Damper Travel

[Rick Iverson]

Gents;

Under advisement from Joey Petree at Essex, I need to know the MINIMUM stroke length for an RF95. Also, what about bump stops and how they will effect stroke lengths. Your input is urgently required, PLEASE!

[Purple Frog]

That's something you need to measure on your chassis.

Not that hard. With the shocks removed. measure the length from the two shock attachment points with the suspension fully lifted.
Usually you don't need to go more than 2" above standard ride height.

ICP may jump in with better instructions.

[Rick Kirchner]

i don't know about other 90-95 owners, but my car did not have bump rubbers, and the chassis bottoms before the shocks do.

[Charles Warner]

i don't know about other 90-95 owners, but my car did not have bump rubbers, and the chassis bottoms before the shocks do.

Out of curiosity, would the springs bind before the chassis would hit the ground? (I assume you have installed bump stops.)

[Rick Kirchner]

no bump stops and the springs don't bind. The skid plate takes all of it.

I've noticed some bulging and cracking of the nose box up around the cutouts for the steering rack. Once I noticed, I started looking at other cars of the era and I believe that's pretty common.

Averill makes and re-conditions a lot of nose boxes, I wonder what his experience is.

[DaveW]

I'd start adding bump rubbers until you notice either the chassis stops crashing into the ground, or you notice a handling issue, likely understeer due to the increasing rate on the "outside" suspension.

You can likely estimate what you need by jumping on the front in the shop with the bump damping at a low level. When it stops hitting the ground, you'd be at a good starting place.

[Jim Edmonds]

Since you said shocks instead of shock I presume you have a Continental. What springs are you running? I'm using 400lb 5inch springs on the front and 850lb 4in on the rear. I really like the car's handling with that combo.

Yes I bottom both nose and tail on very rough tracks and have torn up a couple of nose boxes over the years. On a very rough track you can raise the ride height which helps a little.

For what it's worth, I also tore up a nose box on my prior RF94 FF on the same very rough track running a soft single 300lb spring trying to decrease understeer. I thought of the nose box as sacrificial on that type of track, kind of like fiberglass, Ha.

Crude, Yes. Trading off sacrificial damage for CG. Tried rubber bumpers in the front shock with no effect. Not much luck with damping changes. A real shock wizard might have helped, though.

YMMV

Jim Edmonds
Phoenix, AZ
RF95 FC
RF01 FF
MV Agusta F3 track day bike

[DaveW]

Load-Deflection curves below...

These are particularly good because they are low rate at 1st contact, but stiffen dramatically at higher deflections. This results in minimal handling effects while managing to limit deflection after they are deflected more. A lot of bump rubbers are too stiff initially, which can adversely affect wheel rate. The Dynamic bump stops also feature a fairly high damping coefficient, which adds stiffness during fast deflections and aids in preventing unwanted rebound.

[DaveW]

I'd start adding bump rubbers until you notice either the chassis stops crashing into the ground, or you notice a handling issue, likely understeer due to the increasing rate on the "outside" suspension.

You can likely estimate what you need by jumping on the front in the shop with the bump damping at a low level. When it stops hitting the ground, you'd be at a good starting place.

What I do to tune the bump rubbers is to add one or two and then tune the gap before contact (air gap) first in the shop and then at the track with flexible urethane shim washers ~1/8" thick that are split on one side for easy insertion & removal w/o shock disassembly. I also use these in my rear "3rd-spring" for ride-height control.