Larger wheels also reduce braking efficiency..

E2 · **Posted:** Sun May 10, 2009 1:58 am

Any thoughts?

JeepinJarhead03 · **Posted:** Sun May 10, 2009 2:03 am

it's more in the weight of the rim than the diameter

toy4everyseason · **Posted:** Sun May 10, 2009 2:09 am

Larger, heavier wheels should reduce breaking efficiency. The heavier rotational mass is both harder to get spinning and harder to slow down. Will you notice it? Maybe not if its just a few pounds.

JeepinJarhead03 · **Posted:** Sun May 10, 2009 2:14 am

toy4everyseason wrote:

Larger, heavier wheels should reduce breaking efficiency. The heavier rotational mass is both harder to get spinning and harder to slow down. Will you notice it? Maybe not if its just a few pounds.

pretty much, i don't think a 17 or even 18 inch rim that's within a few lbs of the original 16 inch rim will be noticeable

on the other hand i've noticed differences when swapping rims for the same diameter when the new rims weighed almost three times as much

same principle applies when you throw on larger tires, they weigh more thus going to be harder to slow them down

E2 · **Posted:** Sun May 10, 2009 2:15 am

Well I am really talking about 32" tires ie: 235r16/85 for me or others with even heavier ones if they go with 265r16/75 also 32"

Boblemoche · **Posted:** Sun May 10, 2009 2:50 am

larger tires increase the lever effect on the disk of the brakes so you will have to press harder on the pedal to brake the same even if the wheel is the same weight

32'' tires are 10% bigger than stock so you will loose 10% braking power.

JeepinJarhead03 · **Posted:** Sun May 10, 2009 2:58 am

im gonna ask somethin really stupid but you can tell me it's stupid after i ask it :lol:

one of my uncles used to have a trick for increasing the output of brake boosters on older chevy trucks, he did it to my cheyenne when i put the 44's on it and i could tell a pretty big difference, although it made it really easy to smoke the brakes...

there a similar idea you can think of that would work for our jeeps?

Boblemoche · **Posted:** Sun May 10, 2009 3:07 am

JeepinJarhead03 wrote:

im gonna ask somethin really stupid but you can tell me it's stupid after i ask it :lol:

one of my uncles used to have a trick for increasing the output of brake boosters on older chevy trucks, he did it to my cheyenne when i put the 44's on it and i could tell a pretty big difference, although it made it really easy to smoke the brakes...

there a similar idea you can think of that would work for our jeeps?

the only simple fix I can think of is replacing the brakes pads with better ones. I dont know how much difference it will make on a jeep but on my bikes its pretty radical

Diggerfreek · **Posted:** Sun May 10, 2009 1:12 pm

I have a set of napa adaptive one pads up front... they help, but there is still much to be desired

Mr Nick · **Posted:** Sun May 10, 2009 1:28 pm

JeepinJarhead03 wrote:

im gonna ask somethin really stupid but you can tell me it's stupid after i ask it :lol:

one of my uncles used to have a trick for increasing the output of brake boosters on older chevy trucks, he did it to my cheyenne when i put the 44's on it and i could tell a pretty big difference, although it made it really easy to smoke the brakes...

there a similar idea you can think of that would work for our jeeps?

What did he do? Only "trick" I can think of is putting the booster push rod on the hole in the pedal for manual brakes. Applies more leverage that way. I doubt the Liberty has multiple holes in the pedal arm to pick from. lol

I noticed my braking performance did drop off some with my General Grabber AT2's. Not because of the diameter (same as stock) but they are a lot heavier!

Boiler · **Posted:** Sun May 10, 2009 2:03 pm

Radial inertia is a factor of mass and radius squared. So if you increase the weight by 10%, its 10% harder to turn (or stop). If you make the radius 10% larger, you increase the effort by 21% (1.1 x 1.1 = 1.21). This is a simplification, as in if the rim stays in the same place & weight, a larger tire will only effect part of the inertia of the assembly.

Lastly, as these things do matter, its is only a portion of what your starting and stopping. The weight of the truck itself and friction with the ground makes the wheel want to keep turning. It might contribute so much to the equation that tire size changes aren't noticable. I'm not sure about that. I'm assuming its is in fact the large portion of the equation.

