Drumster Posted April 30, 2002 Share Posted April 30, 2002 What are the advantages/disadvantages of either swapping to an 8% or 22% QR? The 7 will be used mainly on the road with a few trackdays each year. Does it just come down to personal preference? I'd be interested to hear your views. Thanks Chris Alston Se7ening - it's all miles and smile.gifsmile.gifsmile.gif 1800 Supersprint - Loud and Proud teeth.gif ...well it only sounds fast officer blush.gif Link to comment Share on other sites More sharing options...
EFA Posted April 30, 2002 Share Posted April 30, 2002 22% is the preferred ration of those who enjoy sideways excursions - the steerings not havy, and the correction speed is much sharper! Go 22% adn don't listen to girls with weak arms! Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
ashaughnessy Posted April 30, 2002 Share Posted April 30, 2002 I asked Caterham Midlands to give me an 8% quick rack to replace my standard one. I think they gave me a 22% one, judging by the number of turns lock to lock. I find it slightly too quick for road driving (haven't used it on track yet). The larger turning circle (super-tanker style) was a nasty surprise but you get this with both quick racks, I believe. (I've got a clamshell car and I think that has a better turning circle than cycle wing cars anyway). Driving on the road, I remember wistfully how graceful and elegant my old rack was, how fluidly you could drive down twisty roads with a light grip on the wheel and smooth turns. Now I have a death grip and have to concentrate more. For the road I'd rather have my old slow rack, but I could never get round hair-pin bends on the track without taking my hands of the wheel with that. I think it's a personal preference thing. Read the archives and I reckon you'll get a 50/50 split of recommendations between the 8% and 22% Anthony Link to comment Share on other sites More sharing options...
EFA Posted April 30, 2002 Share Posted April 30, 2002 Anthony, Whats a "larger turning circle" - You're not still using the steering wheel for U Turns are you??? Where's your right foot? Fat Arn Visit the K2 RUM siteid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
ashaughnessy Posted April 30, 2002 Share Posted April 30, 2002 Arnie, surely the turning circle will be directly related to power output. As your car has a little over twice the power of mine, won't my turning circle be twice as big as yours? It isn't so easy to do a doughnut with a tired old supersprint on soft compound A032Rs (especially not with a broken engine!) Besides, it frightens the neighbours :-) Link to comment Share on other sites More sharing options...
Paul Ranson Posted April 30, 2002 Share Posted April 30, 2002 IIRC the '8%' has been standard for a long time. Perhaps since the racks started coming in Caterham brand alloy cases? These are the same for clamshell and cycle wings, so an 'upgrade' on a clamshell from the old style rack to new will reduce the turning circle. The 22% is a bit manic, but after a while you stop worrying. I'd always go with it. Even with a Vauxhall or Crossflow. The 'death grip' approach is probably counterproductive, give the car hints about where you want it to go and let it find the way, rather than trying to react to every writhe of the wheel. I remember reading about a problem encountered during WW2 as Spitfires got heavier and heavier, 'Pilot Induced Oscillation'. The aircraft had become slighly unstable in pitch and pilots had a tendency to try and manually correct, because they were always slightly behind the aircraft's motion they would end up driving it into ever more violent pitching and consequent unpleasantness. The issue was fixed with some form of counterweight in the elevator mechanism. A Caterham is more stable than a Spitfire, it basically wants to go in a straight line, if you let it. IMO PIO is also a factor in many sideways related incidents, but that's another thread. Paul Link to comment Share on other sites More sharing options...
Mick Day Posted April 30, 2002 Share Posted April 30, 2002 Check your bump steer if you're having to hang onto your wheel for grim death. I've just changed to a 22% & like the characteristics i.e. one doesn't have to move the wheel far to change direction, suits my lazy style of driving! Mick Link to comment Share on other sites More sharing options...
martinwhitcher Posted April 30, 2002 Share Posted April 30, 2002 anyone know how much a quickrack is?? (no smut pleasesmile.gif) Link to comment Share on other sites More sharing options...
