The Beacon Message Board

For the second time this year, my rear mudguard has snapped in the same place, ie adjacent to the rear brake caliper mounting?

Bearing in mind these are the SKS ones, which are claimed as being virtually unbreakable?

There is some sort of stress situation occuring, but I cannot think why?

When it snapped back in April, when I fitted the new one I was very careful to let it take its own profile and shape to avoid any undue stress.

So I was really suprised this morning when it has gone again in the same place. The worst thing this morning was that when it snapped the rear section went into the wheel and then jammed the rear wheel, forcing me to stop rather suddenly!! Thankfully I had only just pulled away from a junction.

As I see it, the mudguard is fixed at the rear of the bottom bracket, it is then securley fixed by the clamp at the rear brake bridge. So there is no allowance movement there.

Then you have the twin rear 3mm stainless steel stays, it must be this part that is moving creating the stress at the rear brake bridge mounting, which in turn is causing the stress fault line?

I am thinking out loud here, but could you therefore not utilize the rear brake bridge mounting and just rely on the fixing screw adjacent to the bottom bracket to hold it all secure?

Alan, for years and years, I was troubled by rear mudguards cracking at the point you describe and/or by the brackets that attach to the brake bridge failing. In my youth, I don't think I ever had a rear guard that lasted more than a couple of years. However, about 10-15 years ago, I stopped using the brackets that are supplied with the mudguards and started securing my mudguards with zip ties threaded through two pairs of carefully drilled holes in the top of the guard. I did this initially to increase the clearance and thus reduce mud-clogging. But (counter-intuitively, perhaps, given that drilling holes might be expected to create starting points for stress cracks) the arrangement seems to increase mudguard life. My present guards have been on somewhere between 5 and 10 years. On the other hand, maybe it's just that my bike doesn't take as much stick as it used to.

AlanW wrote:I am thinking out loud here, but could you therefore not utilize the rear brake bridge mounting and just rely on the fixing screw adjacent to the bottom bracket to hold it all secure?

I've tried this. The guard shook and rattled insufferably, and the arrangement was rejected after the first ride.

George wrote:Alan, for years and years, I was troubled by rear mudguards cracking at the point you describe and/or by the brackets that attach to the brake bridge failing. In my youth, I don't think I ever had a rear guard that lasted more than a couple of years. However, about 10-15 years ago, I stopped using the brackets that are supplied with the mudguards and started securing my mudguards with zip ties threaded through two pairs of carefully drilled holes in the top of the guard. I did this initially to increase the clearance and thus reduce mud-clogging. But (counter-intuitively, perhaps, given that drilling holes might be expected to create starting points for stress cracks) the arrangement seems to increase mudguard life. My present guards have been on somewhere between 5 and 10 years. On the other hand, maybe it's just that my bike doesn't take as much stick as it used to.

Thanks George, an interesting and useful tip.

I assume that the two carefully drilled drilled holes were drilled either side of the brake bridge so that the zip tie secures the mudguard in a diagonal line, if you get my drift?

And yes, you would have expected any additional holes drills in a already stressed area to maybe create a possible stress pointy wouldn't you?

Alan, it's probably easier to show than to explain.

Yep, as I thought, thanks George.

Guess what I'll be doing this evening then.............

George wrote:

AlanW wrote:I am thinking out loud here, but could you therefore not utilize the rear brake bridge mounting and just rely on the fixing screw adjacent to the bottom bracket to hold it all secure?

I've tried this. The guard shook and rattled insufferably, and the arrangement was rejected after the first ride.

Hmmm, my bike's mudguard is fixed to the bridge using a bolt with low profile head (same as the bottom bracket fixing). When fixing a mudguard to a new frame last week I took one look at the supplied bracket and thought "that looks rattly I'll use a bolt like my other bike because that's never rattled".

CakeStop wrote: Hmmm, my bike's mudguard is fixed to the bridge using a bolt with low profile head (same as the bottom bracket fixing).

The mudguard on my Rourkie bike is secured in the same way, but sadly I cannot do the same with the Ridley frame.

A low-profile bolt under the brake bridge like the one near the BB does sound ideal in terms of security/neatness. However, presumably it means a) having a threaded hole in the frame to accept the bolt and b) having tailored guards (since the position of the hole in the guard will be different for each different frame design and size).

Like Steve's bike my Mercian's sks front and rear guards are fitted with a low profile bolt into a drilling in the bridge and have last over 10years and gone back on the bike after a respray. Some arrangement at the back but not the front with the newer Enigma. In both cases the guards were fitted by the shop so I guess they just "tailored" them with a drill and binned the bent metal clip. I wonder if its the sharp edged clips that do the damage, George's neat holes shouldn't weaken the guard much. Until I read Alan's posting I'd regarded them as indestructible.

Requires a threaded hole under the brake bridge, drill the mudguard to suit, needs to be a short bolt so as not to reach the caliper bolt.

For zip tie shaped holes when I've been modifying a mudguard for a bike without sufficient clearance I've used a small flat screwdriver heated in a gas hob flame.

New mudguards now fitted, went for the SKS P35 narrow version again, but these have the rear reflector and front mudflap fitted, unlike the last set that were plain.

Interesting to note that they are a completely different profile to the SKS P35 mudguards that broke this time and the time before?

But the fact that they were different profiles meant that I had to replace the front as well so it looked the same......oh how I hate OCD.

I spent ages setting the rear one up so that its not under any tension. So fingers crossed then................

The rounded profile ones are sometimes referred to as Bluemels but it's not always clear which type some retailers are selling.

I thought that SKS took over Blumels -they were what I had on my school bike never thought they were very strong. Did SKS keep the profile and but use thermoplastic material?

I think that's perhaps what happened Dave. I've only ever used SKS mudguards, the rounded bluemels seem to be made from the same material as the squarer profile non-bluemels - thin metal foil sandwiched between two sheets of plastic.

It is unusual that in this day and age they are still tooled up to do both profiles? You would have thought that they would have concentrated on just one?