Oversteer

PostPost by: vernon.taylor » Tue Jun 17, 2014 9:13 am

Salut

I have a well-set up +2 - drives nicely usually. I recently took the family to the in-laws - so two adults up front, two kids at the back, and I managed to cram my wife's unreasonable amount of baggage in the boot. Tyre pressure (new Toyos, standard size) 1.5 bar all round.

I experienced oversteer at slow to moderate speed. Is that to be expected given the setup and extra weight ?

Merci.

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PostPost by: rgh0 » Tue Jun 17, 2014 11:16 am

1.5 bar = 22 psi which I would think is to low especially with the full load I would be aiming for more like 28 to 32 psi or 2 bar, this low pressure certainly could contribute to oversteer

Is the suspension standard with standard springs including the rear rubber aeon springs? Lotus added some alloy spacers below the rubber springs on the later plus 2 for better ride height control at full load do you have those?

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PostPost by: miked » Tue Jun 17, 2014 7:56 pm

I have those alloy spacers after Rohan mentioned. I have done many miles loaded up to the nuts on holidays. If anything I found that the car sat better in corners when weighted down. They surely must help when sat low.

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PostPost by: vernon.taylor » Wed Jun 18, 2014 10:20 am

Salut Rohan

Thanks for the tyre pressure tip.

Apart from adjustable shocks up front I think everything is standard. I bought the car restored so I'll have to check for those alloy spacers - are they easily seen ? By aeon springs do you mean the rubber bump stops ?

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PostPost by: rgh0 » Wed Jun 18, 2014 10:37 am

Yes the black rubber things inside the springs! they should be about 100mm long and 60 mm diameter

They are much more than just bump stops as the are part of a variable rate spring system for the rear suspension and critical to overall handling. People often delete or replace them with something different as they think they are just "bump stops".

The alloy spacers are easily seen as they should sit on the top of the strut housing - same diameter as the housing and about 40mm long

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PostPost by: vernon.taylor » Wed Jun 18, 2014 4:35 pm

Salut Rohan

Got the bump stops (or variable rate aeon springs ;-) but I don't seem to have the alloy spacers. Something else to look for.

Thanks for the explanation.

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PostPost by: Bud English » Wed Jun 18, 2014 4:43 pm

Vernon, The aeon spring doesn't show in your picture. Both the spring and the alloy spacer are at the very top of the strut tube. The spring is part 21 in Section DA -- Rear Suspension, here:
http://rdent.com/manuals/index.html

The alloy spacer is not shown but it is listed.
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PostPost by: vernon.taylor » Wed Jun 18, 2014 5:56 pm

Salut Bud

I forgot to delete the photo whilst searching and composing - I think I understand where the spacer goes now - Rohan's wording confused me, but I found one of his older and clearer posts.

I definitely have the aeon 'double doughnut' spring but not the alloy spacer - BTW, the aeon spring/bump stop is available new from Kelvedon - don't know if it has the right characteristics, though.

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PostPost by: Bud English » Wed Jun 18, 2014 6:09 pm

The spacer is a pretty simple part to make if you have or know someone with a lathe. It's just a round piece with a step cut in the bottom that gets dimpled with a center punch to hold it in position at the top of the strut tube. The dimensions may be here on the forum. I haven't looked. Someone may have their suspension apart and could supply them as well.
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PostPost by: rgh0 » Thu Jun 19, 2014 12:55 am

I dug out an original alloy spacer I have. Photo below of it next to the new rubber springs that are now being sold and appear to be a good copy of the originals with the same spring rate when I compared them to an original Aeon unit.

alloy spacer and rubber spring Plus 2.JPG and


Dimensions of the alloy spacer as follows

OD = 57.4mm
Hole in centre = 25.4 mm

Overall length including lip = 32.0mm
Length excluding lip = 25.4mm
Height of lip = 6.6mm
Thickness of lip = 1.7mm

The spacer is fitted to the top of the strut tube with the lip facing down which is then peened over in 2 or places around its circumference to lock it onto the top of the tube. You may need to play with the dimensions a little as some of the after market shocker securing nuts that screw into the top of the tube that it fits over differ in dimensions. There are some shocker securing nuts that have a hex section that sticks up rather than being flat on top that you would also need to allow for if you have those when machining up a spacer.

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PostPost by: vernon.taylor » Thu Jun 19, 2014 7:16 am

Salut Rohan

Thanks again for very useful info. So it sounds like the centre hole dimension is not critical as long as it clears the damper tube/slider and any nuts, and I should perhaps measure the diameter of my strut tube if I resort to maching.

Just to be sure - the spacer effectively increases the length of the strut tube and finds itself between the top of the strut tube and aeon spring ? And the protective rubber sock probably prevents it from being seen directly ...

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PostPost by: rgh0 » Thu Jun 19, 2014 7:25 am

Yes it extends the top of the strut tube and if you still have the original rubber sock in place like your photo it is inside that.

ID not critical along as it clears the shocker rod

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