Bottom Bracket MTB vs Road

UN-72. the only choice.

(PVD) writes:

UN-72. the only choice.
I though UN-72 was out of production, replaced by UN-73.

On Wed, 18 Aug 2004 11:15:20 GMT, "Billy" wrote:



I know that the UN-72/3's are lighter and have hollow shafts. But what is
the difference between a UN-52 and a UN-53? Or, for that matter a UN-72 vs
a UN-73?

Thanks.

Billy


I think that the '3's come with a resin retaining cup for the left
side and the right side retaining cup is built into the BB itself, not
a separate piece. For the 73s, at least. Something similar for the
53s? Either way, basically the same thing except the '3's are the most
recent version. I have a UN-71, 72, and 73 on three different bikes
and I notice no difference. And the 71 is going fine after eight years
or so.

Billy wrote:

The bottom bracket on my mtb is in need of replacement. It has Alivio MC10
components. Perusing through my latest Nashbar catalog shows a section of
BB's for mtb's and a section for road bikes. My Performance catalog doesn't
differentiate. Is there a difference between mtb BB's & road BB's? My BB
is 68 x 113 with a square tapered axle. Will any 68 x 113 with a square
tapered axle work? Any BB recommendations for a bike to be used for
commuting? I need ruggedness. Light weight is not critical.

Yes, but get a Shimano one rather than a Campagnolo one. The taper is
slightly different. The "MTB" ones are probably just longer BBs,
designed for a triple chainset.

dan- I think that the '3's come with a resin retaining cup for the left
side and the right side retaining cup is built into the BB itself, not
a separate piece. For the 73s BRBR

That is correct. right cupo now part of the BB, cannot take it off. hollow
axle, not solid UN-53. Too bad, cuz now ya can't swap cups.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

nospam- That is all very true, but the flip side is that you can't add 3oz to

everything, or you actually will have a very heavy bike. I followed that
philosophy on my MTB and ended up at a disappointing 29lbs, for a bike
that in theory could weigh less than 25. BRBR

4 pounds don't make a difference. I use Phil on my road bike and it weighs 19.5
pounds. Losing 3 pounds on my bike with me on it means nothing. Weight on a
bike is WAY overemphasized....

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

Qui si parla Campagnolo said...

nospam- That is all very true, but the flip side is that you can't add 3oz to

everything, or you actually will have a very heavy bike. I followed that
philosophy on my MTB and ended up at a disappointing 29lbs, for a bike
that in theory could weigh less than 25. BRBR

4 pounds don't make a difference. I use Phil on my road bike and it weighs 19.5
pounds. Losing 3 pounds on my bike with me on it means nothing. Weight on a
bike is WAY overemphasized....

I agree it is mostly ego, bragging rights, and one-upmanship. If you are
a pro in top condition and looking to gain a few seconds per hour over
your competitors, then it matters. For the rest of us, it is just a
pointless diversion. I could lose 15lbs from my too round carcass, and
no matter how many thousands I spent, I couldn't take that much off my
bike.

I got a killer deal on a 330mm Thomson seat post last week at a LBS and
yesterday I was debating whether I should cut it down to 250mm to save
30g for the new road bike that is on its way from GVH bikes. Then in a
moment of sanity I watched myself cramming everything but the kitchen
sink in my seat bag and not even thinking about what any of it weighed.
I decided to keep the seat post just the way it is.

RE/
Then in a
moment of sanity I watched myself cramming everything but the kitchen
sink in my seat bag and not even thinking about what any of it weighed.
I decided to keep the seat post just the way it is.

I wish I'd had that moment before I cut mine down. Worked fine cut down....but
the next frame I wanted to use it on needed a few cm more length....
--
PeteCresswell