Thread: Riva vs R&D ride plates.
11-16-2006, 05:02 AM #1
Riva vs R&D ride plates.
I have just got a R&D plate from J-me and spend a day testing it. Water was flat with light ripples. Here's some useless info on the two plates. Forgive me if I get the terms wrong!
-mounted sits @ 3 degees, 5mm at the front of the pump and 15mm at the rear.
-Has a dip of 12 thou in the last 60mm on the center bottom.
-Center is 10 thou lower than the outter skegs bottoms.
-Has two skegs
-Outer sides start shallow and cut in deeper at the rear.
- Rectangle shape and bigger than the R&D.
-Casting is poor, does not fit nicely around pump and hull area.
Best setup for me was one washer on the front and two on the rear, gave best speed of 63.3. Have had the plate on for a year.
-Mounted sits 0 degees, but sits 10mm higher at the front and 10mm at the rear.(not counting the tappered end)
-Has a angled end on the last 40mm of plate @ 3 degees
-Has a dip of 20thou from the front of the plate till the start of the angled end.
-Side's run at the same angle as the hull shape all the way to the end were it tappers inwards alittle, here its cut out as it's a tongue shape end.
-Casting is nice and fits the hull and pump very well with only @20 thou gap around the hull and pump area.
First impressions are good with stock mounting (no washers) and full tank of gas, trim on neutral.... all the way to 62 without a hint of porpoise. Bow up one and I ran 61.2, I was slower, bow up two and slower again with 60. Doing the runs I would cross over my own wake and now I can understand 97sleeper as it would unhook and land and take off again nice and smooth without a hint of it carrying on jumping and bucking around.... that I liked!!
Holeshot was good, didn't seem to throw the bow up as high as the Riva, it seems to do it with less drama and could be just a tad quicker onto the plane.
The main part of this plate is the noticeable differenceis in the turning, it will spin around with a lot less effort. To do a 180% turn is very easy and quick! The Riva with it's skegs would drag you in and drain more rpm's so alot more throttle is needed to complete the same stunt. At higher speeds I would give the Riva plate the nod as it feels more authoritative, not like the R&D is bad or anything, The Riva just gives you better feedback. High speed tight truns the R&D is faster and alittle wider in the turn as the Riva will trun shaper but you lose more speed.
I did start playing around with washers on the R&D, front and back etc and it's best setting was stock mounting (as groupK find out). I did manage to get another .7mph but I would start porpoising, and funny enough it was near the same angle as the Riva stock mounting.
Still need more time in more water conditions but it seems true that the R&D is around 1 mph slower that the Riva... But with the GroupK cut may pull it back and be on par???
So will keep testing and adding to this as time goes on. Have trim tabs to add etc and what to get to a setting where I can fill in all the holes etc and not have to worry about this area for a while
So for the GPR experts here your input on any tips with plates and hull areas etc would be appreciated.
Last but not least, here's my hull.... why do I have 4 screw holes in the rear??? I thought it maybe a 97 for the trim tabs, but looking at 97sleepers hull that is not the case...(never seen another GP) any idea's as when I had the muffler out and fixed up the sponson mount when I got the ski it has the same glue poo with a bracket on the inside??
The never ending story...
11-16-2006, 09:02 AM #2
At one time, somebody had the 98-99 Riva trim tabs installed on that hull, just like the tabs in the picture you sent me. If it were me, I would get the trim tabs, and get the Group K mod on the R&D ride plate. I would try this combo. See the link below to see my pics of my tabs. You will see my tabs end where the hull recess starts on your hull. However, if you can keep the porpoising down without the 98-99 trim tabs you will be faster in smooth water.
Last edited by 97GPSLEEPER; 11-16-2006 at 09:05 AM.
11-16-2006, 12:59 PM #3
Bill gave me the drawings of the Trim tabs which fill the whole space in the recess(Tau Ceti ones), I have enough alloy to make some strips like Riva ones which I will make as well. Then would like to run both plates again in stock form before I mod them. Yes a groupK mod would be the choice for the R&D and the Riva one I have some ideas.
"Center is 10 thou lower than the outter skegs bottoms" just to be clear, that's with the plate upside down, so you could look at it as 10thou higher when mounted -
11-16-2006, 01:49 PM #4
The setup that worked for me was shimming the plate in the front.
When I shimmed the plate in the rear on the triple piped ski it would unhook the ski by lifting the rear out of the water.
I have a group k cut R&D plate on a stock GP with washers in the front only
Washers are thick possibly 1/8"
This set up is awesome great ride with good speed you should try it.
11-16-2006, 04:32 PM #5
Yes for sure I will try that Scott. I plan on running both plates again when the tabs are on and see how they run. Will do the cut on the R&D plate and run before the tabs go on that trial, to compare the cut with and without tabs. Then start playing around with washers etc. Will try a few mods on the Riva one as well have some idea's on that one. So need some time in the water!
11-16-2006, 10:11 PM #6
Good write up Kiwi !
Like that hull pic too.
I have heard removing the exhaust flap frees up 40 or so revs.
Keep us posted.
Last edited by J-ME; 11-16-2006 at 10:14 PM.
11-19-2006, 10:22 PM #7
Hmmm exhaust flap ah?? would that let a good amount of water back in the exhaust tail pipe area...??
Anyway have taken the R&D plate to get cut this morning... so next week I'll start testing it, then the trim tabs go on etc.
11-20-2006, 07:51 PM #8
Even with the flap installed water can still enter the exit hose and possibly the water box. The vertical rise in the hose before it drops down into the water box makes it difficult to cause problems, in my opinion. I have been running without a flap on mine for 8 years, no problems. It sounds a little nastier too. If an RPM gain results that is even better.
Last edited by 97GPSLEEPER; 11-20-2006 at 07:53 PM.
11-21-2006, 12:29 AM #9
Great information. I have been looking for the solution to my porposing problem and which ride plate was the best. Since you have both plates and both of them seem to work pretty good would you be interested in sellig one of them when you are done testing. It is currently winter in Kansas so i dont need one until about April. Also I PM'ed you on the sponson for my 2000 GP 800.
11-21-2006, 02:14 AM #10
Sponsons yours.... I'll PM ya.
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