Guest scott mich bca # 6619 Posted November 11, 2000 Share Posted November 11, 2000 My speedo is 10-15% fast. I think this is because I have put radial tires on, and the different size makes the tires go faster, compared to the original tire size.<P>Does anybody know how to adjust for this. I have heard that you can change the speedometer gear, but how would you know how many teeth to get and from where?<P>Or can a speedometer shop calibrate this on the car? I'm in the Chicago area.<P>Thanks,<BR>Scott Link to comment Share on other sites More sharing options...
Guest Posted November 11, 2000 Share Posted November 11, 2000 Tranny shop should be able to figure out, obtain and install the proper gears.<P>------------------<BR>Lee C.<BR>81 Electra Park Ave (350 original)<BR>83 Electra Park Ave (307 that wont die) Link to comment Share on other sites More sharing options...
Guest Posted November 11, 2000 Share Posted November 11, 2000 Hey Scott, I got the pkg....Thanks!!! <BR> As for the speedo gears, I recall Buick Farm having some of this stuff. Larger/smaller Dia. tires would mess up speedo calibration.<P> Drop me an E when you can!!<P> don55 Link to comment Share on other sites More sharing options...
old-tank Posted November 12, 2000 Share Posted November 12, 2000 Hi Scott<BR> When I use radials on my 55 Century (P22575R15 instead of 7.60-15) I use a speedometer gear out a 55 Special. The standard axel ratio in Centuries and R-masters is about 3.4:1 and in the special it is 3.6:1...this should get you within 1-3% and the gears should be available from your favorite used parts supplier (I recommend Wheatbelt).<BR>Good luck<BR>Willie Link to comment Share on other sites More sharing options...
Guest scott mich bca # 6619 Posted November 14, 2000 Share Posted November 14, 2000 Thanks Willie, that sounds like something I can do myself, and is simple enough.Either it will work or it won't.<P>Scott<BR> Link to comment Share on other sites More sharing options...
Guest scott mich bca # 6619 Posted November 19, 2000 Share Posted November 19, 2000 Willie,<BR> I tried to get the old speed gear out to count the teeth. Have you ever taken one out, while the trans was in the car. Seems next to impossible.<P>Can't seem to get the right tool on there and work it. I can get a socket on there, but once the ratchet is on it there is no room to turn it. OE wrench too big, crows foot, not enoght room for wrench either.<P>According to the parts book on the RM dynaflow, it calls for a 19 tooth gear. The range of teeth for all the models goes from 19 to 23.<P>I do want one with more teeth, right? The one you are specifing is listed as 20 teeth.<BR>You are also refering to a dynaflow model.<P>There is one listed for an export dyanflow model as 23 teeth. Please advise.<P>Scott Link to comment Share on other sites More sharing options...
old-tank Posted November 20, 2000 Share Posted November 20, 2000 Scott<BR>The 23 tooth gear would be for export axle ratio like 4.11:1.<BR>It's been awile since I changed gears so I'll have to get one of my cars over the service pit to check it out...I'll let you know.<BR>Willie<BR> Link to comment Share on other sites More sharing options...
The Old Guy Posted November 20, 2000 Share Posted November 20, 2000 I usually go to a trans shop and go through their truck speedo adaptors. They have units that screw on the trans and have ratios from .5-1 to 1.8-1 and you can bring your speedo very close without having to fight the old unit out<P>------------------<BR> Link to comment Share on other sites More sharing options...
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