35s.. performance ??

[billiebob]

Jp mag has an article on the 35 "upgrade".

..............................stock vs 35
0-60mph ............ 18seconds vs 30 seconds
60-0mph ............ 137 feet vs 218 feet
gas mileage ........ 15 mpg vs 9 mpg

sound familiar ??????

next month they will address gearing and brakes.

If the department of highway safety were paying attention.... all this would be banned.

 

[billiebob]

then again I remember the '70s

The threshold for stopping was 180 feet.
Corvettes and Mustangs did a bit better.... Torinos and Cadillacs did much worse.
Never saw a number for a CJ5 but I doubt it was any better than 180 feet.

 

[billiebob]

here is the link to the Jp mag article

http://www.fourwheeler.com/how-to/wheels-tires/1512-what-concessions-are-made-when-adding-big-tires/

 

[Chris]

Not surprising at all. Being a big motorcycle track guy myself I know that one of the best modifications you can do to your motorcycle aside from good suspension and brakes, is reducing rotating mass via light weight wheels.

When you add heavier tires and wheels, you are adding to the rotational mass. Most people have no idea what this means, but adding or removing weight through means of wheels and tires makes a huge, huge difference. It may not be as noticeable on a Jeep as it is on a motorcycle (trust me, on a motorcycle it's immediately noticeable, and I mean big time), but it's definitely a factor.

For this very reason I never understood why guys who daily drive their Jeep insist on a mud terrain tire versus an all terrain (the former always weighs considerably more).

 

[billiebob]

So the new Jp Mag is out. They did a big brake upgrade, new pads... and stopping from 60mph came down 10% to 198 feet... still a lot further than a completely stock TJ stopping in 137 feet.

All new when they did the test they are expecting an improvement as the pads/discs get properly seated.

 

[Chris]

It's funny to me that with Jeeps we're always trying to add bigger, stronger and heavier wheels / tires. On the other end of the spectrum (performance cars), you've got guys who are trying to get the lightest weight wheel possible, lightweight (and small) tires, etc.

It's amazing how much of a difference that rotational mass makes in regards to the overall performance of a car (i.e. brake performance, acceleration, cornering, etc.).

 

[StG58]

But, what are we doing with our Jeeps compared to what we are doing with a motorcycle? What's a Jeeps stopping distance 10 - 0 on dirt?

 

[billiebob]

Rotational mass is part of it. Leverage from a larger diameter tire is at least the other half.

 

[mrblaine]

So the new Jp Mag is out. They did a big brake upgrade, new pads... and stopping from 60mph came down 10% to 198 feet... still a lot further than a completely stock TJ stopping in 137 feet.

All new when they did the test they are expecting an improvement as the pads/discs get properly seated.

What big brake upgrade did they do? What pads did they use? As to the test on green pads and rotors, that's a bit silly. Fresh out of the box stuff has to be broken in, the bedding and seasoning process has to be started and if you don't do that, you may as well not even bother putting on new stuff, just keep the old stuff.

 

[billiebob]

Tried to find the online link to the article but no luck...
Jp Magazine, part of Four Wheeler publications. I always buy the news stand version.

Found the first article tho. These are the original test results.

Tire & Wheel Combo

265/75R16 Goodyear Duratrac on factory 16x7 Rubicon wheels
35x12.5R17 Toyo Open Country M/T on 17x8.5 AEV Pintler wheels

Weight 66 pounds vs 106 pounds

0-60 Aceeleration 18.6 seconds vs 29.6 seconds
60-0 braking 137 feet vs 218 feet
Mileage 15mpg vs 9mpg
Approach Angle 45 degrees vs 55 degrees
Departure Angle 40 degrees vs 45 degrees
Clearance Under Differentials 9.25 inches vs 11 inches

Love that change in gas mileage.... stock 15mpg.... 35s 9mpg !!

 

[VirtualRussel]

Approach Angle 45 degrees vs 55 degrees
Departure Angle 40 degrees vs 45 degrees
Clearance Under Differentials 9.25 inches vs 11 inches

Those are the important numbers

Love that change in gas mileage.... stock 15mpg.... 35s 9mpg !!

I don't have the article but I'm assuming they recalibrate the speedometer before calculating the mileage?

 

[billiebob]

^^^^ agreed. approach, departure, clearance can be very critical... off road.

They did all tests with GPS.

The number that catches my attention is stopping !! Stock 137', 35s 218'. I know my TJR stops better with stock size winter tires than the 33 MTRs I run in the summer but really 137' to 218' is a HUGE difference. 5 TJR lengths !! How many guys running 35s even think about that. We hear all kinds of input on gearing but does anyone running 35s plus on a Daily Driver / Mall Crawler consider the implication of an extra 80' to stop ? If you never see pavement, if you built a trail rig, it might be a small consideration but if 80% of yer driving is commuting, paved roads, are 35s, even 33s a wise choice ? I want to see the tests done stock, 33s, 35s, 37s.... Lets see some real world braking results all stock. Then lets see what all the big brake kits REALLY deliver. Same TJ, same tires, same test conditions.

