Cracked Front Mud Guard

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John
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Cracked Front Mud Guard

Post by John » 26 Oct 2016 19:43

I'm hoping someone on here can give me some wisdom on this!

My winter bike has fitted mudguard that mount onto the frame. The front one mounts onto the frame and also directly onto the front brake with a metal mount. The plastic one one side below this bracket has cracked, and this is causing the front of the mudguard to point to one side and rub the tyre.

Does anyone have any ideas of how I can fix the mudguard? The only idea I have had is to use electrical tape and something narrow to create a splint - but I'm not sure if it would work.

Does anyone have a better idea?

The mudguards in question are these: http://tinyurl.com/hg3gz6f#

Tim
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Post by Tim » 26 Oct 2016 20:40

Got a picture in my head of you racing the national hill climb champs with mudguards!

I've had to use a ziptie on one of my mudguards where it had cracked at brake, has worked fine. So sure you can manage something
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laurence_cooley
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Post by laurence_cooley » 26 Oct 2016 21:36

The more usual place for SKS Chromoplastics to break is at the back brake. As a result of that happening to mine, I had to replace the rear one, and now have a spare front if you want a replacement.

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petemarshall
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Post by petemarshall » 26 Oct 2016 21:47

Ditch the bracket. Pass a zip tie through the holes which were filled by the studs that held the bracket to the guard. The zip tie now goes round the brake mount.
I always mount guards front and rear using zip ties rather than the horrid alu mounts. Makes them easy to adjust, remove, replace. Just make sure you always have zip ties with you(and what cyclist leaves home without a couple of zip ties and some gaffa tape?😁)

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George
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Post by George » 27 Oct 2016 10:33

If the plastic is already starting to split, the mudguard's days are numbered. You are going to have to replace it before long, and the longer you leave it, the bigger the chances of it disintegrating in the middle of a ride (with a theoretical risk of a wheel jamming, resulting in a crash).

Until recently, the adjustable rear brackets were very flimsy and, as Pete says, were best replaced with cable ties. However, most front mudguards have a steel bracket that's riveted to the plastic and loops over the brake bolt. These are generally fairly secure and don't often fail. So there's much less incentive to ditch them for cable ties. On top of which, they aren't very easy to remove without damaging the guards. It's also harder to use cable ties on some modern frames with integrated headsets and deep-section forks.

Regardless of how you choose to fasten the front guard, it's too late for this one: it's going to snap soon. Cable-tying at this stage might even hasten the process by distorting the plastic.

Mudguards have a finite lifespan and you simply have to accept that you need to replace them every few years. However, they'll last much longer if they are set up carefully in the first place and you keep them correctly adjusted. It could easily be, for example, that the steel bracket on your front guard was slightly off perpendicular, either due to sloppy fitting by the shop or due to creep over time. If the bracket isn't perpendicular, the forward section of the guard doesn't point exactly straight ahead. Then, if your clearances are close, one front corner of the guard is liable to rub slightly on the tyre every time you go over a bouncy section of road. And that means excessive and poorly distributed strain, leading to earlier failure.

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AlanW
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Post by AlanW » 27 Oct 2016 12:01

To be honest I haven't experienced that much of a problem with the front bracket on the std length SKS mudguards. Other than on the odd occasion I have to peen the rivet heads over a touch as the bracket works loose.

The "Longboards" however were a different story, the front one failing in a very short period of time. A combination of the extra length protruding forward of the front brake caliper and the extra weight on the front leading edge is clearly to much for the plastic to cope with?
"You only need two tools: WD40 and duct tape. If it doesn't move and it should, use WD40. If it moves and it shouldn't, use duct tape"

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George
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Post by George » 27 Oct 2016 15:15

AlanW wrote:A combination of the extra length protruding forward of the front brake caliper and the extra weight on the front leading edge is clearly to much for the plastic to cope with?
Alan, those may very well be contributory factors. However, I believe there was another factor in the failure of my Longboards. In two years, they fractured in three places: immediately below the lower stay bracket, front and rear (repaired by overlapping, drilling and cable-tying) and finally immediately forward of the front-brake-bolt bracket (leading to me binning them). The latter failure being similar to what John is on the point of experiencing. At all three failure sites, I could see that the fracture was right along the line of a metal fixture actually embedded within the plastic of the mudguard. That is in contrast to the way your bog-standard SKS Bluemels are constructed, with the fixture riveted to the underside of the plastic. I believe that the embedding technique is fundamentally flawed. I suspect that it leads to vibrations not being transmitted along the guard, but 'running into the buffers' at the fixing, thus fatiguing the adjacent plastic. I certainly would not recommend Longboards to anyone. Just as you yourself did, I have reverted to basic SKS Bluemels, with home-made mudflaps. Being low on stationery, I opted for a toilet cleaner bottle.

John
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Post by John » 29 Oct 2016 12:59

laurence_cooley wrote:The more usual place for SKS Chromoplastics to break is at the back brake. As a result of that happening to mine, I had to replace the rear one, and now have a spare front if you want a replacement.
I might have to take you up on this! :) I'll pm you

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