Haynes Forums - shocking question?

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Hi Baz,

350lb on the front works fine with the car, pinto or whatever medium size engine, but i did find with 200lb springs on the rear it felt a bit loose. Always put 250lb on the rear now and it does feel a lot better balanced and firmer on the rear (of the car ;) )

Andrew

A Bike engined car will be a lot lighter so each wheel will have less weight acting on it to get things spotty dog ideally you need to know the weight of the finished car....Then it comes down to weight of driver/passenger etc.
Imagine a car corner weighted as it sits then some one as big a bloke as Lesg sits in the drivers seat...said car will be all to wonky so it needs corner weighting with the big fella sat in the drivers seat to get things all tickety boo so he can wazz about safely.

I'm not saying les is huge but his arms are bigger than my legs....:eek:

Thanks for the reply, might borrow the missus bathroom scales under each wheel and see what the front weighs. Think they will tell you the roadsters BMI as well. ;)
Didn't mean to nag earlier its just shocks seem to be a very complicated subject with many options and they're an expensive thing to buy incorrectly especially on a budget.

I suppose springs are pretty cheap though and it these we can play around with.

How does the weight of the car per wheel relate to the spring poundage?

Cheers Chris

ok had a chat with supplier this morning
4x 14-9.5 gaz with 4x any rate 8 or 9" springs would be £264.08+vat and 10 p&p (i make it £326.89)
kit quoted was cheaper as springs suppied are cheaper as thay are shorter and not in the same price bracket :( thay would have been happy to keep the kit same price as long as the all the bits where the same price
all shocks in that size in stock and guy seemed to think spring rates would be in stock in most rates

£328.29 all in to your door from rally design tried arm twisting for pack deal but no joy :rolleyes:
spring prices step up at 8" :mad: and im thinking would be the shortest we can go
would be £37 less than extension type i was quoted :rolleyes:

Quote:

Originally Posted by spud69 (Post 52824)

Had a day and a half away from the 'puter so i think its time to add my experience / thoughts.......:cool:

Springs are rated at whatever poundage / inch of travel irrespective at what state of compression they are in as long as they don't become fully compressed they will always react the same. So, 14" dampers with 9" springs will react the same as 13" dampers + 1" extension with 8" springs just with the 14" dampers you will have more travel. The length of the springs governs the ride height of the car thus screwing the ring nut up and down the damper adjusts the ride height of the car / corner weighting rather than adjusting the handling. Cheaper, 14" springs, will be fine with the correct length, 9", springs on.

From my own cars on the road the rear of the car is ideal with 14" damper + 8 /9" springs, whether 13" + 1" (8" spring) or 14" (9" spring), allowing plenty of adjustment for ride height. Car runs well on 4" front and 4 1/2" rear allowing enough clearance for most speed bumps. The front, however, with 13" + 1" with an 8" spring is at it's lowest setting for the front ride height at 4". Obviously when it comes to track time i would ideally like to lower the car as much as possible so next time i'm going for a 14" damper (for longer travel) with an 7 / 8" spring to give the lower ride height when required. The rear there is plenty of adjustment available.

Ideally, for the cost of springs, i think i'll go for a stiffer track set of springs and also the standard road going springs (350 front and 250 rear). They are easy to change and would make a big difference on the track.

Just my thoughts.....Andrew

Quote:

Originally Posted by spud69 (Post 52959)

so would you agree that 4x 14-9.5" with 8"front and 9"rear springs would be an ideal package for all round use andrew? or anyone else?
would realy like the springs set mid way for normal use idealy :)

Quote:

Originally Posted by baz-r (Post 53689)

Yes Baz, that's what i'll be going for on the Mx-5 car.

Andrew

Thing is if the suspension works at 4" ride height then lowering the car may well upset the handling. Just because it's lower doesn't really mean the geometry is right for it all to work.
Maybe the only way to run the car lower would be to lift the mounting points so the chassis sits lower, suspension is a minefield and one change can alter other things.

Here's a question:
Those that have got built Roadster, when the car is jacked up at the front how do the front wheels sit?..do they go into positive camber or negative? This one thing will show whether things are ideal or not.

It's nice to have the option to lower the car though, main thing on the track for me is the body roll, although not much, so getting the C of G as low as possible will help with this. When the car is lowered the wheels go into a negative camber, again not much though when lowering the car by 1 to 2", but this will help to keep the tyres flat to the tarmac especially with warm sticky tyres and cornering on the limit.

Be nice to try, that's all Mark. Wish it was spring to get out there again, going stir crazy stuck in here all day listening to Planet Rock and Radio 2. Definitely need some adrenalin rushes to put the fire back in the veins......

Spoke to TeamTrain yesterday and the car will be ready for track testing mid-march with the first race, hopefully, at Knockhill for a full shakedown then first round of the Northern Race Series at Croft on Easter Weekend. Going up on Saturday to check on progress and get some more pics. Roll on Spring.....:(

Andrew

Hi Andrew,

Will you supply 4x 14-9.5 dampers and 8/9" springs for mx-5 builders like myself? :D

Cheers

Chris