Tony Posted May 7, 2010 Report Share Posted May 7, 2010 I'm going to say something really out of the usual box..... Can you fit the track-rod ends on the other side of the hubs? meaning if they currently fit under the hub can you fit them over the hub? Before i explain why is this location possible? Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 8, 2010 Author Report Share Posted May 8, 2010 Yes I can do. I am using 1/2" UNF rose joints instead of track rod ends to try and reduce bump steer. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 8, 2010 Report Share Posted May 8, 2010 Are the track rods straight or is there a bend in them. Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 8, 2010 Author Report Share Posted May 8, 2010 There are bends in them both ways, down and in. These are older pics when I still used a track rod end, steering arms are the same though. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 8, 2010 Report Share Posted May 8, 2010 Oh nuts... I wanted to change the Akermann but i can't do this is the pickup point is the hub. The change in the Achermann would belay the slow camber migration due to the deep SAI...... Thinking Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 8, 2010 Author Report Share Posted May 8, 2010 I'm sorry, and I may sound ignorant, but that made no sense to me at all!! What are you thinking of doing? Quote Link to comment Share on other sites More sharing options...
Tony Posted May 8, 2010 Report Share Posted May 8, 2010 I'm sorry, and I may sound ignorant, but that made no sense to me at all!! What are you thinking of doing? Not ignorant all all, it's my poor method of explanation. As i see thing well have a very ( declined ) SAI that's not easy to correct, the castor is a done deal as is the camber. The scrub radius is in the wrong place and you have spacers fitted for mechanical reasons.... Oh and bump steer. My thoughts was to allow the migration of the camber during a turn to be accelerated, this will improve the SR keeping it under the steer axis. Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 8, 2010 Author Report Share Posted May 8, 2010 I'm sorry, and I may sound ignorant, but that made no sense to me at all!! What are you thinking of doing? Not ignorant all all, it's my poor method of explanation. As i see thing well have a very ( declined ) SAI that's not easy to correct, the castor is a done deal as is the camber. The scrub radius is in the wrong place and you have spacers fitted for mechanical reasons.... Oh and bump steer. My thoughts was to allow the migration of the camber during a turn to be accelerated, this will improve the SR keeping it under the steer axis. Ok, I think we have gone past the limits on my knowledge on the subject! I will try and read up to try and make sense of what you just said, but if you could tell me how you plan to do that I will try and make it work mechanically. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 8, 2010 Report Share Posted May 8, 2010 Sorry Paul i'm not trying to over-complicate the reply, it's just i fail to make it read in a more understandable format. Given the current restraints we have i would act to allow the camber/ castor migration to happen quicker during a turn, this would give better control of the cars weight in the steer axis. In order to do this the Achermann actuation would need to be advanced, accelerating the camber/ castor migration, on your car the actual Ackemann would be around 1 degree 30' with the inner wheel at 20 degrees, my ideal position would be 2 degrees 30' at 20 degrees, this migrates the SR much better... Look at this By removing the cast finger that links the hub to the TRE the Acermann has been removed, this wheel you see has seven degrees of camber but on lock and thanks to the removal of the Ackermann it has zero camber. From this it's easy to suggest manipulating the Ackermann activation points could hold great reward if areas like SAI/ Castor cannot be addressed. Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 9, 2010 Author Report Share Posted May 9, 2010 OK, that makes sense. Also, I have failed to mention that the steering arms fitted are from a Metro which are longer and angled in more giving more ackerman. Here they are compared to a mini one: I will have to re-measure ackerman to find out what it is as my memory fails me. If its not close to 2 deg 30' at 20 deg, I could possibly heat them and bend them in to obtain those figures. Quote Link to comment Share on other sites More sharing options...
hms Posted May 9, 2010 Report Share Posted May 9, 2010 Sorry Paul i'm not trying to over-complicate the reply, it's just i fail to make it read in a more understandable format. Given the current restraints we have i would act to allow the camber/ castor migration to happen quicker during a turn, this would give better control of the cars weight in the steer axis. In order to do this the Achermann actuation would need to be advanced, accelerating the camber/ castor migration, on your car the actual Ackemann would be around 1 degree 30' with the inner wheel at 20 degrees, my ideal position would be 2 degrees 30' at 20 degrees, this migrates the SR much better... Look at this By removing the cast finger that links the hub to the TRE the Acermann has been removed, this wheel you see has seven degrees of camber but on lock and thanks to the removal of the Ackermann it has zero camber. From this it's easy to suggest manipulating the Ackermann activation points could hold great reward if areas like SAI/ Castor cannot be addressed. And you ask why Tony is the only one to answer your thread! h Quote Link to comment Share on other sites More sharing options...
Tony Posted May 9, 2010 Report Share Posted May 9, 2010 OK, that makes sense. Also, I have failed to mention that the steering arms fitted are from a Metro which are longer and angled in more giving more ackerman. Here they are compared to a mini one: I will have to re-measure ackerman to find out what it is as my memory fails me. If its not close to 2 deg 30' at 20 deg, I could possibly heat them and bend them in to obtain those figures. Fitting the shorter arm will greatly improve things, if you can tell me the difference between the outer wheel and the inner with the outer on a 20 degree lock and the same for the other lock i can guesstimate the camber/castor/sai positions. Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 9, 2010 Author Report Share Posted May 9, 2010 OK, will do. May take a week or so though as the car is on axle stands with the hubs off as they are away at Hi-spec having the brakes made. HMS: I value everyone's opinion, as its very easy for me to overlook the obvious sometimes! (Cant see the wood for the trees lol!) Not only that, I would like to think that people may find this thread interesting and learn from it, like I'm doing! Quote Link to comment Share on other sites More sharing options...
