RCD belts braking

Hi Guys ,i have been running RCD 75mm belts with not to many probs braking a few smooth idler, So
i up graded to 84mm with tooth idler and HAVE be braking them 3 runs 1 BELT and thats the best, Even gets
worse ,Same blower screw D STD ,Same motor, Same tune up slightly different clutch set, Please help before i use all the old ones to make a NOOSE, 6 belts 3 meetings
Regards MTC

 

I also run 8mm belts, PSI C Rotor, belts run very tight. 3-4 runs if lucky.
Is 84 wide to way to go? What color belts? Blue, Purple or Grey?
No two step, straight timing. Idle 2,800 rpm to 9,600 rpm, in a boat.
Any help?

 

If you were not breaking belts before or not as many, I would go back and look at the changes made. The 84MM belt would not cause you to break belts as long as you didn't go from the Problem Savers (PS) back to a carbon or lesser quality belt.

I have never run a toothed idler but from my understanding, it has to be correctly aligned as it does not give as much lee-way like a smooth idler can. It was a change and I'd consider changing that to a smooth one if you can borrow one from someone. Or at least double check to make sure you have the correct alignment and is not flexing on you.

Going back to the belt, I've had outstanding results with the Star Racer belt which I have run in both 1600 and 1672 84 8MM configuration on a 2-step between 3800-4400 RPM. In fact, even though I don't race every week, I have not broken one of these. With the Gates PS 84MM belts, I'd normally break them a pass or two after I'd pedal it. The Star Racer does not produce the dust that the Gates belts do to which is a bonus if you don't like to clean that stuff up.

 

Hi Mike No two step ,

 

Hi the 75mm i have purple 8mm PS early type,The 84 are the newer Grey i have thought there maybe some thing there (both are Kevlar types)

 

Hi ,when we fitted the 8 mm 84mm ps the tooth idler didn;t line up the best so we machine up a new spacer 7075 T6 spacer same as rcd that fits up in side the bearing ,moving out tooth idler all ok at this point, ive been thinking about (GOing back to the 75mm ps) i even thought that it maybe 84 was to ridged , Ive herd good things about the Star mit, if i keep up with 84 i will have to try
the smooth idle Thanks Mark

 

Belt quality can vary from manufacturing batch to batch. Seems to be more of a problem with the Gates belt these days. We switched to the Star Racer belt (1672mmX84mmX8mm), and have been very happy with these.
Obviously the 84mm wide belt is stronger than the 75mm, but we have had enough success that we are going to try to run the narrower belt this year (they are alittle cheaper)!
Marty

 

dual idlers work for me, had these on now for a number of years - 1792 x 3" 8 mm belts. I see several cars now running this setup.

 

Curious, what is the diameter of your idlers? Flat or crowned?

 

65mm adjuster one and and 68 mm for the guide one, this one has wider flanges. both are flat as a pancake, turned them up on my lathe.

the sizes are not measured when made, they are just what they turned out ( no pun intended ) to be.

 

The one on the tension side of the belt, does it put much pressure against the belt and does it displace the belt "outward" a little bit when everything is set to run?

 

yes lots of tension, i run it pretty tight and yes belt its slightly triangulated