Samo,

Thanks very much for the insight, I guess I was hoping you guys had a better experience with them than most.

We had two leaky ones when we got out J3's, and the press-fit bores on two of them were actually slip fits. That being said, they did fix everything for free, they were easy to get hold of to get them fixed, and they came back promptly.

This summer I am planning on taking at least one apart to see if there is anything that I can do to get the internals at least a little more reliable, if not more consistent. There is an old Vanilla RC of the solar car team's laying around that the new captains might let me take apart too. There could still be some value in using them basically for cores so that if you are going to try to make your own dampers you at least don't have to make the bodies, shafts, perches and ends. They may even be able to be converted to a solid-piston design like the Ohlins stuff.

Best,
Drew

I have to say that despite previous posts I have posted in regards to praising Risse, saying that we've had no problems with them, I must not recommend these shocks to anyone unless they straighten out their act.

Before, I felt compelled to talk them up because of their FSAE sponsorships they do; however, this year has been nothing but a headache for us. We decided to get new Risse shocks because our old ones were, well, OLD. We decided to go with the same models but with the remote reservoirs, the J5R's. At 50% off I felt we couldn't go wrong. Was told the shocks would be shipped in 2 weeks. Two weeks later, as anticipated, I got a shipping notice from them but the shocks never showed up. Apparently the shocks got stolen from there pickup location, which I can't blame them for. After another 3 weeks another set was made and sent our way. Got them to find that only 2 of them worked properly the others when compressed by hand sprayed oil out next to the compression adjustment knob. I called them up they said alright send them back. I paid 30 bucks to overnight them...no, even partial, reimbursement. Got them back again about a week later, one worked, the other one did the same thing still. I called them up and this time they sounded frustrated with me and claimed that they tested it. I said well if you tested it you obviously were blind to the oil spraying out everywhere. Again paid to overnight, got it back another week later with the same problem, sent it out one more time. Got it back and FINALLY it wasn't leaking oil; however, the compression adjustment had zero effect on it and the pressure in it was good so we, now running low on testing time (nearly 9 weeks after originally ordering the shocks) opted to match the compression damping with the adjustable shock to the non adjustable one and deal with the slightly sub-par performance since the other one was stuck only slightly softer than the adjustable one.

Now, we thought everything was good, boy were we wrong. If anyone was watching our skidpad at the west competition I am sure you saw it happen. In the drivers second run halfway through the circle you can see the shock blow out and the driver almost loose control, he regained control and finished the run...excellent driving on his part. We didn't think anything of it at the time and just thought he was getting loose until just after I took it for a spin on the practice track and in a left hand corner I felt the car roll significantly more than it should the body ate the ground and my left rear tire lifted off the ground a couple of inches. We looked under the car and sure enough the front right shock was covered in oil. This was one of the shocks that we thought was good from the beginning... guess they don't ever get it right on the first try. Anyway, we were lucky to have a couple of 550 springs which were stiff enough to compensate for the blown out shock. The car actually handled quite well with the 550's in front and down a shock but that was just luck.

Alright, thats my rant, and that is why we too will be looking for a different shock this year. It is unfortunate because we like the damping characteristics of our Risse's when they work right.

Steve

So if we wanted to look at moving to the Cane Creeks, does anybody have any contact information? Also, wondering where people get custom springs made. Thanks for your help!

If you search here you'll find tons of great spring suppliers. The cane creeks are sold through Motorsports Spares in Indy. The phone # is on here somewhere.

Anyone used Avalanche Racing suspension? Probably a bit on the expensive side, however they do have a reputation for excellent quality & performance.
Link:
http://www.avalanchedownhillracing.com/products.html

Avalanche is expensive, but they are used by professional mtn bike riders that do 30+ ft drops. They are some of the toughest available, no doubt.

yea steve o is right, we had nothing but problems with the risse shocks this year. maybe a bad batch or something because it seemed like a repeat occurance...nice shocks otherwise though

For an update on our Risse Shocks. We found out the hard way, during design judging, that the shocks were not pressurized properly. Our judge jumped on the right rear of the car and the left rear shock compressed more. When we made it back to our shop, I pumped them up and the car did not exhibit this characteristic. Also, we just got back from an autocross weekend with the formula car. We used the weekend to test car setup and adjusted the rebound and compression. Although the adjustment knobs only had small effects, they did help settle the car some.

quote:

Originally posted by exFSAE:
I do have to admit to get them to work we had to use a 1.7 MR or so.

How did you come to this conclusion? Have you been using CCs for a couple of years and every year you changed your motion ratio?

Also, what ride frequency are you trying to achieve with a MR of 1.7? With my calculations, I need a 200lbf/in spring to do that

quote:

How did you come to this conclusion? Have you been using CCs for a couple of years and every year you changed your motion ratio?

Also, what ride frequency are you trying to achieve with a MR of 1.7? With my calculations, I need a 200lbf/in spring to do that

Ride frequency was not my main concern doing a racecar suspension.. particularly for a super smooth track at Ford MPG.

We had the car's handling the year before tuned about where we wanted with ~250 lb/in springs (~85 lb/in wheel rate). There was some question as to the front end bottoming out with hot tires under hard braking.. and we (stupidly) assumed stiffer springs would just mean better handling.. so we eventually settled on 320 lb/in springs for final setup. They were stamped 300 lb/in, but they were all 320+. It kept the front end from bottoming and the rear drivetrain from overextending.

The next year, the reason we kept the 1.7 MR was mostly to accommodate the high damping rates. We could have gone to State an hour north and have them help us bleed and revalve the CC's for a softer rate, but I didn't want to chance F'in up my new expensive dampers.

For the right compromise of roll, pitch, and ride damping with the ~100 lb/in wheelrate we were carrying over, I figured about the softest I'd want to be able to tune the dampers would be about 8 lb/in/s at the wheels. I think the softest damper setting on the stock CC was about 24 lb/in/s, so that necessitated the 1.7MR.

The really stiff roll rate also provided for some good kinematic control, given that the tires we were using.. their cornering stiffness would drop like a brick as you added camber. At least that's what the data said.