madmaninshed Posted August 31, 2008 Share Posted August 31, 2008 Hi, Just got a 7 with soft GG Toyo 888's. Pressures cold are 18 front and 20 rear. They seem fine on smoothe roads but I get a violent kick back though the steering wheel over bumpy bits, certain cambers and big cats eyes. The previous owner said it didn't do this with the original road tyres. Should the camber/tracking etc need adjusting for the different tyres please? and any ideas on the minimum front pressure to experiment with? I planned to try slightly softer pressures but don't want to go too far... Link to comment Share on other sites More sharing options...
martin b Posted August 31, 2008 Share Posted August 31, 2008 I would drop the tyre pressures down to about 16 front, 17-18 rear as a start though I don't think that would cure your problems, does seem as if you should get the tracking checked Post on here what tyres were on previously too Good luck Martin Link to comment Share on other sites More sharing options...
Myles Posted August 31, 2008 Share Posted August 31, 2008 How violent is violent? My R888-shod car loves to climb camber and follow bumps etc., but even with a 22% rack, it's under control. I'm sure the reactions I get are (mostly) down to the camber and toe though. 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester Racing 7s Ecosse™ 🙆🏻 🙆🏻 🙆🏻 🙆🏻 🙆🏻 Alcester-Racing-Sevens.com Link to comment Share on other sites More sharing options...
bstark Posted August 31, 2008 Share Posted August 31, 2008 Might be worth checking the state of the front suspension bushes - especially if it's an early 90's or older model with the anti-roll bar as top link setup. Extra grip from the R888's (especially the sidewall as the tread wraps over) might be moving things around a little where they weren't before. Bob Stark Supersprinter Link to comment Share on other sites More sharing options...
madmaninshed Posted August 31, 2008 Author Share Posted August 31, 2008 Thanks Guys, I don't know what was on there before, but will try to find out. I'll start at 16 f and 18 r and see what happens. I'll also get the tracking checked. Who best to use in W Sussex? Should it be a motorsport place? Do I need to specify any settings?... please forgive ignorance....yet another thing to learn about. Link to comment Share on other sites More sharing options...
Rob Walker Posted August 31, 2008 Share Posted August 31, 2008 18 psi in the rears is too much for the road. I run 16 front and 15 rear on the road and 18 all round on track. Link to comment Share on other sites More sharing options...
Dartmoor7 Posted August 31, 2008 Share Posted August 31, 2008 Agree with Rob, run mine at 17F 15R on the road. MY BLAT-O-METER 2008: 51 (to 28th August) 2007: 70 2006: 89 2005: 91 2004: 64 2003: 66 2002: 66 2001: 79 2000: 32 (divorce!) 1999: NRA Link to comment Share on other sites More sharing options...
Ivaan Posted August 31, 2008 Share Posted August 31, 2008 I had a similar reaction last year going from Avon ZV1's to R888s. The car was/is much more lively to steer. The toe in was reduced to 0 deg, but this didn't reduce the bumping around. I was probably using too high a pressure at 1st, but now use 16psi. I think it's something I've just got used to now and it's not a problem. Clive Link to comment Share on other sites More sharing options...
Grubbster Posted August 31, 2008 Share Posted August 31, 2008 The previous tyres probably had more tread and hence more movement in the tread blocks, this tends to reduce the sensitivity to bumps and camber. When I first went to A048's I found the car to be a lot more 'physical' to steer, got used to it quickly though and now I'm on R888s (which I prefer) with no problems. Link to comment Share on other sites More sharing options...
madmaninshed Posted September 2, 2008 Author Share Posted September 2, 2008 Reduced front pressures to 16 and rears to 17 to start with which has helped a little. Booked the car into Discount Tyres in Worthing on Saturday who have a laser set-up. It's about £20 for the check, and then can cost over £200 if everything needs tweaking. They have set up a number of Caterhams, and say they are familiar. Should I ask for particular settings for 888's please? Link to comment Share on other sites More sharing options...
Jason Plato Posted September 2, 2008 Share Posted September 2, 2008 2 deg neg camber 20mins toe out (or parallel if for road use) 16psi all round here is C7 TOP Taffia rear gunner Link to comment Share on other sites More sharing options...
