revilla Posted January 14, 2015 Author Share Posted January 14, 2015 Mine is an SV with wide track. The 9mm requirement seems to be pretty much universal. I suspect your car will benefit from it. As you say though, easy enough to do and even easier to take them out again. Try it and see. If you like the handling of your car, leave them in. If not, see if it's any better without. It doesn't affect anything enough to make it dangerous if you go the wrong way. Just remember that putting them in or taking them out may throw the toe out a bit so you will need to redo the tracking. Link to comment Share on other sites More sharing options...
Bob L Posted January 14, 2015 Share Posted January 14, 2015 Anyone know a good source for ready made 9mm block shim? There must be a market here. Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted January 14, 2015 Area Representative Share Posted January 14, 2015 TomThat's exactly what I did. Link to comment Share on other sites More sharing options...
Mankee Posted January 14, 2015 Share Posted January 14, 2015 Tom, if you shim the rack at the same time as doing the widetrack conversion (plus probably setting it all up), you won't know if the shims have made a difference or not. For me (pure track use) I don't think the shims make great odds, as I run toe out, which can make the front end fidgety anyway. However, I did notice that, at the big compression at the bottom of Paddock Hill Bend at Brands Hatch, the bump steer was a lot less violent than without the shims. With the shims, I've had to wind some toe out off as well. Link to comment Share on other sites More sharing options...
Paul Deslandes Posted January 14, 2015 Share Posted January 14, 2015 I haven't done the measurements on a standard narrow track (S3) as I upgraded to wide track some time earlier. I have though measured with the older co-located upper wishbone/shock absorber setup and the current arrangement where they are separately located. The result was virually the same at 9mm.As described in the article, raising the rack will change the position of the track rod ends and thus change toe which must be measured and adjusted. Camber/caster aren't affected. Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted January 14, 2015 Area Representative Share Posted January 14, 2015 MankeeNot sure that you will notice much difference on track as they tend to be smooth.TomTo see if there is a difference take it on the M62 between M60 and M6 where the mining subsidence is. That'll test it. Link to comment Share on other sites More sharing options...
TomB Posted January 14, 2015 Share Posted January 14, 2015 As my front end is currently spread around the garage, loosing any adjustment on the toe in the least of my problems! Ill look to get it all set up at The Busted Knuckle Garage in a couple of months Link to comment Share on other sites More sharing options...
Englishmaninwales Posted January 14, 2015 Share Posted January 14, 2015 TomI fitted widetrack to my 94 chassis, it seemed to made bump steer worse, really awful. After a new long front,with post 96 geometry, fitted with 9mm rack spacers (thanks to Mankee) the car was trasformed. But I don't know which change improved the car . Don't forget you'll need longer clamp bolts (1/4" UNF fine - I think 2 1/2" long) and the holes in your sideskins for the track rod will need careful fettling.Malcolm Link to comment Share on other sites More sharing options...
TomB Posted February 9, 2015 Share Posted February 9, 2015 Hi, I've been looking for some Ali bar I can use to make some spacer shims but not managed to find any yet. I'm after rectangular section measuring ~4mm x 10mm so I cut it to length to make the spacers. Does anyone have a source of them? Or any similar material lying around in the garage I could have a short length of? Link to comment Share on other sites More sharing options...
Nigel Riches Posted February 10, 2015 Share Posted February 10, 2015 TomB, how good are you with a hacksaw? Local metal stock supplies companies may well have some off cuts or damaged lengths they would be glad of moving. Regards, Nigel. Link to comment Share on other sites More sharing options...
TomB Posted February 10, 2015 Share Posted February 10, 2015 Hacksaw & drill is the plan! I went to B&Q last night hopign to find some suitable extrusion but they didnt have anything. Thanks for the suggestion, yellow pages it is! Link to comment Share on other sites More sharing options...
SM25T Posted February 10, 2015 Share Posted February 10, 2015 B&Q only seem to do aluminium angle. Link to comment Share on other sites More sharing options...
TomB Posted February 10, 2015 Share Posted February 10, 2015 Our local one does all sorts, but not rectangular section solid extrusions. It does solid square and round section extrusions, but not quite what I want. Ill have to do some more digging. Link to comment Share on other sites More sharing options...
Paul Deslandes Posted February 10, 2015 Share Posted February 10, 2015 I've bought aluminium bar from these people in the past twelve months. Extensive range and stock and very reasonable postage costs.http://www.forwardmetals.co.uk/I got mine within a couple of days.Incidentally, the new Blatchat seems to have lost links from old threads so, if anyone is looking for it, my original article on correcting bump steer can be found here :-http://www.fastgrandad.co.uk/documents/Measuring%20and%20Correcting%20Bump%20Steer%20on%20a%20Caterham%207.pdfPaul Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 14, 2015 Member Share Posted February 14, 2015 Anyone know a good source for ready made 9mm block shim? There must be a market here. Exactly. I know that many members will "just" make these for themselves, but would anyone do some for others, possibly with an NtL contribution?ThanksJonathan Link to comment Share on other sites More sharing options...
