MXR Rear Shock v.1 vs. v.2

Tuner said:

The MXR (with correct serial number shock) has the firmest suspension. Some MXR's had softer valving than intended due to a miss by WP. Please see Phillip regarding details as we had this conversation by phone.

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The MXR valving is too soft for any real motocross for an average rider outside of riding vet tracks, so the EXR will be extremely soft. I have footage of Tony Williams at Cahuilla Creek MX and while he had lots of corner traction, you could tell the suspension was blowing through the stroke without him even fully jumping things.

TCMB371 said:

The MXR valving is too soft for any real motocross for an average rider outside of riding vet tracks, so the EXR will be extremely soft. I have footage of Tony Williams at Cahuilla Creek MX and while he had lots of corner traction, you could tell the suspension was blowing through the stroke without him even fully jumping things.

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Please inspect the shock serial number as stated earlier "Some MXR's had softer valving than intended due to a miss by WP. Please see Phillip regarding details as we had this conversation by phone." Short of Josh Hill, most top level riders have been extremely happy with the MXR production suspension, that is, providing the correct production valving was installed.

Tuner said:

Please inspect the shock serial number as stated earlier "Some MXR's had softer valving than intended due to a miss by WP. Please see Phillip regarding details as we had this conversation by phone." Short of Josh Hill, most top level riders have been extremely happy with the MXR production suspension, that is, providing the correct production valving was installed.

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This is the first I heard of this! How come no performance recall was ever sent out? I would consider the wrong valving boarder line dangerous! WP should have stepped up with recall!!!!

Tuner said:

Please inspect the shock serial number as stated earlier "Some MXR's had softer valving than intended due to a miss by WP. Please see Phillip regarding details as we had this conversation by phone." Short of Josh Hill, most top level riders have been extremely happy with the MXR production suspension, that is, providing the correct production valving was installed.

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Philip and I confirmed i had the updating valving. I posted the compression and rebound stack in the suspension section.

TCMB371 said:

Philip and I confirmed i had the updating valving. I posted the compression and rebound stack in the suspension section.

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I can only speak regarding those that I have tested with, and that list is quite impressive. That said, suspension is very personal and and it is quite difficult to make everyone happy with a single setting. As you are likely aware, rear sag is a critical component, and unlike most other manufacturers the Alta favors a laden sag of 80mm - 90mm as opposed to that of 105mm and up.

Hope this helps.

Tuner said:

The MXR (with correct serial number shock) has the firmest suspension. Some MXR's had softer valving than intended due to a miss by WP. Please see Phillip regarding details as we had this conversation by phone.

Click to expand...

Here are the illustrations of different MXR shocks:

Exhibit 1 -- A bad shock from my first MXR VIN #323:


Exhibit 2 -- A really good shock from my second MXR #445:




As you can see, the part numbers are different. The bad shock ends with a "1". The really good shock from a newer bike ends with a "2".

Tuner said:

I can only speak regarding those that I have tested with, and that list is quite impressive. That said, suspension is very personal and and it is quite difficult to make everyone happy with a single setting. As you are likely aware, rear sag is a critical component, and unlike most other manufacturers the Alta favors a laden sag of 80mm - 90mm as opposed to that of 105mm and up.

Hope this helps.

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Yup, you're totally right. Played around with different sag settings starting with the standard 105. Went as low as 85mm before i went back the other way and found 95-98mm is the sweet spot for me. Just recently bumped the spring rate up to 6.4kg/mm with 98mm sag and approximately 15% stiffer valving and it feels much better. I'm 185 without gear. I'm going to go another 20% stiffer on the compression and rebound damping in both the shock and forks. I think that will be the sweet spot.

@TCMB371 has the same shock as on my newer MXR. He posted its OEM shim specs here:

MXR Updated Stock Shock Valving

Tuner said:

As you are likely aware, rear sag is a critical component, and unlike most other manufacturers the Alta favors a laden sag of 80mm - 90mm as opposed to that of 105mm and up.

Click to expand...

I played with the rear sag today. I ran 102mm sag before because all the tuners recommended 100-105 mm sag. I was unhappy that the bike was understeering mid-corners.

To my shame I have never played with the sag before on any of the bike's that I owned. I kept hearing the advice to play with the fork heights and rear sag, but I didn't understand how such a small change in those tuning parameters could affect the handling so dramatically. Turns out it does.

I tried 90 and 80 mm race sags. With a 90mm sag the bike became more neutral it turns. With a 80mm sag it became too neutral and even a bit tail happy, enough so that I couldn't open the throttle on turn exits because it would oversteer right away, so that wasn't good. I went back to the 90mm sag. Will be fine tuning from there. Thank you, Dale.