Slipping Freehub?
 

Okay, I know this has been discussed a number of times but this is something I have never experienced before so it's a completely new problem to me.

We were going up a short but fairly steep section of road this past weekend on our tandem. The wheelset is a circa 2006 Rolf Prima Vigor. The bike is a recently purchased off craigslist Trek T1000. The 9speed cassette is almost new. Chain and chainrings came with the bike, but appear pretty good.

We had ridden up some pretty steep hills with this bike and set up before with never a hint of a problem

We were leaning heavy on the pedals at this particularly steep section and all of a sudden the pedals slipped with a sort of ratcheting sound. Naturally, locked into the pedals, it was a heart stopping moment as we nearly teetered over!

Having never experienced this before I immediately thought one of the chains had slipped over some sprocket or chainring teeth.

Once off the bike on the side of the road, I began to think it wasn't a slipping chain, but a slipping freehub.

We continued up the hill, under more moderate pedal load and experienced no more slipping on the way home.

Once home, I took the freehub apart. I noticed a tiny amount of wear on the outer edge of the ratchet ring (whatever it's called) but pawls seemed okay and sprung back and forth okay.

To me, never having ever taken apart freehub before, it all looked pretty good. But what do I know? Any insight? (Or if you prefer, incite.)...Oh, if I need a new freehub, can some one make a recommendation. Currently running 9speed Shimano and would stay with that.

Photos to follow:
https://cimg2.ibsrv.net/gimg/bikefor...33a066d6c4.jpg
https://cimg8.ibsrv.net/gimg/bikefor...a260c9627f.jpg


https://cimg1.ibsrv.net/gimg/bikefor...e7a05ee224.jpg
https://cimg9.ibsrv.net/gimg/bikefor...0008c770a8.jpg

Looks like that could use a good cleaning and reoil. I've had do to this recently as well on a prior hub and it didn't slip afterwards. I used Phil's oil.....augh, can't remember the exact name.

Would suggest doing that before spending money on replacing it.

Not saying this is it, but a worn chain will slip on a new cassette. Even if the chain "appears" fine, it's good practice to replace it every time you get a new cassette.

How do your chainrings look, BTW?

Looks very clean so I'm assuming you de-gunked all the grease out of it? Try lubing and re-assembly and try again, cautiously. Check the mfr for recommended lube. Brand of lube is not important but proper viscosity is. Too thin a lube can dribble past the seals and leave you with a dry cassette hub. Too thick can cause the pawls to stick and not engage as yours did. A dirty, gunked up mechanism can also prevent the pawls from engaging.

Thanks to those who've replied.

So I cleaned (really wasn't that grungy), oiled using a medium weight oil and reassembled. Haven't had a chance to ride it yet.

I have a couple of questions; if the freehub continues to slip, would a repair involve a new freehub? Is it likely to be a worn 'star ratchet?' Having never messed with one of these, I assume a bad star ratchet means the hub is toast, no replacing that, I presume?

I read the factory service and it mentioned replacing the springs. That would be the only failure I could think of.
https://rolfprima.com/pages/factory-service

Some ratchet rings are replaceable, but good luck finding a 15 year old part or the tool... It might be easier to find a crashed rear wheel that you can take one off of.

IIRC there were some tandem specific Rolf wheels (that Santana offered) back then. Perhaps contacting one of the few tandem focused shops that has been around a while? Tandems East, Gears to Go Tandems are two that I know of. It's been 12 years since I sold and serviced tandems in a shop (All Star Bike Shop) so memory might not be perfect.

I will say that those wheels don't owe you anything after 15 years. Andy

You don't have a 'star ratchet'. The part you're talking is the drive ring right? The outside ring that the pawls engage? Not sure if it's replaceable on that hub, I would lean towards yes.

Thanks, I didn't know what the heck it is called. I probably would have called it a 'rack' but I knew that wasn't right either. So, it's a 'drive ring, eh? (Yes, the toothed ring the pawls engage)

Jeez, unless that is pressed into the hub and there are some kind of splines to keep it from rotating, I can't see how it could be replaceable. But then again, I haven't gotten that far yet on my YouTube video search!

Thanks again.

Well, these ''ratchet rings' just screw in and out with the proper tool. Learn something new everyday. Thanks for your kind and patient assistance!