16 replies to this topic

[Marco Polo]

Hi all, I need to adjust the Caster settings of my NA car (I have +2.8 and +3.2 or something like that instead of the +3.5 (Factory specs) or +3.8 (TIS specs))... - Do someone have the adjustment procedure (Speedster or Elise) ? (I don't have the TIS installed at this time) - Are the Caster settings so important ? What are the feelings if they are wrong ? - What means +3.5° ? (it's +3.5° forward "/|" or backward "|\" ?) Thanks

[clipping_point]

I would not bother adjusting it. I´m no expert but I think it mainly affects how the steering feels, with 3,5° (O /I O) it will straighten up more. The toe and camber adjustments affect the grip in a dramatic way, the caster do not AFAIK. It is possible to adjust it by putting shims, washers on one side of the wishbone, removing on the other.

[Marco Polo]

My main concern is to balance Right/Left... I would like to make them the same, as I have to adjust, if Caster is sensible, I bother to adjust both side....

[clipping_point]

I asked a chassis pro and he said you will not feel any difference. However, if you insist on adjusing it your foremost goal is to have equal values L/R

[Marco Polo]

Ok, thanks... It was what I was thinking...

[Steve Crisp]

I intend to add slightly more castor to mine. I only use it for normal roads, so a little less "feel" might be the desired result. You adjust it by moving the top wishbone around in relation to the washers either side of the wishbone inner pivot joints. Make sure that if you move the front pivot joint back one washer that you move the rear pivot joint back the same amount. I might be frame/washer/washer/pivot/washer/washer/frame at the moment, so making it frame/washer/pivot/washer/washer/washer/frame will have increased the castor. I believe the washers come in various thicknesses, and you should not just remove them from one place without adding them back to the other (if you see what I mean). Steve

[Steve Crisp]

oh, and castor would always need to be a positive number, I guess. A negative castor would remove the self-centring effect that is pretty essential... Steve

[NOEXCESSBAGGAGE]

FWIW, the larger the castor angle - always positive - the heavier the steering becomes. And heavier steering will be particularly noticeable on the non-assisted VX set-up, and moreso if you have wider boots fitted. The greater the castor angle of dangle, the more pronounced the self-centring becomes. HTH

[SPLAM]

I asked a chassis pro and he said you will not feel any difference. However, if you insist on adjusing it your foremost goal is to have equal values L/R

That is what Sinclaire told me as well, they said they would do it but it is time consuming (£££) and would only be noticed by fractions of a second on track.

I'm and don't track mine anyway so it would have been a waste of money.

I guess if the caster is lots out then it would be worthwhile.

Mines far from equal 2 deg 47 mins front left, 3 deg 04 mins front right.


EDIT:

Oppps caster not castor.

Edited by SamH, 14 March 2005 - 08:33 PM.

[clipping_point]

What will happen is that there is a slight difference between right and left corners, since the geometry is different. A F1 driver may notice it on a race track, thats all.

[Marco Polo]

Well, I have started workin on the Caster... It's a real pain in,e the *ss !!!! Moving the washers is not easy but the more time consuming stuff is to get access to these washers ! You need to undo almost every thing in the suspension (shock/steering rod/...) : I spend 3 hours on one side... Still need to do the other side... One advice, get some spare washers, they are always willing to drop inside the chassis. I really wonder why Lotus had the strangest idea to put big (easy to handle) whasher on the side of the front pivot and small (hell of a pain to handle) washer on the back pivot... I just hope I won't need to adjust this again...

[Steve Crisp]

Having read up on this now, one thing that different caster settings side to side will give you (according to a fair number of people), is that the car will tend to pull to the side with the least positive caster. If your car pulls to one side it may well be uneven caster settings (or a bent wishbone ). Steve

[Marco Polo]

Wishbones are ok... Today I'm out to adjust the other side (left), 3 hours of pain... Then next week back to the geo shop to check everything... I really hope it will be correct... If not..... myself................

[Steve Crisp]

Good luck Marco, I hope it goes well. I'm confident that I can soon post a guide that'll outline how to check (and adjust) the caster, camber and toe at home, with just a few basic tools like a spirit-level and a good tape-measure, etc. I've been researching the Web for the best suggested methods, so I just need to test the best on the VX... I'd far rather rely on my own skills (for free) than someone who isn't too bothered what result he gets. I found this out with wheel-balancing, that it's a nightmare finding someone with the skills, the correctly calibrated equipment, and the attention to detail that I expect. Steve

[Marco Polo]

Thanks Steve Adjustment done (bloody washers !! ) But still a few things to do on the car before the geo shop and before Spa (next waeek-end ! ) This car is so strange.... The more you fix things on it, the more you need to do... (and my car is getting old, 5 years soon... )

[Steve Crisp]

"old" ==== "sorted". Mines four years old and never misses a beat, and has no problems! Steve

[the gits]

"it's a nightmare finding someone with the skills, the correctly calibrated equipment, and the attention to detail that I expect" have you tried searching the archives for "Plans Motorsport"? see this month's Track and Race Car magazine....