Trimming bump stops - necessary?

[OffTheWall503]

I can't find to find any consensus on this. In the Miata community, I know it was common to trim the bumpstops or put in shorter ones in place when adding lowering springs.

Has anyone ran into an issue of needing to trim the bump stops because of potential contact when stationary?

 

[Woods247]

I installed Swift springs and didn't cut them. I've had no problems with bottoming out. I had to cut them on my WRX but it's unnecessary on the FiST with Swift springs.

 

[OffTheWall503]

Good to know, as the Swift springs are what I'll be changing to. Are you on stock dampers?

 

[Woods247]

Yep. I absolutely love them. Initially I thought I'd end up going the coilover route at some point but I'm quite satisfied with the Swift/stock setup. Seems like Swift did their homework with the FiST dampers.

 

[OffTheWall503]

I just bought some Bilstein B8's so I'm thinking it will be an awesome combo.

 

[CanadianGuy]

Never heard the FiST needing the bump stop changed or trim. Read to keep them to avoid rubbing but not trim. Now since I ordered full or parts to build a strut I can tell you there is a base Fiesta bump stop and a fist bump stop.

 

[OffTheWall503]

Never heard the FiST needing the bump stop changed or trim. Read to keep them to avoid rubbing but not trim. Now since I ordered full or parts to build a strut I can tell you there is a base Fiesta bump stop and a fist bump stop.

I saw your post in the Bilstein thread. The FiST bump stop is C1BZ-3020-B, correct?

 

[Mr. Pickles]

the directions in my Eibach prolines said specifically not to cut them

 

[M-Sport fan]

Seems like Swift did their homework with the FiST dampers.

Their compatibility/symmetry with the stock FiST's damper valving is actually part of Swift's marketing policy for these springs.

 

[CanadianGuy]

I saw your post in the Bilstein thread. The FiST bump stop is C1BZ-3020-B, correct?

Yes C1BZ-3020-B is the correct part. I recently got my box of goodies so I just need to decide to keep stock height or go with the Mountune. THe stock spring were $15 CAD so cheap enough that I got them just to have. All OE parts (excluding the strut) was $130 cad shipped to my door. Should be around $80 USD from Tasca Ford. Cheap enough to get new parts to avoid messing with the original struts(older parts, dirty, etc...) and have them as back up or return to stock.

 

[OffTheWall503]

I think I'll be going the same route with my Bilsteins, it only makes sense so that once I'm ready I can just drop the factory ones and bolt these right in.

Do you know the part number for the rear shock "hat" or whatever the weird shaped mount is?

 

[OffTheWall503]

Found it:

http://www.tascaparts.com/ford/fies...ks-and-components-scat/?part_name=upper-mount

So the shock shaft feeds through that mount and then you install the nut on the top side?

 

[OffTheWall503]

All the parts for front shocks and rear mounts.

 

[CanadianGuy]

I did not get the rear top hat. Didn't think about it . Lol. But I think it's tied to the car not the shock.

 

[OffTheWall503]

Well crap, I guess I'll find out the hard way. Oh well, at least it was only $20.

 

[Capri to ST]

Just wanted to share my experience with my other car, which is that cutting bump stops in some applications is absolutely necessary. I lowered it about 2/3" F and 1" R on Tein S-tech springs, which are supposed to ride about like stock. The ride instead was very harsh, hitting very hard on minor road irregularites and manhole covers. It turned out that Tein rec's cutting the oem bump stops about 2/3" in the front only, about the same as the amount lowered. I guess the front of an NSX has less travel. In fairness to the mechanic, the instructions were on an obscure place on Tein's site, but he was supposed to be a specialist and should have figured this out.
After lots of research I figured out why the ride was so harsh and had to have new bump stops, properly cut down, installed. This helped the ride harshness a lot, as the mechanic who did this said it looked like the car was riding on the bump stops about half the time before. If you're riding on the bump stops, you basically have no suspension.
So I would pay careful attention to whether they need to be cut down.

 

[OffTheWall503]

Your mileage may vary, at that point I would go by your particular application and see if the manufacturer recommends cutting them. As another member said, Eibach specifies to keep the bump stop intact.