yuba Posted February 27, 2023 Share Posted February 27, 2023 (edited) Hi, I was looking at a set of inverted Bilstein B6 for TT5. I noticed that the shock body moves and the shock shaft with the piston is stationary and hidden inside of the shock body, it measures 14mm. The exposed shock body is greater than 40mm (can't remember the size off the top of my head). The rule listed in the 5 rulebook is: Non-OEM shocks/struts with an external reservoir (or piggyback) OR with shaft diameter 40mm or greater shall be assessed a Modification Factor. Before I spend a bunch of money and end up sad, does the rulebook use the actual shock shaft size (14mm) for inverted struts? Thank you Edited February 27, 2023 by yuba Quote Link to comment Share on other sites More sharing options...
National Staff Brett B. Posted March 1, 2023 National Staff Share Posted March 1, 2023 Your post: The exposed shock body is greater than 40mm. Does that refer to the yellow housing? The rule: 7) Non-OEM shocks/struts with an external reservoir (or piggyback) OR with shaft diameter 40mm or greater shall be assessed a Modification Factor. The way I read your post and look at the picture, the critical dimension is the outer diameter of the larger of the two internal shafts. If it is less than 40 mm, then no modification factor applies. Quote Link to comment Share on other sites More sharing options...
yuba Posted March 3, 2023 Author Share Posted March 3, 2023 (edited) On 3/1/2023 at 12:56 PM, Brett B. said: Your post: The exposed shock body is greater than 40mm. Does that refer to the yellow housing? The rule: 7) Non-OEM shocks/struts with an external reservoir (or piggyback) OR with shaft diameter 40mm or greater shall be assessed a Modification Factor. The way I read your post and look at the picture, the critical dimension is the outer diameter of the larger of the two internal shafts. If it is less than 40 mm, then no modification factor applies. No, the shock is assembled as shown above - the left side bolts to the camber plate, the shock housing (large silver) inserts into the yellow housing, and the thin shock shaft goes through the bottom of the yellow housing and has a bolt. The shock body travels up and down while the rod is stationary, unlike a traditional shock where the shaft bolts through the camber plate and moves through the body. Anyhow, that is interesting, okay, thank you. Edited March 3, 2023 by yuba Quote Link to comment Share on other sites More sharing options...
National Staff Brett B. Posted March 3, 2023 National Staff Share Posted March 3, 2023 (edited) Oh, I see. This ST stuff makes my head hurt. I'll see if I can get you answer. Edited March 3, 2023 by Brett B. 1 Quote Link to comment Share on other sites More sharing options...
National Staff Greg G. Posted March 5, 2023 National Staff Share Posted March 5, 2023 If the shaft itself is 14mm, then it is not 40mm. There are shocks where the shaft is 40+ mm, but they are getting more rare. 2 Quote Link to comment Share on other sites More sharing options...
National Staff Brett B. Posted March 5, 2023 National Staff Share Posted March 5, 2023 Thank you, Greg. 2 Quote Link to comment Share on other sites More sharing options...
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