Why extend bump stops. Should I extend mine? (1 Viewer)

[leonard_nemoy]

I have always assumed extended bump stops were kind of a band aid for clearing tires without enough lift. I am starting to suspect this is not the case.

Could someone enlighten me as to why so many rigs have extended bump stops?

What got me thinking about this is my rubbing issue. 315's with a 2" ironman lift, 30mm ironman spacers in the front, and I have even pushed my front axle 1" forward with the eimkeith RAM mounts.

With 3" of lift and the axle move I am still rubbing on my front drivers tire, what gives?

The rubbing happens when I am going 20 - 30 mph on dirt roads and hit decent bumps or ditches. Here is where it last happened going about 30mph.

Everybody says a 2" lift will clear 315's, either they are all wrong or something is wrong with my rig.

Do I need to extend by front bump stops?

Thanks

 

[enox]

I'm on 315's
3.5" front (heavy)
2.5" rear (heavy)
castor correction plates.

Never heard rubbing. I don't rock crawl aggressively but I do like to articulate..

I've wanted to install hydraulic bump stops to soften the impacts when bottoming out, but I've yet to really have an issue with it.

Edit*
I think your lift would be equivalent to my lift if I was on 37" and if I was on 37" they would clear but there would be some rubbing for sure..

 

[jonheld]

If your tires don't rub, you can fit bigger tires.

 

[Shoredreamer]

What rim offset? Wheel spacers? An aggressive bottom out with 315s on stock bumps could hit the fender I guess. Seems also like if you are bottoming out on a dip like that in the trail, you may be undersprung.

 

[leonard_nemoy]

I'm on 315's
3.5" front (heavy)
2.5" rear (heavy)
castor correction plates.

Never heard rubbing. I don't rock crawl aggressively but I do like to articulate..

I've wanted to install hydraulic bump stops to soften the impacts when bottoming out, but I've yet to really have an issue with it.

Edit*
I think your lift would be equivalent to my lift if I was on 37" and if I was on 37" they would clear but there would be some rubbing for sure..

I never rub when flexing or articulating, it's only in dips and little washes at speed.

What rim offset? Wheel spacers? An aggressive bottom out with 315s on stock bumps could hit the fender I guess. Seems also like if you are bottoming out on a dip like that in the trail, you may be undersprung.

The dip in the picture is deeper than it looks lol.

No wheel spacers, I am not sure on the offset, but if I am reading the discount tire receipt correctly the offset is -6.

The rubbing is on the outside of the tire, I think it is contacting the bottom outside part of the fender behind the tire.

 

[Pascoscout]

So far as I understand there are really only two reasons you would extend your bump stops. One is if your tires rub and the other is if your shock bottoms out before you hit the bump stop.

Much more than tire height comes into play when dealing with rubbing. Tire width, wheel width, wheel back spacing, wheel spacers, axel position all matter. If you're rubbing the lower outside lip of the fender your tires might be too wide or your backspacing might be off. Think stock on an 8 inch wheel is -10mm. Where on the tire is it contacting? Top of the tread or somewhere on the side wall?

I'd also make sure the stock bump stop hasn't been damaged or shortened somehow. You might also try replacing it with a stock version, it's possible the material is just too far gone to stop the axel movement when its supposed to. The extensions are just spacers usually so you're not out anything if you do end up extending it.

Another option is a body lift. A 1" lift may get you the clearance you need without reducing your up travel. Many opinions on body lifts out there but I have one on my cruiser and it's presented no issues. I would not go more than an inch though.

 

[leonard_nemoy]

Where on the tire is it contacting? Top of the tread or somewhere on the side wall?

Top of the tire, about 1" from the outside edge.

That is a good point about worn out bump stops, I didn't think about that.

 

[leonard_nemoy]

It is definitely worse on the drivers side. Could the OEM front panhard be to blame?

 

[BILT4ME]

It is definitely worse on the drivers side. Could the OEM front panhard be to blame?

Yes, because it is fixed on that side of the truck. As it is lifted, it will pull the front axle to that side.

 

[Pascoscout]

It is definitely worse on the drivers side. Could the OEM front panhard be to blame?

Maybe. The suspension lift changes the side to side position of the axel. The axel is offset slightly to one side at factory height, I forget which way though. A lift will effectively shorten the horizontal distance between the two pan hard rod mounting points, shifting the axel to the drivers side. You could shift it back with an adjustable pan hard rod.

 

[Pascoscout]

Top of the tire, about 1" from the outside edge.

That is a good point about worn out bump stops, I didn't think about that.

