511 pulley worn in 5 runs

[fastinfastout]

I built the car as per manual, had about 5 runs with a 5.5 turn, and noticed the belt started skipping/slipping. The rear pulley has been worn down. The belt was not overly tight or loose, the belt is in very good condition. Seems unusual to get the pulley worn down so quickly. Slipper was not overly tight, just as per normal how I usually have my other cars. Is this the norm? The front looks new!

[KyleHirano]

Diff pulleys have been a weekness, on some vehicles, mainly 501, 511, and db01r. You have to setup the slipper clutch almost perfect as well as the diff, especially if your going to use a 5.5 motor. When the diff pulley gets hot, it's just a matter of time before it fails. Jumping a buggy and immediately punching the throttle with that hot motor, will cause damage every time, if your clutch is not setup properly.

I've gone through two rear diff pulleys on my db01r and I finally loosened my slipper clutch, and now things are good.

[muratti]

I have never had this problem, neither on the DB01R nor the 511. Seems indeed your slipper is too tight and maybe the belt a bit too loose. I alyways check the slipper when hearing the diff slipping i set the diff tighter or the slipper looser, both prevent stripping or overwearing the pulleys.

[fastinfastout]

yeah thanks guys, I might need to set the slipper a little looser as I never had this problem on my db01r and 501x, however back then I ran 8.5's

[Fredrik Emilsson]

Also think slipper is to tight and/or belt too loose.

With old belts (501X) it was important to adjust belt tension after ~8 runs. Once it started to slip, the pulleys would wear out pretty fast.

On 511 I´ve never had that problem. I tighten belts as per manual. The reinforced belts don´t stretch out like the "old" 501 belts did.

So recheck belt tension. Notice that rear diff pulley/belt should be tightened 2 notches. 501X with 369 mm belt was only tightened 1 notch.

[fastinfastout]

yep I have the rear belt as per manual, 2 notches forward. I will put a new pulley on, on the spur if its worn too, and back off the slipper more.

[_valtsu_]

When I built my 511 as manual sed, the belts were way too tight. If belts are too tight that will also kill the pulleys. One way to compare belt tension is to check how many times you can rotate the belt. On my 511 I can rotate the belt 1,5 rounds and that tension works on my car.

[KyleHirano]

It's been my experience with the 511 and DB01R that the slipper clutch is very sensitive to adjustments, it's takes a little trial and error, to find the sweet spot. Never ran a 501 or 502 so not sure on those.

[mattybucks]

I changed the pulleys and belts on my 511 yesterday. I think it's something that happens over time but after 5 runs means you've got a problem.

How do you test the tension of your belts?

Thanks

Matt

[super__dan]

When I built my 511 as manual sed, the belts were way too tight. If belts are too tight that will also kill the pulleys. One way to compare belt tension is to check how many times you can rotate the belt. On my 511 I can rotate the belt 1,5 rounds and that tension works on my car.

Interesting, I tensioned a new rinforced rear belt last night and thought it felt very tight. What setting do others run? What was the 501 setting?

[fastinfastout]

so what I ended up doing now was backing off both front and rear belts 1 notch, as the standard setup does feel quite tight on the belts. I think that may have contributed to the premature wear as suggested before. I have set my slipper now so that it does have a more noticeable slip that you can hear it when accelerating on concrete. I will see how it goes from now on. With regard to the belt tension, it has a slack which is just tighter than what you would run on a touring car, slightly.

[Balders]

I've had a 501 and a 511, never had the pulleys wear out, I run the belts slightly loser than the manual suggests though.

I usually gauge the belt tension by how much movement is in the top front/rear belt. if you can play a tune on it its too tight; i usually set it so that you can lift the belt about 15/20mm from top deck without stretching/forcing it.

never had a belt fail or skip or ruined a set of pulleys..

[fastinfastout]

15-20mm, I would have thought to be too loose. I think I set mine around 8-10mm from memory now