Stability at speed

PostPost by: mark030358 » Mon Jul 09, 2012 12:21 pm

Never in my ownershp of my Sprint have I ever felt really comfortable driving at speed. The car was running on the origional steel wheels and Dunlop SP10's and had been previously set up as best possible.

So bit the bullet and went the whole hog. Four new Minilite 5x13, four new XAS 155x13, complete TTR rear suspension (including all drive shafts, due to QED 420 cams.. another story).

So all fitted ond off to the alignement garage.....

Front toe in 2 mm overall (interesting that the rods ran out of adjustment, I think the arms are slightly too long. Read this on another thread somewhere)
Front camber 1/4 degree negative each side

Rear toe in 3.1 mm per side
Rear camber just under 1/4 negative each side

and WoW!!!

Car is super stable, never been like this before at +100mph (allegedly) the car is rock solid and stable, no twitches, side to side movement, just fantastic. I have never had it so good before.

Over the moon .... just great.

Oh and running 19 psi front, 24 psi rear.

cheers
User avatar
mark030358
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1165
Joined: 29 May 2004

PostPost by: stugilmour » Mon Jul 09, 2012 4:03 pm

Wow Mark, thanks for posting your success and numbers. Very encouraging and gives a great starting point. Thinking I need more rear toe-in (have adjustable wishbones from Spyder), so will check against your number.

Just trying to dial out the last bit of stability issues on my Plus 2. I am considering the XAS's as my current Sumitomo HTR 200's have seen their best and they are now NLA :(. The car does not like the present miss-match of cheap Coopers on the rear and worn HTR's on the front. I can't find an H rated replacement in the popular Plus 2 replacement size (175/70/R13) here, so may bite the bullet and try the correct size XAS's or Vredestein's from the 'States.

Great to hear the XAS works well on the Elan. I always remember them as a great tire on my Alfa sedan back in the day. Have you had a chance to check them out in the wet yet? Memory may be a bit faded, but I recall them being tricky in the wet when they got worn & very good when new, but the Berlina was a heavier car? My current set-up is very questionable in the wet, hence the question/concern.

Anyway, congrats and enjoy! :)
Stu
1969 Plus 2 Federal LHD
User avatar
stugilmour
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 2060
Joined: 03 Sep 2007

PostPost by: ericbushby » Mon Jul 09, 2012 4:58 pm

Thanks Mark
I want some of that. I have printed that out for future reference.
Eric in Burnley
1967 S3SE DHC ( Not running right)
ericbushby
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1349
Joined: 13 Jun 2011

PostPost by: mark030358 » Mon Jul 09, 2012 5:38 pm

Forgot to mention Kelvedon adjustable rear A arms.

cheers

Mark
User avatar
mark030358
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1165
Joined: 29 May 2004

PostPost by: elansprint71 » Tue Jul 10, 2012 9:02 pm

mark030358 wrote:Forgot to mention Kelvedon adjustable rear A arms.

cheers

Mark


The key element! :wink:

I had a quite a conversation with the Guru from Kelvedon earlier this year about rear-end steering. He believes, iihic, that, as the rear suspension is compressed, the toe-in/out varies considerably, this can be either as "bump-steer" where both sides are affected equally, or whilst in a cornering body-roll situation, where one side is in compression and the other going the opposite way.
Pat reckons (and we were talking about racing, rather than road; although the same principles apply) that setting the ride height is the starting point and then dialing in an initial amount of toe-in would help to keep things pointing better. However, there are a host of other factors to take into account (spring-rates...etc).

Interestingly several folks who know their onions have told me that, given a bit more budget, the Elan would have had a proper twin-wishbone rear set-up, rather than the cheapo MacPherson strut which it is saddled with.
User avatar
elansprint71
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 4434
Joined: 16 Sep 2003

PostPost by: mark030358 » Tue Jul 10, 2012 11:15 pm

Pete, the rear setting was as per your post. ie 1/8"

cheers
User avatar
mark030358
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1165
Joined: 29 May 2004

PostPost by: archigator » Wed Jul 11, 2012 11:55 am

Stu,
I had XAS tires (tyres) on my '71 Fiat X1/9 back in the day, and you recall correctly, they were squirrily in the wet. I recall taking a highway curve at no more than 40mph in a light rain, and the car broke loose and did a complete 360! Granted, it was a mid-engine car and a little more prone to not giving feed-back until one reached the cornering 'limit', but I was REALLY shocked when that happened! I don't know if the asymetrical tread doesn't pump the volume of water that a non-asymetrical tread might, but they were not as good in the rain as other subsequent tires (tyres) on that car. Bottom line: Be careful in the wet.

Gary
'71 Sprint FHC
Miami, Florida
User avatar
archigator
Fourth Gear
Fourth Gear
 
Posts: 554
Joined: 15 Sep 2003

PostPost by: TroonSprint » Wed Jul 11, 2012 4:24 pm

Forgot to mention Kelvedon adjustable rear A arms.

Mark, is the Kelvedon price of ?170 for one side wisbone assembly or for a pair? If it's just for a single side, then Spyder are cheaper, but if it's a pair, then Kelvedon are cheaper. I have some experience of rear toe in on my V8 MGB with IRS, so may fit adjustables to my rebuild Elan.

Thanks,
Mike
User avatar
TroonSprint
Fourth Gear
Fourth Gear
 
Posts: 548
Joined: 24 Nov 2011

PostPost by: mark030358 » Thu Jul 12, 2012 5:14 pm

Thats probably per side, I can't remember the exact price been buying them over a period of time.

cheers

Mark
User avatar
mark030358
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1165
Joined: 29 May 2004

Total Online:

Users browsing this forum: No registered users and 28 guests