Specialized Tricross - front brake judder

Giraffoto

I bought my Tricross quite a few years ago, and straight out of the shop it was fine in every respect. Later, I first experienced the now famous brake judder: at the time I put this down to everything being fairly new, adjusted the toe-in and learned to modulate my braking around it. However, the front brake just wanted to keep juddering, and in the usual way of “blame the thing you’re least familiar with” I decided it was a problem with carbon forks and assumed I’d just have to keep adjusting every couple of weeks and being sensitive with the brake. I then came across the internet discussions of the phenomenon . . .

Having already decided that the forks were to blame, the explanations that blamed carbon forks were pretty seductive. Equally persuasive was a look through the Specialized catalogues: their 2010 and 2011 models have a cable hanger on the fork crown, and for 2012 they’ve decided to go with aluminium forks or disc brakes. The Specialized fork crown cable hanger is available from a few places as a separate part – I got mine from Edinburgh Bicycle Cooperative – and a read through the instructions backs up the belief that there has been a known flaw with Tricross brakes and this is a retrofit kit for improving matters. So having bought one, last night I fitted it

First test ride – low speed, grab the brake, the judder’s changed. Still there, but higher frequency (so less intrusive) and seemingly more gentle. Adjust the toe-in of the brakes: judder gone. Time will tell if it comes back as quickly as before, but I now have a new theory regarding the whole brake judder/Tricross issue:

- It’s caused by a lack of toe-in on the brake pads - The frequency of the judder is affected by the length of free cable from the cable hanger: longer = lower - The carbon forks have their own resonant frequency which exacerbates the problem when the brake judder is on or around that frequency - So, fitting the fork crown cable hanger makes the judder more tolerable and less intrusive, but toeing in the brake pads will cure it wherever your cable hanger is

Pseudonym

it's a fairly common problem with cantis on carbon forks - not restricted to the Tricross, by any means.

I don't have a Tricross, but I'm now using a (very) long straddle wire on my front brake and the judder problem is now all but eradicated. Hasn't made that much difference to braking feel either - in fact, you could argue it has improved it, because the judder is no longer an issue. Toe-in made no difference to my judder, incidentally.

A new wire is only a couple of quid, so it's well worth trying....

mister p

AFAIK fitting a set of Mini-V brakes in place of canti brakes should solve the problem.

Chad_c_Mulligan

I had this problem on my bike and the following fixed it.

Fork crown mounted hanger
Switching to Tektro CR720 brakes
Adding a CNC machined brake booster
Tektro dual compound brake pads


These four changes almost eliminated it.

The final change which fixed everything was replacing the horrible alex rim wheels with Mavic Open Sports.

BrianTrousers

I've replaced the standad pads on my CR720's with Koolstop dual compound V brake pads which are properly toed-in.

Haven't noticed the judder so far. (I did buy a crown mounted hanger but couldn't be bothered to fit it as it would have meant a new cable and removing all the bar tape - Shimano 105 concealed cabling!)

mididoctors

fixed this on a friend's tricross by altering toe in of pads and nothing else

Chad_c_Mulligan

mididoctors wrote:

fixed this on a friend's tricross by altering toe in of pads and nothing else

I wish it had been that easy for me, I spent three months trying one thing after another.

jomoj

I used to get variable level of judder with deda carbon forks and shimano cantis even with a short cable drop. Fitted a tektro crown hanger and with no other adjustments the judder was completely gone, replaced only by a light squeal, which I can cope with.

i think toe in is a factor but the fork flex / cable servo effect is the main cause in my experience.

lateralus

+1.

A Kona uphanger completely solved the fork judder on my cross bike after fruitless experiments with different cantis, pads, etc. The braking is really good now.

mikenetic

I've had it on and off with an Easton carbon fork on my CX bike. I tend to find cleaning the rims helps, but the one thing that makes it go away properly is a decent dual-compound pad, combined with a bit of toe-in.

Fixing it does seem to be a bit of a dark art though - what works on one setup might not on another.

Giraffoto

fixed this on a friend's tricross by altering toe in of pads and nothing else

Setting the pads up properly is what always did it for me - it's just a case of having to do it every couple of weeks, and I wanted to see if the crown hanger somehow improved matters without re-adjusting the pads. Which it does and it doesn't, if you see what I mean: it changed the character of the judder so it wasn't so intrusive

To change the focus slightly now - lots of Tricross owners change the brakes, has anyone had particularly good/bad experiences with that? Did your Shorty 6s or SR-550s fix everything, or make no difference?

ColinT2

I have the Tektro CR520 fitted to my CX bike (recent purchase) and there is considerable front brake judder - I read about fitting the Clarks 55mm integral brake block (and replace the Tektro) which allegedly eliminated the problem.
So I have just fitted the Clarks blocks this morning and will post later (after a test ride) as to the effect.

Monty Dog

It's simply a function of a long steerer and flexy forks. I run CR950s on my Kuota and have never experienced any problems and don't toe-in the brake shoes either.

John.T

Toe-in only wears the blocks out faster and lowers brake efficiency as there is less contact area. It soon wear in and needs doing again so the blocks just get tapered. The judder is caused by the fork flex pulling the brake on harder. This makes the fork flex even more. As the pressure evens out the fork act like a spring and releases a bit. This lets the brake off a little. This cycle continues hence judder. I have a Tricross Singlecross with V brakes. No judder at all. The cause is definitely the way cantis react due to the cable run.

ColinT2

What a huge difference the Clarks CPS250 (55mm integral block) has made to eliminate the judder; braking is a lot more assured although there still a very small amount of judder just before you actually stop - probably due to the combination of the forks (Easton EC90X) and the pads are not fully bedded in yet. As to wear - time will tell
I would certainly recommend trying these brakes blocks.

Giraffoto

I finally got round to taking the Tricross out for a thorough test on Friday night. Three main observations:

- The judder's gone - The brakes feel a lot more solid - there's less sponginess in the lever - You don't brake much in a thirty mile ride on regular roads

So the fork hanger may not be the sole cause of the judder no longer being a problem, but it has other advantages in terms of how the brakes feel. Either the hanger on the steerer tube had some flex in it or the cable run to fit in it was inefficient. £15 well spent!