Lower-pro tires to reduce bed height

[Guywithatruck]

I have a stock 99 B2500 which is gonna be needing new tires soon. Since I use it a lot for loading up motorcycles (and car parts and dryers and etc), I was thinking of getting 225/60s or maybe even 50s instead of 70s since it'll bring the bed height down a couple inches more. Do you guys think this is worth it or will it end up looking like crap with too tiny tires? I'm not really interested in buying and installing lower kits or anything like that since I'm just using it as a beater.

 

[Earl43P]

Look at the rear axle spring perches and see if there is any lift block, remove it.

Smaller tires will make the speedo inaccurate, only fixable by re-programming the PCM or 4WABS module if you have 4wABS. Might not matter if you don't go much smaller.

It'll also lower your effective gear ratio, making it accelerate peppier. Here's a calculator to help you out. http://www.miata.net/garage/tirecalc.html

Going down from 245/75/16 to 235/75/15 made my 2000 3.0 4wd peppier, big time.

I wouldn't go shorter than a 60 series tire myself. They ride a lot stiffer (more jolts) but the handling will be improved if you "like to corner".

 

[Guywithatruck]

Just checked the leaf springs and there's no blocks of any kind.

Looking at it now I don't think I'd go any smaller than a 60 series either, just cause the wheels and tires already look small in the wheel wells. According to that calculator that'll be 1.8 inches lower, not bad for tires I'll need to buy anyway. Thanks.

 

[Surrey]

Is that 1.8" lower, or 1.8" of tire difference? Keep in mind half the difference in tire size is on the top side.

 

[TheTopher]

Switching to a lower profile tire will of course give you a smaller overall tire size and will have the same effect as switching to a lower gear ratio in your axle, it'll throw your speedo off and give you a little more power and possible affect gas mileage.

If you want a lower bed height, I'd suggest also looking at the possibility of a shackle flip. It can be done for the cost of a couple bolts and will give a considerable height change. Just take some measurements and make sure you won't have rubbing issues afterwards.


http://www.therangerstation.com/tech_library/64-inch_leaf.html

 

[Guywithatruck]

That shackle flip looks pretty simple but won't I end up with an uneven truck then with the stock front? Unless there is a cheap fix for that?

The 1.8 figure I got from that miata calculator, wheel and tire diameter of 27.4 stock vs. 25.6 with the 60 series.

 

[TheTopher]

The 1.8 figure I got from that miata calculator, wheel and tire diameter of 27.4 stock vs. 25.6 with the 60 series.

That'd give you a height difference of .9 inches.


The shackle flip could possibly make the back lower than the front, but so would anything that lowers it a significant amount. As far as loading things I don't know if I'd even notice a one inch difference.

My rough guess is that the shackle flip would put you somewhere in the 3-4 inch ballpark. But again that's just a guess.

 

[Guywithatruck]

Yeah it's not like it's difficult to load stuff as it sits now, just was thinking about making a good thing better. But maybe I'll just stick to stock and stock size tires cause of the gas mileage.

 

[DRanger024]

Stick with the stock tire size and do a shackle flip. The flip will drop the rear of the truck 1.5 to 2 inches which is more than you would get with smaller tires that will look crappy and throw the speedo off. Also, with the shackles flipped, your truck wont have a saggy rear unless its loaded down. Empty it will sit level or have a slight rake yet. Try it, and if you dont like it change it back. You will only be out about 8 bucks in hardware and maybe 3 hours of your time.