On Sat, 11 Nov 2017 10:39:42 -0800, Joerg
wrote:

On 2017-11-11 07:51, jbeattie wrote:
On Friday, November 10, 2017 at 4:47:56 PM UTC-8, Joerg wrote:
On 2017-10-18 16:41, Joerg wrote:
Attention, a purely technical post :-)

Does anyone know whether these adapters are for going from 160mm
native post mount to 203mm rotors?

https://erpimgs.idealhere.com/ImageF...963c864243.jpg




The bellied version (which I'd need) seems to only be available from
Chinese sellers and they either don't understand English or plain
don't know what they are selling. Or both. For example, when I
asked the either-or question whether the adapter is for 160mm to
203mm or for 180mm to 203mm the answer was "No". Refining the
question in great detail resulted in "It's for 203mm". Needless
to say, asking for dimensions so I can calculate it myself is
generally fruitless as well.


So, I just dunnit. The front and back wheels of the MTB now both
have 8" or 203mm rotors. Shimano SM-RT66 (SLX Deore) for now, long
term I'll be looking for solid rotors.

Other than the usual swap dance of washers for shimming until it
was just right it was a painless switch. Braking feels nice and
sturdy.

Shimano recommends 18 to 35 in-lbs of torque for the rotor bolts.
Seems wimpy and the previous ones sat way tighter, so I gave it a
bit more oomph.

While at it I adjusted out the rattle and play that always develops
in the steerer after a few hundred trail miles. Every time I torque
down those tiny stem bolts at the spec'd 44 in-lbs it feels like
they'll strip the threads out any second.

Shimano has tightening plates on their six-bolt rotors.


All those little things are is a tiny locking lip sticking up for each
screw, pair-wise. That won't hold much. One of the issues with low
torque is the rotor slacking back and forth if you have to hold the bike
from rolling back down a hill, then downhill again, then up, and so on.
Which happens a lot on an MTB. For some reason the manufacturers can't
get the tolerancing in the screws and holes tight enough.


... Avid uses a
higher torque spec. 5nm should be plenty to keep your stem and
headset tight, but probably not in Cameron Park.


It does but only if I smear some grit-laden toothpaste on the fork tube
before sliding on the stem. Not the paste for electric brushing but the
regular paste. What I am saying is that 5nm feels like it's about to
strip the aluminum threads out.

I think I'd buy a torque meter. And use it :-)

Alternately there might be sufficient material to drill and tap bolt
holes out to the next size, i.e., 5mm - 6mm.

Another idea might be to see what the real racing boys are using for
stems and use the same. I doubt that a guy racing for a $750,000 first
prize (The winner of the Munga will take home $750,000, followed by
$100,000 for second, and $50,000 for third place ) plans on having
many problems with the stem on his bike.
--
Cheers,

John B.