Paul Deslandes Posted February 14, 2015 Share Posted February 14, 2015 I've just had a quick look at my original data and plots and, unless you can find 9mm bar, go for 10mm as it's slightly closer to the optimum than 8mm. Frankly there's bu99er all in it, but given a choice.....And there will, of course, be variations between cars anyway.A kit could include new longer bolts, washers and nylocs as well as the two spacers (they're a bit thick to call them shims).Am I talking myself into taking up Jonathan's suggestion ? At a guess they would work out at about £7.50 a set including p&p of which, say, £1.50 to NtL.Caterham Parts do the spacers although they don't give the thickness, saying only that you need two or four!Paul Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 14, 2015 Member Share Posted February 14, 2015 Would you recommend two pillars or a continuous bar? The latter would make the transverse force a bit easier to manage from the bolt clamping force. And how about a range of thicknesses to suit? 1, 2, 5mm should cover it (as with coins and chemical balance weights). But if they were stacked I'd probably want a continuous bar.Jonathan Link to comment Share on other sites More sharing options...
Paul Deslandes Posted February 14, 2015 Share Posted February 14, 2015 Mine are made up of 2 x 4mm + 1mm and their footpint is slightly wider than the individual rack clamps. I don't see the need to have a continuous bar, or a dog bone as offered by CC at one time, as that would be a waste of metal, never mind the weight!. Also, the cost of material will rocket. The clamps are prevented from rocking by the way that they're attached to the rack so the bolts are really only loaded in shear apart from the clamping force.I would only offer 10mm spacers, rather than a selection of thicknesses which would require multiple stock of suitable bar, as anyone wanting to mix and match would presumable have done their own measurements and would be able to knock up a couple of spacers. It could be 'demand driven' though I suppose. I have a local stockist of nuts and bolts and I'll check out the availability of 1/4" bolts next week. Link to comment Share on other sites More sharing options...
TomB Posted February 14, 2015 Share Posted February 14, 2015 Typical! I've just had delivered a bar of 20x4x500mm Ali to cut up into 70mm pieces to lift the rack up by 8mm! I'll probably leave at that and see how it goes. Got new longer bolts this morning too. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted February 14, 2015 Member Share Posted February 14, 2015 Thanks, Paul.Jonathan Link to comment Share on other sites More sharing options...
Paul Deslandes Posted February 14, 2015 Share Posted February 14, 2015 Tom, I'd be surprised if you noticed any difference. With going from 8 to 9mm, the difference can only really be seen at full bump or droop and even then there's only a very small remaining wheel deflection. 8mm takes out about 90% of it.Please let us know how you find the improvement when it's done.Paul Link to comment Share on other sites More sharing options...
TomB Posted February 16, 2015 Share Posted February 16, 2015 I've fitted widetrack over the winter, with no spacers under the rack with narrow track, to 8mm spacers with widetrack, so everything has changed. As such, feeling any difference might not be straight forward u till its all set up and Im used to it. Does the 9mm spacing depend on whether its narrow or widetrack? Link to comment Share on other sites More sharing options...
Paul Deslandes Posted February 16, 2015 Share Posted February 16, 2015 I personally haven't had the opportunity to measure a narrow track car, only widetrack Series 3. However, given the nature of the geometry involved, I would expect the effect and optimum spacer thickness to be the same, given that the pivot points don't change and it's the arcs we're trying to straighten out. Maybe someone has measured a narrow track and can verify or refute my thinking.On the same lines, I would expect a widetrack to have slightly less prounced bumpsteer for a given rack height/error, as the trackrod end movement arc is greater than narrow track and the 'pull' on the steering arm consequently less for a given angle deflection.Paul Link to comment Share on other sites More sharing options...
TomB Posted February 16, 2015 Share Posted February 16, 2015 I'll take your word for it! So do you think 8mm will be a reasonable start with widetrack? Link to comment Share on other sites More sharing options...
Paul Deslandes Posted February 16, 2015 Share Posted February 16, 2015 In a word, yes. Once you get to 8mm it's very close to optimum. If you get the chance to read the article you'll see from the curves what the effect of going from no shims at all through 6mm and then 8mm. 9 to 9.5mm would make it close to perfect but I doubt you'd notice the difference in real life, and the measurements have only been made on two suspension setups. I've no idea what the tolerances are for the rack plate height but it could well vary by 1mm or even more.Paul Link to comment Share on other sites More sharing options...
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