BarryT Posted September 2, 2008 Share Posted September 2, 2008 Hi, YHM, contact me if you need a hand sorting it out. Barry Link to comment Share on other sites More sharing options...
madmaninshed Posted September 2, 2008 Author Share Posted September 2, 2008 Thanks Dave, will go for parallel for the road. Very kind of you Barry...will be in touch. Link to comment Share on other sites More sharing options...
madmaninshed Posted September 11, 2008 Author Share Posted September 11, 2008 Tracking was checked by discount tyres Worthing - Dean there was very helpful. n/s front well out. Camber 1 deg 38 o/s ,2 deg 08 n/s. Caterhams figs state 1 deg 35. I asked for 2 deg and didn't know at the time the figures Caterham give are for crossply tyres ( and nor did DT). Luckily for me I agreed with Dean that he reduced the camber one turn on the 2 deg 08 side. He tried, but he could not release the suspension in order to make the adjustment. He loosened the bolts through the suspension arms a little and lubricated. I then drove over to Barry who kindly helped and made sure that everything was freed up. We left the camber as it was for the moment. Result...steering wheel perfectly straight, no bump steer and now handling like a DREAM. Thanks very much for help - especially Barry. Link to comment Share on other sites More sharing options...
RiF Posted September 11, 2008 Share Posted September 11, 2008 A little confussed What is the new settings? Is it that one side was out or the camber that you think has solved this problem? I have a similar problem with Henrietta's 7 with the Toyo tyres. Very sensitive steering as well for the first half a mile. Sorry to be thick RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON Link to comment Share on other sites More sharing options...
madmaninshed Posted September 11, 2008 Author Share Posted September 11, 2008 Hi, Sorry...the tracking was well out on the near side front. This has been corrected, and has solved my bump steer problems. I also reduced tyre pressures to 16 all round. The camber was not badly out ...2 deg 08 one side and 1 deg 38 on the other. It costs less at the tyre place if you only adjust the camber on one wheel, and because it is done in increments of one full turn of adjustment, as I understand it, it cannot be done absolutely spot on. I had a choice of either leaving the 2 deg 08 side and having the 1 deg 38 side increased to match as closely as possible, or I could have had the 1 deg 38 side left alone and the 2 deg 08 reduced. To be correct on radial tyres (as advised in this thread) I should have chosen to go for 2 deg 08. Because the technician was adamant that 1 deg 35 was correct and showed me the figures from his manual, I went for that. He couldn't adjust it due to bushes or something being jammed, so it has been left as it was for the moment. I am told that it is not critical for the road, and I'll get it looked at again soon. One of my front tyres has worn badly due to the tracking, and I can notice how much easier the car is to push now that the tracking is right. I thoroughly recommend having the tracking and camber checked on a really good laser machine. I learned that the rear of my car is virtually spot on, and now so is the tracking on the front. The handling is totally transformed. It was nervous, twitchy and a nightmare over cambers and bumps. The steering wheel was not straight, and the odd bump would almost rip the wheel from your hands. Now it still gently follows raised lines and cambers a little at times (which I guess is a feature of this type of tyre) but it is comfortable and re-assuring. If only my electrics were the same. My friends are on the Portsmouth ferry for 3 days blatting in France....and my car didn't make it!! Link to comment Share on other sites More sharing options...
RiF Posted September 12, 2008 Share Posted September 12, 2008 Thanks for the info . CA07BON tracks perfectly in a straight line and handles well, just super sensitive to a bumpy road especially on cold tyres. I have all the equipment but one of my settings must be off Will check it out again, things might of changed not the car is run in. So for road what are the suggested settings? I have 1 degree toe in Castor set with washers as per build but not checked Camber 1 degree negative but from what has been said here this should be closer to 2 degrees. 16psi pressure in 888's RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON Link to comment Share on other sites More sharing options...
madmaninshed Posted September 12, 2008 Author Share Posted September 12, 2008 Dave Jackson suggests 2 deg neg camber 20mins toe out (or parallel if for road use) 16psi all round Having spoken to others, I believe he is spot on. Link to comment Share on other sites More sharing options...
RiF Posted September 12, 2008 Share Posted September 12, 2008 Brilliant, thanks RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON Link to comment Share on other sites More sharing options...
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