IMO the reason you need to regear for large tires isn't that the tires themselves are so hard to get going. Its leverage. 100 ft-lbs of torque at the axle would result in 6.66 lbs of tangential force at the tire tread for a 15" radius tire. Increase to 16.5 (33's) and that force drops to 6.06 lbs. 10% increase in tire size makes the same torque apply 10% less force on the ground to accelerate the vehicle.

Boiler · **Posted:** Sun May 10, 2009 2:07 pm

One thing you could do would be to use larger rims so you could fit in larger diameter rotors. The same clamping force applied farther away fromt he wheel center would give you proportionally more brake torque.

hrogi · **Posted:** Sun May 10, 2009 3:39 pm

To help off set some this is to add SS lines.
This heps for the fluid more direclty to the brakes.

Also if you over heat your brakes, change your fluid.
Also change your brake fluid once a year.

Most folks do not do this. I do it on my cars that get driven on windy road for increased safty.

Pads make a differance as well. So yes you can get upgraded pads, but there are trades off's.

More dust, higher temps, squeaks and grinding at time.

nightdrv · **Posted:** Sun May 10, 2009 7:08 pm

I can't believe I'm going to say this, but tjkj actually had a good suggestion from another thread... Powerstop (or Powerslot?) rotors, with NAPA ceramic pads. I am actually going to try this setup myself, as I notice brake fade quite often! Traffic sucks.

And yes, SS brake lines are the way to go!

I wonder if we can up our fluid rating to the next one? (ie DOT3 to 4)

tjkj2002 · **Posted:** Sun May 10, 2009 7:48 pm

nightdrv wrote:

I can't believe I'm going to say this, but tjkj actually had a good suggestion from another thread... Powerstop (or Powerslot?) rotors, with NAPA ceramic pads. I am actually going to try this setup myself, as I notice brake fade quite often! Traffic sucks.

And yes, SS brake lines are the way to go!

I wonder if we can up our fluid rating to the next one? (ie DOT3 to 4)

You can run DOT 4 brake fluid,no issues will result.Do not use DOT 5 brake fluid as it is silicone and will eat your rubber brake parts but DOT 5.1 is okay but a full flush will be needed for a switch to 5.1.

FL RENNY · **Joined:** Mon Nov 07, 2005 4:30 pm **Posts:** 458

Went from the 16" wheels to 22"........a little difference but nothing serious. She sure handles better though.... :wink:

Boblemoche · **Posted:** Mon May 11, 2009 7:08 pm

FL RENNY wrote:

Went from the 16" wheels to 22"........a little difference but nothing serious. She sure handles better though.... :wink:

you changed your wheels but you didnt change the brake rotors to fill those 22's didnt you :wink:

so there should not be a significant difference in braking performance in your case

tjkj2002 · **Posted:** Mon May 11, 2009 9:11 pm

Boblemoche wrote:

FL RENNY wrote:

Went from the 16" wheels to 22"........a little difference but nothing serious. She sure handles better though.... :wink:

you changed your wheels but you didnt change the brake rotors to fill those 22's didnt you :wink:

so there should not be a significant difference in braking performance in your case

No big brake kits available,bigger wheels and smaller tires with dinky rotors.

Boiler · **Posted:** Tue May 12, 2009 1:13 am

Wow, would be great to have a kit with a 3-4 inch larger rotor.

E2 · **Posted:** Tue May 12, 2009 2:03 am

tjkj2002 wrote:

Boblemoche wrote:

FL RENNY wrote:

Went from the 16" wheels to 22"........a little difference but nothing serious. She sure handles better though.... :wink:

you changed your wheels but you didnt change the brake rotors to fill those 22's didnt you :wink:

so there should not be a significant difference in braking performance in your case

No big brake kits available,bigger wheels and smaller tires with dinky rotors.

Nothing? Hmm I have heard of 4runners using the tundra brake / setup. Wonder if the commander or other larger jeep brakes or system would work...

Larger wheels also reduce braking efficiency..

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