Drumster Posted April 30, 2002 Author Share Posted April 30, 2002 Can anyone tell me how many turns lock to lock the standard, 8% and 22% racks are? I've just checked my 7 and its 2 1/4 L2L, so have I got a std or 8% ??? Chris Alston Se7ening - it's all miles and smile.gifsmile.gifsmile.gif 1800 Supersprint - Loud and Proud teeth.gif ...well it only sounds fast officer blush.gif Link to comment Share on other sites More sharing options...
Julian Thompson Posted April 30, 2002 Share Posted April 30, 2002 Looks like you've got an 8% unit then - this is reputedly 2.12 turns lock to lock compared with the 1.93 turns of the 22% item. Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted April 30, 2002 Share Posted April 30, 2002 22% is great! 1.6 turns lock to lock! Love it!!! Link to comment Share on other sites More sharing options...
Alias Posted May 1, 2002 Share Posted May 1, 2002 Currently got a standard. V. nice for town driving but would prefer an 8% 8% supposed to be the best all rounder 22% - I drove a 1.8SS with this for a day, and when I went over a pothole it almost broke my wrists. Also was very heavy at slow speed and very twitchy at 70mph. I guess if your car is a weekender/trackday and is generally used above 40mph then 22% is fantastic. Otherwise go for the 8% Link to comment Share on other sites More sharing options...
Alias Posted May 1, 2002 Share Posted May 1, 2002 Cost of quickracks - Demon Tweeks charge £184.03 (ex vat) for both the 8% and the 22%. Strangely I've never found these items on the Caterham web site. Link to comment Share on other sites More sharing options...
rgrigsby Posted May 1, 2002 Share Posted May 1, 2002 Apparently the 8% rack became standard around 93-94 time, I've just changed from a "0%" rack on a 1992 supersprint to a 22% and its superb. Yes the steering is heavier but you get used to it very quickly. The improved speed of the rack makes track driving so much better (especially in the wet with a heavy right foot). On the road it's fine although I run 032r/021r's on the road not ACB10's. I did try ACB10's on the road briefly but found they followed every single road surface change making the car move about all over the road, again probably something you can get used to/mod the suspension set-up to reduce. One thing to note if you're going from a "0%" rack to either the 8% or 22% rack you will need some extra clamps/mounts which cost around £50+vat. Cheers Rob G www.SpeedySeven.com Link to comment Share on other sites More sharing options...
Blatman Posted May 1, 2002 Share Posted May 1, 2002 Do the 8% and 22% racks give the same turning circlequestion.gif Link to comment Share on other sites More sharing options...
V7 SLR Posted May 1, 2002 Share Posted May 1, 2002 Rob, don't think the 8% was standard until after '96. My old XF was on a 0%'er and that was a '96 car. Bloody slow turning after you drive an uprated one. Seems more like my Scoob Legacy. wink.gif The turning circle has nothing to do with the rack speed. It's more to do with the stops inside the rack itself. I think you can alter them but expect this would be a machining job. Don't recall my older 0% car having a tighter TC than V7. Both could only just make it into my driveway - my house faces away from the direction your approach, requiring a controlled 180 (he he smile.gif). Older 22% racks (like mine) have extension pieces screwed onto the ends of the rods for widetrack suspension, but I believe all newer racks have the correct length rods. Anyone else think there's too much play in the high speed racks? I've had mine apart and I've adjusted it up until it bound, and then slackened it off until it didn't bind and found the slack again. I think I remember Mr PC had managed to all-but eliminate his slack by careful use of a different lubricant but I can't remember the details of this. I originally thought the problem was in the QR steering wheel, but it's definitely in the rack. Link to comment Share on other sites More sharing options...
