AM Classic Cr420

bicycle_disciple said:

I'm looking to purchase these wheels second hand. Does any one have
any thoughts and ideas about their performance.

Performance is great (light and aero), but they're rather
high-maintenance, in my experience.

Quoted message said:

Are they shimano 9 speed compatible?

Yes. To use a Shimano 10spd Cassette (well, definitely the Dura Ace
one, maybe the other Shimano 10spds as well), you need an extra 0.5mm
spacer ring in addition to the normal 1mm one for using a 10spd cassette
on a 9spd hub.

The maintenance problems I've had are:

1. Spoke Freeze (loctite-type compound) used on alu spoke nipples, so
it's tough to true these wheels. You typically have to loosed the
nipple first, removing it completely and greasing it before screwing it
on again, in my experience.

2. The early bladed spoke version of the CR420 had terrible spokes
(stamped "CN"😉 that would break at the elbow pretty easily. The later
ones (stamped AC) seem fine. I have the CN-stamped double-butted spokes
and they seem okay, although I did have one in the front wheel
spontaneously snap a few years ago. I wasn't even riding the bike at
the time - just standing astride it waiting for some friends to finish a
race.

3. Poorly sealed rear hub - I've had several sets of bearings rust due
to water getting in. If you have the new 17mm axle rear hub, you can
get Stainless Steel bearings or Ceramics, which might help. For the
older 15mm axle hub, I've only been able to find standard steel
bearings. I think it might help to pop the seals off the bearings, pack
them with extra grease and replace the seals before installing. I've
done that, and so far, so good (but so far is not very far yet, I admit).

4. The inner races of the bearings are not held apart from each other
(they're free to slide along the axle), so one needs to make sure that
the bearings aren't being preloaded from the side. Do this by adjusting
the 19mm preload nut to allow a tiny bit of play when the wheel is on
the bike and you wiggle the rim from side to side (i.e. alternating
towards and away from the brake blocks). The very latest AC rear hubs
do fix the inner races in place on the axle, so the play is no longer
required. If you're buying 2nd hand, though, you're probably getting
one of the older rear hubs.

All that said, I still love these wheels.

I'm 6'5" at 205, have about 5,000 miles on a set, and have never had to
put a spoke wrench to them. I have the bladed version, purchased about
2.5 years ago. I don't ride them in the rain, so I haven't had the
troubles that the other poster had. Very light for a deep section rim,
almost identical in weight to a set of Bontrager Race X-Lites that I
have. However, The AC420s are rock solid and the Bontragers are
noodlely to say the least. Or, um, *compliant* in marketing-speak.

bicycle_disciple said:

I'm looking to purchase these wheels second hand. Does any one have
any thoughts and ideas about their performance.

Are they shimano 9 speed compatible?

Thanks

Ron

On Feb 8, 6:15 pm, "bicycle_disciple" <[email hidden]>

Quoted message said:

I'm looking to purchase these wheels second hand. Does any one have
any thoughts and ideas about their performance.

Are they shimano 9 speed compatible?

Thanks

Ron

Do a google search, some of these wheels with a specific rear hub have
been recalled.

That's odd. Mine are very low maintenance. One truing in three years!

Anon User said:

bicycle_disciple said:

I'm looking to purchase these wheels second hand. Does any one have
any thoughts and ideas about their performance.

Performance is great (light and aero), but they're rather
high-maintenance, in my experience.

Quoted message said:

Are they shimano 9 speed compatible?

Yes. To use a Shimano 10spd Cassette (well, definitely the Dura Ace
one, maybe the other Shimano 10spds as well), you need an extra 0.5mm
spacer ring in addition to the normal 1mm one for using a 10spd cassette
on a 9spd hub.

The maintenance problems I've had are:

1. Spoke Freeze (loctite-type compound) used on alu spoke nipples, so
it's tough to true these wheels. You typically have to loosed the
nipple first, removing it completely and greasing it before screwing it
on again, in my experience.

2. The early bladed spoke version of the CR420 had terrible spokes
(stamped "CN"😉 that would break at the elbow pretty easily. The later
ones (stamped AC) seem fine. I have the CN-stamped double-butted spokes
and they seem okay, although I did have one in the front wheel
spontaneously snap a few years ago. I wasn't even riding the bike at
the time - just standing astride it waiting for some friends to finish a
race.

3. Poorly sealed rear hub - I've had several sets of bearings rust due
to water getting in. If you have the new 17mm axle rear hub, you can
get Stainless Steel bearings or Ceramics, which might help. For the
older 15mm axle hub, I've only been able to find standard steel
bearings. I think it might help to pop the seals off the bearings, pack
them with extra grease and replace the seals before installing. I've
done that, and so far, so good (but so far is not very far yet, I admit).

4. The inner races of the bearings are not held apart from each other
(they're free to slide along the axle), so one needs to make sure that
the bearings aren't being preloaded from the side. Do this by adjusting
the 19mm preload nut to allow a tiny bit of play when the wheel is on
the bike and you wiggle the rim from side to side (i.e. alternating
towards and away from the brake blocks). The very latest AC rear hubs
do fix the inner races in place on the axle, so the play is no longer
required. If you're buying 2nd hand, though, you're probably getting
one of the older rear hubs.

All that said, I still love these wheels.