View Full Version : Advice on Bump Stops please
How have others worked out their bump stop extension?
I have just fitted new 265/70/17. On their madden voyage, the front tyres were rubbing on the ARB Bull Bar. I tried to pull it forward the bar to get clearance but no give. I think I need to extend my bump stops.
Do you extend them the same amount of lift? and do you take in account the tyres size as well.
Can any one Please suggest the right formula?
What were you doing when you got the scrubbing? If you were really flexing then maybe they might help but if it was normal around town driving you'll have to look at a different solution. I figured my travel on standard shocks and then what my new travel was with the new shocks and added bumpstops to prevent the shocks from compressing to much. All that time though I had no tyre problems but of course I'm in a JK with a bit more room for tyres especially after my flare mods.
Chris
It was full flexing upwards. It hits the arb bar front part, the wing- I looked underneath and it was not even close to touching the bump stops.
Correct me if I'm wrong but if you lift it 3" (as I) probably need need to extend the bumpstop 3" ?? Is that right?
How much gap should there be in normal static ride is my biggest questions
If I had about 3/4" more room, I think I would not have any trouble. Cutting the bar is my last option but may have too. hmmm
Hi Steve,
How much do you estimate vertically you would have to reduce your travel to clear the bar? Is the 3/4 inch to clear the front of the tyre or if you reduced your up travel by 3/4 inch it would not scrub? For me I would not be keen on reducing my up travel too much. I'd be thinking trimming the bar before reducing my articulation.
I did my bumpstop modification to save my shockers as I have long travel shocks in. What shockers are you running and how long are they compressed compared to your originals? Yes I have 3" Bumpstops added to my Wrangler on the advice of Bill from DoubleBlackOffroad.com I also have a 3" lift but my Jeep sits at around 2" with the weight I carry.
Ohh is that you on Ausjeep too?
Paul-JK
01-04-12, 12:02 PM
Hi Steve,
Did you change the control arms when you lifted it? I've just lifted my JK and put longer lower arms on to correct the castor and also to push the axle roughly back where it was as it will be pulled backwards when lifted. The reason I ask is that if you have longer lower arms (or even if you don't to be honest) might it be possible to put shorter upper arms instead to correct the caster? This will pull the axle backwards a little which might give you the clearance you need for the larger tires. Also, as the wheel travels upwards it also travels forward in an arc. With the shorter upper arms it will travel in a smaller (or steeper) arc which again might keep it off your bar.
All of this is pure speculation on my behalf, based on the assumption that the WG front set up is similar to a JK, and I've no idea if it will actually work or what else it may affect so best to run it by someone who knows suspension before trying it. Anyone who is more knowledgable than me about suspension (which wouldn't take much :smile-new:) feel free to shoot this idea down if it's not likely to help, or is likely to create more issues than it solves.
Simple and cheapest answer will be measure how much gap is there between the bumpstop when the tyre just starts to scrape... Add 1/4th of an inch to it and extend the bumpstops by that much.....
Yes I'm on ausjeep too.
It's the front of the tyre that hits and that's where I need 3/4" or so more space.
This morning I started early to install bumpstop spacers. I added 50mm (2.5") aluminium box. This has now left me with 1 & 3/4" bumpstop gap. It think that should be close to normal while still giving me plenty of upward travel. The shocks I have give me heaps of travel for my needs. Probably more than I need but the bilsteins are very good.
Compressed 14.98", Extended 24.61", Stroke 9.63". Shock sits at 19.8" unweighted, which is very very close to mid point of stroke, ((14.98+24.61)/2=19.8"). Thus that means about 4.81" equal up an down travel
I have attached an image and shown where it is hitting. I could trim the bar but it looks soooo nice uncut... unless some one knows how to do it with a professional look. I temporarily removed the inner plastic guard to have a better look around and no other critical components but ill replace it to protect the inner guards etc.
ps I hope I haven't bored you???
1338
Hi Steve,
Did you change the control arms when you lifted it? I've just lifted my JK and put longer lower arms on to correct the castor and also to push the axle roughly back where it was as it will be pulled backwards when lifted. The reason I ask is that if you have longer lower arms (or even if you don't to be honest) might it be possible to put shorter upper arms instead to correct the caster? This will pull the axle backwards a little which might give you the clearance you need for the larger tires. Also, as the wheel travels upwards it also travels forward in an arc. With the shorter upper arms it will travel in a smaller (or steeper) arc which again might keep it off your bar.
All of this is pure speculation on my behalf, based on the assumption that the WG front set up is similar to a JK, and I've no idea if it will actually work or what else it may affect so best to run it by someone who knows suspension before trying it. Anyone who is more knowledgable than me about suspension (which wouldn't take much :smile-new:) feel free to shoot this idea down if it's not likely to help, or is likely to create more issues than it solves.
Thanks for your input.
I thought about control arms as you mentioned but I have no room to move axle backwards, with shorter arms. If you see my other post with image, I have just enough clearance at the rear, not even 1/2". Lucky I had no issue with the rear of the tyre...
You're also right about the arc. The arms I have as they compress move the axle ever sooooo slightly, because my arms are almost horizontal with only a slight pointing down at front. This in actual fact helps me clear just a few extra mm's the rear of the tyre.
Thanks again
Did you try putting in about x2 washers in the steering block..... Had a similiar problem on the ZJ with a 2/3" lift.............. On full flex I would just clear the bit's where I was initially rubbing. The wife found the original set-up receipt from Suburan eeerrr, no mention of extended bump stops fitted/charge................ Trade off is a slighty larger turning circle, but 3 point turns you do them anyway.......... Only remaining issue was that the M/T lug's would just catch the inner lip of the guards on full flex, but a little rubber mallet always used to knock back up and as it is under/inside of the guard, it did not damage the outer part of the guards............
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