One of the front Bilstein Shocks on my car is blown, I only figured this out til I had taken the entire car apart and was putting together a set of DIY Bilsteins. Had to pick up an overpriced Monroe strut to get back home, I can't find any used Hard-S Bilsteins locally, and I can't figure out where to order any used ones online. I have been searching the internet to figure out what part to order, my blown shock shows a part number of NO6734700, which is close to SixShooters pic of his Hard-S Bilsteins P/N of NC1234700, which is also a picture of a front Hard-S Bilstein, off of a 2000 Miata.



Is a Bilstein B8 the same shock as the Hard-S? I know that mazda changed the Hard-S Spring rate between the NB1 and NB2, but did they also change the Hard-S Shock Valving as well as the part number?

UPDATE - Found some Info, the part numbers for the 99-00 and the 01-02 bilsteins are different, shown in this archived forum post
Not sure if they are actually valved differently

 

A B6 is as close as you'll get OTS new to a Hard-S. The B6 & B8 have the same body length and are valved the same, the difference is the B8 has about 1" less stroke / droop travel (they'll have the same bump travel once loaded on the same spring).

There's not much documented about any valving difference between the two. Despite them being different part numbers, my money is on them having the same valving.

 

The valving is very different between them. You can find some old dyno graphs posted by fat cat that show the hard S with a digressive curve on the rebound and the B8/hd with a linear curve.

like i mentioned on facebook, keep looking hard S shicks pop up all the time.

 

Thanks Bronson for the clarification, I was sure the valving was different but I couldn't find solid evidence. Will keep looking around for a front Hard S Bilstein

 

You're getting confused.

The Hard S and NB B6/HD/B8 are basically the same valving. The NA OTS bilstein is probably what you're thinking of with the linear rebound.

The old dyno graphs from fcm that show that Hard S and NB HD/B8 have the same valving:

 

Also this one (which there no longer seems to be a full rez version of anywhere on the internet, this is from google's cached thumbnail):

Red/Blue lines are the NB Bilstein HD/B8 and Hard S. Orange is the MSM bilsteins, black is the NB OE Showas...

 

The spec miata shocks are definately linear rebound rates, and im pretty darn sure those are just HD's....but maybe im wrong. Even then the damping rates arent close enough that i would do just one.

 

I managed to find a junkyard that had two front Bilsteins on the front of a 2004 NB, those should arrive this Thursday. If they are different then I will just replace both of the fronts, but I believe from 1999-2005 all Miata Bilsteins (non msm) are valved the same.

 

Spec Miata are HD's but they're specifically the NA HDs...and that's different to the NB HD's that HowPrayGame would be interested in (and obviously have a different thread length/tophat arrangement, so aren't really relevant). They also ride like crap. Comp/rebound are flipped compared to the dyno's above, but they look like:

 

They're the same as far as anything posted in any of the Bilstein threads here or on the other main forums (pretty sure i've read all of them).

Should be fine to just swap one in, or could chuck both 2004 fronts on if you're feeling energetic.

 

Sweet, I will just throw the one on then, and then dial in my ride height. Time to find the optimum ride height for the harsh streets of Tampa

 

New (to me) Bilsteins are in, they are the same part number as my 2002, these came off a 2004. For future reference, Bilsteins on NB1s have a part number of NC 1234 700D, while NB2 Bilsteins have a part number of NO 6734 700. They both have the same valving and shock body, barring the part number. It would have cost me 239$ for a new NB2 Bilstein from my local dealer, so I would recommend buying used.


Both of them rebound the same, and are in very nice condition for the price I bought them for. Will put them both on tomorrow.