rrdusek Posted January 22, 2018 Share Posted January 22, 2018 it's time for new tires and alignment. I know what I want to set it at, and I love the way it handles now. however, the way these tires have worn, I know I need to make some adjustments. I also have the factory recommended numbers, but I would like to hear what everyone out there is using on their cars. thanks in advance for your help. Link to comment Share on other sites More sharing options...
rrdusek Posted January 25, 2018 Author Share Posted January 25, 2018 nobody knows what their camber and toe-in is set at? hummm, interesting... Link to comment Share on other sites More sharing options...
slomove Posted January 25, 2018 Share Posted January 25, 2018 (edited) nobody knows what their camber and toe-in is set at? hummm, interesting... Well people surely know and for best information you want to go to the Birkinowners Yahoo group. I don't have my Birkin anymore but over the years I experimented a bit with the alignment. Being a Live axle that was for the front wheels only. For radials I started with whatever was recommended for S3 type Caterhams and ended up (IIRC) with modest 0.5-0.8 deg camber and 1 degree toe-in. For the bias ply ACB10 and some slicks that I used for a while that was zero camber and I forgot what the toe was. Edited January 25, 2018 by slomove Link to comment Share on other sites More sharing options...
Davemk1 Posted January 26, 2018 Share Posted January 26, 2018 I owned a Birkin years ago and it too had a live axle so the only thing to take care of in the rear was to be sure the thrust angle was correct. In the front my Birkin had a huge about of caster and all this caster meant that it needed little camber to make it grip very well. I autocrossed on bias ply slicks and ran .5° camber in front and zero toe. I now run a Westfield S2000 and it has an IRS. I run zero toe in front and 1.5mm toe in per side in the rear. I have it set with 1.3° camber all around and it grips very well on the bias ply slicks. dave Link to comment Share on other sites More sharing options...
wemtd Posted January 26, 2018 Share Posted January 26, 2018 So Sorry for the delay.. Work got in the way this week. - I also recommend earlier threads regarding setup for other makes. Link to comment Share on other sites More sharing options...
papak Posted January 26, 2018 Share Posted January 26, 2018 I’ll dig mine out and post tomorrow. Link to comment Share on other sites More sharing options...
rrdusek Posted January 26, 2018 Author Share Posted January 26, 2018 allright, thank you all for contributing. everyone knows more than me and I am trying to learn and understand my car as best as I can. I appreciate any and all help I can get. Link to comment Share on other sites More sharing options...
Davemk1 Posted January 26, 2018 Share Posted January 26, 2018 Do you know what your spec's are now? dave Link to comment Share on other sites More sharing options...
wemtd Posted January 26, 2018 Share Posted January 26, 2018 (edited) As with most things in life The answer to your question is: It Depends... - It will vary based upon driver preference, tires & pressure, engine, track vs. autocross vs. daily driver, etc. What are the Factory Recommended settings? - Keeping that in mind, here are some numbers I've come across. used #1 last year and didn't have any gardening adventures 1) Camber -0.9 all around. Toe in: Front 1/8" rear 1/16". 2) Camber -1 to 1.5 all round. Toe: 0. track use 3) Camber 1deg 20' +/- 0 deg 15' (Negative). Toe Tracking : 0deg 20' +/- 0deg 10' Toe in 4) -1 1/2 camber FandR , 1/16 toe front and 0 rear. 5) Camber : 1deg 30' +/- 0 deg 15' (Negative) 6) Toe: 1/8 in (total) as a start; if you have huge torque, add a little more rear toe in at first until you get used to the car. Half degree negative camber in the rear, nearly a full degree in the front. Harder driving on stickier tires will tolerate bigger negative camber, but will wear quicker in a straight line and won't stop as well. KitCat: –1.8 all around cheers Edited January 26, 2018 by wemtd Link to comment Share on other sites More sharing options...
Kitcat Posted January 27, 2018 Share Posted January 27, 2018 As Slomove suggested, try the Birkin Yahoo group. As a former Birkin owner, I know that the prior USA Birkin dealer, Dick Brink, at Texas Motor Works had very firm ideas on this subject. And I vaguely recall part of the formula was having the rear of the car a bit higher than the front (Helpful, right?). Unfortunately, when I sold my Birkin, I tossed his alignment specs. He still visits the Yahoo group, so put it out there. Link to comment Share on other sites More sharing options...
