pull bar bushings

[Flyin Iowan]

I may be over thinking this because its just a rubber bushing but what brand holds up the best? I have a quick car bar. quick car, southwest speed, xfactor???

Thanks

[Flyin Iowan]

Also, how many nights/laps do you get out of them? Looking for something that goes more then 3 nights if i can

[RRR_Products]

Also, how many nights/laps do you get out of them? Looking for something that goes more then 3 nights if i can

It would depend on many factors. The best way to determine life is by knowing what type of loads they're achieving. To simplify this understanding usually a bushing/biscuit shouldn't be compressed more than 25%. The more you compress these the more often they will need to be changed. Also the more biscuits there are the less you will be compressing them and the more tunable it will be. Also, when choosing a Pull bar for your car write down the pros and cons of them all(price, reliability, tech support, maintenance, etc). Another factor I've found in most bars is the chemical structure used to manufacture the bushings lacks in rebound. This can cause a loss of pre load which leads to an inconsistent car. Any other questions please email. RRR_Products@aol.com

[Flyin Iowan]

they split/crack and all preload is gone

[powerslide]

Flyin dont you run USRA/outlaw on american racers? If so thats likely why jeff's are lasting longer, he has the hockey pucks and only has 450hp.

[Flyin Iowan]

Flyin dont you run USRA/outlaw on american racers? If so thats likely why jeff's are lasting longer, he has the hockey pucks and only has 450hp.

Yes I did. switching to imca this year, no more tracks in iowa are open type rules. So maybe the switch(crate) will make them last longer

[dirtrace09]

That is a good point about the tires. I run ump mods and they last about half a season before you see them start to crack. I am sure the extra horsepower and tires do play a major role in it. What color (rate) bushings are you running?

[RRR_Products]

How do you know they need replaced at 3 nights?Ive measured durometer, uninstalled height on mine etc. no change after 15 nts. I have re measured my pre load etc, its never changed either.Ive never lost drive etc.

The pre load loss when we test is lost while in use. Meaning the rebound isn't adequate like a spring. Simple test would be to place these in your pull bar dyno or spring compressor and can see that they do not rebound like a coil spring. This is because the esters used are not formulated correctly per application. Example a 1/4" preload is lost once the urethane is compressed on throttle. On deceleration there would no longer be the same amount of pre load as when started when re applying the throttle. So you must use more pre load to compensate. Not all urethanes are the same. For instance in your 80 and up durometers rebound mixtures differ from 70 and below and cannot use the same compounds to achieve rebound as desired.

[Flyin Iowan]

That is a good point about the tires. I run ump mods and they last about half a season before you see them start to crack. I am sure the extra horsepower and tires do play a major role in it. What color (rate) bushings are you running?

southwest speed brand - 1 black(hard 88 durometer) 2 red(medium 70 durometer), they sit in the bar as B,R,R from back to front and the middle rubber splits

[JustAddDirt]

On these bushings that are cracking, are they stacked bushing to bushing?
Or are they separated with a thick conical washer, or a flatwasher?
I have only split a bushing 1 time, and the pull bar was getting a bit worn.

[Flyin Iowan]

On these bushings that are cracking, are they stacked bushing to bushing?
Or are they separated with a thick conical washer, or a flatwasher?
I have only split a bushing 1 time, and the pull bar was getting a bit worn.

brand new bar this year. no washers, bushing to bushing. i put a thin coat of grease on them

[JustAddDirt]

The grease could be a problem, as well as not having a conical washer on them.
These bushings are basically a Ford strut rod (64-73 mustangs), or the twin I beam support strut bushing (F-series truck).
Ford put a conical washer on them so they keep their shape, and to reduce deflection because they are constantly in compression, and constant movement.
You don't see them cracking or splitting in 4 trips to Wal-Mart do ya?

Just a thought

[Flyin Iowan]

The grease could be a problem, as well as not having a conical washer on them.
These bushings are basically a Ford strut rod (64-73 mustangs), or the twin I beam support strut bushing (F-series truck).
Ford put a conical washer on them so they keep their shape, and to reduce deflection because they are constantly in compression, and constant movement.
You don't see them cracking or splitting in 4 trips to Wal-Mart do ya?

Just a thought

Thanks, ill look into finding washers for this bar. the grease is to help with friction between the canister and rubbers

[MM90]

When I talked to BSB about pull bar bushings, they said to not use any chemicals to clean with or apply for lube because they react with the rubber and cause friction. They said they have seen them catch fire beacause a guy used WD-40. I also asked about the washer between the two bushings and he said when Terry Phillips was using his bar, he swears the bushing swapped places on him with one getting sucked through the other. So thats why they put a washer between them now, and it does affect the progressive rate of the bushings a little as does the posistion of where the bushings are located front to back.

[js11]

I'd recommend conical washers on the one side and flats on the other. I've run this set up with the bushings Joey mentioned for 8 years (same bar...worn out and everything) and rarely have issues unless there's a bind from the bar hitting a bracket, etc. I have the Quickcar piece that Chris mention also (as a backup) but haven't used it yet. FYI - I change my bushings probably twice a year (maybe three if the preload is really out of the ballpark) and just re-adjust the preload one or twice before changing. You'll know they need changed when you no longer have the forward bite you're used to having.