Underdrive Pulley

[ptrudel]

how much of a smaller belt i need? parts store says he can get an inch shorter, or 1.5 inches shorter...which one will i need? anyone know? :huh:

[Vtolds]

Quick way to find out is to email/call rsm and ask.

[ptrudel]

need a 50" belt...just for anyone else that wants to know

[DRA-GON]

Cool lets us know how it goes for ya. I am looking at getting pulleys to.

[coredump]

Stupid question... what do the pulleys end up doing for you?

[Oldsman]

i have the UR pulley and i have to use a 450mm belt. stock is 475mm

[ptrudel]

Originally posted by Oldsman@Jul 5 2005, 04:18 PM
i have the UR pulley and i have to use a 450mm belt. stock is 475mm
Quoted post


um..wow..this is weird...your american speaking metric, i'm canadian and i need imperial...what the hell is 450mm in inches? :blink:

[Oldsman]

17.7165 inches

[Spilner521]

Originally posted by coredump@Jul 5 2005, 02:27 PM
Stupid question... what do the pulleys end up doing for you?
Quoted post



the crank pulley is lighter and smaller than the stock one. it lets the engine rev quicker which helps the car accelerate faster. you can also get an underdrive pulley for the alternator which will lessen the parasitic drag it puts on the engine, and lets the engine rev even a little quicker still.

[ptrudel]

Originally posted by Oldsman@Jul 5 2005, 05:12 PM
17.7165 inches
Quoted post



whoa whoa whoa...well then wtf was RSM talkin about a 50" belt for??

[ptrudel]

ok i'm confused scott...

i ordered a shorter belt, guy at parts counter said i can get it in 2 smaller sizes...1" or 1.5" shorter...i got one, and its 45.5"long...

so you're 17" belt doesn't add up nowhere in this...

[Oldsman]

the specs that belt manufacture actually put on their belt is in mm. what they do is take the stretch it out and measure from one side to the other.

now if you take the 450mm belt and cut it in half and then measure it it would be 35.433 inches.

So to say it another way they spec them as diameter size rather than circumference.

if the belt you have is 45.5 diameter it might fit on my durango or go around the pullies a few times.

so take your belt, stretch it out (very tight oval) and measure from one side to the other. should be 450mm or almost 17.75"

[ptrudel]

AHHHH.....


nevermind...i obviously got the wrong belt then...mine is 22" measured the way you described :angry:

[Oldsman]

what does the numbers on the belt say?

give me the part number off the belt and i could tell ya better

[ptrudel]

ok, the one they just sent me is a 5050460

i called a different parts store, and they agreed with your 5050450 belt, but they're expensive so i called back the other one, told him i need the 450mm and he says i could use the one he gave me...this is effin rediculous

[Oldsman]

a 460 belt should work fine.

what i have is a 4050450 belt

notice the last 3 digits

[ptrudel]

if i use a 460, it'll wear out quicker tho won't it? well..i'll have less adjustment to it for the tensionner?

[Oldsman]

oh wait............just did some digging and there specs are not mm but a 450 belt is 45.0" the stock belt is a 475 which means 47.5" which this appears to be effective length kinda like circumference.


end result you have the right belt

[Oldsman]

Originally posted by 2000_olds_alero@Jul 6 2005, 02:14 PM
if i use a 460, it'll wear out quicker tho won't it? well..i'll have less adjustment to it for the tensionner?
Quoted post



that depends on the diameter of the rsm pulley. i know with my UR pulley 450 belt i use about every bit of my tensioner. so you will have an easier time getting your belt on than me. being the rsm is not bigger around than the UR.

grab a 15mm wrench and go out and change the belt and find out. unless you don't have the pulley on yet

[ptrudel]

i don't have the pulley on yet..i'm changin it out tonight..but i REALLY wanna make sure i have a belt that'll fit..

[ptrudel]

the pulley's diameter is just under 5.5inches

[Oldsman]

i don't know what the UR diameter is so no help there for ya. sorry.

that belt size should work fine

[Oldsman]

did you get the alternator pulley too or no?

[ptrudel]

Originally posted by Oldsman@Jul 6 2005, 05:17 PM
did you get the alternator pulley too or no?
Quoted post


i couldn't afford it...i will be getting it eventually, but that'll mean a different belt again later :glare:

[ptrudel]

wow....3.5hours to get it done...i've got pics, just have to upload to my photobucket..i'll post...

i must say tho, that stock pulley is HEAVY and BIG compared to RSM's...its not a hold on to your shorts mod, but it is really helpful to get those rev's up a lil quicker

[ptrudel]

ooooo shiny
http://img.photobucket.com/albums/v208/2000_olds_alero/newpulley.jpg


no difference...
http://img.photobucket.com/albums/v208/2000_olds_alero/Pulleynewold.jpg