If it's that far into the tire I don't think the pan hard adjustment will move it that much. With my 3" lift the axel shifted over about 3/4 inch. May be a combination of the pan hard rod and slightly wider wheels/tires than stock.

As I understand the front bump stop is a progressive type, not a solid rubber like the ones on the frame in the rear. They allow some compression before they fully stop the axel movement. Stands to reason they may not work as well to stop movement after all these years.

 

[leonard_nemoy]

Now that I am thinking about it........ I am worried that maybe we installed the springs in the wrong spots. The ironman suspension was installed by myself and a couple other of guys. We were all going to town and working pretty fast. One of the other guys helping with the suspension has owned a bunch of 80 series and is a local expert. I just trusted him when he handed me a spring and told me to stick it in.

Are the ironman springs location specific?

 

[White Sheep]

Now that I am thinking about it........ I am worried that maybe we installed the springs in the wrong spots. The ironman suspension was installed by myself and a couple other of guys. We were all going to town and working pretty fast. One of the other guys helping with the suspension has owned a bunch of 80 series and is a local expert. I just trusted him when he handed me a spring and told me to stick it in.

Are the ironman springs location specific?

Not sure on the ironman's but when I did mine, the stock and OME springs are a pinch taller on the driver's side.

 

[Nay]

Measure the distance between your tire and fender and then the spring cup on the axle and bump stop.

There’s no reason to guess. If the bump stop distance (including compression on the front) is greater than the tire distance, it’s going to hit. Extend as needed.

Typically you have longer shocks with a lift and travel has therefore moved downwards, so you want to extend the bump stops to protect the shock as it shouldn’t act as a travel limiter. They really aren’t for just keeping tires off the body in a properly designed suspension, because that costs you shock travel. But, that’s more about tuning and just a general bit of info to your question.

 

[leonard_nemoy]

So I have decided my next steps.

1. Check springs for #'s and call ironman if I can find any #,s on the springs to verify correct placement.

2. Replace factory bump stops.

If these steps don't correct the issue than.....

3. Adjustable panhard

4. If all else fails extend bump stops.

Fyi, here is where the tire is rubbing...

 

[BILT4ME]

Fyi, here is where the tire is rubbing...

But where on the body/frame?

 

[leonard_nemoy]

But where on the body/frame?

I think it is hitting the fender behind the tire at the bottom......

 

[leonard_nemoy]

Measure the distance between your tire and fender and then the spring cup on the axle and bump stop.

There’s no reason to guess. If the bump stop distance (including compression on the front) is greater than the tire distance, it’s going to hit. Extend as needed.

Typically you have longer shocks with a lift and travel has therefore moved downwards, so you want to extend the bump stops to protect the shock as it shouldn’t act as a travel limiter. They really aren’t for just keeping tires off the body in a properly designed suspension, because that costs you shock travel. But, that’s more about tuning and just a general bit of info to your question.

I will do this also

 

[leonard_nemoy]

But where on the body/frame?

Alright, I just spent 30 minutes crawling under the truck measuring a closely inspecting the wheel wells. It actually looks like I am rubbing at the very top of the fender.

Measure the distance between your tire and fender and then the spring cup on the axle and bump stop.

Nay, I just finished taking measurements.

Drivers front top of tire to the top of fender: 6.5"

Drivers front bump stop to spring cup: 5.5"

Passenger front top of tire to top of fender: 6.75"

Passenger front bump stop to spring: 5.5"

Will the bump stops compress more than 1"? If so I guess I should just extend them.

As for the springs, the two rear springs were both marked toyo25c n/s k0417.

The front passenger was marked toyo24c n/s k116.

The front drivers spring was marked toyo24c d/s k116.

This leads me to believe that the springs are in the correct location.

 

[BILT4ME]

Alright, I just spent 30 minutes crawling under the truck measuring a closely inspecting the wheel wells. It actually looks like I am rubbing at the very top of the fender.



Nay, I just finished taking measurements.

Drivers front top of tire to the top of fender: 6.5"

Drivers front bump stop to spring cup: 5.5"

Passenger front top of tire to top of fender: 6.75"

Passenger front bump stop to spring: 5.5"

Will the bump stops compress more than 1"? If so I guess I should just extend them.

As for the springs, the two rear springs were both marked toyo25c n/s k0417.

The front passenger was marked toyo24c n/s k116.

The front drivers spring was marked toyo24c d/s k116.

This leads me to believe that the springs are in the correct location.

I'm not an authority, but looking at it geometrically, I would say a correct length panhard bar would be the first step, then new bump stops.

The right side doesn't rub because at full articulation, the tire is deeper into the wheel well at full stuff.