Driveshaft RPM Collar Location Question
 

I am wondering if anyone is using the transmission yoke for their magnetic RPM collar? My pinion yoke is 2.280 diameter, closest next size larger collar is 2.375. I am not a machinist so no real good option there. My concern using the transmission yoke is the in/out movement and loss of proximity to the pickup. Appreciate any advice based on experience with this situation.

Re: Driveshaft RPM Collar Location Question
 

I've run my collar on the driveshaft yoke for over 5 years with absolutely no issues. Yes I'm sure the collar moves longitudinally a fraction or two as the rear suspension flexes but it's never been a issue on the data readings. I run a 12 bolt rear and I have never spent the time to purchase a longer rear gear yoke. The 1.5" collars are readily available from Racepak (2 magnet). I looked a few years ago for a 4 or 8 magnet x 1.5" but couldn't find one.
Make sure you set the pick-up location with the car loaded on all four wheels and not while it's on jack stands.

Re: Driveshaft RPM Collar Location Question
 

Thanks for the reply, plan to follow your advice. Best option I had so far was to machine a smaller collar to fit the rear yoke.