mrmustang Posted March 11, 2014 Share Posted March 11, 2014 Took the Birkin out of the garage this AM to install the sump guard I purchased from "11Budlite", clearly a standard item as everything lined right up and bolted right in. Took me all of 5 minutes.... Decided since that was done, I might as well take a test spin out and make sure everything was nice and tight. of course I lowered the tire pressures to 34psi (previous owner had them at 45-48psi) 38 miles later the car passed my inspection as well as the PA state inspection (safety, no emissions in my county). Car ran great, a little cool with the electric water pump, but I am sure as the temps get above 60, the water temps will rise as well. Did have one hiccup at a red light the car stalled (twice), but ran like champ otherwise. Will have to check on that one, along with why the heater fan was not working, but all very minor in my book. Again, a great day for a ride. Bill S. Link to comment Share on other sites More sharing options...
DavidL Posted March 11, 2014 Share Posted March 11, 2014 Glad you had a nice drive! 34 psi seems really really high. Factory rec for my 1990 Caterham is 22 psi, and I autocross at 15 psi on street tires. --David Link to comment Share on other sites More sharing options...
Kitcat Posted March 11, 2014 Share Posted March 11, 2014 Ditto DavidL's comment. I ran my Birkin at 18 rear, 16 front, cold. That has worked well in my Caterhams also. Link to comment Share on other sites More sharing options...
mrmustang Posted March 11, 2014 Author Share Posted March 11, 2014 I'll play around with cold pressures until I like how it feels. Going to drop down to 28psi for the next time out. Bill S. Link to comment Share on other sites More sharing options...
yellowss7 Posted March 12, 2014 Share Posted March 12, 2014 Bill, I don't know what tires you are using, but the guys are right on with the 18 psi for Toyo R888s or Avon Cr500's on a Caterham. Unless you just like to spin the tires and enjoy bouncing around. :jester: Try 20 then go down to 18 and I bet your handling and ride will improve greatly. Tom Link to comment Share on other sites More sharing options...
Nick OTeen Posted March 12, 2014 Share Posted March 12, 2014 Going to drop down to 28psi for the next time out.As others have said that's way too high for such a light car and can make it very skittish - not to mention the rough ride. I run the Toyos on my Caterham around 18psi. Link to comment Share on other sites More sharing options...
mrmustang Posted March 12, 2014 Author Share Posted March 12, 2014 I'm running Euro TA's Link to comment Share on other sites More sharing options...
slomove Posted March 12, 2014 Share Posted March 12, 2014 I also tend to use higher pressures on street tires. I did use 17-19 psi on my track slicks and the old ACB10 (back then when I used to go to the track), but for road use, even with "high performance" tires I need 26-30 psi or the they will show higher wear near the walls after a few 1000 miles. I think these tires don't get the proper shape at lower pressure no matter what the car weighs. I did not feel any squirmishness at that pressure. That said have not tried R888 or CR500s. Link to comment Share on other sites More sharing options...
scannon Posted March 12, 2014 Share Posted March 12, 2014 (edited) I did some hot weather tire pressure testing with R888s summer before last. I did two hot laps then pulled into the hot pit and had a friend measure tire temps with a pyrometer across the tread. I ran two more laps after that. I also recorded lap times. I started with 17 - 19 psi and worked up in 1 and 2 psi increments. I was running 205/50-15s on the front and 225/40/15s on the rear. I found the car to be very squirrley until I got to 22 - 24 psi. Lap times and control gradually improved until the tires were at that pressure. The temperature spread across the tires was most even at that pressure as well. More pressure decreased lap times but felt about the same to the butt g meter. I run the same cold pressures on the street. I also found that adding a passenger required 2 more psi to maintain nearly similar lap times and temperatures gradients. Edited March 12, 2014 by scannon Link to comment Share on other sites More sharing options...
Kitcat Posted March 12, 2014 Share Posted March 12, 2014 Skip: What front fender/cycle wing size do you run? I have a set of 195x50 15" R888s on Caterham wheels that don't remotely fit on the front of my Superlight(Too tall and too wide). They fit OK on the rear but my car runs CSR front fenders and they are tiny. Link to comment Share on other sites More sharing options...
scannon Posted March 12, 2014 Share Posted March 12, 2014 Skip: What front fender/cycle wing size do you run? I have a set of 195x50 15" R888s on Caterham wheels that don't remotely fit on the front of my Superlight(Too tall and too wide). They fit OK on the rear but my car runs CSR front fenders and they are tiny. My SV came from the factory with 205/45-16 Avon tires mounted on the wagon wheels. I assume the cycle fenders are the larger of the two sizes offered at that time. The 205/50-15 R888s on my track wheels are a very tight fit. I had to bend one of the fender stays a bit as the inside of the LF tire would rub on hard turns. The 205/50-15 Dunlop Dirreza Star Spec tires on the street wheels have about 3/8" clearance at the same spot. Not all 205 tires are created equally. Both the street and track wheels are 7 x 15 and have the same offset. I run 225/40-16 Toyo T1Rs on my Miata and they are not quite as wide as the 205/50-15 R888s. They will not fit in the Caterham front fenders due to different offsets. Link to comment Share on other sites More sharing options...
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