How can I measure Castor?

**alfaparticle** · #1 (**permalink**) 09-29-2006, 10:42 AM

Does anyone know of a fairly simple way of measuring Castor angle on a Spider/GTV?

Thanks,
Ed Prytherch, Columbia SC
74 GTV
79 Spider
88 Verde

**ghnl** · #2 (**permalink**) 09-29-2006, 03:43 PM

Well, I don't think it is easy to do at home! Here's one link Google provided:
http://www.quadesl.com/miata_alignment.html

Why not just take it to a good alignment shop? The Alfa is a little different than other cars (at least our Spider is). Print out the shop manual's procedure and ask if the shop will follow it. If they won't, go elsewhere!

**genericwood** · #3 (**permalink**) 09-29-2006, 06:01 PM

If you have the means to measure camber, then doing castor isn't that difficult. You just measure the camber change as the wheel turns by a set number of degrees. But I agree, in most cases, it is much easier to have a good alignment shop do it. Just getting a perfectly level pad on which to do the measurements often takes longer than just taking it to the shop. I agree that you need to be prepared to show the proper procedures to the shop, though. I once had a shop try to change toe with a tie rod, not the center link.

Erik

**alfaparticle** · #4 (**permalink**) 10-01-2006, 08:11 PM

I had forgotten that the complete car must be level for castor measurement. That would be tough to do in my garage or on my driveway. I have a pair of marks on my driveway for getting one pair of wheels level. That has been fine for measuring camber and toe.

My GTV had very light slow speed steering and wandered at higher speeds. I increased the castor by one turn of the adjusting tube and it is a lot better. I would be interested to know what they are set at as my spider, with narrower tires, has much heavier steering. I don't know if it is worthwhile to pay someone to potentially make it worse.

Thanks for the advice.

Ed Prytherch