 

[VirtualRussel]

The number that catches my attention is stopping !! Stock 137', 35s 218'. I know my TJR stops better with stock size winter tires than the 33 MTRs I run in the summer but really 137' to 218' is a HUGE difference. 5 TJR lengths !! How many guys running 35s even think about that. We hear all kinds of input on gearing but does anyone running 35s plus on a Daily Driver / Mall Crawler consider the implication of an extra 80' to stop ? If you never see pavement, if you built a trail rig, it might be a small consideration but if 80% of yer driving is commuting, paved roads, are 35s, even 33s a wise choice ? I want to see the tests done stock, 33s, 35s, 37s.... Lets see some real world braking results all stock. Then lets see what all the big brake kits REALLY deliver. Same TJ, same tires, same test conditions.

Those numbers are definitely shocking. I'm definitely interested in a real study with various brake & tire configurations on the exact same Jeep for comparison.

 

[mrblaine]

^^^^ agreed. approach, departure, clearance can be very critical... off road.

They did all tests with GPS.

The number that catches my attention is stopping !! Stock 137', 35s 218'. I know my TJR stops better with stock size winter tires than the 33 MTRs I run in the summer but really 137' to 218' is a HUGE difference. 5 TJR lengths !! How many guys running 35s even think about that. We hear all kinds of input on gearing but does anyone running 35s plus on a Daily Driver / Mall Crawler consider the implication of an extra 80' to stop ? If you never see pavement, if you built a trail rig, it might be a small consideration but if 80% of yer driving is commuting, paved roads, are 35s, even 33s a wise choice ? I want to see the tests done stock, 33s, 35s, 37s.... Lets see some real world braking results all stock. Then lets see what all the big brake kits REALLY deliver. Same TJ, same tires, same test conditions.

I can tell you that anyone publishing an actual distance number for anything other than grins and giggles is a fool. It is almost impossible to get a stopping distance measurement that is anything but an average of several stops and even then, the first and last stops will skew the average so much it is astounding.

I've been trying to find a way to do comparative distance results but ALL of the testing varies so much between each test, the results are useless. Tire style, road condition, temperature, humidity, and even lift height all affect stopping distances by a great margin.

What we consistently see is the first stop and the second are typically not within 20 feet of each other in back to back stops.

If anyone doubts this, I'd encourage them to find a safe place to test it but not at speeds higher than 45 maybe 50 mph.

Use a sign post, mail box, etc and hit the brakes from your target speed as soon as it lines up with a hood corner or windshield pillar. When you stop, get out and put a rock beside the road at the front tires. Repeat it in the same direction and see how close you get. If you can get 3 stops in a row within 15-20 feet, I'll be very impressed.

 

[mrblaine]

Those numbers are definitely shocking. I'm definitely interested in a real study with various brake & tire configurations on the exact same Jeep for comparison.

I've been looking for an affordable test meter for a few years. The only way I can come up with that makes any sense is one that measures G force very accurately. That would give very comparative results if you logged the conditions and other parameters.

 

[billiebob]

so Mr Blaine... you seem to have the resources plus access to a lot of TJs with various after market parts... how ' bout doing a test.... publish the results.... don't forget to include the testing methods/criteria. I've seen far too many biased tests. I got the impression Jp was out to publish real test results.... without bias.

Me ? Driving a Tj on 33s.... I knew there was a reason I did not want 35s for a DD.... Even with 33s after several "deer" panic stops vs the same with stock size winter grips... I know the 33s are a real compromise. But I do love them for the 10% off road I do.

 

[billiebob]

I'd trust tests done with one of these.... very old school...

 

[mrblaine]

so Mr Blaine... you seem to have the resources plus access to a lot of TJs with various after market parts... how ' bout doing a test.... publish the results.... don't forget to include the testing methods/criteria. I've seen far too many biased tests. I got the impression Jp was out to publish real test results.... without bias.

I'm guessing you would probably have to be living under a rock to not know what I do. I have been designing and building brake products for the Jeep, and Jeep Wrangler Platform for at least 12 years. I am the designer for all the Vanco Big Brake kits and currently have about 14 different applications that we build and offer.

I also have the best stopping brake pad you can use in the stock application.

I would not mind knowing the distances our products are capable of delivering but I doubt I would ever publish them due to liability reasons and the fact that most of the general public will tend to ignore any and all qualifiers about the test results.

If I say that you will see X improvement based on feet or a percentage, the first time someone rear ends someone after not being able to stop within the advertised distance, we're going to have a conversation I never want to have.

Also why I talked about the testing above. We've tried it, we've had customers try it and folks on the net have tried it. There is simply no way for the average person to do back to back tests and arrive at a conclusion worthy of publishing as a real number. I'd really encourage you to take your rig to a safe place and do a few back to back stops just to see how hard it really is.

Me ? Driving a Tj on 33s.... I knew there was a reason I did not want 35s for a DD.... Even with 33s after several "deer" panic stops vs the same with stock size winter grips... I know the 33s are a real compromise. But I do love them for the 10% off road I do.

I get it. But, dig around on the forums, there's lots of folks who clearly believe if you can push on the brake pedal and the rig will stop at some point, then their brakes work and there is no need to do anything else.

 

[Stinger]

Crap I knew there was a reason I ignored you.

 

[mrblaine]

Crap I knew there was a reason I ignored you.

Just one?