ashaughnessy Posted May 1, 2002 Share Posted May 1, 2002 Before quick racks were invented, cycle wing cars had a larger turning circle than clamshells to avoid the cycle wings touching the body. I believe some kind of stop mechanism was put in somewhere. My quick rack has a much bigger turning circle than my original rack on my clamshell wing car. I suppose it's possible that the quick racks are all made to fit cycle wing cars, due to their dominance nowadays, so maybe cycle wing people who move from standard rack to quick rack don't notice a change in turning circle??? Yes, I do notice play in the quick rack. I haven't tried adjusting it yet. I also notice it sometimes is sticky, causing the car to wander because the steering doesn't entirely self centre. This is also something that has been noticed by other people, according to old blatchat threads. I can't wait to get it on the track, but so far I prefer my old rack on the road. Anthony Link to comment Share on other sites More sharing options...
Peter Carmichael Posted May 1, 2002 Share Posted May 1, 2002 You can turn an 8% into a 22% by changing the pinion. (there have been a couple of variations in rack tooth pitch/angle, so you need to get a matched pair when changing - talk to Titan) This also means that the 8% and 22% turning circles are the same. There are no stops to adjust on the quick racks. The travel is determined by how wide the rack is and how far the pinion is offset. The ends of travel of the rack are when the track rod end pivots clout the casing. Link to comment Share on other sites More sharing options...
rgrigsby Posted May 1, 2002 Share Posted May 1, 2002 Nigel, Ahh ok the 92-93 figure came from a Caterham parts guy but sounds like it may not be right. I didn't notice any change in turning circle going from 0% to 22% so I guess that ties in with Anthony's comment and about cycle wings vs clamshells. Cheers Rob G www.SpeedySeven.com Link to comment Share on other sites More sharing options...
ECR Posted May 1, 2002 Share Posted May 1, 2002 Peter I have 2 nylon spacer rings inboard of the rod end pivots which act as limiters. They are about 3/8" wide and obviously could be removed if I required more lock. Your post suggests that these are no longer fitted (my rack is 5 ? years old). Interesting comment about the pinions being replaceable Ex Chairman Roger Link to comment Share on other sites More sharing options...
old captain slow Posted May 1, 2002 Share Posted May 1, 2002 Don't muck about. Just go for the 22%. You will not regret it and it's fine on the road. Caterham say it's too quick, but I have not found this at all. You just think the car in the direction you want to go and it goes! C7 CDW Link to comment Share on other sites More sharing options...
Bilbo Posted May 4, 2002 Share Posted May 4, 2002 Hi All Well when I bought my 22% rack last year, I was told that all the racks have the same turning circle. Thats to say its now the same as the nasty cycle wings ones. Lets face it just yet another down side to having cycle wings (shudder).... biggrin.gif I agree with Arnie there are ways to get the back round and quite fun, but this might attract the attention of Mr Plod. One odd thing the old one screwed into the track rod ends by about 22+ mm, the new one is only 13 mm. question.gif Is this normal or is it just my older car getting a newer part. ECR wrote about the 2 nylon spacer rings... might be interesting to have a look at this, I would like the tighter turning circle again. I do get bump steer but the Toe is set positive and I going to go for a more neutral set up in the next few weeks. Positive is fine on the track but a bit of a pain on the road. I really like the 22% rack! Its a bit heavy parking but not that much of a pain. V7 SLR wrote.. Anyone else think there's too much play in the high speed racks? Well yes, but after a lot of checking I decided that the quick release wheel boss had developed a little play and its only very slight. Really only noticeable when parked but irritating. Marked the steering column with a marker and it was not moving. I thought it was the column length adjustment joint at first. I had decided that this was just the strain on the Boss when turning the steering wheel when parked. I wonder if this is why Caterham seem to lean to the 8% version. Still worth another look. 1988 200 bhp, 146 ft lbs, 1700cc Cosworth BDX with Brooklands and Clamshell wings Q 979 CGY Link to comment Share on other sites More sharing options...
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