Croc Posted January 27, 2018 Share Posted January 27, 2018 I vaguely recall part of the formula was having the rear of the car a bit higher than the front Its called "rake" in chassis set up terms. All sevens are sensitive to rake setting. I expect there is a right number for a Birkin too over at the yahoo group. Link to comment Share on other sites More sharing options...
JohnCh Posted January 27, 2018 Share Posted January 27, 2018 My Westfield is very sensitive to rake. I chased a handling issue for a long time before discovering that was the issue. It turned out that after the rebuild, the shop doing the alignment didn't consider rake when performing the corner balance. As a result the back was about level with the front instead of a bit higher (+20mm at the specified measuring points). Getting this right made a big difference to turn in and got rid of the understeer. I'm curious about your comment "the way these tires have worn, I know I need to make some adjustments." What wear are you seeing? Is it simply a function of more aggressive settings for corners which is generally at odds with even wear on a street driven car where the majority of miles are not covered under load, or is that wear severely compromising tire life? If the former, setting changes that provide even wear may impact the handling you say you currently love. -John Link to comment Share on other sites More sharing options...
wemtd Posted January 27, 2018 Share Posted January 27, 2018 IIRC 6cm for the Birkin Link to comment Share on other sites More sharing options...
rrdusek Posted January 28, 2018 Author Share Posted January 28, 2018 Davemk1- I don't know what things are set at now, will see what that is next week. JohnCh- the tires are not wearing badly at all, just a touch more on the outside quarter, just in from the edges of the front tires a little. (i'm hoping the toe is a touch too much) the camber appears to be pretty straight upright. the rears abe wearing beautifully even. I think I have a good alignment shop and they will put it up this week and see what we are starting with, then discuss what adjustments to make at that time. I do have Birkin shop numbers to help make sure things go right. I've only had the car (bought used) for a year now and just replaced the original tires that came on it yesterday. it's a street car I just use for fun. I think i'm good now. I thank everyone for their advice and time. I love learning this stuff! Link to comment Share on other sites More sharing options...
papak Posted January 28, 2018 Share Posted January 28, 2018 (edited) According to Tom Carlin, the starting point for the alignment is as follows: The front ride height should be set by adjusting the spring perches so that there is 300mm between the upper and lower mounting bolts (center to center). The rear ride height should be set the same way to result in 5 13/16" between the ground and the bottom of the frame rail jacking point at the front of the rear wheel well. This should result in the rear being being ⅜" higher than the front. Once this has been done, set the front and rear camber to ½-¾ degree negative. Toe in should be 1/32" front and rear. The castor is pretty much determined by the front uprights. Mine measured +9.5 degrees. Shocks set to full soft for the street, firmer at the track. I had a local race shop (Johnson Alignment, Torrance, CA) do mine along with corner balance. I opted for ¾ degree camber and .03" toe-in. My rear ride height ended up ¾" higher than the front. F/R balance was 46.6%/53.4%. While I haven't been to the track with it yet, the handling on the street (and on/off ramps) has been nice and well balanced. I will probably firm up the shocks a bit as the bump stops are ending up pretty high on the shafts after a drive around town. Of course, I'm driving in Los Angeles and the roads here suck. With a car this low, you pay a LOT of attention to the road surface when driving. I have 2" clearance between the surface and the sump guard . I am seriously considering a Raceline dry sump for this reason. Hope this helps. Edited January 28, 2018 by papak Link to comment Share on other sites More sharing options...
Davemk1 Posted January 29, 2018 Share Posted January 29, 2018 I'm sure you know this but just in case.....be sure to have the car set up with your weight in the seat. If they can't align it with you in the car then it absolutely has to have your equivalent weight in ballast in the seat. These cars are so light that your weight is a large part of the package weight everything will be off if it's set up without the proper weight. I'll bet the ride height in the rear changes by nearly an inch when you sit in it so it's a waste of time/money to do it without ballast. I've found that many shops tell you that they will put ballast in the car but many don't so buyer beware. dave Link to comment Share on other sites More sharing options...
papak Posted January 29, 2018 Share Posted January 29, 2018 We did it all with the correct weight in the seat and fuel quantity considered as well. All the work was done on sliding plates. Link to comment Share on other sites More sharing options...
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