masi61

I switched cassettes on my Dura Ace 7700 hub from an Ultegra 6500 9 speed to a SRAM 9 speed. The 7700 freehub body had been in perfect condition for over 12,000 miles. I decided to change to the SRAM cassette (I'll have to check which model, the spacers are a translucent orange plastic color) and it shifts well. At the time I changed I attributed a gear slipping symptom to the old 6500 cassette being worn. Turns out that the gear slipping originated from a worn 39 tooth chainring on my Ultegra 6603 triple crank, not the cassette.

I when I removed the SRAM cassette to do a more thorough cleaning, that's when I noticed deeper gouging on the splines of the freehub. Previously, when I had the 6500 cassette(s) I had no gouging or almost none.

So this got me thinking to ask: does swapping SRAM onto a Shimano Dura Ace titanium freehub body lead to more gouging? If you have experienced this, what could the cause be? Is the cassette spline design/manufacturing less precisely implemented?

Erzulis Boat 

Interesting. I just serviced/cleaned my Fulcrum rear wheel, and was pleasantly surprised to see that the freehub body was not deformed at all by the Ultegra cassette.

It stems from a precise fit, and the rear cassette has carriers that unitize the rear sprockets (3 per). Typically I have always observed deformation to a degree, and it's more pronounced with not unitized sprockets (sprocket/spacer/sprocket....etc.)

What are the contact points like on the Sram?

DaveSSS 

The shimano spline pattern only works decently with a steel or Ti body. Campy was smarter and used deeper splines that work with aluminum. The shimano design will soon be replaced with microspline, for 12 speed.

trailangel

I have Dura ace hub with titanium freehub and SRAM cassette and it doesn't chew into the freehub.
Maybe you switched yours to an alloy freehub?

70sSanO

My understanding is spidered cassettes spread the load over a wider contact area. And pinned cassettes also help to some degree. I’ll also throw lockring torque as a potential culprit.

My personal thought has to do with the cog stamping and how square the edge that touches the cassette body spline. As tooling gets worn there is a possibility that the contact edge is not as clean and that could drive the issue. I have no information that this is happening, but it does seem to be a plausible cause when two identical cassette setups yield different results.

John

dsaul

It has nothing to do with Shimano or SRAM, but more to do with the cassette construction. The more expensive cassettes have the larger cogs on an aluminum carrier, which prevents them from biting into the freehub body. The less expensive cassettes are all single cogs that are pinned together and can individually bite into the freehub body. The larger cogs generally have more mechanical advantage and are more likely to cause damage.

trailangel

I'm running the cheap SRAM pinned cassette...no carrier, and it doesn't chew into the freehub. Maybe Masi61 is a real beast of a rider.

masi61

Well I do weigh just below #200 and I like to climb while standing. But I've also been known in my group to be a bit of a "spinner". I believe the SRAM cassette is a "PG-950".

masi61

Nope, it is the 7700 which has the titanium freehub body.

Iride01 

Several years ago there was another thread about this. Or at least very similar. The net take-a-way was that some do and some don't and it's not an issue even if it does. Only negatives were that it made removing cassette harder sometimes and of course there was worry that eventually the splines will give way and the cassette spin. However no one actually had ever had that happen.

woodcraft

IMO, it has a lot to do with getting the cassette torqued on well.

It takes some muscle to get the lockring on to the specified (citation needed) inch/lbs.

Not enough, and the cogs will shift, and bite the freehub.

Cyclist0108

This is interesting. It happened with my White Industries Titanium freehub, but only after I put a SRAM 11-speed 11-36T cassette on it. I just assumed it was an inherent limitation of titanium, but now it makes me wonder. I tighten to 40 Nxm.

jgwilliams

I find it hard to believe that tightening the lock ring will make any significant difference to the cogs shifting. You simply couldn't tighten it enough for that.

Cyclist0108

The problem is under-tightening the lock ring, so the cassette moves a little while shifting. That can chew up the freehub.