire. Clearance, stance and looks are all I really want. with that said, I wanted to go with a tire that is as tall as my Jeep would allow. I need to replace my stock springs due to sagging. I started researching springs/lifts for my 92 YJ. I came to the conclusion that if I'm going to replace my stock springs , then I might as well replace them with lift springs. The 2-2.5" range was about what I could afford, around the 400-500 dollar range. After doing some digging, I came across some pretty good deals on different lifts. Not only on the 2-2.5 range but also the 4" range as well. The difference of price between the 2-2.5" and the 4" lifts is very minimal. OK, so now I'm going with the 4" spring replacement lit. For the attributes that I'm looking for, a stage I or basic kit will work great for me. No hard core wheeling just highway driving.

Now that I have the kit picked out, I went digging for tires and wheels. HERE IS WHERE MY 2 CENTS COMES IN....
As you go up in tire size the width also increases.
30x9.5
31x10.5
33x12.5
35x12.5 or larger
I only have a 4 banger with limited power but want to go as tall as possible. Going from a stock tire of 205x75xR15 (27") to a 31-33" tire would kill the motors power and gas mileage, the gas mileage being one of 4 cylinders better features. Everyone keeps telling me it's the extra weight of the over sized tires is what would kill my motor. I think it has more to do with the rolling resistance of the *** WIDER *** not taller tires. People, cargo and fuel changes on a daily thus changing the weight sometimes dramatically, this changes the drivablity slightly but not too much for you to notice. A 250lb person can get in and out of your jeep as a passenger and you might not even notice any change. I think the rolling resistance of the wider tires has ** MORE ** to play in the power loss then the extra weight.

While looking for tires I came across some BFG AT KO's that were 33x (9.5) x 15's. Tall and skinny. I know there is a compromise on the handling, tire characteristics and performance when you have too much sidewall. The 33x9.5x15 is just about the tallest tire that you can fit on a 15" wheel. As of now I have 235x75xR15's (a 29" tire) which the width on them is 9.25". I still have a 5 gear and wanted to keep it that way if possible. The 33x9.5x15 tire would only be a .25 or a 1/4 of an inch change in the tires width, minimizing the rolling resistance. I was thinking of trying this set up...

I have come across a R/C complete lift shipped to my door for 432.00
The tires I can get M/B/I locally for 143.00 each (572 total)

4" Rough country lift complete 432.00
33x9.5x15 BFG TA KO's 572.00

Total ---1004.00--- ** ! W o W ! **

Has anyone used the tall and skinny tire setup? I have BFG TA KO's on my 2500HD Silverado and know what their characteristics are like. Just wanted to know if anyone has used a tall and skinny set up and how it handled?
Also, is there any other manufacture that makes this tire size? I think the cold weather Jeepers like the Tall /Skinny set up for the snow.

Thanks, John

What about Tuff Country's E-Z Ride System? They have a 2" lift that's reasonable. Again, taking my needs into account.

Who runs that shop?
John

I have already stated what my intentions are and how I will be driving the Jeep. As for Rough Country lifts, Please elaborate on that. I'll take and trust your advice but want to know why. Other then stiffness in driving, there is not much else in the performance department I'll need. Not looking for enhanced performance just drivability on the road, a taller stance with those 235 Yokohama's and to regain those lost inches up front due to aged sagging. I like the advice of replacing all the springs instead of using add-a-leafs. Now the question is since I'm not going to go larger with my tire size, do I want a 1.5 or a 2.5 inch lift. I'm wondering if 2.5" will be too tall with only 235's. I would like to keep the cost of the kit at or around 500.00 bucks. With my needs in mind, which kit do you recommend in that price range?

Thanks, John

Slimer said

Quote

You have to be careful with shackle lifts. Too much will affect your steering because it pushes the front of the spring down which can change your caster.

I'd also not use Add-a-Leafs because the ride will be stiff as hell.

I've thought about what you said slimer and have decided to go with a rough country 2 1/2" suspension lift complete. The kit includes everything

Front/Rear 2" lift leaf springs
New bushings / U-Bolts
T-Case drop kit
(4) hydro 8000 shocks

No Pittman arm needed for 2" lift. This is a new kit that Rough Country has just put on the market. I can get the whole kit shipped to my door for 480.58

Everyone's thoughts on Rough Country Lifts?

Thanks, I knew about the 15 to 20gal conversion. As far as the PCM? I talked to the dealer today and the part I need is the sending unit level kit. The pump is reusable. all you need are these two parts. If anyone else wants to change the level kit, here are the Part #'s......
20gal sending unit level kit ___( 6800-1830 AA ) ______18.20 /at Newark Jeep Eagle
gasket kit _________________( 5212-7833 ) _________11.30 /at Newark Jeep Eagle

I will replace the 15gal level kit with this 20gal level kit after I do the fuel tank conversion. The Dealer didn't know anything about the PCM chip either. I guess the P/O was blowing smoke up my XXX.

I was told when I bought my jeep two weeks ago that the 92 YJ was the only year that they used a pcm chip on the sending unit at the tank. I was also told it looks like a half moon and the size of a watch battery, a dealer item for 14 bucks and that's why my fuel gauge is not working.

Is this true about the pcm?

If so, can the whole sending unit be swapped out with another year in the YJ range without the pcm?

Will a 20 gal fuel tank fit in the stock position of a 15 gal tank on a 2.5/92 YJ?

Thanks, John

It was Yankee19934's 92YJ / 4"lift on 31" tires. I like the taller stance
Mine being a 92 YJ also. This is the look I'm trying to achieve.

Yankee's 4" on 31's
Mine 2" on 29's

Here is a shot of Yankee's 92 YJ and the look I'm trying to achieve

Only having a 4 banger, not wanting to re-gear and only using it as a daily driver for now, I wanted a better look and taller stance. I'm not going to wheel it at this point and don't want to spend the money to re-gear. The Previous owner had already upgraded to 29"/245 Yokohama's and I don't want to go any bigger until this rig becomes a toy. As for now, I'm trying to regain my lost inches due to sag and maybe a 1.5-2" lift for a little better stance since the tires were upgraded to a few sizes larger, from 205's to 245's. I know I don't need the extra height to clear the 245's but I like the taller stance. Another user showed me a picture of his rig after his 4" lift with 31" tires but before he upgraded to 33" tires. I really liked the look of the 4" lift on 31's. I thought I might try a 1.5" lift on 29's to try to achieve the same look.