Retrobike Forum Index

It is currently Mon Dec 05, 2016 1:53 pm

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 10 posts ] 
Author Message
PostPosted: Mon May 27, 2013 3:08 pm 
retrobike rider
retrobike rider
User avatar

Joined: Wed Mar 03, 2010 11:59 am
Posts: 4437
Location: Near Southampton
Hi guys

Looking to replace a knackerd cone/cup BB for a sealed cartridge one...I know from the old one and the chainset that I am fitting (Deore LX M550) that I should need a 122.5mm one. My question is this...I can get 122mm ones cheaper than 122.5mm so will 0.5 mm really make any difference???

Thanks

Doug


Top
 Profile  
 
PostPosted: Mon May 27, 2013 3:42 pm 
retrobike rider
retrobike rider
User avatar

Joined: Fri Mar 13, 2009 7:19 pm
Posts: 3132
Location: Leeds, for ages!
You will be ok with 122mm, wook. the difference is negligible as alloy cranks will open by that much at the taper closing the cranks in by atleast 0.5mm. yes, buy one :wink:

un51/52/53/54 are pretty much the same. un55 looks better manufactured but....no real diference 'til un71>


Top
 Profile  
 
PostPosted: Mon May 27, 2013 3:44 pm 
Gold Trader
Gold Trader
User avatar

Joined: Fri Jan 23, 2009 2:30 pm
Posts: 12408
Location: Surrey
I doubt it. The clearance and chain line will barely notice.


Top
 Profile  
 
PostPosted: Mon May 27, 2013 3:59 pm 
retrobike rider
retrobike rider
User avatar

Joined: Wed Mar 03, 2010 11:59 am
Posts: 4437
Location: Near Southampton
Thanks guys as far as I understand it the differences between the un's is this:

UN51 = solid axle
UN53 = solid axle
UN54 = hollow, plastic NDS cup
UN55 = hollow, alloy NDS cup
UN72 = hollow, ?? cup
UN73 = hollow, alloy NDS cup
UN91 = hollow, alloy NDS cup

In the end managed to get a un51 122.5mm from crc for £7.99 free post! A bit heavier but its for my wifes bike (another 1991 Marin Eldridge!) so weight not really a mega issue!

Cheers anyway guys

Doug


Top
 Profile  
 
PostPosted: Mon May 27, 2013 4:13 pm 
retrobike rider
retrobike rider
User avatar

Joined: Fri Mar 13, 2009 7:19 pm
Posts: 3132
Location: Leeds, for ages!
UN72 twin alloy cups. both removable, one seems fixed but isn't. :wink:


Top
 Profile  
 
PostPosted: Mon May 27, 2013 4:21 pm 
Retro Guru
User avatar

Joined: Thu May 03, 2012 7:13 pm
Posts: 2574
Location: The Cock Inn, Tillett, Herts
Remember that lad who bought a 122 instead of a 122.5? His dog bit him, wife.left him, and he got arrested for cross dressing in the ladies loos. It's jot worth skimping that half a mm!


Top
 Profile  
 
PostPosted: Mon May 27, 2013 4:40 pm 
Retro Guru
User avatar

Joined: Mon Mar 28, 2011 9:29 pm
Posts: 1877
Location: Somerset
marc two tone wrote:
UN72 twin alloy cups. both removable, one seems fixed but isn't. :wink:


Indeed, and it's the cups that are different between 68 & 73mm widths, not the body (have two here of the same axle length).


Top
 Profile  
 
PostPosted: Mon May 27, 2013 4:43 pm 
retrobike rider
retrobike rider
User avatar

Joined: Wed Mar 03, 2010 11:59 am
Posts: 4437
Location: Near Southampton
Chopper1192 wrote:
Remember that lad who bought a 122 instead of a 122.5? His dog bit him, wife.left him, and he got arrested for cross dressing in the ladies loos. It's jot worth skimping that half a mm!



That was my fear...hence I went for the 122.5mm!


Top
 Profile  
 
PostPosted: Mon May 27, 2013 4:53 pm 
retrobike rider
retrobike rider
User avatar

Joined: Fri Aug 08, 2008 2:36 pm
Posts: 16747
Location: Yorkshire, England
wookiee wrote:
Thanks guys as far as I understand it the differences between the un's is this:

UN51 = solid axle
UN53 = solid axle
UN54 = hollow, plastic NDS cup
UN55 = hollow, alloy NDS cup
UN72 = hollow, ?? cup
UN73 = hollow, alloy NDS cup
UN91 = hollow, alloy NDS cup

In the end managed to get a un51 122.5mm from crc for £7.99 free post! A bit heavier but its for my wifes bike (another 1991 Marin Eldridge!) so weight not really a mega issue!

Cheers anyway guys

Doug


There's a few numbers missing from theatre. un54/55 are the same bottom bracket apart from the cup change. I asked Shimano what the change was.
In the scheme of things they are lighter than the previous 5x's but still don't get the axle coating of the UN7x and 9x series.

Chances are 122 is the same as 122.5 anyway.


Top
 Profile  
 
PostPosted: Mon May 27, 2013 5:23 pm 
Old School Grand Master
User avatar

Joined: Sun Aug 21, 2011 11:57 pm
Posts: 4074
Location: Antwerp, Belgium
Chopper1192 wrote:
Remember that lad who bought a 122 instead of a 122.5? His dog bit him, wife.left him, and he got arrested for cross dressing in the ladies loos. It's jot worth skimping that half a mm!


You forgot what happened after he was released.

He tried to get home by bike, but the 0.5mm increased the friction on the bearings so much that they overheated.
His bike caught fire while he passed a petrol station and the resulting explosion caused 3rd degree burns in the genital area.

To top it off, the incident was classified as an act of terrorism, which means he now is on the no-fly list as well.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: james_jc, OllieJones, RickTheUncivil, shed, ti_pin_man and 42 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group