Tiagra compact chainset

[leoc]

Hi,

I've been thinking about changing to a tiagra compact chainset such as this:

http://www.parker-international.co....ID/125/v/bbba2512-84c0-4c0f-b224-a06c0075d23b

My current chainset uses a conventional cartridge bb, so I'd have to get the cups too:

http://www.parker-international.co....yID/35/v/bbba2512-84c0-4c0f-b224-a06c0075d23b

Thing is I remember someone somewhere posting that the bb shell on the frame would need facing before switching to outboard bearings, so is this true? And does anyone have an idea of the cost please? Also, has anyone seen any other good deals on the chainset / cups?

Cheers,
Leo

 

[itisaboutthebike]

I've never had any of my frames 'faced' and I use Shimano outboard BB's. It would(should !) probably have been done by the manufacturer.

Unless your frame is very old(and maybe rusty around the BB area) or the faces look rough then mite be possibly worth it. otherwise I wouldn't bother.

Any reasonably good lightweight bike shop should be able to 'face' a BB shell.

 

[Mortiroloboy]

As above, I changed from my standard 52/39 to a compact 50/34 on my old Spesh Allez, went from tapered axle BB to outboard cups, no need to face the BB shell, and no worries about width of shell either, takes just a few minutes to do too.

 

[robbarker]

Shimano assembly instructions (on their website) warn that the bottom bracket shell faces need to be parallel. Even new bikes can come with laquer etc on the faces. It is worth getting them faced.

http://www.parktool.com/repair/readhowto.asp?id=95#shimano

 

[leoc]

As above, I changed from my standard 52/39 to a compact 50/34 on my old Spesh Allez, went from tapered axle BB to outboard cups, no need to face the BB shell, and no worries about width of shell either, takes just a few minutes to do too.

Cool, thanks both for the advice I guess I need a special too to fit the cups, is there an inexpensive version (I'm not going to be doing this often enough to need a workshop tool hopefully)?

 

[leoc]

Shimano assembly instructions (on their website) warn that the bottom bracket shell faces need to be parallel. Even new bikes can come with laquer etc on the faces. It is worth getting them faced.

http://www.parktool.com/repair/readhowto.asp?id=95#shimano

Thanks for the link Rob

 

[Mortiroloboy]

Cool, thanks both for the advice I guess I need a special too to fit the cups, is there an inexpensive version (I'm not going to be doing this often enough to need a workshop tool hopefully)?

Shimano specific BB tool, look around you can pick 'em up for a few quid, or pop into your LBS from where you purchased the chainset and get them to put the final oomph into the cups, you can tighten 'em up finger tight, the chainset comes with the tool to tighten up the cranks, but you knew that. Personally I wouldn't worry about facing, unless the BB shell looks really uneven due to laquer finish or rust.