Retrobike Forum Index

It is currently Sun Dec 11, 2016 3:40 am

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Wed Apr 13, 2011 2:33 pm 
retrobike rider
retrobike rider

Joined: Fri Jan 29, 2010 11:57 am
Posts: 308
Location: Devon
Has anyone replaced a 650c fork for 700c forks on a TimeTrial type low pro frame?
am wondering how it affects the geometry.


Top
 Profile  
 
 Post subject:
PostPosted: Wed Apr 13, 2011 6:42 pm 
Dirt Disciple
User avatar

Joined: Mon Feb 07, 2011 8:28 pm
Posts: 66
Location: North Essex
No, and don't.

650C wheels are 51mm smaller in diameter compared with 700C, so the front end of your bike will be about 25mm higher than was intended. Worse, the entire geometry of the bike will be skewed - both head and seat angles will be much softer, and the bottom bracket will be appreciably higher, for example.

If the bike's been built for 650, then that's basically what you need to stick with in my opinion.


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 14, 2011 12:05 pm 
Retro Guru

Joined: Mon Jan 15, 2007 12:12 am
Posts: 1513
Location: Gold Coast Australia
Whilst i agree with that ,would the front end not be the entire 51mm higher ?
I did replace a MTB 26in suspension fork with a 29er rigid fork the other year and it feels fine to be honest .


Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 14, 2011 12:15 pm 
Retro Guru

Joined: Mon Jan 15, 2007 12:12 am
Posts: 1513
Location: Gold Coast Australia
I also replaced the original fork on my Y-foil TT bike (rock shox ready) with a shorter pure road Look one that steepened the head and seat angle a tad and it was fine too

warning semi modern pics below !


Attachments:
y foil.JPG
y foil.JPG [ 92.81 KiB | Viewed 718 times ]
Top
 Profile  
 
 Post subject:
PostPosted: Thu Apr 14, 2011 12:23 pm 
Retro Guru

Joined: Mon Jan 15, 2007 12:12 am
Posts: 1513
Location: Gold Coast Australia
the original trek "icon" fork also had steel steerer for threaded headset and quill stems


Attachments:
yfoilspinergy-1.jpg
yfoilspinergy-1.jpg [ 195.31 KiB | Viewed 714 times ]
Top
 Profile  
 
 Post subject:
PostPosted: Fri Apr 15, 2011 12:57 pm 
Dirt Disciple
User avatar

Joined: Mon Feb 07, 2011 8:28 pm
Posts: 66
Location: North Essex
latman wrote:
Whilst i agree with that ,would the front end not be the entire 51mm higher ?


Yes, you're right, of course.

latman wrote:
I did replace a MTB 26in suspension fork with a 29er rigid fork the other year and it feels fine to be honest .


Yes, that was quite common back in the days when front suspension was just becoming popular (or, at least, the reverse was popular!). I think the effects on a TT bike of such an extreme change will be more marked, though.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 13 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