azza_333

I am looking at a set of SKS Bluemels 45 Fenders, BLUEMELS SHINY 28" 45 BLACK SET - SKS-Germany (sks-germany.com)

They say they only fit upto 38mm tires. but I was wondering if anyone had tried wider tires than that on them. Since I want to run a set of 42-622 (28 x 1.60, 700x40C) Schwalbe Marathon Supremes with them.
Tour - Schwalbe Professional Bike Tires

aggiegrads

You won’t have enough clearance.

the consequences of a mishap here are high. It doesn’t take much to get jammed between the fender and tire. This will lock the wheel as the fender folds up and wedges between the tire and stays or fork crown. If the back wheel locks up, you will probably only be very surprised. If it happens on the front wheel, you will almost definitely crash, and not in a safe way.

This is why fenders always have breakaway tabs, but they aren’t always reliable.

mstateglfr 

These are the exact same, just 53 instead of 45 and are designed to fit the 40mm tire you want.
https://www.sks-germany.com/en/produ...-53-black-set/

Koyote

aggiegrads is probably correct, but the final answer depends on the combination of your particular bike's frame and fork, the tires, and the fenders.

For road riding exclusively on good pavement, you don't need as much clearance between the tires and fenders; for anything else, you want some room for junk to pass through and not jam in-between them, as described.

Wanderer

You WILL have to mount them farther away from the tire, to get your clearance.

azza_333

I would get the 53s but I am not sure if the fenders would fit the frame and forks, the frame/forks only official support 45mm tyres.

veganbikes

You can always take a wider set and notch them out as needed if you are careful.

Seu

Try SKS P50 fenders. They clear my 42mm wide 650b tires but not by too much. They are available but not as much as their other sizes.

Pop N Wood

You're being hyperbolic.

Sorry, someone used that phrase on me so I've been dying to use it as well

Seriously though those fenders are plastic. You might get cut by splintering shrapnel but the chances of it halting a tire and causing a crash are slim. I really like the product, have that brand on 3 different bikes now, but I wouldn't sweat them from a safety aspect.

As veganbikes said it is very easy to trim notches to clear frame supports. Get the width you need.

aggiegrads

They were sandwiched aluminum and plastic. Explain to me how the aluminum will splinter.

Are you recommending that the OP go ahead and run with 1.5mm of fender clearance? And that it will merely be annoying, but perfectly safe?

aggiegrads

This is what a sandwiched aluminum and plastic fender does when something catches in it (or It may just be hyperbole and you’ll be fine if this happens).

Moe Zhoost

Nope, this is not at all hyperbolic. I flew over the bars when a small branch got lodged between tire and fender. ESGE fenders (now SKS) and 32mm tires. Fender folded up completely and had to be cut off for me to ride home (sorely). You need a minimum of 3/8" between tire and fender for safety. There's a reason why fenders now have breakaway stays and it's not because the "chances of a crash are slim".

In response to the OP: I have a couple of bikes that I would really like to install fenders; however there is not enough clearance unless I move to a thinner tire, which I may do. You can try to trim around the fork crown and stays and it may work for you, but allowing less than 3/8" clearance is risky.

Pop N Wood

Interesting The SKS fenders I have are plastic. I've had them crack from wind buffeting when on the back of my car.

Maybe different models?