Suspension travel

[30psi 4agte]

FWIW
Im running 275lb on the front and 200lb rear. Cant tell you if its too hard or too soft havent tested it yet. Should be about right though....... id like to think i know what im doin LOL

Car weighs 900 kg

[takai]

Definately shorter stroke shocks for you mullett.

RPM: for the shocks you are thinking of, think about your DH suspension. Not sure what you ride, but most triples have rebound, and low and high compression adjustment, to balance it out, as well as the spring/air coil.
The 70mm of travel in the race car is ultra stiff on high compression, supple on low compression, and medium/high rebound, a chunk of which is assisted by the coil.
The road car will be medium on high comp, low-medium stiffness on low comp and low-medium rebound to try and cope with bump chatter (think cranking rebound up to max and riding a rock garden).

Race car runs 325lbs front 225lbs rear, weighs around 920kg fully wet.
Road car will be approx 400lbs front 275lbs rear, and about 1200kg wet (hopefully)

[RPM016T]

Well mines probably going to be 750-800kg and running 250lb so should be about the same..

Takai, good call.. my main concern was potholes etc, as that used to be the only time i'd experience bottom out, and thats a pretty rapid hit. So providing I run a decent shock abosrber, the shock should do all the work to stiffen things up and prevent bottom out happening.

[30psi 4agte]

TAKAI: Humor me............ what would you race car be like on the street?
IE with the suspension travel and bumps in the road + spring weights etc

It seems pretty similar to my setup.

[30psi 4agte]

my main concern was potholes etc, as that used to be the only time i'd experience bottom out, and thats a pretty rapid hit. So providing I run a decent shock abosrber, the shock should do all the work to stiffen things up and prevent bottom out happening.

That is my theory too.

[takai]

TAKAI: Humor me............ what would you race car be like on the street?
IE with the suspension travel and bumps in the road + spring weights etc

Its absolutely horrible. I had it road registered for a while (still is really) and its really setup too stiffly for small sharp movements to make much of a difference. Would need to be softened again for road use.
For example these braking markers:
http://maps.google.com.au/maps?f=q&s...23.26,,0,27.73
the white things on the road would cause the car to lose traction under brakes. Not ideal.

[30psi 4agte]

what would you go down to in spring rate?

[takai]

I wouldnt necessarily go down in spring rate at all, merely change the valving on the shocks so that it has more bump compliance.

[andrew_mx83]

have many people on here played around with limiting straps?

under heavy braking on the race car i get way too much weight tranfser to the front of the car and the rear hasnt got enough weight over the tyres to get traction, im always losing the back trying to set the corner up. someone has suggested using limiting straps to stop the back coming up so far under heavy braking.....thoughts?

i will also be dropping the back another inch to help the situation and another couple degrees of camber.

[takai]

Shorter stroke shocks help. I only have about an inch of droop on the rear.

[SeptemberSquall]

maybe i'm missing the point but if the problem is excessive weight transfer to the front under braking, then I think that limiting droop travel in the rear will not help much? as the weight transfer is occurring, and whether the shocks extend far enough to keep the tyre just in contact with the road or (as you suggest) are limited in droop travel so you just lift the inner rear at turn in, either way the problem is excessive weight transfer not the semantics of how the rear shocks extend or not?

shouldn't the solution be redistributing weight in the car or increasing resistance to compression under braking in the front suspension to stop the excessive weight transfer in the first place?

[SeptemberSquall]

it's like polar moment of inertia as relevant to front/rear handling bias, but this time applied to forces acting parallel to the car's longitudinal axis, not its transverse one. I.e. move battery from high and a long way in front of the theoretical c.o.g. (in top front of engine bay) to lower and behind the c.o.g. rear passenger side floor or luggage compartment floor for example.

sorry if I hav missed the point

[andrew_mx83]

yeah, im moving the battery and anything else i can to the boot (stripping the whole car)

i agree the problem is with the front not being stiff enough but im trying to find a way to at least "help" the situation without changing the front springs.

the idea being that after say 1 or 2" of lift at the back the straps will go tight and stop it coming up further and HOPEFULLY keep some weight over the back tyres....however i have my doubts that it will work, in my mind the front will still continue to dive. but aparrently it has been done with sucess on other track cars.

[SeptemberSquall]

sounds a bit irish but good luck

[mullett]

Takai: ideas on short-stroke shocks for MA61?

-RM