Tony Posted May 9, 2010 Report Share Posted May 9, 2010 OK, will do. May take a week or so though as the car is on axle stands with the hubs off as they are away at Hi-spec having the brakes made. HMS: I value everyone's opinion, as its very easy for me to overlook the obvious sometimes! (Cant see the wood for the trees lol!) Not only that, I would like to think that people may find this thread interesting and learn from it, like I'm doing! I think h was just pointing out few could answer the question, which is a shame really but that's why wim is wim?.... Anyhoo do the mods and offer some data and we can attack it from there. Quote Link to comment Share on other sites More sharing options...
Rich Posted May 9, 2010 Report Share Posted May 9, 2010 I have to agree with hms...I understand camber and castor but this just goes over my head! I'm enjoying the read and photos though, looks a great track car Quote Link to comment Share on other sites More sharing options...
hms Posted May 10, 2010 Report Share Posted May 10, 2010 OK, will do. May take a week or so though as the car is on axle stands with the hubs off as they are away at Hi-spec having the brakes made. HMS: I value everyone's opinion, as its very easy for me to overlook the obvious sometimes! (Cant see the wood for the trees lol!) Not only that, I would like to think that people may find this thread interesting and learn from it, like I'm doing! Like you I find the thread interesting and am learning as I go along. I bow to Tony's knowledge, he's the only one with the knowledge to give you definative answers. Reading the thread it sound as though you have a good grasp of what's going on. I don't think I could add anything to the thread as it's above my knowledge level! I was struggling with the idea of changing Ackerman and how that would make a difference, until Tony explained it. h Quote Link to comment Share on other sites More sharing options...
Tony Posted May 10, 2010 Report Share Posted May 10, 2010 Aw give it up will you, your making me blush Quote Link to comment Share on other sites More sharing options...
Tony Posted May 10, 2010 Report Share Posted May 10, 2010 Paul Only immediate concern with the new attachment being shorter is that the steering arms will be swept back, in this case attention is needed to check for bump steer on lock because the track rod end pick up point will be very perpendicular. This can be checked visually. Quote Link to comment Share on other sites More sharing options...
Rich Posted May 10, 2010 Report Share Posted May 10, 2010 I bow to Tony's knowledge I think we all do Sorry off topic! Quote Link to comment Share on other sites More sharing options...
Tony Posted May 10, 2010 Report Share Posted May 10, 2010 Any other topic i'm as thick a shiet... It was only through the forums several years back that i learned to spell, i was pants at it through poor parenting and lack of personal interest. According to the medical peeps i've been under over the years back i can see angles from numbers Give me X,Y,Z and some data i can place the wheel in my mind and the forces associated but i obviously thought everyone could do that... seemingly not, hence my advantaged. Throw 9 x 10 - 5 + 6 i would need time and paper to work that out, throw -2 degrees camber on a 15 degree lock and 6 degrees 15' of castor on bump i would say your steering position is off to the left...... Exaggeration obviously but you get me point. Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 10, 2010 Author Report Share Posted May 10, 2010 Wow!! This thread is getting busy now! Checking bumpsteer is not a problem, as I made a gauge up to measure it. If anyone would like to make one for themselves, let me know and I can show you how very easily and cheaply. Also, before discovering this site and forum my knowledge of geo only spanned camber, caster, SAI and toe. I'm learning, but very slowly! I do find this subject very interesting and have a passion to learn more and try and make the car handle the best I can. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 10, 2010 Report Share Posted May 10, 2010 What values have you got Paul, obviously these only need to be within the expected "bump/ droop". Quote Link to comment Share on other sites More sharing options...
Paul XE Posted May 12, 2010 Author Report Share Posted May 12, 2010 What values have you got Paul, obviously these only need to be within the expected "bump/ droop". Again, the figures will have to wait until I get the hubs back from Hi-spec. I may not even have time to recheck the geo before the track day but after that I plan to do a FULL geo check and post the figures up on here. For the track day I will prob run the same geo as before (camber 2 deg, caster 4 deg, KPI 13 deg, 0 toe on the front) and have a play with the rear to see if I can contol it a little more, then if I achieve that I can go back to the front and try and reduce the KPI and bumpsteer, and increase Ackerman angle. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 12, 2010 Report Share Posted May 12, 2010 Can't wait Quote Link to comment Share on other sites More sharing options...
hms Posted May 12, 2010 Report Share Posted May 12, 2010 Also, before discovering this site and forum my knowledge of geo only spanned camber, caster, SAI and toe. I'm learning, but very slowly! I do find this subject very interesting and have a passion to learn more and try and make the car handle the best I can. You've come to the right place! Interesting to read how Tony describes how he can see angles from numbers, I try to imagine the movements in 3D in my head, and try to understand where and how they influence handling, often without any sucess! However slowly, (read very slowly), I am picking up bits and pieces through the forum, and with the practical experience of track days and sprinting, some of it gels as I experience it. Horses for courses. As Tony has implied, all of us are good in one area or another, I've yet to find mine! h Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.