I have a P4 that I’ve used 2x. Once last Aug & once yesterday; a bike is a bike but yesterday after I delicately put my rear wheel in and locked the brake down I check & rechecked it before racing to be sure the rim was not dragging.
Got out there and the speeds weren’t commensurate with the power output. Then I got home and compared power from last year & this year (very similar wind/temp conditions) and see I went a minute faster last year on nearly the same power. I wasn’t super unhappy with my power for Feb but pretty bummed with the time as I figured on the same power I’d go a bit quicker than I did on the old alu P3.
When I finally got around to pulling the bike off the car the rim was indeed dragging.
Curious if anyone else has had something like this happen? Perhaps the skewer wasn’t tight enough and it moved after I’d checked it?
You should search on “P4 brake” or something similar. When this bike was new (three years or so ago) there were a number of discussions of these kinds of issues. This was one of the bigger issues with this bike. After a few running changes, it became quite an awesome bike. But if you’re not knowledgeable about how to work on bikes in general and that rear brake in particular, you’re in for headaches. It’s probably not a bike that should be owned and raced by people who let the shop do all their work for them. Not sayin’ that’s you. Just sayin’.
That’s not entirely me but I do let the shop do “stuff, things”… It’s a 2011 evo so theoretically the issues should have been addressed with it.
I am familiar with some of the issues around the rear brake just surprised it moved and began dragging; mostly curious if this is a known issue; if so what are folks doing to mitigate.
Well, they addressed the rear brake issues somewhat. They’re still finicky. I messed with mine a ton and learned a lot about them. Despite the cover over the brake, they collect a lot of dirt in there and, if the bike has sat, I’ll bet old, crusty dirt is the primary problem. The brake should probably be removed and the parts cleaned and greased. I always used the Shimano “Special Grease” on the posts and all the pivots. But I also discovered there was a trick to how you orient the central sort of pivot triangle that helped the brake actuate and release properly. It’s hard to describe and takes about three hands to do.
Bottom line, that’s a really nice bike with a really crappy rear brake that needs a lot of careful attention. I believe that’s a major contributing factor to why the P4 wasn’t a bigger seller for Cervelo … that and the fact that they did such a horrible job getting them to market.
I sold my P4 because of the braking. I had a light change fast on me. Between the tririg brake in the front and the shitty P4 brake in the back, I came to a stop half way into the intersection, luckily for me the cars were paying attention. I went home and listed the bike for sale.
I bought mine in January 2012…a 2011 model on sale. I use another bike for road training…have only used the P4 for races. Did 9 Sprint races in 2012 (my first full year of tri racing) and 9 OLY’s last year…so the bike really doesn’t have a lot of miles on it. It still looks new and I try to keep it serviced/spotless. Yes, the rear brake is weak but I’ve had no problems with it…including the long, very steep downhill at the 2012 Burlington US Nats. It’s a fast bike and I plan on keeping for a while. Have you owned the bike since new or did you buy it used? Know where it’s been serviced?
What I found was, when it was clean and greased and I had it set up just right, it had all the stopping power anybody could want. Problem is, I don’t know how to describe the trick I learned about how to do that and, since I’ve since sold the bike, I don’t know how to help y’all. As I said earlier, part of the trick was how you pull the cable through the pivoting triangle thingamajiggy before you clamp it and it takes about 3 hands to get it to where it works really well (and this is the 2nd generation “EVO” brake I’m talking about … forget about the earlier version). But when you do, you get both stopping power and it releases completely – right up until it starts to gunk up a bit. Then you have to take it apart and clean it all and then do it all over again.
Huh, that explains alot actually. This bike in particular was set up last August, ridden 1x outdoors for a late season TT. And yes, very fast bike relative to my P3 alu.
Outside of that it sat hanging in my garage and other than that just some rides in my garage.
I think what happened is that I raced with the brake partially “closed” (not even all the way closed actually) and during the TT when I hit my brakes (yes, I had to) the brake didn’t release and started dragging because I was very careful to check it before I que’d for the start.
It will be a TT race day bike and will only ever see time on the trainer or actual races so the likelihood it gets wet, etc. is low.
I’ll just need to be uber careful with the brake because I’m gonna run the darn thing “open” from here on out.