Myles Posted April 15, 2006 Share Posted April 15, 2006 I've done 800 m-way miles and one trackday since getting the 7 back on the road. I have replaced the entire front suspension with widetrack kit with adjustable spring platforms. Due to time-pressures, I basically just bunged the suspension on and set the platforms to the same height (arbitrary - just enough to keep the springs in place - but the same L&R). I initially set the front tracking myself using the string method - and had this checked and reset at the trackday (I achieved slight toe-in, it's now set to an unspecified amount of toe-out). Before and after the td toe setup, I'd noticed that the car drifts to the left on the road. I can hold this in check with a single finger on the wheel, but it certainly doesn't run straight. It's possible (likely) that the camber setting is slightly unequal (by about a turn) - and I fairly arbitrarily set this when building the suspension (counted the number of turns needed to remove the rod-ends from the old narrowtrack and used (approximately) the same number of turns to fit them to the widetrack. Is this likely to be a corner-weight issue - e.g. too much weight on the NSF wheel is causing it to dominate? I can't really see what else could be the problem - the chassis was checked for straightness by Arch during the winter rebuild and the rear end hasn't been touched except to fit new dampers... FWIW, the steering is quite light (quick rack) at speed - but weights up considerably in corners - not something the old narrowtrack (std. rack) used to do... Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
rj Posted April 15, 2006 Share Posted April 15, 2006 Myles, I'd rather think that it's the camber setting, but of course if you have a massive toe-out and only 10% load on one wheel this would be able to produce the problem. What happens if you set the toe to nill? /regin Growing old is mandatory - Growing up is optional Link to comment Share on other sites More sharing options...
rj Posted April 15, 2006 Share Posted April 15, 2006 Just re-read your post. If it doesn't change anything to change the toe-setting I'm fairly sure that it'll be the camber. /regin Growing old is mandatory - Growing up is optional Link to comment Share on other sites More sharing options...
Chris__ Posted April 15, 2006 Share Posted April 15, 2006 Full flat floor camber, tracking, toe etc set up's gotta be a good idea. You know all the setting's are correct then. Ergo I'd take that easy option. Edited by - Chris__ on 15 Apr 2006 21:16:30 Link to comment Share on other sites More sharing options...
jonhill Posted April 15, 2006 Share Posted April 15, 2006 If it only does it on the road, could it just be the camber of the road (for water drainage)? Link to comment Share on other sites More sharing options...
Myles Posted April 15, 2006 Author Share Posted April 15, 2006 Jonhill - it's easy to notice on the road because you are following precise markers (lines) - on the track, there's not so much in the way of reference information. I think it is probably too strong an effect for it to be road-camber alone. Chris__ - it will happen ASAP, but as there doesn't seem to be anything obviously mega-wrong (e.g. an extra inch of spring compression on one corner) I'm curious as to what might be generating the issue. I think I'll try taking equal amounts of toe from both sides - but being as it manifested itself with both toe in and out, I suspect the cause lies elsewhere... Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
sjmmarsh Posted April 16, 2006 Share Posted April 16, 2006 Myles Remember that the car will turn towards the wheel with the most positive camber. As you should have about 1 to 1.5 deg negative camber, the car should turn toward the wheel that is closer to the vertical (i.e. the least amount of negative camber). You can set the camber roughly equal by using a sprit level and noting where the bubble is. It won't tell you what the camber is, just that it is nearly the same. Steve Link to comment Share on other sites More sharing options...
CharlesElliott Posted April 16, 2006 Share Posted April 16, 2006 In general I would say: - Uneven camber at the front - Bent chassis (unlikely) - Uneven rear toe Rear toe can be a little difficult to check as you need absolute toe relative to the chassis/DeDion rather than the relative toe you tend to measure at the front Charles --- My SuperGraduates 2006 diary My SuperGraduates 2005 diary, My Caterham Academy 2004 build and race diary Link to comment Share on other sites More sharing options...
Myles Posted April 16, 2006 Author Share Posted April 16, 2006 Charles - thanks. Everyone seems to be pointing towards camber. Arch confirmed that the chassis was straight and the back end should be fine. I don't have a flat bit of ground to make any useful measurements on - but a quick check of the thread remaining on the top links suggests that the NSF might have a tad less negative camber than the OSF (more thread showing - just...) 'spose I could go and measure the thread... Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
Neill Anderson Posted April 16, 2006 Share Posted April 16, 2006 I don't have that much 7 experince but in my past life with bigger engined Bristish sportscars then even quite unmatched camber settings do not really create a pull. Uneven castor would but again you would need at least 1/2 degree more on one side than the other, possibly even more. Tyre pressures and even the most obvious, tyre size and direction are possibilities, unless these were not changes. But if you only noticed it AFTER a track day then it is most likely simply due to the (usually heavily laden) NSF taking a set to its tread after all the track abuse (understeer?). A few hundred road miles and it will come back straight again, unless the tyre looks really paggered. Perhaps the most unlikley cause, diff bias? With the usual relatively soft springs then it is unlikely that corner weight in itself is the cause Best of luck Neill New 7 Owner 1996 VX 2.0 Link to comment Share on other sites More sharing options...
Stuart Faulds Posted April 16, 2006 Share Posted April 16, 2006 Myles, you have 30' toe out. Link to comment Share on other sites More sharing options...
Myles Posted April 16, 2006 Author Share Posted April 16, 2006 Thanks Stuart. Project Scope-Creep is live... Alcester Racing 7's Equipe - 🙆🏻™ Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
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