TT vs. Road bike. Pedal clearance?
Moderator: robbosmans
-
- Posts: 212
- Joined: Wed Sep 21, 2011 7:19 pm
Trying to justify a TT purchase. Is the pedal clearance any lower on a TT bike (aka is the TT frame any lower on the road)? Otherwise, I can't find any other reason not to throw on clip aerobars on my road bike, and fit it like a TT bike.
Generally a TT bike has a steeper seat tube angle. That gets the rider to rotate their position more forward and more weight on the arms. This position also allows for a flatter back thus more aero.
Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓ Broad Selection ✓ Worldwide Delivery ✓
www.starbike.com
-
- Posts: 212
- Joined: Wed Sep 21, 2011 7:19 pm
I'm aware. Slamming the saddle forward would mitigate that.
It won't change the geometry of the front end though.
TT bikes generally have a much slacker head tube angle, which leads to more trail so they are more stable in a straight line (conversely, don't handle as quick.) TT bikes also generally have a longer wheel base. BB drop is usually close.
The biggest benefit of a TT bike is being able to shift from the aerobars. You could do something dual purpose with a Di2 set up though. If you only want to use this bike for TT stuff, you might be okay.
The biggest benefit of a TT bike is being able to shift from the aerobars. You could do something dual purpose with a Di2 set up though. If you only want to use this bike for TT stuff, you might be okay.
I have done the road bike conversion thing and it is the most awkward and uncomfortable I've ever felt on a bike, and it handled horribly. If you're going to be doing a fair amount of time trialing, I strongly recommend getting a proper TT frame. They are easier to get yourself into a proper time trial position via fit, and they are way more comfortable at speed in the TT position.
Edit to address your actual question:
I doubt most time trial bikes have significantly lower bottom brackets (mine doesn't), but even if they did, it shouldn't really affect you in a time trial. You won't be pedaling through tight corners very often in a TT.
Edit to address your actual question:
I doubt most time trial bikes have significantly lower bottom brackets (mine doesn't), but even if they did, it shouldn't really affect you in a time trial. You won't be pedaling through tight corners very often in a TT.
To echo what other's have said, STA is the killer. You can get a 0 offset post and you can slam the saddle forwards but rarely if ever will you be anywhere near as steep as a good fit on a TT specific bike. This has a big effect on your pedal stroke and how low a position you can sustain without losing power. It also has major knock on effects on the cockpit length - you'll be stretching significantly to rest into the pads. Not really an issue on 10 milers, but a 25 or over could get pretty difficult to sustain.
Compare an S3 54 with a P3 54 in a few metrics that have been mentioned: BB drop, P3 is 7mm lower. HTA, P3 is 0.6 degrees slacker. Fork offset, they're the same. All fairly neglible. But when it comes to fit: Stack: P3 is 33mm lower. Reach: P3 is 33mm longer. STA, the P3 is 6 degrees steeper. These are huge differences, and there is a good reason for it.
Bottom line is that yes, you can throw aerobars on your road bike and use it but no, you can't fit it like a TT bike.
Compare an S3 54 with a P3 54 in a few metrics that have been mentioned: BB drop, P3 is 7mm lower. HTA, P3 is 0.6 degrees slacker. Fork offset, they're the same. All fairly neglible. But when it comes to fit: Stack: P3 is 33mm lower. Reach: P3 is 33mm longer. STA, the P3 is 6 degrees steeper. These are huge differences, and there is a good reason for it.
Bottom line is that yes, you can throw aerobars on your road bike and use it but no, you can't fit it like a TT bike.
Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓ Broad Selection ✓ Worldwide Delivery ✓
www.starbike.com