Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Galleries NEW FAQ Contact About
It is currently Mon Jun 27, 2016 3:12 am
Recently the board software has been updated and there are some known bugs/failures:
- Avatars are currently not being displayed ✔ FIXED
- Tapatalk connection is currently broken ✔ FIXED
- Avatars cannot be uploaded ✔ FIXED

Please note that we will soon do some changes in WW board template design in case to get a fully mobile/desktop responsiveness board!
If you find more errors please post it here: http://weightweenies.starbike.com/forum/viewtopic.php?f=7&t=139062


All times are UTC+01:00





Post new topic  Reply to topic  [ 8 posts ] 
Author Message
PostPosted: Sun Feb 10, 2013 1:34 pm 
Offline
User avatar

Joined: Mon Dec 31, 2012 8:31 pm
Posts: 21
Hi,

Just completed my first Duathlon of the year and came across an interesting issue. The course I had to ride was completely flat and I found myself totally under geared as I have my bike setup with a Shimano 7950 compact 50/34 chainset (use it as it's very hilly where I live and train).

So the big question is, what are my options as it looks like I can't easily change the 50/34 ratio to something bigger without the chainset looking odd. Should I just buy a non compact Shimano 7900 chainset or are there better/lighter options I could consider as I don't mind changing the pressfit bottom bracket at the same time? Guessing the bottom bracket will have to be a Shimano pressfit as I've tried looking around and ended up totally confused within 5 secs.

_________________
Regards

Portia Baines


Top
   
PostPosted: Sun Feb 10, 2013 4:17 pm 
Offline

Joined: Fri Jan 27, 2006 1:38 pm
Posts: 671
Location: Greater Pittsburgh
What cassette were you using? 50-11 is slightly taller gear than 53-12, so that should give you all the top end you need... For really flat terrain, 11-21 would be ideal (straight block cassette, allowing equal spacing between gears), or 11-23 is a good option. Personally, I'm not a big fan of the 34, swap that for a 36 and you still have a useful compact, but much better shifting.

_________________
"Suddenly the thought struck me; my floor is someone elses ceiling" - Nils Ferlin


Top
   
PostPosted: Sun Feb 10, 2013 6:52 pm 
Offline

Joined: Mon May 30, 2005 7:13 am
Posts: 1536
While I'd be a little surprised that a 50 was holding you back, as a 50/12 at 90rmp is 30mph, maybe just pick up some Praxis 7950 52/36 rings and get a 11 tooth cassette:
http://shop.praxis-works.com/Compact-DA ... oductId=32


Top
   
PostPosted: Mon Feb 11, 2013 12:54 pm 
Offline

Joined: Fri Jan 27, 2006 1:38 pm
Posts: 671
Location: Greater Pittsburgh
NGMN wrote:
While I'd be a little surprised that a 50 was holding you back, as a 50/12 at 90rmp is 30mph, maybe just pick up some Praxis 7950 52/36 rings and get a 11 tooth cassette:
http://shop.praxis-works.com/Compact-DA ... oductId=32" onclick="window.open(this.href);return false;



Sound advise, but if you're keeping 30MPH, then call Praxis as I'm certain they will sponsor you. :lol:

_________________
"Suddenly the thought struck me; my floor is someone elses ceiling" - Nils Ferlin


Top
   
PostPosted: Mon Feb 11, 2013 9:37 pm 
Offline
User avatar

Joined: Mon Dec 31, 2012 8:31 pm
Posts: 21
Hi and thanks for the replies.

The cassette is currently a 11-28 so I'm guessing that could be changed also.

If I was to change the whole chainset what would be some good non-compact alternatives? What gear ratios are more normal for time trial bikes? Is there anything lighter than the 7950 which will easily fit?

_________________
Regards

Portia Baines


Top
   
PostPosted: Mon Feb 11, 2013 10:11 pm 
Offline

Joined: Mon May 30, 2005 7:13 am
Posts: 1536
BB86 is probably the most "limiting" standard as you have to run a ~86mm length spindle and ideally a 24mm diameter spindle. There are some "hacks" to allow the use of 30mm spindles, but you'll use a smaller bearing with potentially shorter life span.

Dura Ace 7900 in a standard is a good bet, all things considered. Its on sale lots of places, good shifting, stiffness and decent weight.

Fairwheel bikes carries all usual more "exotic" options like Lightning, Clavicula...


Top
   
PostPosted: Mon Feb 11, 2013 10:45 pm 
Offline

Joined: Tue Feb 05, 2013 8:29 pm
Posts: 236
I'd be interested to see some of the maths involved here. You say 50-34 with 11-28 is too low for you, but as noted 50/11 is 32mph at 90rpm. When you feel that the current chainset is under-geared, are you at the top gearing? What's your target cadence? What's a regular cruising speed for you?


Top
   
PostPosted: Mon Feb 11, 2013 11:22 pm 
Offline

Joined: Tue Sep 13, 2011 9:45 pm
Posts: 77
I run 54/42 and 11-25 cassette and it works well. On a drag-strip course with a tail wind/slight downhill then 50*11 is not enough.

Having said that the last TT I did I was passed by Alex Dowsett like I was standing still...

_________________
____________________________________________________________________________
Firefly FF050
Argon E-116
Trek Fuel EX9


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 8 posts ] 

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. fsa chainset

in Road

toastie

14

668

Sun Jan 24, 2016 5:48 pm

rcb78 View the latest post

There are no new unread posts for this topic. Cannondale SIS2 chainset

in Road

lone wheeler

13

777

Wed May 04, 2016 4:19 pm

KimJaeCheon View the latest post

There are no new unread posts for this topic. Cannondale Hollowgram Si Chainset FSA chainring alternative

in Road

Galatzo

11

837

Sun Dec 13, 2015 6:02 pm

Galatzo View the latest post

There are no new unread posts for this topic. Ultegra 6800 chainset with Campagnolo shifters and mech

in Road

solarider

14

1102

Tue Nov 24, 2015 11:22 pm

sawyer View the latest post

There are no new unread posts for this topic. Attachment(s) Campagnolo Record 10 Speed Ultra Torque Chainset

[ Go to page: 1 2 3 4 ]

in Road

cmcdonnell

50

1514

Fri Feb 12, 2016 2:41 am

Tenlegs View the latest post


All times are UTC+01:00


Who is online

Users browsing this forum: Bing [Bot], fordred, Yahoo [Bot] and 25 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:  
Powered by phpBB® Forum Software © phpBB Limited