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Old 01-31-2009, 12:12 PM   #1
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Default Bump stops?

1. Has anyone cut their bump stops. I have a attachment from Racing Beat that I wouldn't attach.

But anyway you cut from the top all but 1/8h inch. Then you cut off the top corners, from the top bend inward making a slope, only leaving 1/8th of thickness. That way the contack of the bump stop to the shock is not messed with. It looks like it would work.
I'm going to try it, unless I find some cheap replacements.

2. What about switching top hats. Is it worth it?

I have Tokico Illuminas, Racing beat springs and swaybars.
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Old 01-31-2009, 12:21 PM   #2
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Todd; I can't open that pdf file.


Edit: nevermind, I saw you took out the pdf reference.
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Old 01-31-2009, 12:23 PM   #3
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Mabe I can just copy it.

The subject of shock absorper bump rubbers is not simple. The following recommendations are the result of long-term experience
with suspension tuning.
In general, anytime a car is lowered, the bump rubbers should be shortened. On a car equipped with struts, it is desirable to
shorten the bump rubbers by an amount equal to the amount of lowering. On an A-frame car (Miata, 1993-95 RX-7, etc...)
the bump rubbers should be shortened about 70% of the amount of lowering. Unfortunately, this can cause other problems.
The most notable is that, assuming that you start cutting the bump rubber from the top (as we recommend), you more
quickly lose the bump rubber ’s ability to grip the shock rod because you have removed the “reduced inside diameter” portion
- which is at the top (shown in dark gray). This allows the bump rubber to fall down onto the top of the shock body where it
may trap and hold dirt near the shock rod and seal.
Our recommendation is this: Cut off as much as possible from the top while still leaving 1/8” of the “reduced inside diameter”
portion, then chamfer the outer shoulder at 45 extending down from a 3/4” diameter circle on the top of the bump rubber.
In this way, the length of the bump rubber is reduced a bit, and the bump rubber’s “spring rate” is reduced a considerable
amount, and the bumper rubber retains the ability to grip the shock rod.
4789 Wesley Drive, Anaheim CA 92807 (714)779-8677 • Fax (714)779-2902
If you wish to see if the bump rubber is contacting the shock body under a particular set of conditions, try placing a small
piece of modeling clay on top of the shock body. This can assist you in understanding the dynamics of your suspension. If
the clay is quickly smashed flat, this suggests that bump rubber is coming into play too often and/or too much. The answer
may be a stiffer sway bar, more “bump” (compression) setting on the shocks, stronger and/or longer springs - or remove
more of the bump rubber.
One final caution: Most of the techniques you might use to shorten/reshape the bump rubber - sanders, grinders, saws and
knives - are dangerous. Plan your actions carefully to avoid injury.
Shortening The “Bump Rubbers” on
1999+ Miata Applications
45
1/8” 3/4”
After
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Old 01-31-2009, 12:43 PM   #4
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No this isn't Kenny. LOL
You get the ideal of how to cut it. LOL
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File Type: bmp 111.bmp (268.6 KB, 157 views)
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Old 01-31-2009, 12:45 PM   #5
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Basically cut into the red, and leave atleast 1/8th inch of rubber thickness everywhere for strength.

This is a little better than the drawn dead Kenny's.

And if I am wronge, please let me know. I don't want to jack this up. That is why i am asking.
It is better to ask and look stupid, than to mess it up and be stupid. LOL
Attached Thumbnails
Bump stops?-fixed_shock_boot.jpg   Bump stops?-better.jpg  

Last edited by Toddcod; 01-31-2009 at 01:07 PM.
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Old 01-31-2009, 01:12 PM   #6
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Quote:
Originally Posted by Rafa View Post
Todd; I can't open that pdf file.


Edit: nevermind, I saw you took out the pdf reference.
If you want to see the attachment I can forward it to you via your email. I couldn't get it to attach for some reason.

I'm going to look back over your thread on bump stops. My car is bottoming out too.
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Old 01-31-2009, 01:43 PM   #7
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Quote:
Originally Posted by Toddcod View Post
If you want to see the attachment I can forward it to you via your email. I couldn't get it to attach for some reason.

I'm going to look back over your thread on bump stops. My car is bottoming out too.
Don't worry. I already got what you're saying. If you are facing issues with the rear suspension, then: you need to change the tophats. Either use the ones sold by Dansecrations or get some NB ones. The problem with the rear is that the springs are too short.

In my case, I couldn't be more pleased with the results.


Hope this helps.
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Old 01-31-2009, 01:49 PM   #8
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Get some NB or FatCat bumpstops. They work waaaaaaaaaaaaay better than NA bumpstops.
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Old 01-31-2009, 01:53 PM   #9
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U should really try the FatCatMotorsports MCU stops or something similar. They made an incredible difference. Shorter and better engagement. They have them in different sizes and durometers(sp?).

It's like the NB style bumps. FM and GC sell some too.
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Old 01-31-2009, 01:54 PM   #10
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Quote:
Originally Posted by JasonC SBB View Post
Get some NB or FatCat bumpstops. They work waaaaaaaaaaaaay better than NA bumpstops.
Damn. beat me.
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Old 01-31-2009, 11:18 PM   #11
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FCM bump-stop crew. They're magical.
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