anyone know what weight oil is typically found in a racing shock Strut??

LAT has great shock oil

It typically depends upon the manufacturer or tuner who sets up the suspension, and even one manufacturer may use different viscosities depending upon the application.

I have a set of Struts that (one) developed a leak at the top seal, considering there is only one lip seal and two O rings inside them, I simply wanted replace the seals/O rings and replenish the oil. The mfg didn’t/wouldn’t tell me the visc only stated to use 50wgt if I wanted to stiffen them up until I can send them in for service. Well its $300/strut to install $10 in seals and O rings and oil in struts that are working fine otherwise. I don’t want to stiffen them up so I guess I'll have to do some comparative analysis, at least I know it’s less than 50 wgt…

Go to a Motorcycle place, they sell all kinds of shock oils

"Old school" motorcycle front suspension regularly used "fork oil" with advertised weights of 20 - 30. When the more sophisticated cartridge-style forks using tunable stacked shims came into play, those units were typically spec'd to use 5 - 7.5 suspension fluid. One of the reasons was because the heavier weight lubes broke down so much faster when exposed to on-track demands. I just found this list of various manufacturers' suspension fluid specs to use for reference. Maybe it'll help. https://transmoto.com.au/comparative-oil-weights-table/

Wow, what manufacturer has that "customer service" policy?

When I contacted Koni about rebuilding my SPA1 front shocks, the quote was more than I paid for the shocks when I bought them new.

I don't recall if I threw them away or parked 'em on a parts shelf to be forgotten until my next cleaning spree. All I know for sure is I didn't bother w/ them after that.

I agree with CSK. I would be tempted to have a motorcycle place do them. $300 is just stupid. A good tech may be able to get close on the oil weight just by examining what is currently in them. There is a guy here who does offroad stuff and he quoted me $70 to change the shim pack for an air shock that had both nitrogen and oil. He had a machine that would show the difference in dampening rates before and after.

Im not going to name names as that wasnt the point of the post and I dont feel they have "Wronged" me. They are on par with the other suspension mfgs with their policy’s and pricing. They (and others) sell it as a "Freshen up" and I am probably minimizing their efforts. I have already taken the offending strut apart and all looks good aside from a weeping seal, so fresh oil, new seal/orings and back in service they go. I can find oil easily enough I was looking for input to save some time. Looks like Im starting with a 30wgt synthetic shock oil as that is what viscosity it moast closly compares to.

You'll find as Brad said 5-7.5 weight is the norm for what we do. I woudl guess by the price Strange is the strut in question, one for the price two for the issue.

I paid $575 per pair, for revalving new Afcos. Pretty typical for what I priced, summer 2021.

Shock Dyno?

It likely was- I am a bit out of my depth here. I have heard of a shock dyno but he didn't call it that at the time. My issue turned out to be something different so I didn't wind up revalving them. Ya called me out!

You are fortunate to even find replacement seals. Some vendors hold you up with non-serviced replacement parts.

(except by them, of course)

In my experience there are few brand specific seals in the after market industry, most are "stock" type items. Its too costly to have a proprietary seal made based on cost vs volume of sales. When I disassembled the strut I measured the O rings and found the part number on the seal. I even ordered them from a less than cost effective place McMaster-Carr.